chengcg – Page 28 – CNC Machining & Turning, Milling, Metal parts

Mold maintenance mode

Management of mold field use

Dispatchers should go through relevant procedures according to the corresponding management system when collecting and returning the molds, and be responsible for the whole process of the molds from receiving to returning.
The die should be processed according to the stamping process and the corresponding tonnage of punch press. The mold should be adjusted and installed by the mold adjuster, and ensure that the leakage is smooth, the spring top is normal, the feeding is convenient, the stroke is reasonable, and the production can be started after the qualified sample is tested.
The punch operator shall strictly follow the operation procedures. If any abnormal phenomenon is found in the production process, it should be reported in time, and the production can be carried out after troubleshooting. In case of mold damage caused by barbaric operation, the responsible person shall fill in the mold accident liability sheet and give certain punishment.
In case of die waste fracture, guide plate guide deformation, die and punch damage caused by pressing and bending die stuffy, it is necessary to trace the responsibility of the adjuster.
The usage of the mould shall be clear during the shift handover of day shift and night shift. The successor shall be responsible for the accident after the handover.
After the completion of the production task, the dispatcher shall be informed in time to handle the warehouse return procedures. The production site should not keep the mold without production instructions or complete the batch task. If the mould is lost, the responsibility of the final receiver will be traced.

Purpose of mold maintenance system

Master the history of the mold 2. Maintain the mold in time after mold production 3. Improve the service life of the mold 4. Ensure the quality of the mold and smooth production

Mold maintenance mode mold maintenance is divided into four modes

Preventive inspection: take every 15 days as a cycle to check the mold status directly on the production machine, and record the results in the “mold preventive inspection record form”. This part of the inspection is in the charge of the mold group, assisted by the injection molding department.
General maintenance (A-level maintenance): it refers to the general maintenance items of the mold during the daily mold test and trial production, which are responsible and recorded by the production department.
Regular quantitative maintenance (B-level maintenance): when the mold has not been used for more than one year or has accumulated more than 50000 beer each time, detailed inspection shall be carried out, and the inspection results shall be recorded in the “mold maintenance inspection record form”. The production department is responsible for and records.
Mold maintenance (C-level maintenance): when the injection molding material has serious appearance problems or the mold is damaged, the parts need to be replaced or repaired.

The motor does not run;

Switching power supply (± 15V) transformer TL and power switch tube v69 are abnormally hot.

This is a typical case of syndrome, and there may be some causal relationship between the faults, so we need to deal with the faults in sequence, otherwise we may get twice the result with half the effort, or even cause the fault area to expand. Through the analysis, we make the following maintenance order: switching power supply one > under voltage light > motor running. Firstly, check the power supply board. After measuring the 150V DC voltage of the main circuit and disconnecting the ± 15V load, we know that the fault is inside the switching power supply board. In the check of the power supply board, we find that the voltage of the 10V regulator V32 is only 9.5v. From this, we can find the cause of the fault: the current limiting resistance rl85 of V32 becomes larger. After replacing rl85, the ± 15V power board and “under voltage” lamp returned to normal, but the motor still did not run. It can be seen that the above flashing lights and hot components are caused by rl85 variation, and there is another reason for the motor not running. According to the usual inspection method, it can be detected step by step, but due to experience, we only did a simple transformation and steering test, and found that the reverse operation was normal, so we quickly found out the cause of the fault: the integrated block N5 (tl084) of the commutation circuit failed, and everything was normal after replacing N5

PC interface method

Because the signal transmission and control between each unit (except driver) of NC machine tool and NC system are realized through PC interface (1 / O), many faults will be reflected through PC interface signal. We can diagnose various complex machine tool faults or judge whether the fault is in NC system or in machine tool electrical by consulting 1 / O signal of PC machine tool side. The method is very simple, that is, it is required to be familiar with the current state and normal state of all PC (machine side) interface signals (or make a table). During diagnosis, check and compare the current state and normal state of all PC (machine side) interface signals one by one to find out the faulty interface signals, and then find out the fault causes according to the external logic relationship of the signals. When you are familiar with the PC interface signal, the application of this PC interface comparison method is very simple and fast, and avoids the complicated ladder program.

Recovery of abnormal data in Siemens 3GG system

The grinder s45-6 of Switzerland is equipped with Siemens 3GG system, which is a dual n C dual PLC structure. The system has a strong self diagnosis function. When a fault occurs, it can quickly diagnose and repair the fault with the help of the screen prompt. However, if the system cannot be started, and the PLC is in the stop state, the screen is not bright, then the self diagnosis function of the system will not play a role, leading to the difficulty of diagnosis. If the battery voltage is lower than 2.7V, the battery must be replaced; if the NC or PLC hardware is damaged, the circuit board needs to be replaced; if the 24 V power supply of the machine tool is lower than 21 V, the power supply circuit and load need to be checked.

But we encounter more faults, the reason is not the hardware fault, but the machine data abnormal such as soft fault. The reasons are complex, such as power grid interference, electromagnetic wave interference, battery failure, operation error and so on, which may cause the loss or confusion of machine data, so that the system can not start.

Abnormal noise of spindle in CNC machining

Cause of failure: it usually occurs in the process of deceleration, and there is something wrong with the spindle drive device, such as the regeneration circuit fault in AC drive.

CNC machining center spindle abnormal noise is most operators will encounter things, understand the cause of the failure, we should take what measures to solve it?

When the machining center is in use, some customers often find that the spindle is transported by belt. After a long time of use, there will be abnormal noise. When the forward transmission and reverse transmission are switched, there will be noise. According to years of assembly experience, it is determined that most of the problems are caused by the belt, The belt tension at the joint of servo motor and spindle is too tight, which leads to the phenomenon of belt slipping, so the spindle will make abnormal noise.

Another situation is that the tension of the belt connecting the servo motor is not enough, so it will appear that the belt of the motor is too loose, which can be seen intuitively. When the machining center is used for heavy chip, it will slip and make abnormal noise. After the machining center is used for a long time, the belt will be worn, which is part of the cause of abnormal noise.

After the abnormal noise of CNC machining center spindle occurs, some economical customers will choose to replace the drive wallet. After the replacement, the belt drive gear and the tooth profile of the motor and the spindle do not match, and they can make do with it. However, there will be a lot of abnormal noise during use, which seriously causes the wear and damage of the gear of the servo motor and the spindle. It is suggested to observe whether the belt model purchased is the same as that replaced. Spindle is an important guarantee for high-speed and high-precision machining of CNC machining center, so the maintenance methods and skills of spindle fault are the basic knowledge that operators and maintenance personnel of CNC machining center must master. In the operation of CNC machining center, the spindle will inevitably have some faults. What is the specific reason?

Different types of CNC machining centers adopt different types of spindles. According to the different transmission systems, the spindle system can be divided into the main transmission spindle with variable speed gear, the main transmission spindle with belt transmission, the dual motor drive spindle and the motor spindle integrated spindle. No matter what type of spindle application, the common faults in use are as follows:

Overload.

Fault causes: excessive cutting amount, frequent forward and reverse rotation, spindle motor fault, spindle drive device fault.

The spindle does not rotate

Fault causes: spindle drive failure, CNC device can not output speed signal, spindle motor failure, spindle drive failure, drive belt fracture.

The spindle speed deviates from the command value

Fault causes: motor overload, CNC system output spindle speed command output problem, speed measuring device failure or speed feedback signal disconnection.

Abnormal noise and vibration of spindle

Key points of complex parts processing

The continuous fine blanking die for complex parts is the frontier basic technology of fine blanking technology. Taking this as the leader, the research is expected to promote the whole fine blanking technology in our country. Taking the synchronizer ring, clutch plate, longitudinal compound continuous fine blanking process and die for complex parts as the breakthrough point, the key technology of fine blanking die design and manufacturing is studied, and the development of fine blanking die technology in our country is realized The gap between China and advanced countries should be shortened as soon as possible.

Study on the life promotion of fine blanking die and its related key technologies

Die life is a comprehensive reflection of die material, small process and supporting product level. Taking the life of fine blanking die as the leader to carry out technical research can not only solve the problem that the life of fine blanking die is too low, but also drive the technical development of die material, fine blanking process, supporting tooling and other auxiliary products.

Research and development of fine blanking precision forging composite technology

Precision blanking and precision forging are two advanced manufacturing technologies developed in parallel. If the precision blanking parts are too thick and need precision forging, the precision forging must be too thin. They are closely related. The basic idea of developing precision forging and fine blanking compound process is to find the combination point of the two processes (such as gear parts with wheel hub and cam parts with short shaft). The precision forging in China has a long history and has a high level, so it is a good way to improve the overall level of precision blanking technology in China.

Computer gong processing vertical processing

The height of the vertical machining center is limited, which reduces the processing range of the workpiece, which is the disadvantage of the vertical machining center. However, the workpiece clamping and positioning is convenient for vertical machining center; the cutting path is easy to observe and debug, the program inspection and measurement is convenient, the problems can be found in time, and the treatment or modification can be stopped; the cooling conditions are easy to establish, and the cutting fluid can directly reach the cutting tool and machining on the surface; the three-axis and Cartesian coordinate system, intuitive feeling, conforms to the design point of view, and the chip is easy to eliminate, Surface treatment to avoid scratches.

Vertical machining center

Mainly used for:

Using grease and oil circulation in machining center will produce abnormal heating.
Spindle, need high-definition washing, high-speed bearing sealing place

working principle:

The use of compressed air flow pipe, transmission oil along the pipe caused by continuous flow, stirring and transportation of oil and gas processing center spindle part and other parts of the screw need lubrication. The constant pressure dry compressed air (bar) 5 – 8 continuous supply, according to the spindle and lubricating oil lubrication, screw oil and other parts of the fuel consumption different quantitative supply. Therefore, each lubrication circuit must use a separate micro pump power supply of oil. After the oil pump, it must enter the oil and natural gas mixing valve. In the oil and natural gas mixing valve, the compressed air flow blows into small oil drops and adheres to the wall to form an oil film. The flow direction of the air flow between the oil film and the pipe wall, and the thickness of the medium oil film gradually becomes thinner, but not together.

CNC machine tool processing principle, all kinds of processing tools, all kinds of workpiece processing tool path method, all kinds of workpiece feed and speed, cutting amount.

Maximum depth allowed for each cutting, actual m auxiliary function, s speed, t tool change, R radius, u, W are relative G: preparation command M: auxiliary command T: tool s: spindle speed, R: arc radius, and then p q R, where R means different.

Precision CNC machining

When the precision of precision machining is nanometer or even atomic unit (the atomic lattice distance is 0.1-0.2 nanometer), the cutting method can not adapt to it. It needs the help of special machining method, that is, the application of chemical energy, electrochemical energy, thermal energy or electric energy, to make these energies exceed the bonding energy between atoms, so as to remove the adhesion, bonding or bonding between some atoms on the workpiece surface In order to achieve the goal of ultra precision machining. This kind of processing includes mechanical chemical polishing, ion sputtering and ion implantation, electron beam exposure, laser beam processing, metal evaporation and molecular beam epitaxy. The characteristic of these methods is that the amount of material removed or added to the surface layer can be controlled very finely. However, to obtain ultra precision machining accuracy, it still depends on precision machining equipment and precise control system, and uses ultra precision mask as intermediary. For example, in VLSI plate making, electron beam is used to expose the photoresist (see lithography) on the mask to make the atoms of the photoresist polymerize (or decompose) directly under electron impact, and then the polymerized or unpolymerized parts are dissolved by the developer to make the mask. Electron beam exposure plate making requires ultra precision processing equipment with positioning accuracy of ± 0.01 micron.

What are the characteristics and functions of the system? It is an automatic machine tool controlled by program. The control system can logically process the program with control code or other symbol instructions, decode it by computer, so that the machine tool can execute the specified action, and the blank can be processed into semi-finished parts by cutting tools.

The traditional mechanical lathe processing is manual operation, ordinary machine operation, lathe processing with hand shaking mechanical tool cutting metal, rely on the eyes with calipers and other tools to measure the accuracy of the product. Modern industry has long used computer-controlled machine tools for operation, which can automatically process any product and parts according to the program compiled by technicians in advance.

The information is stored in the information carrier (such as disk, perforated tape, magnetic tape, etc.) and then read in by the CNC system on the machine tool (or directly input through the keyboard of the CNC system, or input through the communication mode). By decoding the information, the lathe can process the action and parts, and the modern CNC machine tool can be widely used It is a typical product of mechatronics and the technical foundation of new generation production technology and computer integrated manufacturing system.

The development trend of modern CNC lathe precision machining is high speed, high precision, high reliability, multi-function, compound, intelligent and open structure. The main development trend is to develop intelligent full-function universal numerical control device with open structure in both software and hardware. Numerical control technology is the basis of machining automation and the core technology of numerical control machine tools. Its level is related to the national strategic position and the level of reflecting the national comprehensive strength. It develops with the development of information technology, microelectronics technology, automation technology and detection technology. CNC machining is a kind of numerical control machine tool with tool magazine, which can automatically change the tool and process the workpiece in a certain range.

Computer gong processing and clamping

Roughening: under the maximum load of the machine tool, in most cases of processing, select the largest possible tool, the largest possible feed amount and the fastest possible feed. In the case of the same tool, the feed is inversely proportional to the feed amount. In general, the load of the machine tool is not a problem. The principle of tool selection mainly depends on whether the two-dimensional angle and three-dimensional arc of the product are too small The principle is that the length of the tool is greater than the depth of processing. For large workpieces, it is necessary to consider whether the collet can be lowered. Otherwise, it is necessary to go as follows. 0 I4 Q6 x1 f5 l N& u

The purpose of light knife: to meet the workpiece processing requirements: finish, flying die allowance, copper male spark position, etc., at the same time, as large as possible, as fast as possible, because the precision knife takes a long time, with the most appropriate feed and feed, in the same feed, the larger the transverse feed, the faster. The surface feed is related to the finish after processing, and the feed size is related to the surface shape In the case of no damage to the surface, the minimum allowance should be left, the maximum knife should be used, the fastest Belt should be rotated, and the proper feeding should be carried out.

Clamping method:

All clamps are long horizontally and short vertically;
Vise clamping: the clamping height should not be less than 10 mm. When processing the workpiece, the clamping height and processing height must be specified. The processing height should be about 5 mm higher than the vise plane, so as to ensure the firmness and not damage the vise. This kind of clamping belongs to general clamping, and the clamping height is also related to the size of the workpiece. The larger the workpiece is, the higher the clamping height will be;
Splint clamping: the splint is fixed on the worktable with the code, and the workpiece is locked on the splint with the screw. This kind of clamping is suitable for the workpiece with insufficient clamping height and large processing force, generally medium and large workpieces, and the effect is very good. 1 ` Q( F9 k, n
When the workpiece is large, the clamping height is not enough, and it is not allowed to lock the thread at the bottom, it should be clamped with code iron. This kind of clamping needs secondary clamping. The procedure is as follows: A. code the four corners first, process other parts, then code the four sides, and process the four corners. The principle is that during the secondary clamping, be very careful not to let the workpiece loose, code first and then loosen. B. code both sides first, process the other two sides, 8 L # y% @# \: e’ N% P

Code iron has an advantage, large contact area, not easy to deformation, such as aluminum, magnesium within the soft metal must use code iron to prevent deformation;

Tool clamping: diameter more than 10 mm, not less than 30 mm; diameter less than 10 mm, not less than 20 mm,

Note: the impact of the tool on the workpiece can cause: a. the workpiece moves; B. the tool is broken; C. the tool is deformed and the workpiece is damaged; D. the tool is loose, the tool is dropped or the workpiece is not processed correctly

Therefore, the clamping of tool and workpiece should be firm. Strictly prevent Tool Collision and direct insertion of workpiece, & H #: X # {3 W

Classification of cutting tools and their application scope:% Q + e’c. B-Z

By material:

White steel knife: easy to wear, used for roughening of copper and small steel

Tungsten steel knife: used for angle cleaning (especially steel material) and light knife. . g4 k+ L1 U0 h/ s3 P+ T

Alloy knife: similar to tungsten steel knife

Purple knife; used for high speed cutting, not easy to wear

According to the cutter head:, ~. A “{2 s; t

Flat bottom knife: used for plane and straight body side cleaning (plane angle / m3 Z / M)_ , Z

Ball cutter: used for all kinds of surface medium light, light knife) F + I-m: B0 F8 G-V) H

Ox nose knife (one side, two sides and five sides): used for roughening steel (r0.8, r0.3, r0.5, r0.4) – X / F9 x, H: v

Rough leather knife: used to cut rough, pay attention to the remaining method (0.3)

According to the arbor: straight knife: straight knife is suitable for all kinds of occasions 9 a # x E + x0 a% E

Slant bar cutter: but not suitable for straight face and face with inclination less than the inclination of bar (S2 [7 d & D% O6 M0~

According to the blade: two blade, three blade, four blade, the more blades, the better the effect, but the more work, speed and feed corresponding adjustment, more blades, long life, ball knife and flying knife light knife difference: {: Q & i7 U3 | 0e

Ball knife: when concave ruler is smaller than ball ruler and plane ruler is smaller than ball R, the light can not reach (clear the bottom angle).

CNC computer gong processing tool introduction

From the cutting process can be divided into:

Turning tools, including cylindrical, internal hole, thread, cutting tools, etc.; drilling tools, including drill, reamer, tap, etc.; boring tools; milling tools, etc.

In order to comply with the requirements of CNC machine tools for tool durability, stability, easy adjustment, replaceability, etc., in recent years, the machine clip indexable tool has been widely used, reaching 30% – 40% of all CNC tools in quantity, and the metal removal amount accounts for 80% – 90% of the total.

Tool selection

Tool selection is carried out under the condition of human-computer interaction in NC programming. According to the choice of milling cutter, the choice of milling cutter diameter and the number of milling cutter teeth. Selection of milling cutter diameter: generally, small diameter milling cutter is selected as far as possible. Because of the large diameter of milling cutter and the increase of cutting torque, it is easy to form cutting vibration, and the cutting length of milling cutter increases, which reduces the milling efficiency. Of course, not necessarily, when the rigidity of the milling cutter is poor, the larger diameter milling cutter should be selected according to the processing environment to increase the rigidity of the milling cutter.

In the machining process of economical CNC machine tools, because the grinding, measurement and exchange of cutting tools are mostly carried out manually, which takes a long time, it is necessary to reasonably allocate the order of cutting tools.

Rough and finish machining tools should be used

The name of NC milling and machining is diverse. The machining instruments are divided into two categories: fine and coarse. Different work contents and machining products have different examples of necessary tools in the detailed milling process. If only one kind of cutting tool is used for processing, then the processed products are more equal, it is difficult to distinguish accurately, and the processed products are also difficult to meet the use requirements, which is not in line with the actual use. In order to improve the quality level of products, meet the utilization scale and ensure the effectiveness of products, it is only necessary to adopt different cutting tools, combine the real environment of processing and production, and accurately classify the cutting tools.

Compared with ball end tool, flat end tool has a great advantage in surface processing quality and cutting efficiency, so it is necessary to ensure the processing, whether in rough machining or finish machining, flat end tool is preferred. When milling three-dimensional workpieces, it is best to choose the flat end cutter, and combine the material of the cutter and the characteristics of the processed products to make a more accurate choice. In contrast, in order to avoid overcutting phenomenon, it is best to use ball head cutter when milling curved surface products, and pay attention to the accuracy of machining and the interval of cutting, so as not to reduce the work efficiency.

Using the active tool changing effect of machining center to improve production efficiency

With the rapid development of science and technology, the previous NC milling objects and related tools can not meet the new requirements of real processing, and the work efficiency can not meet the new requirements of social development.

It has become a general trend to adopt the object of active tool change. In the past, most of the CNC milling work was manual operation, which was inefficient and easy to squander a large number of manpower, material resources and financial resources, which was not conducive to the promotion of the quality of the work. Adopting active tool changing technology and scientifically improving the utilization of cutting tools can improve the effectiveness of tool utilization, select cutting tools quickly and adopt active means for cutting. It not only saves time, but also improves the processing quality and effect of milling, and meets the new characteristics of rational utilization of modern science and technology. Of course, the use of active tool changing technology is not only a simple name, it must complete the inorganic combination of itself and the object, and the time and distance of active tool changing should also be precise, in order to improve the production efficiency.

What are the differences of CNC milling machine

The biggest difference of CNC milling machine is that the machining center has the ability to exchange machining tools automatically. By installing different tools on the tool magazine, the machining tools on the spindle can be changed through the automatic tool changing device in one clamping, so as to realize a variety of processing functions.

CNC machining center is composed of mechanical equipment and CNC system, which is suitable for processing complex parts. CNC machining center is one of the most widely used CNC machine tools with the highest output in the world. Its comprehensive processing ability is strong, the workpiece can complete more processing content after clamping at one time, and the processing accuracy is high. For the batch workpiece with medium processing difficulty, its efficiency is 5-10 times higher than that of ordinary equipment, especially it can complete the processing that many ordinary equipment can’t complete, and it is more suitable for single piece processing with complex shape and high precision requirements or small and medium batch multi variety production. It concentrates the functions of milling, boring, drilling, tapping and cutting threads on one equipment, so that it has a variety of technological means. Machining centers are classified into horizontal and vertical machining centers according to the spatial position of the spindle. According to the classification of process uses: boring and milling machining center, composite machining center. According to the special functions, there are single table, double table and multi table machining centers. Machining center of single axle, double axle, three axle and changeable headstock.

CNC computer gong programming matters needing attention

The speed of white steel knife should not be too fast.
Copper workers use less white steel knives and more flying knives or alloy knives.
When the workpiece is too high, it should be roughened by layers with knives of different lengths.
After roughening with a big knife, use a small knife to remove the remaining material to ensure that the remaining material is consistent.
The plane should be processed with flat bottomed cutter and less ball cutter to reduce the processing time.
When cleaning the corner, check the size of R on the corner first, and then determine the size of the ball knife.
The four corners of the calibration plane should be level.
Where the slope is an integer, the slope cutter shall be used for processing, such as pipe position.
Before each process, think about the remaining allowance after the previous process,

In order to avoid the blank tool or too much processing and knife.

Try to use simple cutting path, such as shape, trenching, single side, less walking around and so on.
When walking wcut, those who can walk finish should not walk rough.
When the shape of the knife is smooth, rough first and then fine. When the workpiece is too high, smooth the edge first and then the bottom.
Set reasonable tolerance to balance machining accuracy and computer calculation time. The tolerance is set to 1 / 5 of the allowance for roughening and 0.01 for smooth cutting.
Do more process to reduce the time of empty tool.

Do more thinking and reduce the chance of mistakes.

Do more auxiliary lines and auxiliary surfaces to improve the processing condition.

Establish a sense of responsibility and carefully check each parameter to avoid rework.
Be diligent in learning, good at thinking and make continuous progress.

17 milling non planar, more ball cutter, less end cutter, do not be afraid of the knife;

18 small knife clear angle, big knife refined;

Don’t be afraid of patching, proper patching can improve the processing speed and beautify the processing effect

20 high hardness of blank material: reverse milling is better, low hardness of blank material: forward milling is better

Good accuracy, good rigidity and finishing: it is more suitable for forward milling, otherwise it is more suitable for reverse milling

It is strongly recommended to use forward milling for finishing the inner corner of parts.

Rough machining: reverse milling is better, finish machining: forward milling is better

Tool material toughness is good, low hardness: more suitable for rough machining (large cutting amount processing)

Poor toughness and high hardness of tool material: suitable for finish machining (small cutting amount machining)

CNC computer gong machining accuracy function debugging

Before the debugging of CNC computer gong processing machine tool, the debugging methods of precision and function of computer gong processing machine tool are as follows:

Using precision level instrument and other testing tools, the main bed level of the computer gong processing machine tool is precisely adjusted by adjusting the pad iron, so that the geometric accuracy of the machine tool can reach the allowable tolerance range;
For the automatic tool changing device, adjust the position of tool magazine, manipulator, stroke parameters, etc., and then check the action with instructions to ensure accuracy;
For the machine tool with APC automatic exchange table, after adjusting the relative position, carry out automatic exchange;
After adjusting 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, and the execution of common instructions.

Check the auxiliary functions and accessories of the machine. CNC computer gong NC machining is the basis of modern manufacturing technology, this invention for the manufacturing industry, has epoch-making significance and far-reaching influence.