September 2020 – Page 20 – CNC Machining & Turning, Milling, Metal parts

CNC lathe processing suitable industry

CNC lathe processing suitable for which industries? The following brief introduction:

CNC lathe is used for processing: straight line cylinder, oblique line cylinder, arc and various threads.

CNC lathe, turning center, is a kind of high precision, high efficiency automatic machine tool. Equipped with multi station turret or power turret, the machine tool has ordinary processing performance. It can process linear cylinder, oblique line cylinder, circular arc and various kinds of thread, groove, worm and other complex workpieces. It has various compensation performance of linear interpolation and circular interpolation, and has carried forward the excellent economic effect in the batch production of complex parts.

Numerical control technology refers to the technology of controlling the behavior of one or more mechanical equipment with digital instructions composed of numbers, ink and symbols. Numerical control usually selects general or special computer to complete digital program control, so numerical control is also called computer numerical control, referred to as CNC, overseas is usually called CNC, rarely use the meaning of NC. It usually controls the position, angle, speed and other mechanical quantities and the switch value related to the mechanical energy flow direction. The occurrence of numerical control depends on the appearance of data carrier and binary mode data operation. In 1908, the perforated sheet metal exchange data carrier came out; at the end of the 19th century, the control system with paper as data carrier and auxiliary performance was created; in 1938, qingxiangnong carried out rapid data calculation and transmission at MIT, laying the foundation of modern computer, including the basic computer digital control system. Numerical control technology is closely integrated with machine tool control. In 1952, the first CNC machine tool came out, which became an epoch-making event in the history of the world’s machinery industry and promoted the development of automation.

Numerical control technology is also called computer numerical control technology, it is the use of computers to complete the digital program control technology. This technique uses a computer to control the movement track of the equipment and the operation sequence logic of the peripheral devices according to the control program stored in advance. Because the computer is used to replace the numerical control device composed of hardware logic circuit, the storage, processing, calculation, logic inference and other control functions of input operation instructions can be completed through computer software. The micro instructions generated by processing are transmitted to the servo drive device, driving motor or hydraulic actuator to start the equipment running.

Traditional machining is manual operation of ordinary machine tools. When machining, metal is cut by hand, and the accuracy of products is measured by eyes with calipers and other equipment. The modern industry has already used the machine tools controlled by computer Digitalization for homework. CNC machine tools may as well follow the program prepared by technical staff to automatically process any products and parts directly. This is what we call CNC machining. NC machining is not only used in any boundary of all mechanical processing, but also the development trend and important and necessary technical means of mold processing.

The above is the practical boundary of CNC lathe processing, I hope to help you.

Advantages of CNC plus tools

The given machining route of CNC lathe refers to the path that the turning tool moves from the tool setting point (or the fixed origin of the machine tool) until it returns to the point and ends the machining program. It includes the path of cutting and the path of non cutting empty stroke such as cutting in and cutting out. Today we will learn what advantages CNC processing has?

① A large number of tooling is reduced, and complex tooling is not needed to process parts with complex shapes. If you want to change the shape and size of parts, you only need to modify the part processing program, which is suitable for the development and modification of new products.

② The machining quality is stable, the machining precision is high, and the repetition precision is high, which can meet the processing requirements of aircraft.

③ In the case of multi variety and small batch production, the production efficiency is higher, the time of production preparation, machine tool adjustment and process inspection can be reduced, and the cutting time is reduced due to the use of the best cutting amount.

④ It can machine complex surface which is difficult to process by conventional method, and even can process some parts which cannot be observed.

How to improve CNC machining quality

With the improvement of living standards, the quality of life has been greatly improved. Many people are thinking about how to improve the quality of life. The better the technology is, the more market demand will be, and the higher the efficiency will be. So how to improve the quality of CNC machining parts? Let’s learn about it together

Before CNC machining, use the calibration table to check whether the tool swing is within the allowable tolerance range. The tool head and lock nozzle should be blown clean with air gun or cleaned with cloth before machining. Foreign matters have a certain impact on the accuracy and quality of the workpiece.
The use of special cutting oil products can effectively avoid the problem of poor precision due to the performance of rapeseed oil, mechanical oil and other non-specific oil products. At the same time, the special cutting oil has good anti-oxidation and corrosion ability, which can effectively prevent the yellow robe rust problem.
CNC machining program sheet should be consistent with the reference angle direction marked on the mold, and then check whether it is aligned with the upper 3D drawing, especially for the workpiece with water transportation, it is necessary to see whether the 3D drawing is consistent with the water transportation of the workpiece. If there is any ambiguity, it is necessary to timely feed back to the programmer or find the fitter to check the 2D drawing to see whether the 2D and 3D datum angles are consistent.
Before processing, it is necessary to understand the contents of CNC processing program sheet. There must be 2D or 3D drawings on the program list, and the hexagonal data of “x length, y width and Z height” shall be marked. If there is a plane, it shall be marked with “Z” value. After processing, the operator can easily check whether the data is correct, and the tolerance data shall be indicated if there is tolerance.
Ensure that the equipment operates under the temperature and humidity within the specified working range to avoid the influence of external factors on the process accuracy to the greatest extent.

The above is the whole content of the article, hope to help you.

The function of machining procedure

Process specification is a technical document to guide construction. It generally includes the following contents: process route of parts processing, specific processing contents of each process, cutting amount, man hour quota and equipment and process equipment adopted. So what are the functions of machining process specification?

Process specification is the main technical document to guide production

The production planning and scheduling of machining workshop, the operation of workers, the quality inspection of parts processing, and the accounting of processing cost are all based on the technological procedures. Processing problems in production are often based on the process specification. In case of handling quality accident, the responsibilities of relevant units and personnel shall be determined according to the process specification.

Process specification is the main basis of production preparation

When the workshop wants to produce a new part, it is necessary to formulate the machining process specification of the part first, and then prepare for production according to the process specification. For example: the analysis and research of key processes in the processing technology of new parts; the preparation of necessary knives, clamps and measuring tools (purchased or self-made); the purchase or manufacturing of raw materials and blanks; the purchase of new equipment or the modification of old equipment, etc., must be carried out according to the process.

Process specification is the basic technical document of the newly-built Machinery Factory (workshop)

When building (rebuilding and expanding) a batch or large-scale machining workshop (section), the type and quantity of machine tools required and the layout in the workshop shall be determined according to the process specification, and then the area size, power and hoisting equipment configuration of the workshop as well as the type of work, technical level and quantity of workers required shall be determined.

Advantages of fine hardware processing

Fine hardware processing is widely used in our life, so what are the advantages of fine hardware processing? Let’s have a simple understanding:

CNC machining precision of fine hardware axis is high, with stable processing quality;
Multi coordinate linkage can be carried out, and parts with disordered shapes can be processed;
When the CNC machining parts of fine hardware are changed, only the NC program needs to be changed, which can save the production preparation time;
The machine tool itself has high precision and rigidity, and it can choose favorable processing amount and high productivity (generally 3 to 5 times of ordinary machine tool);
The machine tool automation degree is high, can reduce the labor intensity.

The above is the advantage of fine hardware processing, hope to help you.

Matters needing attention in fine parts processing

What should we pay attention to when processing fine parts

The number of working procedures of fine stamping parts mainly depends on the complexity of its structure and shape, and is determined by the number of tortuous angles, relative orientation and tortuous direction. When the zigzag radius of the zigzag part is less than the allowable value, a shaping process is added after the zigzag.
The process quantity of fine stamping parts is related to the data nature, drawing height, drawing steps, drawing diameter, data thickness and other conditions, which can only be determined by drawing process calculation. When the fillet radius of the drawing part is small or the scale precision is required to be high, a shaping process should be added after the drawing.
The determination of the number of processes should also be in line with the existing mold making ability and stamping equipment. Mold making ability should be able to ensure the mold processing, installation accuracy of the corresponding progress requirements. Otherwise, you can only add the number of operations.
When the cross-section quality and dimension precision of fine stamping parts are required to be high, it can be considered to add finishing process after blanking process, or select fine blanking process directly.
In order to improve the stability of fine stamping process, it is sometimes necessary to add process number to ensure the quality of fine stamping parts. For example, the additional positioning technology hole punching of zigzag parts, the addition of deformation in the forming process to reduce the hole blanking to transfer the deformation area and so on.
The blanking of fine stamping parts with simple shape is completed by single process die. Because the structure or strength of the die is limited, the inner and outer parts of blanking should be divided into several parts, and multiple stamping processes should be selected.
Special stamping oil should be selected for fine stamping. Rapeseed oil, machine oil, recycled oil and other non special oil products do not contain additives suitable for stamping processing, which will lead to quality problems such as reduced precision of workpiece, burr of burr edge and surface hole damage. And the chemical substances in non-specific oil products will form rust on the machine, yellow robe, and skin allergy of workers.

The above is the need to pay attention to the fine parts processing, I hope to help you

Advantages of CNC machining

CNC is also called computer gong, cncch or CNC machine tool. In fact, it was introduced into the Pearl River Delta of mainland China. It is actually a CNC milling machine. In Guangzhou, Jiangsu, Zhejiang and Shanghai, a new type of machining technology is called CNC machining center. Its main work is to compile processing programs, that is, to convert the original manual work into computer programming. So let’s take a look at the advantages of CNC machining?

② The machining quality is stable, the machining precision is high, and the repetition precision is high, which can meet the processing requirements of aircraft.

④ It can machine complex surface which is difficult to process by conventional method, and even can process some parts which cannot be observed.

The disadvantage of NC machining is the high cost of machine tools, which requires maintenance personnel to have a high level.

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.