2020 – Page 57 – CNC Machining & Turning, Milling, Metal parts

What are the principles of CNC processing of aluminum alloy

Compared with manual machining, CNC machining of aluminum alloy has great advantages, such as aluminum alloy parts produced by CNC machining are very accurate and repeatable; CNC machining of aluminum alloy can produce parts with complex shape that cannot be completed by manual processing. What are the principles of CNC processing of aluminum alloy?

CNC machining robot

(1) In order to ensure the CNC machining accuracy of aluminum alloy, roughing and finishing should be carried out separately. During rough machining, the cutting amount is large, the cutting force and clamping force on the workpiece are large, the heat generation is more, and the machining surface has obvious work hardening phenomenon. There is a large internal stress in the workpiece. If the rough machining and rough machining are carried out continuously, the precision of the parts after finishing will be lost quickly because of the redistribution of stress. For some parts with high machining accuracy. After rough machining and before finishing, low temperature annealing or aging treatment should be arranged to eliminate internal stress.

(2) Reasonable selection of CNC processing equipment for aluminum alloy. Rough machining is mainly to cut off most of the machining allowance and does not require high machining accuracy. Therefore, rough machining should be carried out on machine tools with high power and low precision, while the finishing process requires high-precision machine tools. Rough machining and finish machining are processed on different machine tools, which can not only give full play to the equipment capacity, but also extend the service life of precision machine tools.

(3) Heat treatment process is often arranged in CNC process of aluminum alloy. The arrangement of heat treatment process is as follows: in order to improve the cutting performance of metal, such as annealing, normalizing, quenching and tempering, it is generally arranged before machining. In order to eliminate internal stress, such as aging treatment, quenching and tempering treatment, it is generally arranged after rough machining and before finishing. In order to improve the mechanical properties of parts, such as carburizing, quenching, tempering, etc., they are generally arranged after machining. If there is large deformation after heat treatment, Zui finishing process must be arranged.

The correct operation and maintenance is one of the key factors for the correct use of aluminum alloy CNC processing equipment. In the correct operation and use, it can prevent abnormal wear and tear of machine tools and avoid sudden failure; in daily maintenance, the equipment keeps good technical status, delays the deterioration process, timely finds and eliminates the hidden trouble, and ensures the safe operation

What should be paid attention to in CNC machining aluminum parts

Pay attention to some details in CNC processing of aluminum parts can avoid quality problems of aluminum parts and improve the production efficiency of enterprises. What should we pay attention to before CNC processing?

CNC machining of aluminum shell

1. For the new die, the processing drawing should meet the requirements and the data should be clear; the processing drawing of the new mold should be signed by the supervisor, and all columns of the processing drawing have been filled in.

2. The workpiece has the qualification mark of quality department.

3. After receiving the program sheet, check whether the workpiece reference position is consistent with the drawing reference position.

4. Check every requirement on the procedure list and confirm whether the program is consistent with the requirements of the drawing. If there is any problem, you must work with the programmer and production team to solve the problem.

5. According to the material and size of the workpiece, judge the rationality of the selection of the tool for the program of roughening or smooth cutting. If the application of the tool is found to be unreasonable, the programmer should be informed immediately to make corresponding changes, so as to improve the processing efficiency and machining accuracy of the workpiece.

In the process of using CNC to process aluminum parts in normal production, the following contents should be paid attention to:

1. When the surplus on the top surface of the workpiece is too large, when using a large knife to manually remove the surplus, remember not to use the depth of the gong.

2. The most important machining tool is the first tool. If you operate and check carefully, you can know whether the tool length compensation, tool diameter compensation, program, speed, etc. are wrong, so as to avoid damaging the workpiece, cutter and machine tool.

3. Try the cutting procedure as follows:

a. The height of Di point is the highest elevation of 100 mm, and the eye is used to feel whether it is correct;

b. Control “fast move” to 25% and feed to 0%;

c. When the tool approaches (about 10 mm, machining surface), stop the machine;

d. Check whether the remaining stroke and program are correct;

e. After starting the machine again, put one hand on the pause button to stop the machine at any time, and the other hand controls the feed rate;

f. When the tool is very close to the workpiece surface, it can be stopped again, and the remaining stroke of Z axis must be checked.

g. After the machining and cutting is smooth and stable, adjust the control back to normal state.

4. After inputting the program name, use a pen to copy back the program name on the screen, and then check it with the procedure sheet. When opening the program, pay attention to check whether the tool path size in the program is consistent with the procedure sheet, and fill in the file name and cutter diameter size in the signature column of the process sheet immediately. It is forbidden to fill in the file name and cutter diameter size after or before the process.

5. In principle, NC technicians are not allowed to leave when the workpiece is rough. If it is necessary to leave due to tool change or assistance in adjusting other machine tools, please ask other NC team members or come back regularly for inspection.

6. When making the middle light, the NC technician should pay special attention to the place that is not opened during the roughening to prevent the cutter from hitting this area.

7. Program cutting. In case of interruption of the program during processing and it wastes too much time to start from the beginning, the team leader and the programmer shall be informed to modify the program and cut out the part that has been passed.

8. Program exception. In case of abnormal conditions of the program, and not sure, you can hang high to observe the process, and then decide the next action.

9. NC technicians can adjust the speed and speed provided by the programmer according to the actual situation. However, special attention should be paid to the fact that the speed of small pieces of copper can not be turned fast when it is exposed to rough, so as to avoid the loosening of workpieces due to oscillation.

10. During the process of workpiece processing, the NC technician should check with the spare parts drawing to see if there is any abnormal condition. Once the two do not match, they must stop the machine immediately and inform the team leader to check whether there is any error.

11. When using the tool with a length of more than 200 mm, it is necessary to pay attention to the allowance, feed depth, rotation speed, travel speed and other issues, so as to avoid tool swing. At the same time, the travel speed of the corner position should be controlled.

12. If the tool diameter is required to be detected on the program sheet, the operator must be responsible for it carefully, and record the diameter of the test. If it is beyond the tolerance range, it should be immediately reported to the team leader or tool change.

13. When the machine tool is in automatic operation or free, the operator should go to the workstation to understand the remaining processing programming, prepare and grind the appropriate tool for the next machining standby, so as to avoid shutdown.

14. Process error is the main reason for waste of time: wrong use of inappropriate tools, wrong processing sequence, waste of time in the position without processing or non computer processing, improper processing conditions (too slow speed, empty tool, too dense tool path, too slow feed, etc.), when the above events occur, it can be connected with programming, etc.

15. In the process of machining, we must pay attention to the wear condition of the cutting tool. We should change the cutter grain or the tool properly. After changing the cutter grain, we should pay attention to whether the contact boundary of the machining is consistent.

CNC machining technology of aluminum shell

With the progress of society, the development of science and technology, with the improvement of living standards, the quality of life has been greatly improved. Many people are thinking about how to improve the quality. The better the technology is, the more market demand will be, and the higher the efficiency will be. What are the CNC processing techniques of aluminum shell? Let’s have a look!

CNC machining of aluminum shell

1. Reasonable selection of cutting amount, the staff according to the need to be processed material, hardness, cutting state, material type, cutting depth and so on to choose the cutting speed. These conditions are the ideal conditions to effectively protect the machine from wear.

The three factors of cutting conditions: cutting speed, feed rate and cutting depth directly cause tool damage. With the increase of cutting speed, the tool tip temperature will rise, which will produce mechanical, chemical and thermal wear. If the cutting speed is increased by 20%, the tool life will be reduced by 1 / 2

The relationship between feed condition and tool back wear occurs in a very small range. But the feed rate is large, the cutting temperature rises, and the back wear is large. It has less effect on the tool than the cutting speed. Although the influence of cutting depth on the tool is not as great as the cutting speed and feed rate, but when the cutting depth is small, the hardened layer of the material to be cut will also affect the tool life.

The user should select the cutting speed according to the material to be processed, hardness, cutting state, material type, feed rate, cutting depth, etc.

The selection of suitable processing conditions is based on these factors. Regular and stable wear is the ideal condition for service life.

2. Choose the right tool. For rough turning, generally speaking, it is better to choose high strength and durable cutting tools, which can better meet the requirements of rough turning.

How to select machining tool reasonably? How many factors are there in cutting parameters? How many kinds of tools are available? How to determine the tool speed, cutting speed, cutting width?

① No regrinding cemented carbide end milling cutter or end milling cutter should be used in plane milling. In general, the second tool path should be used as far as possible, and the end milling cutter can be used for rough milling, and the cutter can be continuously moved along the surface of the workpiece.

② End mills and end mills with cemented carbide inserts are mainly used for machining boss, groove and box face.

③ Ball cutter and round knife (also known as round nose knife) are commonly used to process curved surface and variable bevel profile. The ball cutter is mostly used for semi finishing and finishing.

3. Choose a reasonable fixture. Parts should fully meet the needs of the machine, in order to reduce unnecessary positioning error, good choice of special fixture clamping tools. Machining route refers to the motion track and direction of the cutter relative to the parts in the process of NC machine tool processing.

① The machining accuracy and surface roughness requirements shall be guaranteed;

② The processing route should be shortened as far as possible to reduce the tool idle travel time.

4. The working route of the front waist is determined. Shorten the machining route as far as possible to reduce the wear of the machine.

The technical requirement of CNC machining technology is that the control system can logically process the program with control code or other symbol instructions, and decode it by computer, so that the machine tool can move and process parts. The blank is processed into semi-finished products by cutting tool.

Preparation for CNC machining of aluminum shell

In order to meet people’s demand for diversity and high quality of aluminum alloy shell products, the process skills must be summarized in the process of processing. Based on years of experience in CNC processing of aluminum alloy shell, the author summarizes the preparation work that should be paid attention to in the processing of aluminum alloy shell. Operators need to make preparations when using CNC machining center with aluminum shell. Of course, each operator has his own set of skills. Here, the author would like to say is whether novice or has a certain experience in the use of personnel to do well

In order to meet people’s demand for diversity and high quality of aluminum alloy shell products, the process skills must be summarized in the process of processing. Based on years of experience in CNC processing of aluminum alloy shell, the author summarizes the preparation work that should be paid attention to in the processing of aluminum alloy shell. Operators need to make preparations when using CNC machining center with aluminum shell. Of course, each operator has his own set of skills. Here, the author would like to say that both novice and experienced personnel should be prepared for use. What are the specific contents?

How to maintain CNC machine tool for aluminum shell

The production process of aluminum profile mainly includes casting, extrusion and coloring. Among them, coloring mainly includes: oxidation, electrophoretic coating, fluorocarbon coating, powder coating, wood grain transfer and so on. With the continuous improvement of people’s requirements for products, more and more enterprises choose to use CNC processing technology of aluminum shell in the process of aluminum shell processing. For aluminum shell CNC processing equipment, it is necessary to do a good job in regular maintenance. What are the specific contents?

CNC machining of aluminum shell

1. Daily inspection

Its main items include hydraulic system, spindle lubrication system, guide rail lubrication system, cooling system and air pressure system. Daily inspection is based on the normal situation of each system to detect. For example, when the process detection of the spindle lubrication system is carried out, the power light should be on, and the oil pressure pump should run normally. If the power light is not on, the spindle should be stopped and contact the mechanical engineer. Carry out maintenance.

2. Weekly inspection

Its main items include machine parts and spindle lubrication system, which should be checked correctly every week, especially for machine parts, iron filings should be removed and external sundries should be cleaned.

3. Monthly inspection

It is mainly to check the power supply and air in the dryer. Under normal conditions, the rated power supply voltage is 180v-220v, and the frequency is 50 Hz. If there is any abnormality, it should be measured and adjusted. The air dryer should be removed once a month, and then cleaned and assembled.

4. Quarterly inspection

Check the hydraulic system of the machine tool from three aspects. For example, when checking the machine tool bed, it mainly depends on whether the accuracy and level of the machine tool meet the requirements in the manual. If there is any problem, contact the mechanical engineer immediately. When checking the hydraulic system and spindle lubrication system, if there is any problem, the oil should be replaced by 6ol and 20L respectively and cleaned.

5. Semi annual inspection

After half a year, the hydraulic system, spindle lubrication system and x-axis of the machine tool should be inspected. If there is any problem, the new oil should be replaced, and then the cleaning work should be carried out. After being familiar with and mastering the knowledge of preventive maintenance, it is necessary to have a deeper understanding and necessary mastery of the causes and treatment of abnormal phenomena in the oil pressure system.

What kind of hardness tester should be used for different metal stamping materials

Stamping parts processing factory, processing metal stamping parts, stainless steel stamping parts, various mechanical accessories, with the development of society, stamping products have been applied to various fields, metal stamping parts used materials are also divided into many kinds, making metal stamping parts, we need to understand the characteristics of products, material performance, among them, we also need to test the hardness of metal stamping parts The main purpose is to determine whether the annealing degree of the purchased sheet metal is suitable for stamping parts processing;

Different kinds of metal stamping parts processing technology, need different hardness level of the plate. Each kind of plate hardness detection has a specified hardness tester to measure, let’s take a look at it;

1. Hot rolled steel plate is usually relatively thick, and it is generally stipulated to use Brinell hardness tester to test hardness and Rockwell hardness tester to test hot-rolled steel plate; HRB scale can be used and portable Rockwell hardness tester can be used to test hot-rolled steel plate without sampling, and the operation is simple;

2. The hardness of cold-rolled steel sheet used for processing metal stamping parts is mainly measured by Rockwell hardness tester, usually HRB scale is used, and HRC scale is used for harder steel plate;

3. The material of the thin plate can be made of either the Vickers hardness tester or the surface Rockwell hardness tester hrn or HRT scale;

4. The hardness of brass plate used for metal stamping parts can be tested by HRB scale of Rockwell hardness tester, and HRF scale can be used for softer brass and copper plate;

5. The aluminum alloy plate used for processing metal stamping parts can be tested by Vickers hardness tester. When the material thickness island is 13mm, the Babbitt hardness tester can be used, and the bus hardness tester should be used for pure aluminum plate or low hardness aluminum alloy plate;

The main material of stamping die is die steel, and sometimes cemented carbide is used. The stamping die usually requires high hardness and wear resistance, and heat treatment is essential. The hardness of die steel is tested by Rockwell hardness tester. When the die is large and inconvenient to move, Leeb hardness tester can be used. In order to improve the surface hardness and wear resistance, many metal stamping dies and Die accessories need surface heat treatment, such as surface nitriding;

What problems should be paid attention to when designing stretch metal stamping parts?

Stretch forming is a stamping process in which the plate is formed into an open hollow part using a processing method. As one of the main stamping processes, drawing has been widely used. The drawing process can be used to manufacture thin-walled metal stamping parts with irregular shapes such as cylindrical, rectangular, trapezoidal, spherical, conical and parabolic. If combined with other stamping processes, more complex parts can be produced.

1. The design of drawing hardware stamping parts should be simple and symmetrical as far as possible, and can be drawn once. In the design of drawing parts, it should be noted that the external or internal dimensions must be guaranteed;

2. The wall thickness tolerance or thinning of metal stamping parts in deep drawing should not exceed the variation law of drawing process wall thickness. Generally, the maximum thickness of tube wall is (0.2 ~ 0.3) t, and the maximum thinning amount is (0.1 ~ 0.18) t, where t is the sheet thickness.

3. For the workpiece to be drawn for several times (H ＞ 0.5d), the inner and outer walls or flange surface of flange drawing parts shall be allowed to have indentation during drawing.

4. On the premise of ensuring the assembly requirements, the side wall of the drawing part should be allowed to have a certain slope.

5. All dimensions not noted on the part drawing belong to free dimension. The dimension tolerance can be determined according to IT14 level by looking up the tolerance table. The dimension in the diameter direction and height direction of the part meets the requirements of the part tolerance grade in the drawing process.

What are the advantages of metal spring stamping?

In the stamping process of metal spring piece, because the high-speed punch is used, the risk coefficient is relatively high. If the operation is improper, the mold will be seriously damaged, and the safety of the operator will also be hurt. Therefore, when the mold needs to be off the machine, remember to implement the following operation to ensure the safety of the mold and operators

There are two kinds of status of hardware spring die, normal and abnormal

1、 Hardware shrapnel is normally off the machine:

1. Turn the punch to “inching” and turn off the counter;

2. Use the inching switch to set the punch to the bottom dead point (180 °) and cut off the material belt; prevent the belt from cutting when the die is dead, which may cause deformation of the belt and damage of the die parts

3. Loosen the upper and lower die screws

4. Hit the punch to the top dead center and pull the die to the base of the die car together. Two people are required to finish the die drawing. One person is not allowed to pull the die to ensure safety

5. It is necessary to pull the die car away from the punch for a certain distance before lowering the height of the die car, so as to prevent the die car from getting stuck in the way of the punch and forming the sliding of the die

6. The locking screw, scissors, material hook, flashlight, etc. should not be placed on the operation surface of the punch when the mold is lowered

2、 Hardware shrapnel is out of order:

1. Turn off the power supply and counter of the host computer;

2. After the flywheel is completely broken off, place plastic or paper core on the front and rear diagonal stop column of the mold. Do not place it between the stripper plate and the mold core fixing plate, or place iron block in the mold instead of plastic

3. Swing the flywheel with safety rod (do not pull the flywheel by hand or use safety rod to stop flywheel operation before the flywheel is interrupted) and stick the upper and lower stop posts

4. Loosen the upper and lower die screws, pull the flywheel to 0 ° to 70 ° with safety rod, and then pull the die down

3、 Precautions for dismounting hardware shrapnel:

1. Before pulling the mold, it is required to acknowledge that the support plate of the feeding port of the mold has been loosened and removed

2. When the mold can not be pulled, one person can pull out and one person can push backward. (avoid pushing backward together to push the mold out of the punch). It can also be used to screw the screw hole of the lower die base and lift both hands up a little and then pull it out

3. When the die is pulled away from the punch, the die car shall not turn too fast to prevent the guide plate or the data support plate from hanging on the punch or the sound insulation cover of the punch, which may cause damage to the die parts or slide of the die

4. It is not allowed to move the mold when it is abnormal, especially after the mold height stop column is padded with plastic

5. Turn off the main machine and other power supply after the die is lowered to prevent capital waste

6. When the mold is shut down normally, it is necessary to move the mold inching until the guide needle enters the round hole of the tape. (to prevent the data formed by the feeder not holding the data when there is no air pressure, which causes the wrapping tape.) stop the mold from stopping at the bottom dead point. (it is easy to reduce the service life of the tension spring in the mold.)

Attention should be paid to the maintenance of metal stamping parts after installation

Attention should be paid to maintenance of metal stamping parts after installation to prevent rusting and corrosion. In daily use, it is necessary to close and open gently to prevent damage caused by hard closing and hard opening. There is no noise, there are now nylon wheels. It not only has no noise when pushing and pulling, but also is more smooth and light, and its service life is not shorter than the above various pulleys. To make (door) window normal and smooth operation, it is necessary to select a high-quality pulley for (door) window. Poor quality pulley from the surface, the workmanship is relatively rough. It’s not smooth. It is not flexible to slide, small and light.

Hardware spring piece belongs to the category of hardware stamping parts and electronic hardware data. Selection of stainless steel or manganese material after heat treatment is a primary component of the switch, with the help of the conductivity of metal shrapnel, it plays an excellent switch role between the operator and the commodity. Together, the safe resilience (automatic return after pressing) and super long life span of the pot are used to provide excellent tactile response for operators.

In the production of metal stamping parts, in order to meet the needs of different stamping work, different types of presses are used. There are many types of press, which can be divided into mechanical pressure and hydraulic press according to different transmission modes. Among them, mechanical press is the most widely used in stamping production. With the development of modern stamping technology, high-speed press and CNC rotary head press are widely used.

Common faults of metal stamping parts

In the progressive die, the shape of the metal stamping part is formed by punching the surplus material around the stamping part. The main reason of turning over and twisting is the influence of blanking force. During blanking, due to the existence of blanking clearance, the material is stretched on one side of the female die (material warps upward), and the side close to the punch is compressed. When the unloading plate is used, the unloading plate is used to compress the material to prevent the material on the die side from warping upward. At this time, the stress state of the material changes correspondingly. With the increase of the pressing force, the material near the punch side is stretched (the compression force tends to decrease), while the material on the die surface is compressed (the tensile force tends to decrease). The overturning of stamping parts is caused by the stretching of the material on the die surface. Therefore, when blanking, pressing and pressing the material is the key to prevent the stamping parts from turning over and twisting. The causes and Countermeasures of turning over and twisting of stamping parts during bending.

It is caused by the burr of the blanking part. It is necessary to study the cutting edge and check whether the blanking clearance is reasonable.

When blanking, the stamping parts have been turned over and twisted, which leads to poor forming after bending, which needs to be solved from the blanking station.

It is caused by the instability of stamping parts during bending. Mainly for U-shaped and V-shaped bending. In order to solve this problem, the key to solve the problem is to carry out the lead position before bending and during the bending process, and to hold down the material during the bending process to prevent the stamping parts from sliding during bending.