2020 – Page 41 – CNC Machining & Turning, Milling, Metal parts

Method of eliminating spherical error of CNC

With our processing, is more and more extensive, many products, are to be used for processing, for processing problems, how to solve, how to deal with, CNC machining is the same, then CNC machining parts spherical surface easy to produce shape error elimination method is what?

Caused by system gap

In the transmission pair of CNC machining equipment, there is a certain gap between the lead screw and the nut. With the increase of the equipment operation time, the gap is gradually increased due to wear. Therefore, the corresponding gap compensation during the reverse movement is the main factor to overcome the shoulder on the machined surface. The gap measurement usually adopts the dial indicator method, and the error is controlled within 0.01-0.02 mm. It should be pointed out here that the meter base and the meter rod should not be extended too long, because the cantilever is long, the meter base is easy to be forced to move, resulting in inaccurate counting, and the compensation value is not true.

Caused by uneven machining allowance of workpiece

Before the design surface of CNC machining parts is realized, whether the machining allowance of the surface to be machined is uniform is also an important reason for whether the forming surface can meet the design requirements, because the uneven machining allowance is easy to cause “remapping” error. Therefore, for the parts with high requirements on surface shape, the machining allowance should be even as much as possible before forming, or the method of machining one more profile to meet the design requirements.

Improper tool selection

CNC cutting tools remove materials through the main cutting edge. However, after the arc passes through the quadrant, after the arc is tangent to the cutting edge of the tool pair (the intersection line between the back of the pair and the base plane), the secondary cutting edge may participate in the cutting (i.e. backhoe). Therefore, the wedge angle of the tool must be considered when selecting or grinding the tool.

CNC processing convenience

CNC machining is the CNC machine tool controlled by the computer to process parts and components. The working principle of CNC machine tool is the same as that of a robot. It must be used with the program and in accordance with all the footnotes. So, what are the advantages of CNC processing? Let’s have a simple understanding:

The key goal of CNC machining is to remove the surplus parts of raw materials and make them have proper forms, such as circle, rectangle, etc. in traditional way, these machines are operated by the operators who operate these machines. Large number of jobs require accurate processing, and operators should have sufficient professional strength for careful processing.

In CNC machine tools, the operator’s role is minimized. The operator must only input the instruction program in the computer to load the required equipment into the machine, and the rest of the work is automatically completed by the computer. The computer instructs the machine tool to carry out various processing operations according to the instruction program given by the operator.

The above is the easy part of CNC processing, I hope to help you.

Machining steps

The operation of machinery is very important. If there is a wrong step in the operation, the consequences may directly affect the quality of the product. These are not what we want, so we must follow the steps in the operation. Let’s learn about the specific steps of machining?

Finishing: this processing principle is roughly some grinding and polishing, which is usually carried out after the product has completed the structure.
Face before hole: in the process of precision mechanical parts, for the workpiece such as bracket, it is necessary to carry out both plane processing and mechanical hole processing. In order to make the accuracy error of the hole processed smaller, machining the plane before processing the hole is conducive to reducing the error.
Dividing the processing stage: when the product is in the precision mechanical parts, the processing degree needs to be divided according to different product requirements. If the accuracy requirement is not high, then a simple rough machining stage is OK. The product schedule requirements are more and more strict, the follow-up will be semi finishing and finishing stage.
Datum first: when using mechanical equipment to process products, a datum plane must be determined, so that there can be a positioning reference in the subsequent processing. After the datum plane is determined, the datum plane must be processed first. In precision mechanical parts, there will be a lot of workpieces are not produced by one-time production, but when the workpiece is produced, it is just a rough model.

Classification of hardware processing

Perhaps many people think that in the hardware processing is the same, as long as the hardware parts processing is the same method. If you think so, it’s wrong. The surface processing of hardware needs to be divided more carefully. Generally, it can be divided into: metal painting processing, electroplating, surface polishing, metal corrosion processing, etc. today, the hardware processing editor will give you a general explanation.

Spray paint processing: hardware factory in the production of large hardware products are used in spray painting processing, through the painting process to avoid hardware rust, such as: daily necessities, electrical shell, handicrafts and so on
Electroplating: electroplating is also the most common processing technology of hardware processing. Through modern technology, the surface of hardware parts can be electroplated to ensure that the products will not mildew and rust for a long time. The common electroplating processing methods include screws, stamping parts, batteries, turning parts, accessories, etc,
Surface polishing processing: surface polishing is generally used in daily necessities for a long time. Through the surface burr treatment of hardware products, for example, we produce a comb. The comb is made of hardware by stamping. Then the edges and corners of the comb are very sharp. We have to polish the sharp parts of the edges and corners into a smooth face, so that in the process of use No harm to human body.

The reason of precision drop

The precision of hardware parts almost determines the quality of the products. The more careful the hardware parts are, the higher the accuracy requirements will be. So what are the reasons for the drop of precision? Let’s have a simple understanding below:

One factor is the poor machining accuracy of the parts themselves. Generally speaking, if the dynamic deviation between shafts is not adjusted well during installation, it may also be because the shaft drive chain changes due to wear, which will affect the accuracy of the parts. Generally speaking, it is advisable to adjust the compensation amount from the beginning in order to check the accuracy caused by the deviation of this variety. If the deviation is too large and even if an alarm occurs, it is necessary to check the servo motor to see if its speed is too high.

The two factors are that the overshoot during the operation of the machine tool will also affect the processing accuracy. It is possible that the acceleration and deceleration time is too short, and the appropriate lengthening of the transition time. Of course, it is also very likely that the link between the lead screw and the servo motor is loose.

The three factors are the roundness out of tolerance caused by the linkage of the two shafts, the axial deformation of the circle caused by the mechanical failure, the compensation error of the screw clearance of the shaft, or the deviation of the shaft positioning, which may affect the precision of the detailed parts.

The above is the cause of precision drop, I hope to help you

Reduce noise produced by CNC machining

Mechanical equipment will always have some sound when it is in operation. It is very difficult to completely mute it. Although we can not completely control the noise, we can use some methods to generate bottoming noise. Then we will learn how to reduce the noise generated during CNC parts processing?

Civilized production: more than 30% of gear transmission noise is caused by burr and bump. It is a passive way to remove burr and bump before gearbox assembly in some precision mechanical parts processing factories.
Ensure the accuracy of gear blank: the accuracy of gear hole size is required to be distributed around the middle difference of the deviation value of the hole, which is set at ± 0.003 ~ ± 0.005mm; if the error is out of tolerance and within the design requirements of the hole, it must be classified and transferred to the gear cutting process.
Control gear accuracy: the basic requirements of gear accuracy: after practical verification, the gear accuracy must be controlled at the level of gb10995-887 ~ 8, and the linear speed should be higher than 20m / s. The limit deviation of pitch, radial runout tolerance of gear ring and tooth alignment tolerance must be stable and reach the accuracy of grade 7

CNC processing piecework method

Piece counting is one of the most basic movements in the die and mold industry, and the piece counting performance of the CNC machine tool is often related to the performance of its internal parts. What are the piecework methods of CNC machining center? Let’s have a brief understanding of the following:

CNC machining center piecework is related to the detailed mechanical system. Some systems are easy to use, and the program only needs to be implemented once, which can be automatically memorized, and then can be modified after configuring the code required by users. Therefore, these piecework methods will improve the work efficiency. Compared with other mold machinery, machining center is a relatively easy-to-use product. It is not only highly automatic, but also has good work efficiency. It is more and more in the way of piecework, which seems to be a tedious process. In such a machine, it can be finished easily, so the machine will be very popular.

Every machine that can play a major role in the industrial production movement is originally a major product to maintain. The most important part of CNC machining center is its programming software, and the appearance of CNC machining center programming software ensures the excellent performance of the machine in the process of operation. CNC machining center piecework is related to the detailed mechanical system. Some systems are easy to use, and the program only needs to be implemented once, which can be automatically memorized, and then can be modified after configuring the code required by users. Therefore, these piecework methods will improve the work efficiency. CNC machining center programming software may have a number of choices, some software is relatively simple, so learning is also very easy, welcomed by users, and in all the mold industry, the use of contrast more often than some brand famous contrast high, of course, about its use will also put forward some good demand for the elite.

The above is the CNC machining center piece work method, I hope to help you

Machining precautions

In order to ensure the quality of the product, we need to be careful in the operation to reduce the probability of error. Therefore, there are many matters needing attention when operating. But many new users don’t know what matters should be paid attention to when operating. What are the precautions for machining?

The clamping method of mechanical parts processing should reasonably choose the positioning datum and clamping scheme

When setting our benchmark, we should follow the two principles of “benchmark unification” and “benchmark coincidence”.

In large-scale machining, all surface processing should be completed in one positioning and clamping as far as possible. Therefore, it is necessary to select a positioning method that is easy to process all surfaces of the workpiece.
When determining the position of the workpiece on the worktable, we must consider the influence of the processing of each position, the length of the tool and the stiffness of the tool on the machining quality.
The fixture used in machining should be assembled by common parts and can be adjusted as far as possible, which can effectively shorten the production preparation cycle.

Problems needing attention in arranging large machining sequence

(1) In order to arrange the machining sequence, we must follow the basic principles of “surface before hole” and “rough first and then fine”.

(2) Determine the tool point and tool change point, once determined, not suitable for replacement.

(3) According to the centralized process of cutting tools, the same tool can be avoided to be reused, and the times and time of tool replacement can be reduced.

(4) For the hole system with very high coaxiality requirement, the hole system in other coordinate positions should be processed after the completion of all the processing of the hole system after one positioning, which can effectively eliminate the error caused by repeated positioning and improve the coaxiality of the hole system.

CNC machining fixture requirements

Fixture is an essential part of CNC machining center. Each CNC machining center will use fixture. According to the different products processed, the fixture used is different, and the requirements for fixture are different. However, CNC machining center has similar requirements for fixture, and special workpiece has different requirements for fixture. So what are the requirements of CNC machining center for fixture? Let’s have a brief understanding:

High precision fixture

As we all know, CNC machining center has a very high precision, which is usually used to process parts or molds with high precision. For this reason, CNC machining center also puts forward the requirements of fixture high-precision positioning and installation, as well as the requirements of transposition and positioning accuracy.

The fixture should be convenient and fast when clamping the workpiece

In order to meet the high-speed machining fixture of CNC machining center, hydraulic and pneumatic fast locking power is adopted, especially for the workpiece locking with long processing time. The general hydraulic clamping system will be attached with a storage device, which can supplement the internal leakage and prevent the workpiece from loosening on the fixture.

The fixture should be open

CNC machining center is processed by the tool contacting the workpiece. Under the clamping of the workpiece, the workpiece should provide relatively spacious operation space for the fast moving tool and tool changing quick action. Especially for the complex workpiece with multiple tool changes, the fixture structure should be as simple, convenient, fast and open as possible to make the tool easy to enter and exit, and prevent the tool from colliding with the fixture workpiece in the process of processing.

The fixture should have high adaptability

We all know that CNC machining center is flexible and multi deformation, so the fixture should have high efficiency adaptability to different workpiece and different clamping.

The above is the CNC machining center on the clamp requirements, I hope to help you.

Hardware processing precautions

Hardware products are very common in our life and often need to be used. But I believe you are not familiar with the word of hardware processing, and even more unfamiliar with this process. Because usually in life contact is the finished product, we do not know the process, so the following small series to take you to understand what matters need to pay attention to in the hardware processing?

1、 The design of drawings should be precise, detailed and accurate

Some of our drawings are provided by our customers, and some are designed by ourselves. After the design is completed, we should print a complete set of drawings and check them carefully. It is better to use 3D design software to complete assembly once and check the size of each part.

2、 The compilation of the detailed list should be fully consistent with the actual situation

The preparation of detailed list is a meticulous work. Every spare part should be checked carefully, and it should be compared with the model plate and drawing on site. There should be no mistakes, omissions or more.

3、 Die acceptance can not be sloppy

Mold acceptance is a highly professional work, product developers, mold designers, mold manufacturing personnel should participate in it, mold material, part size, mold structure rationality, life are very important indicators.

4、 Problems should be found in product trial assembly and sample production

The purpose of product trial assembly is to find out the problems, record the problems and solve them one by one.

5、 The product code should be checked carefully

Product tagging is the most error prone place, we also have many lessons in this respect. The name, quantity, material and technical requirements of parts and components are very important data. If a certain data is wrong, it will cause great economic losses to the enterprise. Especially for the loan parts, the product tagging personnel, developers and technicians must check carefully.

The above points are in the hardware processing need to pay attention to the matters, want to learn more information, welcome to visit our website