Monthly Archive October 10, 2020

Processing center: Hong Kong, Taiwan, Guangdong area known as the computer gong, is a highly automated multi-functional CNC machine tool with tool magazine and automatic tool change device. The first machining center appeared in the United States in 1958. High speed computer gong machining can realize the centralized processing of milling, drilling, boring, reaming, tapping and other processes after the workpiece is clamped once, with special emphasis on “milling”.

Engraving machine: its spindle speed is high, suitable for small cutting tools processing, torque is relatively small, focusing on the “carving” function, such as wood (wood carving machine for special processing of wood), dual color board, acrylic plate and other plates with low hardness, which are not suitable for large workpieces with strong cutting. Most of the products on the market with the banner of engraving machine are mainly for processing handicrafts with low cost. Due to the low precision, they are not suitable for mold development. However, there are also exceptions, such as wafer engraving machine.

Carving and milling machine: as the name implies. It can be carved or milled. On the basis of the engraving machine, the power of the spindle and servo motor is increased, and the bearing force of the lathe bed is maintained. At the same time, the high speed of the spindle is maintained. More importantly, the precision is very high. Engraving and milling machine also to high-speed development, commonly known as high-speed machine, cutting ability is stronger, processing accuracy is very high, but also can directly process hardness above HRC60 materials, one-time molding.

The highest spindle speed (R / min): Machining Center 8000; engraving and milling machine is the most common 240000, high-speed machine is the lowest 30000; engraving machine is generally the same as engraving and milling machine, the engraving machine used for high gloss processing can reach 80000, but the air bearing spindle is not used.

Spindle power: the machining center is the largest, ranging from several thousand watts to tens of kilowatts; carving and milling machines are the second, generally within ten kilowatts; engraving machines are the smallest.

Cutting capacity: high speed computer gong machining center is the largest, especially suitable for heavy cutting and rough cutting; engraving and milling machine is the second, suitable for finishing; engraving machine is the smallest.

Speed: because engraving and milling machines and engraving machines are light and light, their moving speed and feed speed are faster than the machining center, especially for high-speed machines equipped with linear motor, the maximum moving speed is 120m / min

Accuracy: the accuracy of the three is similar.

From the processing size: the worktable area can better reflect this. The smallest worktable area (unit mm, the same below) of domestic machining center (computer gong) is 830 * 500 (850 machines); the largest worktable area of engraving and milling machines is 700 * 620 (750 machines), and the smallest is 450 * 450 (400 machines); engraving machines generally do not exceed 450 * 450, and the common ones are 45 * 270 (250 machines).

In terms of application objects: the machining center is used to complete the processing equipment of large milling amount of workpieces, large molds and materials with hardness comparison, which are also suitable for the opening of common molds; the engraving and milling machine is used to finish the finishing of small molds with small milling amount, which is suitable for copper and graphite processing; the low-end engraving machines are inclined to those with low hardness such as wood, double color board and acrylic plate Plate processing, high-end suitable for wafer, metal shell polishing and polishing.

Generally speaking, machining center and engraving and milling machine can do both products and molds, while engraving machine can only do products.

Tool magazine: Machining Center, where there is a tool library, is a machining center; if there is no tool library, it is called computer gong or CNC milling; generally, engraving and milling machines do not have a tool library, even if the tool magazine is selected, it is umbrella type tool library with 12 knives or in-line tool library with 6 knives; carving has no tool library.

In foreign countries, there is no term for CNC Engineering and milling machine. Strictly speaking, carving is a part of milling, so there is only the concept of machining center in foreign countries, and the concept of small machining center is derived to replace engraving and milling machine. Purchase engraving machine or CNC milling machining center is often asked their own questions, to see the actual production needs. In addition, there is a popular high-speed cutting machine (hscmachine), which is called high-speed machine in China.

2、 Analysis from the angle of numerical control

1. — the CNC milling center requires a general speed for the CNC system, and the spindle speed is about 0 ~ 8000 rpm
2. – engraving and milling machine requires high-speed CNC system, high-speed computer gong processing spindle speed of 3000 ~ 30000 rpm
3. High speed cutting machine requires high-speed CNC system and excellent servo motor characteristics, spindle speed of 1500 ~ 30000 rpm

The highest spindle speed (R / min): Machining Center 8000; engraving and milling machine is the most common 24000, high-speed machine is the lowest 30000; engraving machine is generally the same as engraving and milling machine, engraving machine used for high gloss processing can reach 80000, but it uses air bearing spindle instead of ordinary motorized spindle.

Spindle power: the machining center is the largest, ranging from several thousand watts to tens of kilowatts; carving and milling machines are the second, generally within ten kilowatts; engraving machines are the smallest.

Cutting amount: machining center is the largest, especially suitable for heavy cutting and rough cutting; engraving and milling machine is the second, suitable for finishing; engraving machine is the smallest.

Speed: because engraving and milling machines and engraving machines are light and light, their moving speed and feed speed are faster than the machining center, especially for high-speed machines equipped with linear motor, the maximum moving speed is 120m / min

Accuracy: the accuracy of the three is similar.

From the processing size: the worktable area can better reflect this. The smallest worktable area (unit mm, the same below) of domestic machining center (computer gong) is 830 * 500 (850 machines); the largest worktable area of engraving and milling machines is 700 * 620 (750 machines), and the smallest is 450 * 450 (400 machines); engraving machines generally do not exceed 450 * 450, and the common ones are 45 * 270 (250 machines).

From the application object: the machining center is used to complete the processing equipment of large milling amount of workpieces

Fast wire in the professional terminology is called: mechanical parts processing high-speed reciprocating wire EDM wire cutting machine

Slow wire is called low speed unidirectional WEDM in professional terms

The wire speed of reciprocating WEDM is 6-12 m / s. The biggest characteristic of the product is that it has 1.5 degree taper cutting function, and the processing thickness can be more than 1000 mm. It is used in all kinds of medium and low-grade mold manufacturing and special parts processing, and has become one of the most widely used machine types in China’s CNC machine tools. However, due to the fact that the reciprocating WEDM machine can not implement constant tension control on the electrode wire, and the computer gong processing, the electrode wire jitters greatly and is easy to break in the process of processing. Because the electric grade wire is used repeatedly, it will cause electrode wire loss, machining accuracy and surface quality reduction.

The electrode wire of low-speed WEDM uses copper wire as tool electrode and generally moves unidirectionally at the speed of less than 0.2m/s. A pulse voltage of 60-300v is applied between the copper wire and the processed materials such as copper, steel or superhard alloy, and a gap of 5-50um is maintained. The gap is filled with insulating medium such as deionized water (close to distilled water), which causes spark discharge between the electrode and the workpiece This is consumed and corroded, and numerous small pits are etched on the surface of the workpiece. Through the monitoring and control of NC control and the execution of servo mechanism, the discharge phenomenon is uniform and consistent during the machining of mechanical parts, so that the processed products can be processed into products with the required size and shape accuracy. At present, the accuracy is up to 0.001mm, and the surface quality is close to the grinding level. The electrode wire is no longer used after discharge, and no resistance anti electrolysis power supply is adopted. Generally, it is equipped with automatic threading and constant tension device. It has the advantages of stable, uniform, small jitter, high machining accuracy and good surface quality, but it is not suitable to process large thickness workpieces. Due to the precise structure of the machine tool, high technology content, high price of the machine tool, the use cost is also high.

It can form plastic parts with deep holes and complex shapes.

Under heat and pressure, the plastic can be heated quickly and evenly through the mold pouring system to ensure short hardening time.

The dimensional accuracy of plastic parts is easy to ensure and the flash of parting surface is thin. It is difficult to extrude plastics with fluidity less than 80mm. The forming pressure is higher than that of the glue pressing method. The consumption of plastic must be increased (pouring part).

3) Injection method: the granular or powdered plastic is heated and melted into the flowing state in the barrel of the injection machine, and then the whole cavity is filled with a narrow nozzle and the pouring system of the mold with a very high pressure and poor speed. After a certain period of setting, the mold is opened, and the plastic parts can be taken out from the mold. The characteristics of injection molding are as follows

The forming cycle is short and easy to realize. The dimensional accuracy of plastic parts is easy to guarantee.

The mold is usually designed to be fixed. When there are many metal inserts in the plastic parts, the installation of the inserts is more difficult. 4.3.2 classification of plastic mould according to forming mode

It can be divided into: thermosetting plastic pressing mold, thermosetting plastic extruding mold, thermosetting plastic injection mold and thermoplastic injection mold.

According to the form of material cavity, thermosetting plastic pressing mold can be divided into: (a) open type pressing mold, that is, the cavity is the feeding cavity; (b) the semi closed pressing mold, that is, the cross section of the feeding cavity; and (3) the shape of the cavity;

(c) The feeding cavity is the continuous part of the cavity, and the forming pressure is completely transmitted to the pressed plastic parts through the upper die.

According to the structure form, it can be divided into: (a) movable pressing die, (b) fixed pressing die. 5. Factors affecting the quality of EDM

There are many factors affecting the processing quality, which are related to the selection of electrode materials, electrode manufacturing, electrode clamping and alignment, the selection of machining standards and the appropriateness of operation process. To prevent waste products, the following points should be paid attention to. 5.1 correct selection of electrode materials

In cavity machining, graphite is a common electrode material. However, due to the variety of graphite, not all graphite materials can be used as electrode materials for EDM. Special graphite with high strength, high density and high purity should be used. Dongguan high speed computer gong processing copper electrode is often used in precision. One is: the discharge end of EDM, which is used to process cavities, lettering, etc., and is usually made into the required shape. The material is graphite, copper or aluminum (rare) CNC machining center. The other is: the discharge end of WEDM is made of molybdenum wire. Its principle is to apply high-frequency and high-voltage to the discharge end through the electric control part. When the electrode (molybdenum wire) contacts with the grounding end (workpiece), it will form high-frequency ignition and generate high temperature, which will quickly dissolve the workpiece surface (a very small gap) in contact with molybdenum wire, which is called wire cutting.

The so-called multi electrode machining refers to the parts to be processed with high precision, and the discharge parts should be discharged twice or more. In the early stage, it is rough discharge machining with larger translation, and the later is fine discharge machining with small translation

Fault analysis is the first step in the maintenance of computer gong processing machine tool. Through fault analysis, on the one hand, it can quickly find out the cause of the fault and eliminate the fault; at the same time, it can also play a role in preventing the occurrence and expansion of the fault. Generally speaking, the main methods for fault analysis of computer gong processing machine tools are as follows:

1. Conventional analysis method conventional analysis method is a method of routine inspection on mechanical, electrical, hydraulic and other parts of mechanical parts processing machine tool, so as to determine the cause of failure. On machine tools, conventional analytical methods usually include the following contents:

1) Check whether the specifications of the power supply (including voltage, frequency, phase sequence, capacity, etc.) meet the requirements; 2) check whether the connection of CNC servo drive, spindle drive, motor and input / output signal is correct and reliable; 3) check whether the printed circuit board in the CNC servo drive device is firmly installed and whether the plug-in position is loose; 4) check the CNC servo drive, spindle drive and other parts 5) check whether the oil pressure and air pressure of the hydraulic, pneumatic and lubricating parts meet the requirements of the machine tool; 6) check whether the electrical components and mechanical parts are obviously damaged

1. The action analysis method is a method to determine the bad action position by observing and monitoring the actual action of the machine tool and trace the root cause of the fault. Generally speaking, the hydraulic and pneumatic control parts of the computer gongs processing machine tool, such as automatic tool changing device, worktable exchange device, fixture and transmission device, can be used to determine the cause of the fault through action diagnosis.
2. State analysis method state analysis method is a method to determine the cause of failure by monitoring the working state of the actuator. This method is most widely used in the maintenance process of computer gongs processing machine tools. In modern CNC system, the main parameters of servo feed system, spindle drive system and power module can be tested dynamically and statically. These parameters include: input / output voltage, input / output current, given / actual speed, position, actual load condition, etc. In addition, the status of all input / output signals of CNC system, including internal relays and timers, can also be checked by the diagnostic parameters of the CNC system. Through the state analysis method, the cause of failure can be quickly found out according to the internal state of the system without instruments and equipment. It is widely used in the maintenance of computer gongs, and the maintenance personnel must be skilled Master.
3. Operation, programming analysis method operation, mechanical parts processing programming analysis method is a method to confirm the cause of failure through some special operations or compiling special test program segments. For example, through manual single step to execute automatic tool change, automatic table exchange action, execute single function processing instructions and other methods to detect the action and function. By this method, the cause and components of the fault can be determined and the correctness of the program can be checked.
4. Self diagnosis of CNC system is a self diagnosis and testing method for the key hardware and control software of the system by using the internal self diagnosis program or special diagnosis software. It mainly includes boot self diagnosis, online monitoring and offline testing.
5. Using precision level instrument and other detection tools, mainly by adjusting the pad iron way to fine adjust the level of the main bed of the computer gong processing machine tool, so that the geometric accuracy of the machine tool can reach the allowable tolerance range;
6. For the automatic tool change device, adjust the position of the tool magazine, manipulator, travel parameters, etc., and then check the action with the command, which is required to be accurate;
7. For the machine tool with APC automatic exchange table, after adjusting the relative position, carry out automatic load exchange;
8. After the adjustment of the machine tool, carefully check whether the parameter setting values in the numerical control system and the programmable controller conform to the data specified in the random index, and then test the main operation functions, safety measures, execution of common instructions, etc.

Computer gong processing is a kind of artificial intelligence, which is controlled by computer to complete complex processing. The most complex part of the computer gong lies in the control system. In the high-speed computer gong processing, the computer sends various instructions to control the three-axis servo motors of the machine table to cooperate with each other according to the established route, so as to process various complex processes and ensure high processing accuracy. Today, we will talk about the matters needing attention when starting the main computer gong processing:

1. When the computer gong machining machine tool is started or reset by pressing the emergency stop, it first returns to the reference zero position of the machine tool, so that the machine tool has a reference position for its later operation.
2. Clamping workpiece:
3. Before the workpiece is clamped, the surface should be cleaned, and there should be no oil stain, iron filings and dust during machining of mechanical parts, and the burr on the surface of the workpiece should be removed with a file (or oilstone).
4. The equal high-speed rail used for clamping must be grinded flat by grinding machine to make it smooth and flat. The weight iron and nut must be firm, which can reliably clamp the workpiece. For some small workpieces that are difficult to be clamped, they can be directly clamped on the vise.
5. The worktable of the machine tool shall be clean and free of iron filings, dust and oil stains.
6. Pad iron is generally placed at the four corners of the workpiece, and equal height pad iron should be added in the middle of the workpiece with too large span.
7. According to the size of the drawing, use a ruler to check whether the length, width and height of the workpiece are qualified.
8. When clamping the workpiece, according to the clamping and placing mode of the programming operation instruction, it is necessary to consider avoiding the processing position and the situation that the cutter head may encounter the fixture during the processing.
9. After the precision computer gong processing workpiece is placed on the pad iron, it is necessary to pull the table on the workpiece reference plane according to the drawing requirements. The workpiece length direction error is less than 0.02mm, and the top surface x, Y direction horizontal error is less than 0.05mm. The perpendicularity of the workpiece which has been ground on six sides shall be checked to see if it is qualified.
10. After pulling the watch, the nut must be tightened to prevent the workpiece from shifting in the process due to the loose clamping.
11. Pull the meter again to make sure that the error is not out of tolerance after clamping.
12. Workpiece collision number: for the clamped workpiece, the collision number can be used to determine the processing reference zero position. There are two kinds of collision head: photoelectric type and mechanical type. The collision selection method can be divided into middle collision number and single side collision number. The steps of dividing the collision number are as follows:
13. Collision method: photoelectric static, mechanical speed 450-600 rpm.
14. Manually move the x-axis of the worktable to make the colliding head touch one side of the workpiece. When the bumping head just touches the workpiece and the red light is on, the relative coordinate value of this point is set as zero; after high-speed computer gong processing, manually move the x-axis of the workbench to make the collision head touch the other side of the workpiece. When the collision head just touches the workpiece, record the relative coordinates at this time.
15. According to the relative value minus the diameter of the bumping head (i.e. the length of the workpiece), check whether the length of the workpiece meets the requirements of the drawing.
16. Divide the relative coordinate number by 2, and the value is the middle value of the x-axis of the workpiece. Then move the table to the middle value on the x-axis. Set the relative coordinate value of the x-axis at this point to zero, which is the zero position on the x-axis of the workpiece. With the rapid development of modern machine manufacturing industry, the requirements for machine parts are increasing. Some important parts must work under the conditions of high speed, high temperature, high pressure and heavy load. Any defect in the surface layer not only directly affects the working performance of the parts, but also causes accelerated wear, corrosion and failure of the parts. Therefore, attention must be paid to the surface quality problems.

The machining quality of machine parts, in addition to the machining accuracy, also has the machined surface quality, which is the characterization of the integrity of the surface layer after machining.

The deviation of the actual geometric parameters from the ideal geometric parameters is called machining error. The level of machining accuracy is measured by the size of machining error. If the error is large, the precision will be low, otherwise it will be high.

Machining accuracy includes three aspects: dimensional accuracy, shape accuracy and position accuracy.

① The degree to which the actual shape of the machined part surface is consistent with the ideal part surface shape. The ideal surface shape of parts refers to the absolutely accurate surface geometry.

② Dimensional accuracy the degree of correspondence between the actual size of the machined part surface itself or between the surfaces and the ideal part size. The ideal part size refers to the middle value of the dimension marked on the part.

④ The degree of correspondence between the actual position of each surface of the part and the position between the ideal parts after position precision machining. The position between the surfaces of an ideal part refers to the absolutely accurate position between the surfaces.

Computer gongs processing aluminum alloy surface treatment what

(1) Geometrical characteristics of surfaces

① Surface roughness surface roughness refers to the micro geometric error of the machined surface. The surface roughness of high-speed computer gong machining is usually formed by the moving track of cutting tool in machining, and the ratio of wavelength to wave height is generally less than 50.

② Surface waviness surface transit is a periodic geometric error between macro geometric error (△ *) and micro geometry error (i.e. roughness).

Although the gear industry is developing rapidly and there are more and more types, such as reducer spiral bevel gear, spiral bevel gear and so on, there are not many manufacturers specializing in gear mold, most of which are made by gear factory themselves, especially plastic gear in gear industry.

In terms of plastic gears, generally speaking, plastic gears and their molds are mainly distributed in two regions: Ningbo, Zhejiang Province, where there are more than 340 plastic gear factories, which is also the largest plastic gear mold production base in China; the other is Shenzhen Bao’an, which is dominated by Hong Kong funded enterprises with high product precision, which is mainly used for export. Among them, the demand for plastic gear mold is relatively large.

Throughout the current situation of gear mould in China, it can be said that there are mixed feelings. Computer gongs processing is pleased that gear mold production has a certain foundation, and the development trend of plastic gear will bring greater market space for gear mold; The worry is that there is still a gap between the level of domestic gear mould production and that of the world’s predecessors. Moreover, with the development trend of the gear industry, especially the plastic gear industry, the domestic response to market changes is not sharp enough, and the supporting research is difficult to keep up with the market demand. At present, medium and low-grade gear molds can be produced at home, and high-grade gear molds are mostly imported. The application scope of high-speed computer gongs for machining domestic gears can be roughly divided into three aspects: plastic gear mold, powder metallurgy gear mold and precision forging bevel gear mold.

It can be seen that there is still a large space for the development of China’s gear industry. Our company specializes in the production of spiral bevel gears and other products. The advanced equipment and technology ensure the quality of the products, which has been recognized by customers. Plastic gear has the advantages of low transmission noise, vibration absorption, self lubrication, high efficiency of mold processing. In recent years, the application of plastic gear in gear industry will be more and more, which will become a worldwide trend.

Domestic precision gear mould needs to keep pace with the development of world gear mould

However, at present, the middle and low-grade gear mould can be produced in China, and the high-grade gear mould mostly depends on import. There are not many factories specialized in gear mould in China, most of them are made by gear factories themselves. In the application range of gear mold, the demand of plastic gear mold is relatively large, and the market potential is huge.

Relevant experts in the industry put forward three strategies for future development

First, speed up the adjustment of industrial structure; in the future development, the gear mold industry should pay more attention to the strategic adjustment of its product structure, so as to make the high-end die with complex structure and high precision develop faster. At the same time, the mold industry should also closely follow the market demand to develop. Without product demand and product upgrading, there will be no technological progress in the mold industry, and there will be no scale and grade of mold products. The level of mold technology determines the quality, efficiency and development ability of new products to a great extent.

At present, there is neither national standard nor ready-made industrial standard for gear mold processing, especially in plastic gear mold. The technical standard is a kind of open standard, but it is very difficult to make the product standard. It is necessary to consider the test standard, precision standard and test device standard of gear mould.

Third, strengthen the density of cooperation between industries; the development of modern industry is a relationship of mutual cooperation, which is equally important for the gear mold industry. This cooperation is first of all direct cooperation in industry research. For example, several universities are engaged in the research of gear mold, concentrating the strength of gear industry and some university research institutions, and doing integrated research and cooperation in the aspects of process equipment and internal deformation law of plastics.

At the same time, from the whole industry, the voice of gear mold is very small, and it is in a spontaneous state, and the establishment of relevant professional associations is to change this situation. This is to focus on discussing and solving the problems existing in the production of small module gear, so as to promote the development of domestic precision gear mold industry.

In the trend of gear industry, especially plastic gear industry, the domestic response to market changes is not sharp enough, supporting research is difficult to keep up with the market demand, and the domestic precision gear mold still needs to keep up with the development level of the world gear mold.

Shaft gear is the most important part in the gearbox, and its machining accuracy directly affects the overall quality of the gearbox. At present, the gear tooth processing method we adopt is hobbing shaving method. In order to produce high-precision gears by hobbing and shaving, the hobbing and shaving process must be brought into full play. The shaving accuracy depends on the saddle hobbing accuracy to a large extent, so some error items in hobbing must be strictly controlled to produce high-quality gears. Gear hobbing is a common gear processing method. On the hobbing machine with high precision, gear teeth of grade 4-5 can be machined with precision hob. On the ordinary gear hobbing machine, only 8-grade precision gear teeth can be machined with ordinary precision hob. The accuracy of gear tooth of transmission shaft is required to be 8-7-7, and the positioning datum is mainly based on two center holes and end faces during gear hobbing. Therefore, it is very important to analyze the error sources of hobbing and master the methods to ensure and improve the machining accuracy.

Analysis of hobbing accuracy

The accuracy of shaft teeth is mainly related to motion accuracy, stability accuracy and contact accuracy. Common control method in Hobbing

CNC machining simulation system can reduce or even completely eliminate the process of trial cutting and manual verification. Before the new NC machining program is actually processed, the programmer can use the NC machining simulation system to carry out virtual machining environment and processing process on the computer, and detect the possible problems in the program design.

In the process of NC machining, it is easy to appear over cutting, undercutting and other phenomena. At the same time, the damage of cutting tools, or the processing of waste products, the interference and collision between parts and tools, tools and fixtures, tools and worktables, will cause a certain cost waste. Computer gong processing and numerical control machining simulation system can well simulate the relevant program, reduce the loss to the greatest extent.

Before the actual machining, the programmer can confirm whether the finished cutting product is consistent with the original design drawing through the simulation system, and can make better detailed analysis.

collision detection

In the actual processing, five axis CNC machining has more advantages than three axis CNC machining, can achieve a wider range, has faster material and efficiency, can reduce processing time and improve surface accuracy. However, due to the high degree of freedom of the two additional rotating axes, it is easy to cause collision and damage to the machine tool.

Therefore, before the actual processing, it is necessary to detect the collision with the help of NC machining simulation system. The main detection algorithms are as follows:

The machine tool includes many parts, but the collision detection algorithm between different parts is similar. The simulation system takes the tool, workpiece and fixture as the main research object to detect the possible global collision.

1. According to the tool location, the grid voxel model of the tool head scanning body and the grid voxel model of the tool holder scanning body are solved respectively. The tool holder scanning body is used to detect whether there is a global collision between the tool, workpiece and fixture, and the tool head scanning body is used to calculate the intersection between the tool and the workpiece.
2. A feature attribute of voxel model is cuboid envelope box. The envelope box is used for rough judgment. If the envelope box does not intersect, the objects enclosed in the envelope box must not intersect. At this time, the position data information of the object envelope box is updated, and other information remains unchanged. Computer processing is used to prepare for the generation and collision detection of the next tool location scanner It can speed up the detection.
3. Once a collision occurs, the system stops reading data and reports the error message and the precise location of the collision.

CNC machining of milling machine is carried out according to the instruction given by digital style. Under normal environment, the labor process does not need manual interference, and the computer gong processing eliminates the man-made deviation of the dominator. When planning to manufacture CNC machine tools, many methods are adopted to make the machine parts of CNC machine tools reach higher accuracy and stiffness. The movement equivalent of CNC machine tool worktable is widely up to 0.01 ~ 0.0001 mm, and the reverse clearance of feed drive chain and screw pitch deviation can be compensated by CNC device. The high-grade CNC machine tool adopts the closed-loop control of working table movement with grating ruler. The machining accuracy of the computer gong machine tool has improved from ± 0.01 mm to ± 0.005 mm or even higher. The positioning accuracy has reached ± 0.002mm to ± 0.005mm in the early 1990s. In addition, the transmission system and layout of CNC machine tools have high stiffness and thermal stability. Computer gongs processing decision compensation skills, CNC machine tools can get higher precision than its own. In particular, it improves the generality of the production of unified batch parts, with high qualified rate and stable processing quality. The selection of milling cutter diameter depends on different products and production batches. The selection of cutter diameter mainly depends on the specification of equipment and the processing size of workpiece.

Plane milling cutter

When selecting the diameter of the plane milling cutter, the power required by the cutter should be within the power range of the machine tool, and the diameter of the spindle of the machine tool can also be used as the basis for selection. The diameter of plane milling cutter for computer gong processing can be selected as d = 1.5D (D is the diameter of the spindle). In mass production, the tool diameter can also be selected according to 1.6 times of the cutting width of the workpiece.

end mill

The selection of end mill diameter should mainly consider the requirements of workpiece processing size, and ensure that the power required by the cutter is within the rated power range of the machine tool. If it is a small diameter end mill, whether the highest speed of the machine tool can reach the minimum cutting speed (60m / min) should be mainly considered.

Slot milling cutter

The diameter and width of the groove milling cutter should be selected according to the size of the workpiece to be processed, and the cutting power should be within the allowable power range of the machine tool. Before using the CNC machine tool, you should carefully read the machine tool manual and other relevant information, so as to correctly operate and use the machine tool, and pay attention to the following points:

(1) The PLC program of the machine tool is designed by the machine tool manufacturer according to the needs of the machine tool and does not need to be modified. Incorrect modification may cause damage to the machine tool and even damage the operator;

(2) It is suggested that the machine tool can be operated continuously for up to 24 hours. If the continuous operation time is too long, the service life of the electrical system and some mechanical components will be affected, thus affecting the accuracy of the machine tool

(3) The operators and maintenance personnel of machine tools must be professionals who have mastered the corresponding professional knowledge of machine tools or have received technical training, and must operate the machine tools according to the safety operation rules and regulations