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What should be paid attention to before CNC machining

1、 CNC precision machining machine maintenance

1. Clean and maintain the machine tool half an hour before going to work every day. If the air gun or oil gun is used to clean the chips, there must be a knife on the spindle.

2. It is forbidden to use air gun or oil gun to blow the taper hole of the main shaft, so as to avoid the small particles such as chips being blown into the main shaft hole and affecting the cleanliness of the main shaft.

3. Check whether the lubricating machine works normally and whether the lubricating oil is sufficient. Start the machine in normal order.

4. Before the machine tool is put into operation, start the spindle (speed is 501r / M) to preheat the spindle.

2、 CNC precision machining machine operation

1. Before operation, confirm the model, size and machining allowance of the workblank according to the program sheet, and sand and polish the workblank.

2. Confirm the placement position of the workpiece and the processing sequence after the machine is put on, and complete the comparison action

3. If it is necessary to “split the middle bar” during split, the rotating speed is 501r / m. if it is necessary to split the middle bar with a knife, the rotating speed depends on the cutter. In this process, it should also be noted that the data must be taken at the same height to ensure the accuracy of split. After split, it can be inspected with “G0 g54 x0 Y0”

4. Before formal processing, recheck and confirm whether the placement position and access of workpieces are correct

3、 Precautions for CNC precision machining

1. Before each process, it is necessary to strictly confirm whether the upper tool is consistent with the program

2. It is necessary to confirm the length of the tool and whether the selected clamping head is suitable when installing the tool

3. In the same workpiece, each tool setting should be kept in the same area to ensure the accuracy of tool receiving

4. Try to blow with air in the opening procedure, and spray oil in the smooth knife procedure

5. Clean up the aluminum slag in the machine tool before oil injection of the smooth knife to prevent oil absorption of the aluminum slag

6. During the self operation of CNC precision machining, the operator shall not leave the machine tool or check the operation condition of the machine tool regularly. If it is necessary to leave in the middle of the process, relevant personnel must be appointed to check

7. If too much machining allowance is found during machining, it is necessary to use “single section” or “pause” to clear x, y and Z values, then manually mill them out and then swing them back to “zero” for self operation

8. In case of knife impact during machining, the operator must stop the machine immediately, such as pressing the “emergency stop” button or “reset” button or setting the “feed rate” to zero, etc

9. Do not open the door to avoid flying knife or workpiece during the operation of the machine tool

10. The workpiece shall be cleaned and deburred in time after dismounting

11. At the end of work, the operator must make timely and accurate handover to ensure the normal follow-up processing

12. Before shutdown, make sure the tool magazine is in the original position and the XYZ axis is in the center position. Turn off the power supply and the main power supply on the operation panel of the machine tool in turn

13. In case of severe thunderstorm, the power must be cut off and the work must be stopped immediately

What are the processing methods of Automatic Parts

Stamping: the pre manufactured die is used for cold stamping with punch, and the focus is on sheet metal processing, that is, most of the processed materials are sheet metal, and the processing efficiency is compared with high and appropriate mass production.

The process flow of automatic parts is divided into engineering die and continuous die, which is also called single punch die. Some complex parts are compared with several sets of dies, while the continuous die divides the product form into several parts in a mold in the mold cavity, so that one stroke of punch machining is a molding article. High speed continuous press can process 340 products per minute.

Lathe: the lathe for the processing of fine parts belongs to the fine processing machinery, which is divided into ordinary lathe, automatic lathe, instrument lathe and computer lathe. After the material is clamped, it can rotate and be processed radially or axially by turning tool.

Now the use of automatic lathe and computer lathe is more and more ordinary. Because both of them are fully automatic machining, the precision deviation caused by manual operation is reduced to the lowest point, and the machining speed is fast, which is used for mass production. Now most of the computer lathes are equipped with side turning tools and back turning tools, that is to say, milling can also be carried out on the lathe.

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WHAT IS 5-AXIS MACHINING?

5-axis machining is an advanced cutting method that creates some of the highest quality parts. It runs with computer numerical control (CNC) technology. While previously reserved for only the highest-budgeted manufacturers, 5-axis machining has come a long way and is now commonly available to the rest of the manufacturing world.

The 5-axis mills and machines are used heavily in aerospace applications and can cut even the most intricate of patterns. They can also offer efficiency improvements for products that may only need 3-axis machining. However you choose to use it, successful 5-axis machining can have significant benefits for your manufacturing operations.

Repair and treatment of guide rail of gantry milling machine

Repair of guide rail of gantry milling machine: the guide rail of machine tool is mostly made of steel or cast iron. If such guide rail is scratched, it should be repaired, otherwise, it will enlarge the scratch and even affect the use of machine tool. In the long-term use of machine tool guide rail and other conflict pairs, due to the conflict of different levels between the two contact surfaces, the surface of the conflict pairs will wear at different levels, which will affect the machining accuracy and production efficiency of the machine tool when it is important. For the repair of machine tools and other worn parts, metal plates and polymer raw materials are usually used for inlaying or exchanging, which not only requires a large number of accurate processing and manufacturing, but also requires manual scraping and grinding of the processing surface. There are many repair processes and long construction period.

Treatment method: the first polymer 2211f metal repair material in the world is selected to repair the guide rail scratch of the gantry milling machine. It only takes a few hours to complete the repair of the part of the guide rail scratch and put it into use. Practice shows that this method is simple to operate, time saving, good repair quality and low cost. Swindling its special adhesion, outstanding compressive strength, oil resistance and wear-resistant functions can provide a permanent protective layer for the parts. It may be useful to deal with the problems that can not be handled by the traditional maintenance methods for large-scale equipment that can not be disassembled, so that the function of the equipment can be increased, the fitting gap of the parts is improved, and the normal operation of the production can be guaranteed with maximum control, so as to save the customers Save a lot of time and money, for the normal operation of enterprise equipment to provide a long-term excellent guarantee.

Repair Principle: polymer composite raw material is a composite raw material based on polymer, metal or ceramic ultrafine powder, fiber, etc. and under the action of curing agent and curing promoter. All kinds of raw materials interact with each other in function and have synergistic effect, which makes the comprehensive function of composite raw materials better than that of raw materials. It has strong adhesive force, mechanical function and chemical corrosion resistance. Therefore, it is commonly used in the repair of mechanical wear, scratch, pit, crack, leakage, forging sand hole of metal equipment and the chemical corrosion protection and repair of various chemical tanks, reaction tanks and pipelines.

On the operation steps of metal parts processing

On the operation steps of metal parts processing

On the operation steps of metal parts processing

1、 Before entering the work position, all employees shall check whether their clothes meet the work requirements. Do not wear slippers, high heels or clothes that affect safety. Those with long hair should wear safety helmet. Maintain a precise posture at work, and have enough energy to deal with the work. If you find any body discomfort, you should leave the job immediately and report to your boss. When operating, we must gather our thoughts, forbid chatting and cooperate with each other. Operators should not operate in the form of fidgety and tired, so as to avoid accidents and ensure the safety of operation.

2、 Before mechanical work, check whether the movable part is filled with smooth oil, then start up and check whether the clutch and brake are normal, and run the machine tool for 1-3 minutes without air, and it is forbidden to operate when there is any mechanical obstacle.

3、 When changing the die, first turn off the power supply. After the movable part of the punch stops running, start to install and debug the die. After the installation and adjustment is completed, move the flywheel by hand twice for trial punching, and check whether the upper and lower dies are symmetrical and correct, whether the screws are firm, and whether the blank holder is in the correct position.

4、 Only after the rest of the staff leave the mechanical work area and take away the sundries on the workbench can the power supply start the machine.

5、 After the machine is started, one person shall transport materials and operate the machine. The rest of the people shall not press the electric building or step on the foot switch board, nor put their hands into the mechanical working area or hit the moving part of the machine with their hands. When the machine is working, it is forbidden to extend the hand into the working area of sliding block, and it is forbidden to take and place the workpiece by hand. When taking and placing the workpiece in the die, the equipment conforming to the standard must be used. In case of any abnormal sound or mechanical failure, turn off the power switch immediately for inspection.

6、 When leaving work, turn off the power supply, and clean up the molding articles, leftovers and sundries on the position to ensure the working environment is clean and safe. The above operation procedures must be consciously followed. Do not operate in violation of regulations. In case of any obstacle, cooperate with the maintenance staff for inspection. In case of any event, cut off the power supply immediately, and keep the site report to the factory Department for handling. The party concerned shall bear all the consequences of violating the operation procedures

Advantages and disadvantages of CNC machining

Advantages and disadvantages of CNC machining

Advantages and disadvantages of CNC machining

CNC machining has the following advantages:

① The number of tooling is greatly reduced, and complex tooling is not required for parts with complex processing forms. If we want to change the form and size of the parts, we only need to modify the processing program of the parts, which can be used in the development and modification of new products.

② The machining quality is stable, the machining precision is high, and the repeated precision is high, which is suitable for the machining requirements of aircraft.

③ Under the condition of multi type and small batch production, the production efficiency is high, which can reduce the time of production planning, machine tool adjustment and process inspection, and reduce the cutting time due to the use of the best cutting amount.

④ It can be used to process complex surfaces which are difficult to be processed by conventional methods, and even to process some processing parts which cannot be observed. The disadvantage of NC machining is the high cost of machine tools and equipment, which requires high level of maintenance staff.

Technical problems of aluminum processing

There are many reasons for the deformation of aluminum parts, which are related to the material, shape and production conditions. There are mainly the following aspects: deformation caused by internal stress of blank, deformation caused by cutting force and cutting heat, and deformation caused by clamping force.

1、 Technological measures to reduce processing deformation

1 reduce the internal stress of blank

The internal stress of the blank can be partially eliminated by natural or artificial aging and vibration treatment. Pre processing is also an effective process. For the blank of fat head and big ear, because of the large margin, the deformation after processing is also large. If the surplus part of the blank is pre processed and the surplus of each part is reduced, not only the processing deformation of the subsequent process can be reduced, but also the internal stress can be released after pre processing for a period of time.

2. Improve the cutting ability of tools

The material and geometric parameters of cutting tools have an important influence on cutting force and cutting heat. The correct selection of cutting tools is very important to reduce the machining deformation of parts.

(1) Reasonable selection of tool geometry parameters.

① Front angle: under the condition of maintaining the strength of the cutting edge, the front angle should be larger. On the one hand, it can grind out a sharp edge, on the other hand, it can reduce cutting deformation, make chip removal smooth, and then reduce cutting force and cutting temperature. Never use a negative rake tool.

② Back angle: the size of the back angle has a direct impact on the wear of the back cutter face and the quality of the machined surface. The cutting thickness is an important condition to select the back angle. In rough milling, due to the large feed, heavy cutting load and large heat output, it is required that the heat dissipation condition of the cutter is good, so the back angle should be smaller. When finishing milling, it is required to have sharp edge, reduce the friction between the back face and the machining surface, and reduce the elastic deformation. Therefore, the back angle should be larger.

③ Helix angle: in order to make milling stable and reduce milling force, the helix angle should be selected as large as possible.

④ Main deflection angle: properly reducing the main deflection angle can improve the heat dissipation conditions and reduce the average temperature of the processing area.

(2) Improve the tool structure.

① Reduce the number of milling cutter teeth, increase chip space. Because of the large plasticity of aluminum material, the large cutting deformation and the need for large chip space, the bottom radius of chip holding groove should be larger and the number of milling cutter teeth is less.

② Sharpen the teeth. The roughness value of cutting edge should be less than RA = 0.4um. Before using a new knife, it is necessary to use a fine oilstone to slightly grind the front and back of the knife teeth, so as to eliminate the remaining burrs and slight serrations when grinding the knife teeth. In this way, not only cutting heat can be reduced, but also cutting deformation is relatively small.

③ Strictly control the tool wear standard. After tool wear, the surface roughness of workpiece increases, the cutting temperature increases, and the deformation of workpiece increases. Therefore, in addition to the selection of good wear-resistant tool materials, the tool wear standard should not be greater than 0.2mm, otherwise it is easy to generate chip accretion. When cutting, the temperature of workpiece should not exceed 100 ℃ to prevent deformation.

3. Improve the clamping method of workpieces

For thin-walled aluminum parts with poor rigidity, the following clamping methods can be used to reduce deformation:

① For thin-walled bushing parts, if the three jaw self centering chuck or spring chuck is used to clamp from the radial direction, the workpiece will be deformed once it is loosened after machining. At this time, the method of axial end face compression with better rigidity should be used. Locate the inner hole of the part, make a self-made threaded through mandrel, insert it into the inner hole of the part, press the end face with a cover plate and back it with a nut. When machining the outer circle, the clamping deformation can be avoided and the satisfactory machining accuracy can be obtained.

② When machining thin-walled sheet metal, it is better to select vacuum sucker to obtain uniform clamping force, and then to process with a small cutting amount, which can prevent the deformation of the workpiece well.

In addition, the filling method can be used. In order to increase the technological rigidity of thin-walled workpiece, the medium can be filled in the workpiece to reduce the deformation of workpiece during clamping and cutting. For example, fill the workpiece with urea melt containing 3% – 6% potassium nitrate, after processing, immerse the workpiece in water or alcohol, then the filler can be dissolved and poured out.

4 reasonable arrangement of process

In high-speed cutting, because of large machining allowance and intermittent cutting, the milling process often produces vibration, which affects the machining accuracy and surface roughness. Therefore, NC High-speed machining process can be generally divided into: rough machining – semi finish machining – angle cleaning machining – finish machining and other processes. For parts with high precision requirements, sometimes it is necessary to carry out secondary semi finishing, and then finish machining. After rough machining, the parts can be naturally cooled to eliminate the internal stress caused by rough machining and reduce the deformation. The allowance left after rough machining shall be larger than the deformation, generally 1-2mm. During finishing, the machining allowance of the finished surface of the part shall be kept even, generally 0.2-0.5mm is the best, so that the cutter is in a stable state during the machining process, which can greatly reduce the cutting deformation, obtain good surface machining quality, and ensure the accuracy of the product.

Medical device processing

Medical equipment processing not only needs to meet the requirements of high precision and high surface brightness of parts, but also faces the challenge from difficult to process raw materials.

The products of artificial key include hip, knee, shoulder, elbow, wrist, ankle, shin, spine, etc. In the artificial critical processing industry, because it is related to the health and safety of human remains, there are quite high requirements for the processing accuracy, quality and generality.

In the medical industry, the manufacturing enterprises usually have the following requirements for tool suppliers:

1. Partners and joint design strength. The manufacturing enterprises of artificial critical products have a good understanding of the raw materials and design of artificial critical products, but they don’t have much experience in the detailed processing technology of products, so they usually form a strategic partnership with tool suppliers. In the process of new product research and development, the tool supplier enters the joint development, and more researches are made on the stability of processing cost and processing technology, and the controllability of product quality.

2. Quite specific use. The products of artificial critical industries are relatively stable, and the design and use of products are relatively specific. Although the products provided by different companies are different, due to the relatively unchanged human body structure, there will be no significant difference in the products. In this way, the product processing technology and quality assurance system are also relatively similar. This also poses a greater challenge to tool suppliers, constantly improving the quality of tools, improving the level of processing technology, reducing processing costs, and improving the stability and controllability of processing technology.

3. High quality requirements. Most of the artificial critical products need to be implanted into human body, so the raw materials and quality of the products have the highest requirements. In the same way, the same requirements will be put forward for the suppliers including the tool suppliers of the manual critical processing enterprises. In the grinding equipment, the grinding oil temperature, air temperature, tool temperature and grinding point temperature are all detected online. When the temperature is too high or insufficient, the system will automatically adjust the air conditioning system and correct the temperature, so as to maximize the control to ensure the accuracy, quality and generality of the tool and meet the requirements of the medical industry.

4. Product traceability. All artificial critical products have their specific numbers, which are used to track the use of products, so as to achieve the traceability of product quality. If there is a problem with a certain product, it is advisable to trace all batches of the same product and recall the same product. This requirement is certain for the medical industry. Shangao tool has its specific number for tracking. As long as you check the number of this tool, you can immediately track the production date, production equipment, production process, product detection, product transportation and other information of the product.

5. Product certification. Due to the unique use of medical industry, the access threshold for suppliers is also quite high. The supplier must also possess the product certification system to meet the requirements of the medical industry.

The raw materials at the artificial juncture are also improving with the development of the industry. The demand for raw materials meets the requirements of biocompatibility (no adverse effect on human body), bioconversion (the artificial juncture must be integrated with the surrounding tissues), and of course, it also includes the strength and elasticity of raw materials. Moreover, the raw materials required by people of different ages are definitely different, which are suitable for more activities and late hours of young people The recovery of human body and bones in the year of 2000 was slow.

Common raw materials for artificial key include titanium alloy, cobalt chromium alloy (containing cobalt chromium molybdenum alloy), stainless steel, UHMWPE, peek and ceramics, and the heat treatment of raw materials is different, such as forging and forging.

Different raw materials and different heat treatment methods have a huge impact on the machinability of workpiece raw materials. Shangao cutting tool also specially develops a targeted cutting tool and processing plan for different raw materials in the medical industry. For example, when machining titanium alloy, it is advisable to select jhp750 series high efficiency milling tools to remove the surplus in the fastest time. At the same time, this tool can also be used for finishing. For cobalt chromium alloy, jh141 series high-speed milling tools can be selected with unique coating to ensure the surface quality and processing life of the workpiece. Peek raw materials, more and more found in many carbon fiber raw materials are widely used in the artificial critical industries, the selection of a unique custom diamond coated tool greatly improves the efficiency, life and process stability of the tool.

The processing of UHMWPE raw materials, such as the joint surface used in the knee joint, has quite high requirements for the quality of the processed surface, such as RA < 0.20 μ m, and also has different requirements for the workpiece difference target. Seco jabro has developed a special Super meticulous finishing milling cutter, Premier finish, which will be delivered with a unique serial number, product certificate, inspection report, unique tool packaging, etc. for product tracking, and this cutter can also be used for regrinding to reduce processing cost. Customers choose this cutting tool, the efficiency can be increased up to 70%, the process is stable, and the cost of the cutting tool also drops more than 30%.

The medical critical industry is related to human health interest, and the market scale is huge, and the development potential in developing countries is more and more obvious, and it is not affected by the market operation cycle. Most of the overseas key market occupiers still set up branches in China and carry out production. In recent years, the production scale has increased dramatically. Chinese production companies are also trying to catch overseas companies outsourcing a large number of products to China in order to reduce costs

Factors affecting the machining accuracy of precision parts

Factors affecting the machining accuracy of precision parts

Factors affecting the machining accuracy of precision parts

As we all know, the reason why the processing of well-rounded parts is called well-rounded machining is precisely because of the high requirements of its processing procedures and processes, as well as the high requirements for the accuracy of products. The processing accuracy of well-rounded parts includes the accuracy of position, size, form, etc. today’s small compilation summarizes the following factors that affect the processing accuracy of well-rounded parts:

(1) The rotary run out of the machine tool’s spindle can produce certain deviation to the machining accuracy of the parts.

(2) The inaccuracy of the guide rail of machine tool can also cause the deviation of the workpiece form of the careful parts.

(3) Transmission parts can also cause workpiece machining deviation, which is also the most important factor of workpiece surface deviation.

(4) The difference of tool and fixture will also affect the accuracy of workpiece.

（5） In the process of machining and cutting, due to the change of the position of the stress point, the system will deform, which will lead to differences, and also can make the accuracy of the workpiece deviate from the standard.

(6) The difference of cutting force will also affect the accuracy of workpiece.

(7) In the process of machining, the process system will have certain thermal deformation under the action of various heat sources.

(7) The deformation of the process system caused by heating usually affects the accuracy of the workpiece.

(8) The deformation of the machine tool caused by heating will cause the deformation of the workpiece.

(9) The hot deformation of the tool will have a great influence on the workpiece.

(10) The workpiece itself is deformed by heating, mainly if it is deformed by heating in the cutting process

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