The significance of the invention of the automatic machine. Spinning machine. History of invention and production. Successes and failures of Joseph Jacquard

In fact, something similar was known in slave-owning Hellas several hundred years BC. The principle of obtaining bodies of rotation, in which it is necessary to rotate the workpiece by touching its surface with a stronger and sharper object, was easy to come up with.

There were no problems with the source of energy, since healthy and strong slaves were available in abundance. In more civilized times, such a machine was driven by a tightly stretched bowstring. But there was a significant limitation - the speed of revolutions fell as the bowstring untwisted, so in the Middle Ages models of foot-driven lathes appeared.

Design and principle of operation lathe CNC

They very vaguely resembled a sewing machine - because they included a traditional crank mechanism. This turned out to be a very positive change: the rotating workpiece now had no accompanying oscillatory movements, significantly complicating the work of the master and deteriorating the quality of processing.

However, by the beginning of the 16th century, the lathe still had a number of significant limitations:

• The cutter had to be held manually, so during prolonged metal processing the turner’s hand became very tired.
• The steady rest supporting long workpieces was attached separately from the machine, and therefore its installation and verification were quite lengthy.
• The problem of removing the chips was never solved: an apprentice was needed to periodically brush the chips off the master's hand.
• The issue of uniform movement of the cutter during processing was not resolved either: everything was determined by the qualifications and experience of the master.

The next few hundred years were spent designing a rotation drive for the moving center of the machine, in which the workpiece was mounted. The most successful was the design of Jean Besson, who was the first to use a water drive for these purposes.

The machine turned out to be quite cumbersome, but it was on it that threads were cut for the first time. This happened in the middle of the 16th century, and a few years later, Peter I’s mechanic Andrei Nartov invented a mechanized machine on which it was possible to cut threads with a variable speed of rotation of the moving center. A characteristic feature of Nartov’s machine was also the presence of a replaceable gear block.

Who invented the caliper?

The support is the key component of a modern lathe; everything else could, to one degree or another, be borrowed from other mechanisms. At the same time, having a device for precise movement of a metal-cutting tool along the surface being processed, and in all three coordinates, one could talk about a fully functional machine for turning. But, as in most other cases from the history of technology, it is impossible to establish sole authorship in the invention of the caliper.

What does it say about Andrei Nartov’s priority?

• A self-propelled support appeared in Nartov's copying machine in 1712, while Henry Maudsley introduced his version only in 1797.
• For the first time, the joint movement of the copier and the support in the Nartov version of the machine was carried out using one mechanism - a lead screw.
• Changing the cross-feed speed was technically ensured by different thread pitches on the lead screw.

The term “support” (from the French word support - support) was first introduced into use by Charles Plumet, and the machine built by his compatriot Jean Vaucanson was practically similar to the one with which all turners now work.

This mechanism had V-shaped guides that were accurate for its time, and the caliper had the ability to move not only in the transverse, but also in the longitudinal directions. However, not everything was in order here either - in particular, there was no chuck where the workpiece to be processed would be secured.

This significantly narrowed the technological capabilities of the equipment: for example, turning of workpieces that had different lengths was impossible. And in general, perform any other operations other than cutting threads on screws, bolts, etc.

And then Henry Maudsley appears on the historical stage.

Universal lathe – the time has come

In many branches of human creative activity, the palm goes to the one who not only invented something, but was also able to analytically correctly generalize the experience of previous generations. Henry Maudsley is no exception.

There is no reason to claim that Maudsley simply stole the caliper circuit from Andrey Nartov. Yes, during the time of Peter I, ties with England were not particularly welcomed, but relations with Holland were strong. But given the fact that the Dutch, in turn, often hosted English entrepreneurs and simply craftsmen, it is likely that Nartov’s invention very soon became known on the shores of Foggy Albion (although Maudsley himself could have learned about Nartov’s machine, since in Those years he was engaged in the construction of steam engines for Russia).

The greatness of Henry Maudsley lies elsewhere - he presented to the court of interested parties (and in England by that time the industrial revolution was in full swing) the concept of the first, truly universal machine for performing various turning operations. Equipment in which all the problems of the turning method of processing products were organically solved.

By later adding a set of replaceable gears to the machine, Maudsley achieved what is now inherent in any lathe - versatility and technological ease of operation.

Video: Operating a lathe

For many years, punched cards served as the main media for storing and processing information. In our minds, a punched card is firmly associated with a computer that takes up an entire room, and with a heroic Soviet scientist making a breakthrough in science. Punched cards are the ancestors of floppy disks, disks, hard drives, and flash memory. But they did not appear with the invention of the first computers, but much earlier, at the very beginning of the 19th century...

Falcon's machine Jean-Baptiste Falcon created his machine based on the first similar machine designed by Basil Bouchon. He was the first to come up with a system of cardboard punched cards connected in a chain.

Alexander Petrov

On April 12, 1805, Emperor Napoleon Bonaparte and his wife visited Lyon. The country's largest weaving center in the 16th-18th centuries suffered greatly from the Revolution and was in a deplorable state. Most of the manufactories went bankrupt, production stood still, and the international market was increasingly filled with English textiles. Wanting to support Lyon craftsmen, Napoleon placed a large order for cloth here in 1804, and a year later he arrived in the city in person. During the visit, the emperor visited the workshop of a certain Joseph Jacquard, an inventor, where the emperor was shown an amazing machine. The huge thing, installed on top of an ordinary loom, jingled with a long ribbon of perforated tin plates, and from the loom stretched, winding onto a shaft, silk fabric with the most exquisite pattern. At the same time, no master was required: the machine worked on its own, and, as they explained to the emperor, even an apprentice could easily service it.

1728. Falcon's machine. Jean-Baptiste Falcon created his machine based on the first such machine designed by Basil Bouchon. He was the first to come up with a system of cardboard punched cards connected in a chain.

Napoleon liked the car. A few days later, he ordered that Jacquard’s patent for a weaving machine be transferred to public use, and that the inventor himself be given an annual pension of 3,000 francs and the right to receive a small royalty of 50 francs from each loom in France on which his machine stood. However, in the end, this deduction added up to a significant amount - by 1812, 18,000 looms were equipped with the new device, and in 1825 - already 30,000.

The inventor lived the rest of his days in prosperity; he died in 1834, and six years later the grateful citizens of Lyon erected a monument to Jacquard on the very spot where his workshop had once been. The Jacquard (or, in the old transcription, "Jacquard") machine was an important brick in the foundation of the industrial revolution, no less important than Railway or steam boiler. But not everything in this story is simple and rosy. For example, the “grateful” Lyons, who subsequently honored Jacquard with a monument, broke his first unfinished machine and made several attempts on his life. And, to tell the truth, he didn’t invent the car at all.

1900. Weaving workshop. This photograph was taken more than a century ago in the factory floor of a weaving factory in Darvel (East Ayrshire, Scotland). Many weaving workshops look like this to this day - not because the factory owners spare money on modernization, but because the jacquard looms of those years still remain the most versatile and convenient.

How the machine worked

To understand the revolutionary novelty of the invention, it is necessary to general outline represent the operating principle of a loom. If you look at the fabric, you can see that it consists of tightly intertwined longitudinal and transverse threads. During the manufacturing process, longitudinal threads (warp) are pulled along the machine; half of them are attached through one to the “shaft” frame, the other half - to another similar frame. These two frames move up and down relative to each other, spreading the warp threads, and a shuttle scurries back and forth into the resulting shed, pulling the transverse thread (weft). The result is a simple fabric with threads intertwined through one another. There can be more than two heald frames, and they can move in a complex sequence, raising or lowering the threads in groups, which creates a pattern on the surface of the fabric. But the number of frames is still small, rarely more than 32, so the pattern turns out to be simple, regularly repeating.

There are no frames at all on a jacquard loom. Each thread can move separately from the others with the help of a rod with a ring that catches it. Therefore, a pattern of any degree of complexity, even a painting, can be woven onto the canvas. The sequence of movement of the threads is set using a long looping strip of punched cards, each card corresponding to one pass of the shuttle. The card is pressed against the “reading” wire probes, some of them go into the holes and remain motionless, the rest are recessed with the card down. The probes are connected to rods that control the movement of the threads.

Even before Jacquard, they knew how to weave complexly patterned canvases, but only the best masters, and the work was hellish. A worker-puller climbed inside the machine and, at the command of the master, manually raised or lowered individual warp threads, the number of which sometimes amounted to hundreds. The process was very slow, required constant concentrated attention, and mistakes inevitably occurred. In addition, re-equipping the machine from one complex patterned canvas to another work sometimes took many days. Jacquard's machine did the work quickly, without errors - and by itself. The only difficult thing now was stuffing the punch cards. It took weeks to produce a single set, but once produced, the cards could be used again and again.

Predecessors

As already mentioned, the “smart machine” was not invented by Jacquard - he only modified the inventions of his predecessors. In 1725, a quarter of a century before the birth of Joseph Jacquard, the first such device was created by the Lyon weaver Basile Bouchon. Bouchon's machine was controlled by a perforated paper belt, where each passage of the shuttle corresponded to one row of holes. However, there were few holes, so the device changed the position of only a small number of individual threads.

The next inventor who tried to improve the loom was named Jean-Baptiste Falcon. He replaced the tape with small sheets of cardboard tied at the corners into a chain; on each sheet the holes were already located in several rows and could control a large number of threads. Falcon's machine turned out to be more successful than the previous one, and although it was not widely used, during his life the master managed to sell about 40 copies.

The third who undertook to bring the loom to fruition was the inventor Jacques de Vaucanson, who in 1741 was appointed inspector of silk weaving factories. Vaucanson worked on his machine for many years, but his invention was not a success: the device, which was too complex and expensive to manufacture, could still control a relatively small number of threads, and fabric with a simple pattern did not pay for the cost of the equipment.

1841. Carkill weaving workshop. The woven design (made in 1844) depicts a scene that occurred on August 24, 1841. Monsieur Carquille, the owner of the workshop, gives the Duke d'Aumalle a canvas with a portrait of Joseph Marie Jacquard, woven in the same way in 1839. The fineness of the work is incredible: the details are finer than in engravings.

Successes and failures of Joseph Jacquard

Joseph Marie Jacquard was born in 1752 in the outskirts of Lyon into a family of hereditary canutes - weavers who worked with silk. He was trained in all the intricacies of the craft, helped his father in the workshop and after the death of his parent inherited the business, but he did not take up weaving right away. Joseph managed to change many professions, was tried for debt, got married, and after the siege of Lyon he left as a soldier with the revolutionary army, taking his sixteen-year-old son with him. And only after his son died in one of the battles, Jacquard decided to return to the family business.

He returned to Lyon and opened a weaving workshop. However, the business was not very successful, and Jacquard became interested in invention. He decided to make a machine that would surpass the creations of Bouchon and Falcon, would be quite simple and cheap, and at the same time could produce silk fabric that was not inferior in quality to hand-woven fabric. At first, the designs that came out of his hands were not very successful. Jacquard's first machine, which worked properly, made not silk, but... fishing nets. He read in the newspaper that the English Royal Society for the Promotion of the Arts had announced a competition for the manufacture of such a device. He never received an award from the British, but his brainchild became interested in France and was even invited to an industrial exhibition in Paris. It was a landmark trip. Firstly, they paid attention to Jacquard, he acquired the necessary connections and even got money for further research, and secondly, he visited the Museum of Arts and Crafts, where Jacques de Vaucanson’s loom stood. Jacquard saw him, and the missing parts fell into place in his imagination: he understood how his machine should work.

With his developments, Jacquard attracted the attention of not only Parisian academics. Lyon weavers quickly realized the threat posed by the new invention. In Lyon, whose population at the beginning of the 19th century was barely 100,000, more than 30,000 people worked in the weaving industry - that is, every third resident of the city was, if not a master, then a worker or apprentice in a weaving workshop. Trying to simplify the fabric making process would put many people out of work.

Incredible precision of the Jacquard machine

The famous painting “The Visit of the Duke d'Aumale to the Weaving Workshop of Monsieur Carquille” is not at all an engraving, as it might seem, the design is completely woven on a loom equipped with a jacquard machine. The size of the canvas is 109 x 87 cm, the work was carried out, in fact, by the master Michel-Marie Carquilla for the company Didier, Petit and Si. The process of mis en carte - or programming an image on punched cards - lasted many months, with several people doing it, and the production of the canvas itself took 8 hours. The tape of 24,000 (over 1000 binary cells each) punched cards was a mile long. The painting was reproduced only on special orders; several paintings of this type are known to be stored in different museums around the world. And one portrait of Jaccard woven in this way was commissioned by the Dean of the Department of Mathematics at Cambridge University, Charles Babbage. By the way, the Duke d’Aumale, depicted on the canvas, is none other than the youngest son of the last king of France, Louis Philippe I.

As a result, one fine morning a crowd came to Jacquard’s workshop and broke everything he had built. The inventor himself was strictly punished to leave his evil ways and take up a craft, following the example of his late father. Despite the admonitions of his brothers in the workshop, Jacquard did not abandon his research, but now he had to work secretly, and he completed the next car only by 1804. Jacquard received a patent and even a medal, but he was wary of selling “smart” machines on his own and, on the advice of merchant Gabriel Detille, he humbly asked the emperor to transfer the invention to the public property of the city of Lyon. The emperor granted the request and rewarded the inventor. You know the end of the story.

Punch card era

The very principle of the jacquard machine - the ability to change the sequence of operation of the machine by loading new cards into it - was revolutionary. Now we call it “programming”. The sequence of actions for the jacquard machine was given by a binary sequence: there is a hole - there is no hole.

1824. Difference machine. Babbage Charles Babbage's first attempt at building an analytical engine was unsuccessful. The bulky mechanical device, which was a collection of shafts and gears, calculated quite accurately, but required too complex maintenance and highly qualified operator.

Soon after the jacquard machine became widespread, perforated cards (as well as perforated tapes and disks) began to be used in a variety of applications.

Shuttle machine

At the beginning of the 19th century, the main type of automatic weaving device was the shuttle loom. It was designed quite simply: the warp threads were pulled vertically, and a bullet-shaped shuttle flew back and forth between them, pulling a transverse (weft) thread through the warp. From time immemorial, the shuttle was pulled by hand; in the 18th century this process was automated; the shuttle was “shot” from one side, received by the other, turned around - and the process was repeated. The shed (the distance between the warp threads) for the passage of the shuttle was provided with the help of a reed - a weaving comb, which separated one part of the warp threads from the other and lifted it.

But perhaps the most famous of these inventions - and the most significant on the path from the loom to the computer - is Charles Babbage's Analytical Engine. In 1834, Babbage, a mathematician inspired by Jaccard's experience with punched cards, began work on an automatic device for performing wide range mathematical problems. He had previously had the unfortunate experience of building a “difference engine,” a bulky 14-ton monster filled with gears; The principle of processing digital data using gears has been used since the time of Pascal, and now they were to be replaced by punched cards.

1890. Hollerith's Tabulator. Herman Hollerith's tabulating machine was built to process the results of the 1890 American Census. But it turned out that the machine’s capabilities went far beyond the scope of the task.

The analytical engine contained everything that is in modern computer: a processor for performing mathematical operations (“mill”), memory (“warehouse”), where the values ​​of variables and intermediate results of operations were stored, there was a central control device that also performed I/O functions. The analytical engine had to use two types of punched cards: large format, for storing numbers, and smaller ones - program ones. Babbage worked on his invention for 17 years, but was never able to finish it - there was not enough money. The working model of Babbage's Analytical Engine was built only in 1906, so the immediate predecessor of computers was not it, but devices called tabulators.

A tabulator is a machine for processing large volumes of statistical information, text and digital; information was entered into the tabulator using huge amount punched cards The first tabulators were designed and created for the needs of the American census office, but they were soon used to solve a variety of problems. From the very beginning, one of the leaders in this field was the company of Herman Hollerith, the man who invented and manufactured the first electronic tabulating machine in 1890. In 1924, Hollerith's company was renamed IBM.

When the first computers replaced tabulators, the principle of control using punched cards was retained here. It was much more convenient to load data and programs into the machine using cards than by switching numerous toggle switches. In some places, punch cards are still used today. Thus, for almost 200 years, the main language in which people communicated with “smart” machines remained the language of punched cards.

The article “The Loom, the Great-Grandfather of Computers” was published in the magazine Popular Mechanics (

Under management machine is usually understood as a set of influences on its mechanisms, ensuring that these mechanisms carry out the technological processing cycle, and by control system- a device or a set of devices that implements these effects.

Manual control is based on the fact that the decision to use certain elements of the work cycle is made by a person - the machine operator. The operator, based on the decisions made, turns on the appropriate mechanisms of the machine and sets the parameters of their operation.

Manual control operations are carried out both in non-automatic universal and specialized machines for various purposes, and in automatic machines. In automatic machines, manual control is used to implement adjustment modes and special elements of the work cycle.

In automatic machines, manual control is often combined with a digital display of information coming from position sensors of the actuators.

Automatic control lies in the fact that decisions on the use of work cycle elements are made by the control system without operator participation. It also issues commands to turn the machine mechanisms on and off and controls its operation.

Processing cycle called a set of movements of working bodies that are repeated during the processing of each workpiece. The complex of movements of the working parts in the machine operating cycle is carried out in a certain sequence, i.e. according to the program.

Control program – this is a set of commands corresponding to a given algorithm for the operation of a machine for processing a specific workpiece.

Algorithm name a method of achieving a goal (solving a problem) with an unambiguous description of the procedure for its implementation.

By functional purpose, automatic control can be divided as follows:

control of constant, repetitive machining cycles (for example, control of machine tools that perform milling, drilling, boring and tapping operations by executing motion cycles of multi-spindle power heads);

control of variable automatic cycles, which are specified in the form of individual analogue material models for each cycle (copiers, sets of cams, stop systems, etc.) An example of cyclic control of machine tools (CPU) are control systems for copying lathes and milling machines, multi-spindle automatic lathes and etc.;

CNC, in which the program is specified in the form of an array of information recorded on one or another medium. Control information for CNC machines is discrete, and its processing during the control process is carried out using digital methods.

Cyclic program control (CPU)

The cyclic program control system (CPU) will allow you to partially or completely program the machine’s operating cycle, processing mode and tool change, as well as set (using preliminary adjustment of the stops) the amount of movement of the machine’s executive bodies. It is an analog closed-loop control system (Figure 1) and has fairly high flexibility, i.e., it provides easy change in the sequence of switching on the equipment (electrical, hydraulic, pneumatic, etc.) that controls the elements of the cycle.

Picture 1– Cyclic program control device

The cycle programmer contains block 1 for specifying the program and block 2 for its step-by-step input (a program step is the part of the program that is simultaneously entered into the control system). From block 1, information enters the automation circuit, consisting of block 3 for controlling the machine’s operating cycle and block 4 for converting control signals. The automation circuit (which, as a rule, is carried out using electromagnetic relays) coordinates the operation of the cycle programmer with the actuators of the machine and the feedback sensor; strengthens and multiplies teams; can perform a number of logical functions (for example, provide execution of standard loops). From block 3, the signal enters the actuator, which ensures the processing of commands specified by the program and includes actuators 5 (drives of the machine’s actuators, electromagnets, couplings, etc.). The latter are working out the stage of the program. Sensor 7 monitors the end of processing and, through block 4, gives a command to block 2 to turn on the next stage of the program. Sensor 7 monitors the end of processing and, through block 4, gives a command to block 2 to turn on the next stage of the program. To control the end of a program step, track switches or time relays are often used.

In cyclic control devices, in numerical form, the program contains information only about the cycle processing modes, and the amount of movement of the working bodies is set by adjusting the stops.

The advantages of the CPU system are simplicity of design and maintenance, as well as low cost; The disadvantage is the laboriousness of dimensional adjustment of stops and cams.

It is advisable to use CNC machines in conditions of serial, large-scale and mass production of parts of simple geometric shapes. CPU systems are equipped with turning-turret, turning-milling, vertical drilling machines, aggregate machines, industrial robots (IR), etc.

The CPU system (Figure 2) includes a cycle programmer, an automation circuit, an actuator and a feedback device. The CPU device itself consists of a cycle programmer and an automation circuit.

Figure 2 -

Based on the achievements of cybernetics, electronics, computer technology and instrument engineering, fundamentally new program control systems were developed - CNC systems, widely used in machine tool building. In these systems, the magnitude of each stroke of the machine's executive body is specified using a number. Each unit of information corresponds to a discrete movement of the executive body by a certain amount, called the resolution of the CNC system or the value of the impulse. Within certain limits, the actuator can be moved by any multiple of the resolution. The number of pulses that must be applied to the drive input in order to carry out the required movement L is determined by the formula N = L/q, Where q– impulse price. The number N, written in a certain coding system on a storage medium (punched paper tape, magnetic tape, etc.), is a program that determines the amount of dimensional information.

A CNC machine means control (according to a program specified in an alphanumeric code) the movement of the machine’s executive bodies, the speed of their movement, the sequence of the processing cycle, the cutting mode and various auxiliary functions.

CNC system – this is a set of specialized devices, methods and means necessary for the implementation of a CNC machine. CNC device (CNC) is a part of the CNC system designed to issue control actions by the executive body of the machine in accordance with the control program (CP).

Structural scheme The CNC system is shown in Figure 3.

Part drawing (BH), to be processed on a CNC machine, simultaneously enters the system preparation of programs s (SPP) and technological training system (STP). STP provides SPP data about the technological process being developed, cutting mode, etc. Based on these data, a control program is developed (UP). Installers install devices and cutting tools on the machine in accordance with the documentation developed in STP. Installation of the workpiece and removal of the finished part is carried out by an operator or an automatic loader. Reader (SU) reads information from the software. Information comes to CNC, it issues control commands to target mechanisms (CM) machine tools that carry out the main and auxiliary processing movements. Feedback sensors (DOS) based on information (actual positions and speed of movement of the executive units, actual size of the surface being processed, thermal and power parameters of the technological system, etc.) control the amount of movement CM. The machine contains several CM, each of which includes: an engine (E), which is a source of energy; transmission P, serving to convert energy and transfer it from the engine to the executive body ( AND ABOUT); actually AND ABOUT(table, slide, support, spindle, etc.) that performs coordinate movements of the cycle.

Figure 3– Block diagram of the CNC system

Universal CNC systems provide the user and operator with great possibilities. They can be adapted by programming to a wide class of objects, including different machine tools; At the same time, they provide all types of interpolation - linear, circular, parabolic, etc., as well as preparation and debugging of the control program directly at the machine in interactive mode. The control program can be stored in memory and read from it during processing, which in some cases makes it possible to avoid the need to first enter the program by reading it from the program carrier. CNC systems have ample program editing capabilities and allow automatic correction (from memory) without the use of remote control correctors. It should be noted that there are special diagnostic programs for checking the operation of components in order to identify sources of malfunction, as well as the ability to store in memory information about systematic errors in kinematic chains and eliminate or compensate for these errors when reproducing a given profile; the possibility of introducing restrictions on the processing area into the system to avoid defects or machine breakdown; return to any point where the processing process was interrupted. Universal CNC systems operate in linear and polar coordinates, providing transformation of coordinate axes, for example, when using programs compiled for vertical milling machines on horizontal milling machines.

The main operating mode of the CNC device is automatic mode. In the process of automatic processing of the control program, a wide range of tasks of varying levels of complexity are solved: polling the operator console buttons; distribution and output of data for display on the operator console; calculation of the current position by coordinates and output of information to the operator’s console; calculation of processing cycles; calculation of the offset of the equidistant; introduction of correction; error compensation; polling of electrical automation sensors; polling readiness signals of input-output devices; interpolation; speed calculation; calculation of acceleration and deceleration modes; polling feedback sensors; issuing control actions on process equipment; current time analysis; control of control program execution time; analysis of the execution of the program contained in this frame; preparing initial information for processing the next frame.

The CNC system can be modified depending on the type of program carrier, the method of encoding information in the NC and the method of transmitting it to the CNC system.

Numerical control (CNC)– this is control in which the program is specified in the form of an array of information recorded on some medium. Control information for CNC systems is discrete and its processing during the control process is carried out using digital methods. Process cycle management is almost universally carried out using programmable logic controllers, implemented on the basis of the principles of digital electronic computing devices.

Programmable controllers

Programmable controller (PC ) – this is a device for controlling the electrical automation of a machine using certain algorithms implemented by a program stored in the device’s memory. A programmable controller (command device) can either be used autonomously in a CPU system or be part of common system control systems (for example, flexible manufacturing module control systems (GPM)), and can also be used to control equipment automatic lines etc. The block diagram is shown in Figure 4.

Figure 4- Block diagram of a programmable controller:

1 – processor; 2 – timer and counters; 3 – reprogrammable memory; 4 – random access memory (RAM); 5 – common block communication bus; 6 – communication unit with a CNC device or computer; 7 – remote control connection block for programming; 8 – input modules; 9 – input-output switch; 10 – output modules; 11 – programming console with keyboard and display.

Most programmable controllers have a modular design that includes a power supply, a processing unit and programmable memory, as well as various input/output modules. Input modules (input modules) generate signals coming from various peripheral devices (limit switches, electrical devices, thermal relays, etc.). Signals arriving at the input have, as a rule, two levels “O” and “1”. Output modules (output modules) supply signals to controlled actuators of the machine's electrical automation (contactors, starters, electromagnets, signal lamps, electromagnetic couplings, etc.). When the output signal is “1”, the corresponding device receives a command to turn on, and when the output signal is “O”, it receives a command to turn off.

A processor with memory solves logical problems of controlling output modules based on information supplied to input modules and control algorithms entered into memory. Timers are configured to provide time delays in accordance with operating cycles PC. Counters also solve the problems of implementing the work cycle PC.

Entering a program into the processor memory and debugging it is carried out using a special portable remote control, temporarily connected to PC. This remote control, which is a program recording device, can serve several PC. During the process of recording a program, the remote control display shows the current state of the controlled object in relay symbols or symbols. The program can also be entered through a communication unit with a CNC device or computer.

The entire program stored in memory can be divided into two parts: the main one, which is an object control algorithm, and the service one, which ensures the exchange of information between PC and the managed object. The exchange of information between the PC and the controlled object consists of polling inputs (receiving information from the controlled object) and switching outputs (issuing a control action to the controlled object). In accordance with this, the service part of the program consists of two stages: polling inputs and switching outputs.

Programmable controllers use different types of memory , in which the machine’s electrical automation program is stored: electrical reprogrammable non-volatile memory; free access RAM; UV erasable and electrically reprogrammable.

Programmable control has a diagnostic system: inputs/outputs, errors in the operation of the processor, memory, battery, communication and other elements. To simplify troubleshooting, modern intelligent modules have self-diagnosis.

Programmable Logic Controller (PLC) is a microprocessor system designed to implement logical control algorithms. The controller is designed to replace relay contact circuits assembled on discrete components - relays, counters, timers, hard logic elements.

Modern PLC can process discrete and analog signals, control valves, stepper motors, servos, frequency converters, and carry out regulation.

High performance characteristics make it advisable to use PLC wherever logical processing of signals from sensors is required. Application PLC ensures high reliability of equipment operation; easy maintenance of control devices; accelerated installation and commissioning of equipment; quick update of control algorithms (including on running equipment).

In addition to the direct benefits from using PLC, conditioned by low price and high reliability, there are also indirect ones: it becomes possible to implement additional functions without complicating or increasing the cost of the finished product, which will help to more fully realize the capabilities of the equipment. A large assortment PLC makes it possible to find optimal solutions for both simple tasks and complex production automation.

Software carriers

The operating program of the machine's executive bodies is specified using a program carrier.

Software carrier is a data medium on which the control program is recorded.

The software may contain both geometric, so and technological information. Technological information provides a certain cycle of operation of the machine, contains data on the sequence of putting various tools into operation, changing the cutting mode and turning on the cutting fluid, etc., and geometric – characterizes the shape, dimensions of the elements of the workpiece and tool being processed and their relative position in space.

Most common software carriers are:

card - made of cardboard, shaped like a rectangle, one end of which is cut off for orientation when inserting the card into the reader. The program is written by punching holes in place of the corresponding numbers.

eight-track punched tapes (Figure 5) 25.4 mm wide. Transport track 1 serves to move the tape (using a drum) in the reading device. Working holes 2, carrying information, are punched using a special device called a puncher. Information is applied to punched tape in frames, each of which is integral part UP. In a frame, you can only record a set of commands in which no more than one command is given to each executive body of the machine (for example, in one frame you cannot specify the movement of the EM both to the right and to the left);

Figure 5- Eight-track punched tape

1 – code tracks; 2 – base edge; 3 – code track number; 4 – serial number of the bit in the code combination

magnetic tape – a two-layer composition consisting of a plastic base and a working layer of ferromagnetic powder material. Information on the magnetic tape is recorded in the form of magnetic strokes applied along the tape and located in the UE frame with a certain step corresponding to the given speed of the EUT. When reading the CP, magnetic strokes are converted into control pulses. Each stroke corresponds to one pulse. Each pulse corresponds to a certain (discrete) movement of the EUT; the length of this movement is determined by the number of pulses contained in the magnetic tape frame. Such a recording of commands for moving the EUT called decoded .

Decoding is done using an interpolator , which converts the encoded geometric information about the contour of the workpiece entered into it (on punched tape or from a computer) into a sequence of control pulses corresponding to the elementary movements of the EUT. The decoded program is recorded on magnetic tape using a special device, which includes: an interpolating device with an output intended for recording; tape mechanism with magnetic heads for erasing, recording and playback.

Information in decoded form is recorded, as a rule, on magnetic tape, and in encoded form - on punched tape or a punched card. Magnetic tapes are used in lathes with stepper motors, which require a decoded view of the program.

Interpolation is the development of a program for the movement of a working body (tool) along the contour of the workpiece surface, sequentially in separate sections (frames).

Interpolator is a CNC block responsible for calculating the coordinates of intermediate points of the trajectory that the tool must pass between the points specified in the NC. The interpolator has as initial data a NC command to move the tool from the start to the end point along a contour in the form of a straight line segment, a circular arc, etc.

To ensure trajectory reproduction accuracy of the order of 1 micron (the accuracy of the position sensors and the caliper positioning accuracy are of the order of 1 micron), the interpolator issues control pulses every 5...10 ms, which requires high performance from it.

In order to simplify the algorithm of the interpolator, a given curvilinear contour is usually formed from segments of straight lines or from circular arcs, and often the steps of movement along different coordinate axes are performed not simultaneously, but alternately. Nevertheless, due to the high frequency of control inputs and the inertia of the mechanical drive units, the broken trajectory is smoothed out to a smooth curved contour.

Interpolator, part of the CNC system, performs the following functions:

based on the numerical parameters of the section of the processed contour (coordinates of the start and end points of the straight line, the value of the arc radius, etc.) specified by the software program, it calculates (with a certain discreteness) the coordinates of the intermediate points of this section of the contour;

generates control electrical pulses, the sequence of which corresponds to the movement (at the required speed) of the machine's executive body along a path passing through these points.

In systems CNC machines are mainly used for linear and linear-circular interpolators; the former ensure the movement of the tool between adjacent reference points along straight lines located at any angle, and the latter - both along straight lines and along circular arcs.

Linear interpolation– areas between discrete coordinates are represented by a straight line located in space in accordance with the trajectory of the cutting tool.

Circular interpolation– provides for the representation of a section of the processing contour in the form of an arc of the corresponding radius. The capabilities of CNC devices make it possible to provide interpolation by describing a section of a contour with a complex algebraic equation.

Helical interpolation– a helical line consists of two types of movements: circular in one plane and linear perpendicular to this plane. In this case, either the circular motion feed or the linear feed of the three used coordinates (axes) of the machine can be programmed.

The most important technical characteristic of the CNC system is hers resolution or discreteness .

Discreteness– this is the minimum possible amount of movement (linear or angular) of the machine’s executive body, corresponding to one control pulse.

Most modern CNC systems have a resolution of 0.01 mm/pulse. They are mastering the production of systems with a discreteness of 0.001 mm/pulse.

CNC systems are practically replacing other types of control systems.

Classification of CNC systems

According to technological capabilities and the nature of movement of the working bodies CNC systems are divided into three groups:

Position systems provide linear movement of the machine's executive body along one or two coordinates. The IO moves from position to position at maximum speed, and its approach to a given position is carried out at minimum (“creeping”) speed. Drilling and jig boring machines are equipped with such CNC systems.

Contour systems are designed to perform working movements along a specific trajectory at a given speed according to the processing program. CNC systems that provide rectangular, rectilinear and curved shaping are classified as contour (continuous) systems, since they allow the part to be processed along a contour. In CNC systems with rectangular shaping, the tool tool of the machine moves along the coordinate axes alternately, so the tool path has a stepped form, and each element of this path is parallel to the coordinate axes. Number of controlled coordinates in such systems reaches 5 , A number of simultaneously controlled coordinates 4 . In CNC systems with rectilinear shaping, the movement of the tool during cutting is distinguished along two coordinate axes (X and Y). These systems use a two-coordinate interpolator that issues control pulses to two feed drives at once. General number of controlled coordinates 2–5. CNC systems with curved shaping allow you to control the processing of flat and volumetric parts containing areas with complex curved contours. CNC contour systems have a stepper motor. Lathes, milling machines, and boring machines are equipped with such systems.

Combined systems (universal) have features of both positional and contour systems and are most typical for multi-purpose machines (drilling-milling-boring).

In machines with CNC systems, control is carried out from a program medium on which geometric and technological information is entered in numerical form.

A separate group includes machines with digital display and pre-set coordinates. These machines have electronic device for specifying the coordinates of the desired points (preset coordinates) and a cross table equipped with position sensors, which gives commands to move to the required position. Wherein Each current position of the table is displayed on the screen (digital display) . In such machines, you can use a preset of coordinates or a digital display; The initial work program is set by the machine operator.

In models of machine tools with PU, the letter F with a number is added to indicate the degree of automation:

F 1– machines with digital display and preset of coordinates;

F 2– machines with rectangular and positional CNC systems;

F 3– machines with contour rectilinear and curved CNC systems;

F 4– machines with a universal CNC system for positional contour processing.

In addition, the prefixes C1, C2, C3, C4 and C5 can be added to the designation of the CNC machine model, which indicates different models of CNC systems used in the machines, as well as the different technological capabilities of the machines. For example, a machine model 16K20F3S1 is equipped with a Kontur 2PT-71 CNC system, a machine model 16K20F3S4 is equipped with an EM907 CNC system, etc.

For machines with cyclic PU systems entered in the model designation index C , With operating systems – index T (for example, 16K20T1). CNC provides control of the movement of the working parts of the machine and the speed of their movement during shaping, as well as the sequence of the processing cycle, cutting mode, and various auxiliary functions.

To characterize CNC machines, the following indicators are used:

Accuracy class :N– normal accuracy, P– increased accuracy, IN– high precision, A– particularly high precision, WITH– ultra-high precision (master machines);

Technological operations , performed on a machine : turning, drilling, milling, grinding, etc.;

Basic machine parameters : for chuck machines– the largest diameter of the installed product above the frame; for centering and chuck machines– the largest diameter of the workpiece above the support; for bar-turning machines machine tools – the largest diameter of the processed rod; for milling and boring machine tools – overall dimensions (length, width) of the working surface of the table, diameter of the working surface of the round rotary table; for drilling machine tools - the largest drilling diameter, the diameter of the retractable spindle, etc.;

The amount of movement of the working parts of the machine – a support along two coordinates, a table along two coordinates, a spindle unit along linear and angular coordinates, etc.;

Discreteness value (division value) the minimum task of moving according to the program (step);

Accuracy and repeatability of positioning according to controlled coordinates ;

Main drive – type, nominal and maximum power values, spindle speed limits (stepped or stepless), number of operating speeds, number of automatically switched speeds;

Machine feed drive – coordinate, type, nominal and maximum moments, speed limits of working feeds and the number of speeds of working feeds, speed of rapid movement;

Number of tools – in the tool holder, turret, tool magazine;

Type of tool change – automatic, manual;

Overall dimensions of the machine and its weight .

According to the method of preparing and entering the control program distinguish:

CNC operating systems(in this case, the control program is prepared and edited directly on the machine, during the processing of the first part from the batch or simulating its processing);

adaptive systems, for which the control program is prepared, regardless of where the part is processed. Moreover, independent preparation of the control program can be performed either using computer technology included in the CNC system of a given machine, or outside it (manually or using an automation programming system.)

By level of technical capabilities V international practice The following designations for numerical program control systems are accepted:

NC(Computer Numerical Control) - CNC;

HNC(Hand Numerical Control) - a type of CNC device with the operator setting a processing program from the remote control using keys, switches, etc.;

SNC(Speiher Numerical Control) - a CNC device that has memory for storing the entire control program (the program is stored in internal memory);

CNC– the CNC device allows you to control one CNC machine; the device corresponds to the structure of the control minicomputer or processor; expands the functionality of program management, it becomes possible to store the program program and edit it at the workplace, interactive communication with the operator, ample correction possibilities, the ability to change the program during its operation, etc.;

D.N.C.(Direct Numerical Control) – higher-level systems that provide: control of a group of machines at once from a common computer; storing a very significant number of programs in memory; interaction with auxiliary GPS systems (transportation, storage); choosing the start time for processing a particular part; accounting for operating time and equipment downtime, etc.

By number of information flows CNC systems are divided into closed, open and adaptive.

Open-loop systems are characterized by the presence of one stream of information coming from the reading device to the executive body of the machine. The mechanisms of such systems use stepper motors. It is a master device, the signals of which are amplified in various ways, for example, using a hydraulic torque booster, the shaft of which is connected to the feed drive lead screw. In an open-loop system there is no feedback sensor and therefore there is no information about the actual position of the machine's actuators.

Closed systems CNCs are characterized by two flows of information - from the reading device and from the feedback sensor along the path. In these systems, the discrepancy between the specified and actual displacement values ​​of the executive bodies is eliminated due to the presence of feedback.

Adaptive systems CNCs are characterized by three flows of information: 1) from the reading device; 2) from a feedback sensor along the way; 3) from sensors installed on the machine and monitoring the processing process according to such parameters as wear of the cutting tool, changes in cutting forces and friction, fluctuations in allowance and hardness of the material of the workpiece, etc. Such programs allow you to adjust the processing program taking into account real cutting conditions.

The use of a specific type of CNC equipment depends on the complexity of the part being manufactured and the serial production. The smaller the production volume, the greater the technological flexibility the machine should have.

When manufacturing parts with complex spatial profiles in single small-scale production, the use of CNC machines is almost the only technically justified solution. This equipment is also advisable to use in cases where it is not possible to quickly produce equipment. In mass production it is also advisable to use CNC machines. Recently, autonomous CNC machines or systems of such machines have been widely used in conditions of reconfigured large-scale production.

The fundamental feature of a CNC machine is that it works according to a control program (CP), on which the operating cycle of the equipment for processing a specific part and technological modes are recorded. When changing a part processed on a machine, you just need to change the program, which reduces the labor intensity of changeover by 80...90% compared to the labor intensity of this operation on manually controlled machines.

Basic advantages of CNC machines:

the productivity of the machine increases by 1.5...2.5 times compared to the productivity of similar manually operated machines;

combines the flexibility of universal equipment with the accuracy and productivity of an automatic machine;

the need for skilled workers - machine operators - is reduced, and production preparation is transferred to the field of engineering work;

parts manufactured using the same program. They are interchangeable, which reduces the time of fitting work during the assembly process;

the time required for preparation and transition to the production of new parts is reduced, thanks to preliminary preparation programs, simpler and more universal technological equipment;

The cycle time for manufacturing parts is reduced and the stock of unfinished production is reduced.

Control questions:

What is software control of machine tools? What types of PU machines do you know?

What do CPU machines mean?

What is a CNC machine tool? What CNC systems do you know?

What is the fundamental feature of CNC machines?

List the main advantages of using CNC machines?

Coordinate axes and motion structures of CNC machines

All CNC machines are used unified system coordinate designations recommended by the ISO standard - R841: 1974. Coordinates indicate the position of the axis of rotation of the machine spindle or workpiece, as well as the linear or circular feed movements of the tool or workpiece. In this case, the designation of the coordinate axes and the direction of movement in the machine tools are set so that the programming of processing operations does not depend on whether the tool or workpiece moves or not. The basis is the movement of the tool relative to the coordinate system of the stationary workpiece.

The standard coordinate system is a right-handed rectangular system associated with the workpiece, the axes of which are parallel to the linear guides of the machine.

All linear movements are considered in the coordinate system X , Y , Z . Circular motion in relation to each of the coordinate axes denoted by capital letters of the Latin alphabet : A, B, C (Figure 6). In all machines, the Z axis coincides with the axis of the main movement spindle, i.e., the spindle that rotates the tool (in machines of the drilling-milling-boring group), or the spindle that rotates the workpiece (in machines of the turning group). If there are several spindles, the spindle perpendicular to the working surface of the table on which the workpiece is mounted is chosen as the main one.

Figure 6- Standard coordinate system in CNC machines

Axis movement Z in a positive direction must correspond to the direction retracting the tool from the workpiece . On drilling and boring machines, machining occurs when the tool moves in a negative direction along the Z axis.

Axis X should preferably be positioned horizontally and parallel to the workpiece mounting surface. On machines with a rotating workpiece (lathe), movement along the X axis is directed along the radius of the workpiece and parallel to the transverse guides. Positive axis movement X occurs when the instrument , installed in the main tool holder of the cross slide, moves away from the axis of rotation blanks.

On machines with rotating tools (milling, drilling) with a horizontal Z axis positive axis movement X directed to the right when looking from the main tool spindle towards the workpiece. With the Z axis vertical, the positive movement along the X axis is to the right for single-column machines, and for double-column machines - from the main tool spindle to the left column.

Positive axis direction Y should be chosen so that the Y axis, together with the Z and X axes, forms a right-handed rectangular coordinate system. To do this, I use the rule of the right hand: thumb - X axis, index finger - Y axis, middle finger - Z axis ( drawing).

If, in addition to the main (primary) linear movements along the X, Y and Z axes, there are secondary movements parallel to them, then they are designated U, V, W, respectively. If there are tertiary movements, they are designated P, Q and R.

Primary, secondary and tertiary movements of the working parts of the machine are determined depending on the distance of these bodies from the main spindle.

Secondary rotational movements, parallel or not parallel to the A, B and C axes, are designated D or E.

Methods and origin of coordinates

When setting up a CNC machine, each executive element is installed in a certain initial position, from which it moves when processing the workpiece to strictly defined distances. This allows the tool to pass through the specified path reference points. The magnitudes and directions of movement of the executive body from one position to another are specified in the NC and can be performed on the machine in different ways depending on the design of the machine and the CNC system. Modern CNC machines use two methods of counting movements: absolute and relative (in increments).

Absolute coordinate reference method – the position of the origin of coordinates is fixed (motionless) for the entire workpiece processing program. When compiling a program, the absolute values ​​of the coordinates of successively located points specified from the origin of coordinates are recorded. When processing a program, the coordinates are counted from this origin each time, which eliminates the accumulation of movement errors during program processing.

Relative coordinate reference method – each time the zero position is taken to be the position of the executive body, which it occupies before moving to the next reference point. In this case, coordinate increments are written into the program to sequentially move the tool from point to point. This reference method is used in CNC contour systems. The positioning accuracy of the actuator at a given reference point is determined by the accuracy of processing the coordinates of all previous reference points, starting from the initial one, which leads to the accumulation of movement errors during program processing.

For ease of programming and setting up CNC machines, the origin of coordinates in some cases can be selected anywhere within the strokes of the executive bodies. This origin of coordinates is called " floating zero" and is mainly used on drilling and boring machines equipped with CNC positioning systems.

Development of control programs

When developing a control program it is necessary:

design route processing technology in the form of a sequence of operations with a choice of cutting and auxiliary tools and devices;

develop operating technology with the calculation of cutting modes and determination of the trajectories of movement of cutting tools;

determine the coordinates of reference points for the trajectories of movement of cutting tools;

draw up a calculation and technological map and a machine setup map;

encode information;

put information on the program carrier and send it to the memory of the machine’s CNC device or manually type it on the CNC device’s remote control;

check and, if necessary, correct the program.

For programming, you need a drawing of the part, a machine operating manual, programming instructions, a catalog of cutting tools and standards for cutting conditions.

According to GOST 20999-83, program elements are recorded in a certain order in the form of a sequence of frames and using the appropriate symbols (see Table 1).

Table 1 Meanings of control characters and signs

Program block (phrase)- a sequence of words arranged in a certain order and carrying information about one technological work operation (Figure 8).

Program word– a sequence of symbols that are in a certain connection as a single whole.

Figure 8– Program block

Each block of the control program must contain:

the word “Frame number”;

information words or word (may not be used);

"End of Frame" symbol;

tab character (can be omitted). When using these symbols, they are placed before each word in the UE frame, except for the word “Frame number”.

the word (or words) “Preparatory function”;

the words “Dimensional movements”, which are recommended to be written in the following sequence of symbols: X, Y, Z, U, V, W, P, Q, R, A, B, C;

the words “Interpolation parameter” or “Thread pitch” I, J, K;

the word (or words) “Feed Function”, which refer only to a specific axis and must immediately follow the words “Dimensional Move” along that axis; the word “Feed function”, referring to two or more axes, must follow the word “Dimensional movement”;

the word “Main movement function”;

the word (or words) “Tool function”;

the word (or words) “Auxiliary function”.

The order and multiplicity of writing words with addresses D, E, H, U, V, W, P, Q, R, used in values ​​other than the accepted ones, are indicated in the form of a specific CNC device.

Within one NC frame the words “Dimensional movements” and “Interpolation parameter” or “Thread pitch” should not be repeated; The words “Preparatory function” included in the same group should not be used.

After the “Main Frame” symbol (:), all information necessary to start or resume processing must be recorded in the NC. This symbol is used to identify the start of a program on the storage medium.

Each word in the UE frame must consist of an address symbol (a capital letter of the Latin alphabet according to the table), a mathematical sign “+” or “-“ (if necessary), a sequence of numbers.

Words in UE can be written in one of two ways: without using a decimal point (the position of the decimal point is implied) and with its use (the explicit position of the decimal point). An explicit decimal point is indicated by the symbol "DS". The intended decimal point position must be defined in the specifications of the specific CNC device.

When writing words using a decimal place, words that do not have a decimal place must be treated as integers by the CNC. In this case, insignificant zeros appearing before and/or after the sign may be omitted: X.03 means a size of 0.03 mm along the X axis; X1030 – size 1030.0 mm along the X axis.

Currently, when programming, the address method of recording information on punched tape is more often used. The information of each frame is divided into two types: 1) letter (address), designates the executive body of the CNC system (or machine tool) to which the command is given; 2) the number following the address and indicating the amount of movement of the machine’s executive body (with a “+” or “-” sign) or a code entry (for example, feed amount, etc.). The letter and the number following it are a word. A program block consists of one, two or more words.

The encoded recording of a number of NC frames for processing a workpiece on a lathe can have the following form:

No. 003 X +000000 - moving the cutter to the zero point along the X axis;

No. 004 Z +000000 - moving the cutter to the zero point along the Z axis;

No. 005 G26 - command to work in increments

No. 006 G10 X -006000 - G10 -linear interpolation (rectilinear

movement path)

No. 007 X -014000 F10080

No. 008 Z +000500 F10600

No. 009 X +009500 F70000

No. 010 X +002000 Z -001000 F10100

………………………………………………………..

…………………………………………………………….

№………M102

The numbers after the letters determine the number of digits of the numerical part of a given word. In brackets of addresses X, Z, I, K, possible digits of numbers expressing geometric information under different operating modes of the CNC are indicated. This information is recorded in the form of a number of pulses (the number of millimeters of movement of the EO divided by the discreteness of their processing).

Word (or words ) "Preparatory function" must be expressed by a code symbol in accordance with Table 2.

Table 2 - Preparatory functions

Note: G07,G10-G16,G20,G32,G36-G39,G60-G62,G64-G79,G98,G99 are reserve codes.

All dimensional movements must be specified in absolute values ​​or increments. The control method must be selected from one of the preparatory functions: G90 (absolute size) or G91 (incremental size ).

The address of each word “Dimensional movement” is followed by two digits, the first of which shows the number of digits before the implied decimal point, separating the integer part of the number from the fractional part, the second - the number of digits after the decimal point. If it is possible to omit the zeros preceding the first significant digit and after the last significant digit in the words "Dimensional Moves", the "Dimensional Moves" address must be followed by three digits. If zeros preceding the first significant digit are omitted, then the first digit must be a zero. If zeros after a significant digit are omitted, the zero must be the last digit.

All linear movements must be expressed in millimeters and their decimal parts. All angular dimensions are given in radians or degrees. It is allowed to express angular dimensions in decimal fractions of a revolution.

If the CNC device allows dimensions to be specified in absolute values ​​(positive or negative) depending on the origin of the coordinate system, then the mathematical sign (“+” or “-”) is part of the word “Dimensional movement” and must precede the first digit of each dimension.

If the absolute dimensions are always positive, then no sign is placed between the address and the number following it, and if they are either positive or negative, then a sign is placed.

If the CNC device allows for specifying dimensions in increments, then a mathematical sign must precede the first digit of each dimension, indicating the direction of movement.

The movement of the tool along a complex trajectory is ensured by a special device - an interpolator. Interpolation of linear and arc segments is carried out separately along sections of a given trajectory. Each of the sections can be written in one or more frames of the control program.

The functional nature of the interpolated trajectory section (straight line, circle, parabola or higher order curve) is determined by the correspondingpreparation function (G01 – G03, G06). To set interpolation parametersaddresses I, J, K are used, using them to determine the geometric characteristics of curves (for example, the center of a circular arc, radii, angles, etc.). If a mathematical sign (“+” or “-”) needs to be written along with the interpolation parameters, it must follow the address character and before the numeric characters. If there is no sign, then the “+” sign is assumed.

The starting point of each interpolation section coincides with the end point of the previous section, so it is not repeated in the new frame. Each subsequent point lying on this interpolation section and having certain coordinates corresponds to a separate frame of information with movement addresses X, Y or Z.

Modern CNC devices have “built-in” functions in their software to perform simple interpolation. Thus, in CNC lathes, a chamfer at an angle of 45° is specified by the address WITH with a sign and final size along the coordinate along which the part is being processed before the chamfer. Sign under the address WITH must coincide with the processing sign along the X coordinate (Figure a). The direction along the Z coordinate is specified only in the negative direction.

To specify an arc, indicate the coordinates of the end point of the arc and the radius under the address R with a positive sign when processing clockwise and negative when processing counterclockwise (Figure 9).

Figure 9- Programming chamfers (a) and arcs (b) on a CNC lathe

The feed and speed of the main movement are encoded in numbers, the number of digits of which is indicated in the format of a specific CNC device. Choicefeed type G93 (feed in inverse time function), G94 (feed per minute), G95 (feed per revolution).

Choicetype of main movement must be carried out by one of the preparatory functions:G96 (constant cutting speed) or G97 (revolutions per minute).

The main method of encoding the feed is the direct designation method, in which the following units should be used: millimeter per minute - the feed does not depend on the speed of the main movement; millimeter per revolution - feed depends on the speed of the main movement; radians per second (degrees per minute) – Feed refers to circular motion only. When directly coding the speed of the main movement, the number indicates the angular speed of the spindle(radians per second or revolutions per minute) or cutting speed (meters per minute). For example, if the spindle speed in the program is set to S - 1000, this means that the spindle rotates clockwise at a speed of 1000 rpm.(If there is no minus sign, then the spindle rotates counterclockwise).

The word "Tool Function" is used to select a tool . It can be used to correct (or compensate) the tool. In this case, the word “Tool Function” will consist of two groups of numbers. The first group is used to select a tool, the second – for correction. If a different address is used to record tool offset (compensation), it is recommended use the symbol D or H.

Number of digits following addresses T, D and H , is indicated in the format of a specific CNC device.

Word (or words) "Auxiliary function" expressed by a code number in accordance with Table 3.

Table 3 - Auxiliary functions

The thread pitch value must be expressed in millimeters per spindle revolution. The number of digits in words that specify the thread pitch is determined in the format of a specific CNC device. When cutting threads with variable pitch, the words under addresses I and K must specify the dimensions of the initial thread pitch.

The word “Feed function” should not be programmed with a constant thread pitch.

Each control program must begin with the “Start of Program” symbol, followed by the “End of Block” symbol, and then a block with the corresponding number. If it is necessary to designate a control program, this designation (number) must be located immediately after the “Start of program” symbol before the “End of block” symbol.

The control program must end with the “End of program” or “End of information” symbol. Information placed after the “End of information” symbol is not perceived by the CNC device. Before the “Start of Program” symbol and after the “End of Program” and “End of Information” symbols on the punched paper tape, it is recommended to leave areas with the PUS (“Empty”) symbol.

Debugging and adjusting the program

When preparing a control program, an important point is the development trajectories of movement of cutting tools relative to the part and on this basis - a description of the movements of the relevant organs of the machine. For this, several coordinate systems are used.

Main settlement system – machine coordinate system , in which the maximum movements and positions of its working bodies are determined. These provisions are characterized base points , which are selected depending on the design of the machine . For example, for spindle unit the base point is the point of intersection of the end of the spindle with the axis of its rotation, for cross table– the point of intersection of its diagonals, for rotary table– center of rotation on the table mirror, etc. The position of the axes and their directions in the standard coordinate system are discussed above.

The origin of the standard coordinate system is usually aligned with the base point of the node carrying the workpiece. In this case, the unit is fixed in a position in which all movements of the working parts of the machine occur in the positive direction(Figure 10). From this base point,called zero machine , the position of the working bodies is determined, if information about their position is lost (for example, due to a power outage). The working elements move to the machine zero by pressing the corresponding buttons on the control panel or using commands from the control program. Accurate stopping of the working bodies in the zero position along each of the coordinates is ensured by zero position sensors. For example, during turning, the machine zero is set offset to avoid accidents.

Part coordinate system with a base point, is considered when securing the workpiece on the machine, to determine the position of this system and the machine coordinate system relative to each other (Figure 9). Sometimes this connection is made by using the base point of the mounting fixture.

Tool coordinate system is intended to specify the position of its working part relative to the fastening unit. The tool is described in its working position assembled with the holder. In this case, the axes of the tool coordinate system are parallel to the corresponding axes of the standard machine coordinate system and directed in the same direction. The origin of the tool coordinate system is taken to be the base point instrument block, selected taking into account the features of its installation on the machine.

The position of the tool tip is specified by the radius r and the X and Z coordinates of its setting point. This point is usually used when defining a trajectory whose elements are parallel to the coordinate axes. For a curved trajectory, the center of rounding at the tool tip is taken as the design point. The connection between the coordinate systems of the machine, the part and the tool can be easily seen in Figure 9.

Figure 9- Part coordinate systems when processed on milling (a) and turning (b) CNC machines

When developing a control program and processing a part use the program's coordinate system. Its axes are parallel to the coordinate axes of the machine and are also directed.

The origin of coordinates (the starting point of the machine) is chosen based on the convenience of measuring dimensions. To avoid significant idle strokes, the initial position from which processing begins and in which tools and workpieces are changed is set so that the tools are as close as possible to the workpiece.

To “reference” the machine’s movement measurement system in space, a zero (base) reference point is used. Each time the machine is turned on, this point “ties” the measuring system to the zero point of the machine.

When changing cutting tools during the processing of parts, there may be a discrepancy between the processing results and the requirements for it (loss of accuracy, increase in roughness, occurrence of vibrations, etc.). In this case, it is necessary to promptly adjust the program. Processing errors that require correction can occur when drilling holes, turning conical and shaped surfaces due to the presence of apex radius in the cutters.

Two types of correction are possible – for length and for tool radius.

In the first case, correction of the length of the drill or the overhang of the cutter holder is carried out using Team H with a set of numbers corresponding to the correction value. For example, frame N 060 T 02 H 15

Indicates the introduction of a length correction of 15 mm for tool No. 2.

The second case provides correction of the tool radius and is due to the fact that when turning conical and shaped surfaces when milling contours, the trajectory of the center of the tool radius surface must be equidistant relative to the shape of the surface (Figure 11).

Here is a fragment of the program for compensating the cutter radius:

Fragment of the program providing for equidistant milling (Figure 12)

N 005 G 90 G 00 X 0 Y 0 S 1000 T01 M 03

N 006 G 41 G 01 X 220 Y 100 F 100

N 007 X 220 Y 430 F 50

N 008 G 02 G 17 X 370 Y 580 I 370 J 430

N 009 G 01 X 705 Y 580

N 010 X 480 Y 190

N 011 X 220 Y 190

N 012 G 00 X 0 Y 0 05M

Function G 41 (correction of the cutter diameter if the cutter is located to the left of the part) in block N 006 ensures that the center of the cutter moves equidistant relative to the surface being machined.

In some cases, it is necessary to adjust the feed in order to reduce the roughness of the machined surface, eliminate vibrations, etc. To do this, you need to set a new feed value on the control panel and enter it into the memory of the CNC device.

Figure 12- Equidistant movement of the cutter when milling the outer contour

Design features of CNC machines.

CNC machines have advanced technological capabilities while maintaining high operational reliability. The design of CNC machines should, as a rule, ensure the combination of various types of processing (turning - milling, milling - grinding), ease of loading workpieces, unloading parts (which is especially important when using industrial robots), automatic or remote control of interchangeable tools, etc. .

Increased processing accuracy is achieved by high manufacturing accuracy and rigidity of the machine, exceeding the rigidity of a conventional machine for the same purpose. Why are the lengths of its kinematic chains reduced: they replace autonomous drives and, if possible, reduce the number of mechanical transmissions. The drives of CNC machines must also provide high speed.

The elimination of gaps in the transmission mechanisms of feed drives and the reduction of friction losses in guides and other mechanisms also contribute to increasing accuracy. Increasing vibration resistance, reducing thermal deformation, using feedback sensors in machine tools. To reduce thermal deformations, it is necessary to ensure a uniform temperature regime in the machine mechanisms, which, for example, is facilitated by preheating the machine and its hydraulic system. The temperature error of the machine can also be reduced by adjusting the feed drive from the temperature sensor signals.

The basic parts (frames, columns, bases) are made more rigid due to the introduction of additional stiffeners. Movable load-bearing elements (supports, tables, slides) also have increased rigidity. Tables, for example, are constructed in a box-like shape with longitudinal and transverse shapes. Basic parts are made cast or welded. There is a tendency to make such parts from polymer concrete or synthetic granite, which further increases the rigidity and vibration resistance of the machine.

The guides of CNC machines have high wear resistance and low friction force, which makes it possible to reduce the power of the servo drive, increase the accuracy of movements, and reduce the misalignment of the servo system.

To reduce the coefficient of friction, the sliding guides of the frame and the support are created in the form of a sliding pair “steel (or high-quality cast iron) - plastic coating (fluoroplastic, etc.)”

Rolling guides have high durability, are characterized by low friction, and the friction coefficient is practically independent of the speed of movement. Rollers are used as rolling bodies. Preload increases the rigidity of the guides by 2..3 times; adjusting devices are used to create tension.

Drives and converters for CNC machines. In connection with the development of microprocessor technology, converters are used for feed and main motion drives with full microprocessor control - digital converters or digital drives. Digital drives are electric motors that operate on direct or alternating current. Structurally, frequency converters, servo drives and main starting and reversing devices are separate electronic control units.

Feed drive for CNC machines. Motors are used as drives, which are synchronous or asynchronous machines controlled by digital converters. Commutatorless synchronous (valve) motors for CNC machines are made with a permanent magnet based on rare earth elements and are equipped with feedback sensors and brakes. Asynchronous motors are used less frequently than synchronous motors. The feed movement drive is characterized by minimal possible clearances, short acceleration and braking times, and large friction forces, reduced heating of drive elements, and a large control range. Providing these characteristics is possible through the use of ball and hydrostatic screw gears, rolling guides and hydrostatic guides, backlash-free gearboxes with short kinematic chains, etc.

The main motion drives for CNC machines are usually AC motors for high power and DC motors for low power. The drives are three-phase four-pole asynchronous motors that can withstand large overloads and operate in the presence of metal dust, chips, oil, etc. in the air. Therefore, their design includes an external fan. Various sensors are built into the motor, such as a spindle position sensor, which is necessary for orientation or providing independent coordinates.

Frequency converters for controlling asynchronous motors have a control range of up to 250. The converters are electronic devices, built on the basis of microprocessor technology. Programming and parameterization of their operation is carried out using built-in programmers with a digital or graphic display. Control optimization is achieved automatically after entering the motor parameters. The software includes the ability to configure the drive and put it into operation.

Spindles of CNC machines are made more precise, rigid, with increased wear resistance of journals, seating and basing surfaces. The design of the spindle is significantly more complicated due to the built-in devices for automatically releasing and clamping the tool, sensors used in adaptive control and automatic diagnostics.

Spindle supports must ensure spindle accuracy over a long period of time under variable operating conditions, increased rigidity, and small temperature deformations. The spindle rotation accuracy is ensured, first of all, by the high precision of the bearings.

I most often use rolling bearings in spindle supports. To reduce the influence of clearances and increase the rigidity of the supports, bearings with preload are usually installed or the number of rolling elements is increased. Sliding bearings in spindle supports are used less frequently and only in the presence of devices with periodic (manual) or automatic clearance adjustment in the axial or radial direction. In precision machines, aerostatic bearings are used, in which there is compressed air between the shaft journal and the bearing surface, due to which wear and heating of the bearing are reduced, rotation accuracy is increased, etc.

The positioning drive (i.e., moving the working body of the machine to the required position according to the program) must have high rigidity and ensure smooth movement at low speeds, high speed of auxiliary movements of the working bodies (up to 10 m/min or more).

The auxiliary mechanism of CNC machines includes tool changers, chip removal devices, lubrication system, clamping devices, loading devices, etc. This group of mechanisms in CNC machines differs significantly from similar mechanisms used in conventional universal machines. For example, as a result of an increase in the productivity of CNC machines, there was a sharp increase in the flow of chips per unit time, and hence the need arose to create special devices for removing chips from the processing zone. To reduce time loss during loading, devices are used that allow you to simultaneously install the workpiece and remove the part while processing another workpiece.

Devices for automatic tool changing (magazines, auto operators, turrets) must ensure minimal time spent on tool changing, high operational reliability, stability of the tool position, i.e. consistency of the overhang size and axis position during repeated tool changes, have the required magazine or turret capacity.

The turret is the simplest tool changing device: the tool is installed and clamped manually. In the working position, one of the spindles is driven into rotation by the main drive of the machine. Turret heads are installed on lathes, drilling, milling, and multi-purpose CNC machines; 4 to 12 instruments are fixed in the head.

Control questions:

Name the main design features of CNC machines.

List the design features of the base parts, drives of the main movement and feed movement, as well as auxiliary mechanisms of CNC machines.

CNC lathes.

CNC lathes are designed for external and internal processing of complex workpieces such as rotating bodies. They constitute the most significant group in terms of product range in the CNC machine tool fleet. CNC lathes perform a traditional set of technological operations: turning, cutting, drilling, threading, etc.

The classification of CNC lathes is based on the following features:

location of the spindle axis (horizontal and vertical machines);

the number of tools used in the work (one - and many - tool machines);

methods of securing them (on a caliper, in a turret, in a tool magazine);

type of work performed (center, cartridge, cartridge-center, rotary, bar machines;

degree of automation (semi-automatic and automatic).

CNC centering machines are used for processing workpieces such as shafts with straight and curved contours. On these machines you can cut threads with a cutter according to the program.

CNC chuck tanks are designed for processing, drilling, reaming, countersinking, counterbore, tapping in axial holes of parts such as flanges, gears, covers, pulleys, etc.; It is possible to cut internal and external threads with a cutter according to the program.

CNC chuck centering machines are used for external and internal processing of various complex workpieces of parts such as rotation hoists and have the technological capabilities of centering and chuck lathes.

CNC rotary machines are used for processing blanks of complex housings.

CNC lathes (Figure 12) are equipped with turrets or a tool magazine. Turret heads come in 4-, 6- and 12-position, and at each position you can install two tools for external and internal processing of the workpiece. The axis of rotation of the head can be parallel to the spindle axis, perpendicular to it, or oblique.

When installing two turret heads on a machine, tools for external processing are secured in one of them (1), and tools for internal processing in the other (2) (see Figure 13). Such heads can be located coaxially relative to each other or have different axes. Indexing of turrets is typically accomplished by using hardened and ground flat-toothed face couplings, which provide high precision and rigidity for indexing the turret. Replaceable interchangeable tool blocks are installed in the grooves of the turret heads, which are adjusted to size outside the machine, on special devices, which significantly increases the productivity and accuracy of processing. The cutting blocks in the turret head are based either on a prism or using cylindrical shanks 6 (Figure 14). The cutter is secured with screws through the clamping bar 3. To adjust the cutter to the height of the centers, a lining 2 is used. Two adjusting screws 5, located at an angle of 45° to one another, allow the tip of the cutter to be brought to the specified coordinates during adjustment. Coolant supply to the cutting zone is carried out through a channel in housing 1, ending with nozzle 4, which allows you to adjust the direction of coolant supply.

Tool magazines (capacity 8...20 tools) are rarely used, since practically turning one workpiece requires no more than 10 tools. The use of a large number of tools is advisable in cases of turning difficult-to-cut materials, when the tools have a short service life.

Expansion of the technological capabilities of lathes is possible due to erasing the line between lathes and milling machines, adding eccentric drilling, contour milling (i.e. spindle rotation is programmed); in some cases, thread cutting of misaligned workpiece elements is possible.

Control questions:

How are CNC lathes classified according to the type of work performed?

What tool mounting devices are equipped with CNC lathes?

How are the cutting blocks located in the turret head of the machine?

CNC milling machines

CNC milling machines are designed for processing flat and spatial surfaces of workpieces of complex shapes. The designs of CNC milling machines are similar to those of traditional milling machines, the difference from the latter lies in the automation of movements along the NC during shaping.

The classification of CNC milling machines is based on the following features:

Spindle location (horizontal and vertical);

Number of coordinate movements of the table or milling head;

Number of tools used (single-tool and multi-tool);

The method of installing tools into the machine spindle (manually or automatically).

Based on their layout, CNC milling machines are divided into four groups:

vertically – milling machines with a cross table;

cantilever milling machines;

longitudinally – milling machines;

widely-universal tool machines.

In vertical milling machines with a cross table (Figure 15, a), the table moves in the longitudinal (X axis) and transverse (Y axis) horizontal directions, and the milling head moves in the vertical direction (Z axis).

In cantilever milling machines (Figure 15, b), the table moves along three coordinate axes (X, Y and Z), and the headstock is not movable.

In longitudinal milling machines with a movable crossbar (Figure 15, c), the table moves along the X axis, the spindle head - along the Y axis, and the transverse one - along the Z axis. In longitudinal milling machines, with a fixed crossbar (Figure 15, d), the table moves along the X axis, and the spindle head along the Y and Z axes.

In widely universal tool milling machines (Figure 15, e), the table moves along the X and Y axes, and the spindle head moves along the Z axis.

Figure 15 – Coordinate system in various modifications of milling machines:

a) – milling machine with a cross table; b) cantilever milling machine; c) longitudinal milling machine with a movable cross member; d) longitudinal milling machine with a fixed cross member; d) a universal milling machine.

Milling machines are mainly equipped with rectangular and contour CNC devices.

With rectangular control ( symbol in the machine model - F 2) the machine table moves in a direction parallel to one of the coordinate axes, which makes it impossible to process complex surfaces. Machines with rectangular control are used for milling planes, bevels, ledges, grooves, uneven-high bosses and other similar surfaces.

With contour control (symbol in the machine model - F 3 and F 4), the trajectory of the table movement is more complex. Machine tools with contour control are used for milling various cams, dies, molds, and other similar surfaces. The number of controlled coordinates is usually three, and in some cases four or five. With contour control, the shaping movement is carried out along at least two coordinate axes simultaneously.

In some cases, CNC systems are also used on milling machines when processing simple-shaped workpieces in medium- and large-scale production.

In CNC milling machines, asynchronous electric motors (in these cases there is a gearbox) or DC electric motors are used as the main movement drive.

On small milling machines with rectangular CNC, one DC drive motor and a gearbox with automatically switched electromagnetic clutches are used, and on heavy machines with contour control, each controlled coordinate movement is carried out from an automatic DC electric drive.

The feed motion drives of CNC milling machines have short kinematic chains that transmit movements from the engine directly to the executive body.

Let's consider the design of a cantilever vertical milling machine mod. 6Р13Ф3. This machine is a console machine, i.e. its table has a working movement in the horizontal plane (along the X and Y coordinates) and (together with the console) an installation movement in the vertical direction (along the W coordinate); the working movement along the Z coordinate has a slider with a spindle. The bed 8 is the base on which the components and mechanisms of the machine are mounted. At the front of the frame there are vertical guides, covered by a casing 9, along which the console 1 moves. A slide 2 is mounted on the horizontal guides, along the longitudinal guides of which the table 3 moves. A milling head 6 is fixed on the mating plane of the frame, along the vertical guides of which a slider 7 with a spindle 5 moves In accordance with safety requirements, the slider has a protective shield 4. At the rear of the machine there is a cabinet 10 with electrical equipment and a CNC.

Figure 16 – Vertical milling machine mod. 6R13F3:

1-console; 2-sled; 3-table; 4-protective shield; 5-spindle: 6-milling head; 7-slider; 8-bed; 9-casing;

10-cabinet with electrical equipment.

Control questions:

What layouts of CNC milling machines do you know?

What CNC systems are equipped with milling machines?

CNC drilling machines

Vertical - CNC drilling machines, unlike similar manually controlled machines, are equipped with cross tables that automatically move the workpiece along the X and Y axes, resulting in no need for jigs or preliminary marking.

Radial CNC drilling machines have a column movable along the X axis, a sleeve movable along the Y axis spindle head, in which a drilling spindle is mounted, moving along the Z axis. In addition, the sleeve can move in the vertical direction when applied.

Automated movement of the working bodies of drilling machines along the X and Y axes ensures hole processing and milling.

Drilling machines are equipped with positional CNC controls, which allow the working parts to be automatically installed in the position specified by the program. The cutting tool on CNC drilling machines is fixed directly in the conical hole of the spindle or using intermediate bushings and mandrels.

A general view of a vertical drilling machine model 2Р135Ф2 - 1, equipped with CNC, is shown in Figure 17. On the base of machine 1, a column 10 is mounted, along the rectangular vertical guides of which a support 4 moves, carrying a turret head 3. On the column 10, gearboxes 5 and a feed reducer are mounted 6. Slide 2 of the cross table moves along the horizontal guides of the base 1, and the upper part 11 of the table moves along the guides of the slide. On the right side of the machine there is a cabinet 8 with electrical equipment and a CNC 9. The machine has a pendant control panel 7.

Figure 17 – Vertical drilling machine model 2Р135Ф2:

1-base; 2-sled; 3-turret head; 4- caliper; 5-speed box; 6-feed reducer; 7-pendant control; 8- cabinet with electrical equipment; 9-UCHPU; 10-column; 11-top of the table.

Control questions:

What is the fundamental difference between vertical drilling machines with CNC and without CNC?

What CNC systems are equipped with vertical drilling machines?

CNC grinding machines

The CNC system is equipped with surface grinding, cylindrical and centerless grinding and other machines. When creating CNC grinding machines, technical difficulties arise, which are explained by the following reasons. The grinding process is characterized, on the one hand, by the need to obtain high precision and surface quality with minimal dispersion of sizes, on the other hand, by a feature consisting in the rapid loss of dimensional accuracy of the grinding wheel due to its intensive wear during operation. In this case, the machine requires automatic compensation mechanisms for grinding wheel wear. The CNC must compensate for deformations of the LED system, temperature errors, differences in allowances on workpieces, machine errors when moving along coordinates, etc. Measuring systems must have a resolution that provides tight tolerances for positioning accuracy. For example, in cylindrical grinding machines, such devices provide continuous measurement of the diameter of the workpiece during processing with a relative error of no more than 2 × 10 -5 mm. The longitudinal movements of the table are controlled with an error of no more than 0.1 mm.

For grinding machines, CNC-type systems with control over three to four coordinates are used, but in machines operating several circles, control over five, six or even eight coordinates is possible. The relationship between the operator and the CNC system of the grinding machine is in most cases carried out interactively using the display. The control system uses built-in diagnostic systems to increase machine reliability.

The most common are CNC cylindrical grinding machines, which give maximum effect when processing multi-stage parts such as spindles, electric motor shafts, gearboxes, turbines, etc. from one installation. Productivity increases mainly as a result of reduced auxiliary time for installing workpieces and removing the finished part, for reinstallation for processing the next shaft journal, for measuring, etc. When processing multi-stage shafts on a CNC cylindrical grinding machine, a time saving of 1.5 is achieved – 2 times compared to manual control.

Centerless cylindrical grinding machines are effectively used when processing parts of small and large diameters without length restrictions, or thin-walled parts, as well as parts with complex external profiles (piston, fist, etc.). In conditions of mass production, these machines are characterized by high productivity and processing accuracy. In small-scale and individual production, the use of such machines is limited by the complexity of readjustment. The expansion of the areas of application of centerless cylindrical grinding machines is hampered by two factors: the large amount of time spent on dressing wheels and the complexity of setting up machines, which requires a significant investment of time and highly qualified personnel. This is explained by the fact that the design of the machines uses grinding and driving wheels; dressing devices that provide the appropriate shape to the surfaces of the grinding and driving wheels; possibility of setting the position of the support knife; mechanisms for compensating feeds of the grinding wheel to the workpiece and to dressing, as well as the drive wheel to the workpiece and to dressing; setting the position of the loading and unloading device.

The use of CNC control made it possible to control the multi-axis operation of centerless cylindrical grinding machines. The control system of machine tools uses software modules that calculate the trajectories of the tool (wheel, diamond), and its correction of interaction with a person. To process parts with various geometric shapes (cone, ball, etc.), software6 is created for a mode manager, an interpolator and a drive control module.

When processing and editing, the number of combined controlled coordinates can reach up to 19, including two or three coordinates separately for editing the grinding and driving wheels.

In conditions of mass production, the use of CNC provides a flexible construction of the grinding and straightening cycle, which allows you to quickly reconfigure machines for processing other products.

The presence of a multi-coordinate CNC system provides greater versatility of the machine, small amounts of wheel feed, which allows you to effectively control the grinding and dressing process.

The control system of centerless cylindrical grinding machines is built according to the aggregate principle (for example, on machines from Japanese companies). On the machine it is possible to install any of four options for controlling the machine from the CNC:

one controlled coordinate – transverse feed of the grinding wheel;

two controlled coordinates - transverse feed of the grinding wheel and the dressing diamond in order to synchronize them;

three controlled coordinates - transverse feed of the grinding wheel, as well as transverse and longitudinal feed of the diamond when dressing it;

five controlled coordinates - transverse feed of the grinding wheel, as well as transverse and longitudinal feed of diamonds when dressing the grinding and driving wheels.

The use of CNC control to control centerless cylindrical grinding machines makes it possible to significantly simplify the design of a number of mechanical components: dressing devices (as a result of the abandonment of carbon rulers, diamond feed mechanisms, etc.), drives for the longitudinal movement of dressing devices, fine feed mechanisms for grinding and driving wheels , control and control devices, etc.

Control questions:

What are the technical challenges of creating CNC grinding machines?

What CNC systems are equipped with grinding machines?

CNC Multi-Tasking Machines

By equipping multi-tasking machines (MS) with CNC devices and automatic tool changing, auxiliary time during processing is significantly reduced and changeover mobility is increased. Reducing auxiliary time is achieved through automatic installation of the tool (workpiece) according to coordinates, execution of all elements of the cycle, tool change, turning and changing of the workpiece, changing cutting modes, performing control operations, as well as high speeds of auxiliary movements.

According to their purpose, MSs are divided into two groups: for processing blanks of body and flat parts, and for processing blanks of parts such as bodies of rotation. In the first case, MS drilling-milling-boring groups are used for processing, and in the second - turning and grinding groups. Let's consider the MS of the first group, as the most frequently used.

MS have the following characteristic features: the presence of a tool store, which provides equipment with a large number of cutting tools for a high concentration of operations (roughing, semi-finishing and finishing), including turning, boring, milling, drilling, countersinking, reaming, threading, processing quality control and etc.; high accuracy of finishing operations (6…7th qualifications).

The MS control system is characterized by an alarm system, digital indication of the position of machine components, various shapes adaptive control. MS are basically single-spindle machines with turret and spindle heads.

Multi-purpose machines (machining centers) for processing blanks of body parts. MS for processing blanks of body parts are divided into horizontal and vertical machines (Figure 18).

Horizontal MS mod. IR-500MF4, designed for processing body parts. This machine has a spindle head 4 that moves along the vertical guides of the rack 7. The tool magazine 6 is fixedly mounted on the rack 7; the tool is installed in the spindle 3 by the auto operator 5 in the upper position of the spindle head. The workpiece is placed on table 1, moving along the X coordinate. At the right end of the frame there is a rotating platform 8, on which two satellite tables with workpieces are installed.

Figure 18 – Multi-purpose machine (machining center) mod. IR-500MF4:

1-rotary table; 2-device; 3-spindle; 4-spindle headstock; 5-automatic operator; 6-tool magazine; 7-movable stand; 8-turn platform; 9-satellite table; 10-guides; 11-UCHPU; 12-cabinet with electrical equipment.

Processing workpieces on MS has a number of features compared to their processing on milling, drilling and other CNC machines. Installation and fastening of the workpiece must ensure its processing from all sides in one installation (free access of tools to the surfaces being processed), since only in this case is multilateral processing possible without reinstallation.

Processing on MS does not, as a rule, require special equipment, since the workpiece is secured using stops and clamps. MS are equipped with a tool magazine, placed on the spindle head, next to the machine or in another place. To mill planes, small-diameter cutters are used and processing is carried out in stitches. Cantilever tools used for processing shallow holes have increased rigidity and, therefore, provide the specified processing accuracy. Holes lying on the same axis, but located in parallel workpiece machines, are bored on both sides, turning the table with the workpiece for this purpose. If the blanks of body parts have groups of identical surfaces and holes, then to simplify the development of the technological process and program for their production, as well as to increase processing productivity (as a result of reducing auxiliary time), constant cycles of the most frequently repeated movements (drilling, milling) are introduced into the memory of the CNC machine ). In this case, only the processing cycle of the first hole (surface) is programmed, and for the rest, only the coordinates (X and Y) of their location are specified.

As an example, Figure 19 shows some canned cycles included in the software and used when processing on machine tools of the IR320PMF4 model.

Figure 19 – Constant processing cycles on a multi-tasking machine model IR320PMF4:

1-milling of the outer contour (with circular interpolation), 2-deep drilling with drill exit for chip removal; 3-boring stepped holes; 4-reverse counterbore using spindle orientation; 5-boring a hole Ø 125 mm using a special mandrel; 6-milling along the contour of the internal ends; 7-column by contour milling (with circular interpolation); 8-drilling a hole Ø 30 mm; 9-thread cutting (up to M16); 10-milling of internal grooves with a disk cutter (with circular interpolation); 11-collar holes; 12-end milling with a cutter; 13-processing of surfaces such as bodies of rotation.

The device for automatically changing the device - satellite (FS) on the machine model IR500MF4 is shown in Figure 20. PS 11 is installed on platform 7 (capacity of two PS), on which hydraulic cylinders 10 and 13 are mounted. The hydraulic cylinder rods have T-shaped grips 14 and 6. When installed on the platform (moving in the direction of arrow B), the PS with cutout 12 engages with the rod gripper 14. On the platform, the PS is based on rollers 9 and is centered (on the sides) by rollers 8 (the initial position of the PS is in the waiting position). The movement of the hydraulic cylinder rod 10 causes the satellite to roll (on rollers).

Figure 20 – Device for automatically changing a companion device:

1-base plate; 2-adjusting bolts; 3- gear wheel; 4-rail; 5, 13,16-hydraulic cylinders; 6, 14 - rod grip; 7-platform; 8.9-rollers; 10, - hydraulic cylinder rod; 11-satellite device; 12-figure cutout; 15-piece stand.

When the rod of the hydraulic cylinder 13 moves, the gripper 6 moves (along the guide rod) and rolls the PS along rollers 9 and 8 (in the direction of arrow A) onto the rotary table of the machine, where the satellite is automatically lowered onto the clamps. As a result, the gripper 6 disengages from the PS and the machine table (with the satellite attached to it) moves at high speed into the processing zone.

The workpiece is fixed on the satellite during processing of the previous workpiece (when the machine is in the waiting position) or in advance, outside the machine.

After the workpiece has been processed, the machine table automatically (at high speed) moves to the right to the device for changing the satellite and stops in a position in which the shaped groove of the PS is under grip 6. The hydraulic cylinder of the turntable unlocks the satellite, after which the PS enters engagement with gripper 6, and the oil enters the rod cavity of the hydraulic cylinder 13, the rod moves to the extreme right position and the satellite moves from the workpiece to platform 7, where the PS with the new workpiece is already located. To change places of the satellite, the platform is rotated 180° (on machine 15) by a gear wheel 3 mated to a rack 4 driven by hydraulic cylinders 5 and 16.

Platform 7 is accurately aligned relative to the rotary table of the machine using adjusting screws 2 and 7, screwed into the protrusions of the base plate 1, fixedly fixed to the foundation.

Control questions:

How do multi-purpose CNC machines differ from turning, milling, drilling and other CNC machines?

Tell us about the main components of a multi-purpose machine for processing blanks of body parts.

CNC processing

The author of the most famous automatic weft changing device, James Northrop, was born on May 8, 1857 in the English city of Keighley. After receiving a technical education, he worked for some time as a mechanic, after which he moved to the USA to the city of Hopedale, where he began working for the Draper company, which produced textile equipment. The invention of a thread guide for a winding machine attracted the attention of the owners of the company, and he was selected to develop ideas for an automatic knotter for winding machines. The developed device was interesting, but impractical, and the disappointed inventor left his job at the company and became a farmer.

On July 26, 1888, William Draper Jr. heard about a shuttle-changing machine invented in Providence. After examining the machine and talking with the inventor Alonzo Rhodes, he found it imperfect. The company carried out a thorough patent study on the idea of ​​automatic weft feeding of looms, and although there was nothing fundamentally new in this device, it was decided to invest 10 thousand dollars in the experiments. On December 10 of the same year, this amount was transferred to the inventor to improve the design of the shuttle changing mechanism. 28th of February next year the machine was ready for work. Over the next few months, some further minor improvements were made to the machine, without changing its basic principles, after which the machine was put into operation and worked well. This can be confirmed by the fact that 12 years later, during one patent litigation, the machine was started up again and worked for several hours, causing the approval of the expert.

Rhodes' device was noticed by Northrop, who returned to work at the company, and told management that in a week he could present a similar mechanism costing no more than a dollar if he was given the opportunity. Northrop received this opportunity and on March 5 demonstrated a wooden model of his device. The Drapers liked both the model and Northrop’s efficiency, and from April 8 all conditions for work were created for him. By May 20, the inventor was convinced of the impracticality of his first idea, but a new one had already matured, and he asked for time until July 4 to create a second design. Northrop managed to meet the deadline, and on July 5 his machine started working, showing top scores than the Rhodes machine. On October 24, the Northrop machine with new improvements was put into operation at the Sikonnet factory in Fall River. By April 1890, several machines of this type were operating at the Syconnet factory. However, Northrop himself came to the conclusion that this direction was futile and decided to create a mechanism for changing bobbins.

A kind of creative group was organized, the main participants of which were Charles Roper, who developed the automatic warp feed mechanism, Edward Stimpson, the author of the shuttle with a self-winding machine, Northrop himself, as well as William and George Draper. As a result, a mechanism for changing spools, a main regulator, a main observer, a feeler, a dial mechanism, and a spring device for rolling goods were created. Northrop received a patent for his device in November 1894. Northrop's machine was completed in its final form in 1895 and in the same year received universal recognition at the Trade and Industrial Exhibition in London. By the beginning of the 20th century, the company had already produced about 60 thousand automatic machines, mainly for the American market. In 1896, a large group of machines was delivered to Russia for the first time. The thoroughness of the design of the new machine is evidenced by the fact that from July 1, 1888 to July 1, 1905, 711 patents were used, of which 86 belonged to Northrop.

An attempt to equip mechanical machines with the Northrop mechanism failed. This explains the rapid spread of automatic machines in countries with rapidly developing textile industry, in particular in the USA, and relatively slow in countries with a traditionally developed textile industry. In 1902, the British company Northrop was founded, and in the fall of the same year, factories in France and Switzerland began producing automatic looms of this type.

Assessing the significance of Northrop’s invention, the famous Russian weaving specialist Ch. Ioximovich wrote that “the creation of the Northrop machine outlined new paths for inventors from which they will not soon leave. The Northrop machine leaves a unique mark on the work of modern mechanical engineering in the weaving industry. You can think whatever you want about this machine, you can deny its significance as a machine of the future - it still stands at the head of the modern design of weaving machines, and there is no doubt that further development in this area will proceed from the main principles that guided the inventor this machine."

Northrop's failure to equip mechanical machine tools from different companies with his device that were already installed in production did not bother other inventors. The urgency of the task at hand has caused a huge number of inventions in this area. The most famous instruments were those of Whittaker, Gabler and Valentin, created at the beginning of the 20th century.

machine, m.

1. A machine for processing smb. materials (metal, wood, etc.) or for manufacturing, production of something. of them.

Lathe. Milling machine. Printing press. Loom. Numerically controlled machine. Machine performance. Machine repair. Switch the machine to automatic mode. Stand at the machine

theoretical machine performance

Cm. .

2. Device, device for smb. works

Arc bending machine. Gold washing machine.

cartoon machine

Cm. .

3. Shaving device with safety razor.

Disposable machine. Floating blade machine. Shave with a machine. Change the cassette on the machine.

4. Military The base on which the weapon is mounted, a machine gun.

Anti-aircraft gun machine. To protect the combat crew from bullets and shrapnel, a shield is installed on the upper machine.

5. Claim. A wooden tripod with a rotating round or square board-stand for strengthening the canvas, installing a frame, sculptural material (when working on a painting, sculpture).

Remove the painting from the machine. Unfinished sculptures stood on the machines.

6. Special Support device for some training activities.

A ballerina practices at the barre. Sighting machine for shooting training.

7. Theater Part of a set that serves to create various elevations, platforms, etc. on the stage.

Theater mobile machines with adjustable height. Maximum installation height of the machine.

8. Agro. A device in which an animal is placed (for shoeing, treatment, etc.).

Shoe a horse in a machine. Machine milking of cows is carried out in machines.

9. Agro. A separate fenced-off room for an animal in a stable, barn, etc.; stall.

Calf pen. Pen for a pig with piglets.

home » Earn money online » The significance of the invention of the automatic machine. Spinning machine. History of invention and production. Successes and failures of Joseph Jacquard