June 2020 – CNC Machining & Turning, Milling, Metal parts

Some key points to improve the quality of CNC machining workpiece

1. Reasonable CNC machining tools

The smooth knife for processing steel and copper should be strictly distinguished and used, and the allowance of the smooth knife should be reasonable, so that the smoothness of the workpiece and the service life of the cutter will be better.

2. Before CNC machining, check whether the tool swings within the allowable tolerance range with the calibration table. Before machining, the tool head and locking nozzle can be installed only after being blown clean with the air gun or wiped clean with a cloth. Too dirty will have a certain impact on the accuracy and quality of the workpiece.

3. When clamping, pay attention to see whether the name and model of CNC machining workpiece and program sheet are the same, whether the material size matches, whether the clamping height is high enough, and use calipers to count.

4. The CNC processing program sheet shall be consistent with the direction of the reference angle indicated by the die, and then check whether the upper 3D drawing is correct, especially for the workpieces that have been drilled for water transportation. It is necessary to see whether the 3ddrawing is consistent with the water transportation of the upper workpieces. If it is unclear, it is necessary to timely feed back to the programmer or find a fitter to align the lower 2D drawing to see whether the 2D and 3D reference angles are consistent.

5. The program list of CNC processing documents shall be standardized, including die number, name, program name, processing content, tool size, feed amount, especially the safe length of tool clamping, reserved allowance of each program, and smooth tool. The place where the R-plane and plane should be connected shall be indicated on the program list. The operator shall increase the processing speed by 0.02-0.05mm, and first process several tools Stop to see if it’s connected, touch it with your hand to see if it’s up, and if it’s not, lower the gong.

6. Before processing, understand the contents of CNC processing program list. The program list must have 2D or 3D drawing, and mark “x length, y width, Z height” six side data,

If there is a plane, the “Z” value shall be marked. It is convenient for the operator to check whether the data is correct after machining. If there is a tolerance, the tolerance data shall be marked.

7. The machining speed of the machine tool shall be strictly controlled by the operator. The rotation speed of F-speed and s-axis shall be reasonably adjusted to each other. When F-speed is fast, it shall be faster than s-axis, and the feed speed in different areas shall be adjusted. After processing, the machine can be removed only after the quality is checked and no problem is found, and one-time processing is required to be perfect.

What is CNC boring

What is CNC boring? CNC boring refers to expanding or refining the original holes on the workpiece. The boring feature of CNC machining is to correct the eccentricity of the lower hole, to obtain the precise position of the hole, and to obtain high-precision roundness, cylindricity and surface finish. Therefore, boring is often used in the final process.

Compared with other machining, CNC boring is a kind of difficult machining. By adjusting only one blade (or blade holder), it processes micron sized holes like H7 and H6.

What are the characteristics of CNC boring?

1. Tool rotation

CNC machining is different from lathe machining. Because of the tool rotation, it is impossible to control the condition of the tool tip in time to adjust the feed amount. It is also impossible to change the machining diameter just by adjusting the CNC button like the CNC lathe. This has become a big obstacle to fully automated processing. Because the machining center does not have the function of automatic machining diameter adjustment (except for the one with U-axis function), it is required that the boring cutter must have a fine adjustment mechanism or automatic compensation function, especially in the case of fine boring, sometimes it must be adjusted at the micron level according to the tolerance requirements.

In addition, the direction of chip flow out is constantly changing when boring in machining center, so the cooling of tool tip, workpiece and chip discharge are much more difficult than when machining in lathe. Especially when the vertical machining center is used for steel blind hole rough boring, this problem has not been completely solved up to now.

2. Spring knife

The most common and troublesome problem in boring is the spring knife. The main reasons for the spring knife in the machining center are as follows

① Rigidity of tool system: including the rigidity of tool handle, boring bar, boring head and intermediate connecting part. Because it is cantilever machining, especially the machining of small holes, deep holes and hard workpieces, the rigidity of the tool is particularly important.

② Dynamic balance of tool system: relative to the rotating axis of tool system, if the tool itself has an unbalanced mass, it will cause chatter due to the effect of unbalanced centrifugal force during rotation. Especially in high-speed machining, the dynamic balance of tools has a great influence.

③ Fixed rigidity of workpiece itself or workpiece: for example, some smaller and thinner parts cannot be fully fixed with reasonable jigs due to insufficient rigidity or workpiece shape.

④ Blade tip shape: the cutting resistance is also different due to the different front angle, escape angle, tip radius and chip breaking groove shape of the blade.

Speed control of CNC machining

CNC machining in China is developing towards high speed and high efficiency. This includes the speed control of CNC machining in China. If we want to make full use of the effective working stroke, we must make the moving parts accelerate to the high-speed stroke in a very short time, and stop at the instant in the high-speed stroke. This is why it is necessary to control the speed of CNC machining in Dongguan.

According to the open control idea, we propose a method of automatic acceleration and deceleration control for the movement of CNC machine tools according to any curve. This method will push the automatic acceleration and deceleration control from the traditional fixed mode to the new flexible mode, and explore a new way to effectively improve the dynamic performance of CNC machine tools.

1. Flexible acceleration and deceleration control

In Dongguan CNC machining, the system program directly realizes the specific automatic speed control function. In this way, it is necessary to change the acceleration and deceleration characteristics of the system or modify the numerical control program by adding and subtracting control, so ordinary users can not make the numerical control machine tool have the best acceleration and deceleration performance according to their own wishes. Therefore, our flexible acceleration and deceleration control method adopts the principle of database, divides acceleration and deceleration control into two parts: acceleration and deceleration description and implementation, and separates acceleration and deceleration description from system program. In the software of CNC system, a general control channel is designed, which has nothing to do with the content of acceleration and deceleration database.

2. Flexible automatic acceleration control

Set the acceleration curve, analytical curve and non analytical curve, and store them in the acceleration and deceleration curve library as a template in the form of a number table.

3. Flexible automatic deceleration control

As a sample, acceleration control is stored in acceleration and deceleration curve Library in the form of data table. Reasonable automatic acceleration and deceleration control is an important link to ensure the dynamic performance of CNC machine tools. Because of the lack of flexibility, the traditional automatic acceleration and deceleration control based on fixed curve is not easy to ensure that the acceleration and deceleration process is compatible with the performance of the machine tool, and it is difficult to achieve the best dynamic characteristics of the machine tool movement.

The importance of machining factory management

For the machining plant, no matter the scale, as long as it is an organization, it must be managed. Only in this way can we ensure the long-term development of enterprises. However, for small and medium-sized mechanical processing plants in China, most managers do not pay enough attention to scientific management. Therefore, there will be a variety of problems in machining, which will affect the future development. So, what problems should be paid attention to in strengthening the management of machining plants?

1. Standardization of factory management

Whether the factory implements standardized system management is one of the conditions to measure whether the factory management is competitive, efficient and sustainable. As the staff are changing, a set of mature management system should be established. No matter what the characteristics of the factory are, its basic management is unchanged, which needs to be determined by the system to form a consensus so that everyone can understand and abide by it.

Factory management is not standardized. In the long run, factory management is unstable, basically hovering at a low level, and it is difficult to reach a new level. Its common performance is that the factory system is not perfect, the task is often difficult to complete on time, the problem is difficult to find the reason, excuses and disputes occur from time to time. However, it is also necessary to pay attention to humanization, not just paper documents.

2. Factory performance, employee performance evaluation

If we can’t evaluate the performance of the factory effectively, it’s difficult to find out the key problems accurately, and it’s difficult to grasp the next step. Only use some incomplete data and experience or feeling to deal with the daily production tasks, the daily work of employees will become inefficient, low efficiency will only make a factory lack of core competitiveness!

A perfect employee performance evaluation system is mainly to affirm the achievements, promote the employees to have a positive attitude towards work, help to find and correct the existing deficiencies, and make a plan to correct within a time limit. Therefore, we can not only find talents, train reserve forces of machining plants, but also solve the general unreasonable phenomenon of “governing by inaction”.

Machining plant – knurled nuts

3. Professional people do professional things

The concept of “responsibility is greater than power” should be set up in the machining factory, and the working attitude should be put into practice. Employees should perform their duties and care about the development of the factory. Work hard and work together. To cultivate the development concept of employees, everyone should be enterprising. Instead of being a monk and banging a clock.

4. Production flexibility

Some factories shuffle and kick each other, but they don’t work at last. Simple things are extremely complicated. What else can we talk about in the case of work delay? In fact, many factories have not achieved satisfactory results in this regard. There are many reasons for this. The key is to release the centralized management system and give the responsible person enough management responsibility and rights.

Machining plant – stainless steel nuts

5. Professional talent management and factory development culture

Factory culture is accumulated by the joint efforts of all the people in a company, and it is the promotion of factory management accumulated by the factory for a long time. Good corporate culture is the core competitiveness of the factory, which is the soul of the factory. In particular, a manufacturing factory should have the spirit of research in technology, rather than a word that can’t be done when encountering difficulties. A good technician often helps the factory to expand the scope of business processing. With such a healthy development of internal environment, it is the basic element for the factory to be invincible to cultivate young employees for rapid growth and the factory to constantly cultivate high-quality reserve forces.

Precautions before starting NC machining

1. Precautions before starting NC machining:

(1) Before the start of NC machining, be familiar with the performance, structure, transmission principle, operation sequence and emergency stop method of NC machine tools.

(2) Check the lubricating oil and the oil quantity in the gearbox.

(3) Check the fastening screws and do not loosen them.

(4) Clean the surrounding environment of the machine tool, keep the machine tool and the control part clean, and do not remove the cover to start the machine tool.

(5) Correct the tool and meet the use requirements.

CNC machining

2. Precautions for NC machining programming:

(1) Use the correct tool, strictly check whether the machine origin and tool parameters are normal.

(2) Confirm whether the operation procedure and processing sequence are consistent.

(3) It is not allowed to undertake operations beyond the machining capacity of CNC lathe.

(4) Adjust the tool when the machine stops, and make sure that the tool does not collide with other parts during tool change.

(5) Confirm whether the fixture of workpiece has enough strength.

(6) After the program is adjusted, it shall be checked again, and the processing can be started only after it is confirmed to be correct.

CNC machining

3. Precautions after the CNC machining is started:

(1) After the machine tool is started, the running state of the machine tool must be monitored before its automatic and continuous operation.

(2) Make sure the coolant output is smooth and the flow is sufficient.

(3) When the machine tool is running, the protective cover shall be closed, the size of the tool and the measuring workpiece shall not be adjusted, and the hand shall not be close to the rotating tool and workpiece

(4) When the machine is stopped, remove the chips from the workpiece or tool.

CNC machining

4. Precautions when finishing machining of CNC lathe:

(1) Clean the machine tool.

(2) Anti rust oil lubricates machine tools.

(3) Turn off the system, turn off the power.

CNC machining knowledge

Create CNC process function and CNC process plan:

(1) CNC process considers the process of machining parts, clamping and positioning of machining parts, tool selection, simplified process route, cutting method and process parameters in conventional process.

(2) CNC machining process design is mainly used to guide CNC programming. Our company combines the responsibilities of CNC technicians and programmers, and the programmers are responsible for the whole CNC machining process of the mold, which improves the working efficiency.

(3) CNC machining has a high degree of automation and many influencing factors. Quality and safety are very important in CNC machining and must be guaranteed.

(4) The preparation of CNC machining process should be strict with the rationality of strip steel. The CNC process is complex and has many influencing factors. It is necessary to think deeply about the whole process of CNC processing and have good strip rationality in order to program the CNC process well. Due to the high degree of automation and poor adaptability of CNC processing, when there are problems, it is difficult for the staff to correct them on site, and the manufacturing and processing defects of the light-duty people occur safety accidents on the way, so it is necessary to systematically design CNC process in advance.

(5) good inheritance of CNC technology. It has been proved to be a good CNC technology in production. It can make templates and save them as documents. It can be used to process similar parts in the future, saving time and ensuring quality.

For CNC machining process planning, it will be considered as the state space of a series of programs from the initial state (male and female die core blank) to the final state (part). CNC sequence sorting must conform to the following general rules:

1. The primary parameter is followed by the secondary parameter.

2. Face before hole, milling before drilling.

3. First coarse, then fine.

4. The inner cavity is processed first, and then the shape is processed.

5. According to the sequence of working procedure, the diameter of cutter varies from large to small.

6. The processing of the previous process will not affect the clamping and positioning of the next process.

7. Put the same tooling and fixture together to reduce repeated clips and positions.

8. CNC process must be centralized.

9. Do not use the program instruction to weaken the part stiffness first.

Good CNC process planning needs to consider the following aspects:

Whether it can meet the technical requirements of parts, whether it can improve the efficiency of CNC processing, low processing cost and good quality control.

Therefore, the overall CNC processing plan is generally as follows:

1. Selection of CNC machine tools.

2. Select the treatment method.

3. Determine how to clamp the part and select clamp.

4. Positioning method.

5. Inspection requirements and methods.

6. Select the tool.

7. Error control and tolerance control in machining.

8. Define CNC process.

9. CNC sequence.

10. Select cutting parameters.

11. Prepare NC machining program table.

Process of metal parts processing

We have hardware everywhere in our daily life, which can be said to be endless. So what is hardware? Most people don’t understand, I don’t know, I haven’t touched. Therefore, hardware, as the meaning of five kinds of metals shows, is made of gold, silver, iron, copper and aluminum as raw materials, through cutting, pressing, brazing and other physical processing, to produce all kinds of metal device parts we need.

Our common screws, nuts, etc. Do not look at the small screws so common, hardware processing into finished products seems easy. In fact, the process is quite tedious. One is to have drawings of screw samples, and then select processing equipment according to the tolerance and accuracy requirements of the drawings. After the semi-finished products are made by the equipment, the burr on the burr shall be removed by fine vibration grinding to make the surface smooth and glossy, so as to prevent the contact from hurting the user.

Finally, the surface plating process to prevent rusting is carried out according to the material requirements. Such a small screw was born, and every program should be taken seriously. In the fastener market, ordinary parts can not meet the requirements of high-end consumers, but as long as there are models and drawings, we can process them by CNC or ordinary lathe to make the parts we want. Parts are an indispensable part in our life, and play an important role in all places.

It can be said that with the transformation and upgrading of industrial modernization and the growth and development of social economy, the fastener industry of hardware processing will play an important role

Continuous improvement of Chinese hardware Customization Technology

With the continuous improvement of domestic hardware customization technology, the dimensional tolerance and performance parameters of products are further improved. Due to the cost advantage of hardware customization products, precision hardware customization parts gradually replace forged parts.

At present, precision hardware components are mainly used in mechanical equipment, parts and components, electrical toys, electronic products, etc. the manufacturing process of customized precision hardware products is about 30% less than that of traditional metal forging process, and the utilization rate of materials is up to more than 80%. The manufacturing process conforms to the concept of environmental pollution, environmental protection, energy conservation and emission reduction, and sustainable development. In the future, domestic enterprises will use more CNC processing hardware customized process to produce more product parts, while improving the quality and cost management requirements of energy conservation and emission reduction policies.

In the background of Chinese market, domestic hardware accessories customization enterprises are trying to improve their technology and technology, so that they can cover the needs of all walks of life for hardware accessories customization. To provide customers with a variety of high-precision and complex mechanical parts hardware products, customized overall solutions and services, to multiply the productivity effect!

We must have rich experience in project practice to produce precision hardware accessories customized accessories processing products. The processing and customization of special-shaped frame put forward higher requirements for function and precision, and the existing processing of ordinary machine tools can not meet the requirements of new materials and new structures.

The structure of special shape becomes more and more complex. Compared with the traditional process, the cost of individual products increases directly. The technical difficulty and cost complement each other. By determining the alloy elements of special shape structure components and hardware tools, and improving some technical treatment, we can meet the requirements of different precision and hardness performance of precision parts. In addition, we can increase the same profile structure It does not increase the cost. Precision hardware customization including sheet metal pressure nut, furniture hardware hinge, small motor carbon brush copper sleeve, mining machinery Stone copper sleeve, motor oil shaft, coffee oil bearing, etc. technical innovation can meet the high quality requirements, which plays an important role in energy saving, performance improvement and productivity improvement.

CNC machining – precision hardware parts

In the production of CNC lathe, precision control has an important influence on the product quality. The machining accuracy depends on the mechanical accuracy, programming accuracy, servo accuracy and error compensation value accuracy. In order to improve the machining accuracy of CNC lathe, the machining accuracy of CNC lathe can be effectively improved in the design stage through CAD design and computer simulation technology. Strengthening the maintenance of the machine in use can effectively guarantee the high precision state of the CNC lathe.

1. Analysis of machining accuracy of CNC lathe

At present, the classification of CNC lathe is mainly set precision, position precision and machining precision. Different brands of CNC lathes have different material rigidity (the quality of CNC lathe equipment), and the working temperature will have a variety of effects on the machining accuracy of CNC lathes. The geometric accuracy of CNC lathe can be further subdivided into spindle geometric accuracy and linear motion accuracy.

In the machining operation of CNC lathe, the relative position between the main shaft and the rotating shaft remains relatively fixed. In actual production and theoretical knowledge, the relative spatial position between the two shafts does not have to be relatively fixed. This is because the bearing elements that make up the spindle may have different degrees of errors in the production plant where the lathe equipment is manufactured, and will be affected by the temperature, working strength, lubrication and other conditions during the use process. Due to the bearing accuracy of the main shaft, the manual assembly quality of the main shaft box is different, the mechanical vibration of the main shaft and rotating parts in the process of processing causes the runout, the roundness of the bearing journal of the central shaft is unstable in the manufacturing process, the concentricity before and after has certain error, and the thermal deformation may occur in the working process of the main shaft. All these factors affect the spindle geometric accuracy of CNC lathe.

In addition to the geometric accuracy error caused by the spindle in CNC lathe machining, the orbit may also affect the position accuracy of the machine due to the friction and the inertia matching of the servo motor used in CNC lathe machining. Some parts of CNC lathe that need to work continuously, such as cylinder pump, motor, hydraulic machine, etc., need to work continuously for a long time (even 24 hours). In the process of working, friction causes the specific internal parts. Because of the thermal expansion and deformation of the processing heat, the actual production size of the parts deviates from the designed predetermined size. Because of the role of internal heat, the asymmetry of the components of CNC lathe equipment results in the deformation of the production and processing parts. Therefore, the thermal deformation of the components of CNC lathe equipment will have a great impact on the position accuracy of the machine The effect of the key.

The machining accuracy of CNC lathe is closely related to the geometric accuracy of the whole CNC lathe, not only to the position accuracy, but also to the transmission system failure of CNC lathe machining, the inspection of fault compensation system, the friction of machine structural parts, the position error of cutting tools, etc., as well as to whether the program editing of CNC lathe machining is correct and the production process is reasonable. Therefore, in the actual production, in order to improve the machining accuracy of CNC lathe, we must improve the geometric accuracy and position accuracy of CNC lathe machining.

Selection of CNC milling machine

1、 To buy a machine, you still need to choose a brand. Although the brand is more expensive, it’s worth the money. I believe the assembly gap will not exceed 50000 yuan, but it’s still cost-effective in a comprehensive way. A good machine can create value for you virtually. If you buy a bad machine for three days or two ends fail, or the accuracy cannot be reached, you’re exhausted. In the end, all the customers are gone.

2、 Choose a regular manufacturer and register with the industrial and commercial department. It’s better to have quality certification. Those small factories without factory agents or with only a few people should not be tested. They can’t figure out how to be cheap for a while. When no one can be found, they will have to cry a lot in China.

3、 Look at the service attitude. No matter how good the machine is, there will be colds. At this time, you need to choose a good service provider. Those who don’t trust us and don’t repair them in time should not be ignored. When choosing machines, sometimes I prefer to choose the ones with slightly poor quality, but the ones with timely service make people feel relieved.

4、 Choose the domestic assembly machine, if it is a brand machine, then rest assured. For the sake of their long-term efforts to establish credit, merchants do not need to quote random prices, and the machine will not cut corners. For example, Yongjin, Chaoqun, Zhongmao (now called Shenghong), Liwei, Dali, you can buy with ease. If other brands want to see if the controller is Mitsubishi m64sm, don’t spend the price of m64sm to buy a m64as controller (to prevent businesses from selling mutton and dog meat). Although they are all 64 series, the price difference is more than 10000, and the performance gap is even less high-speed and high-precision, which is an important function. Although some businesses agree to reduce the price, they buy different things. Therefore, we need to eliminate the cost The fee maker thought that he had taken advantage of it. In fact, the merchant was stealing it