What are the technical requirements of Fujian CNC lathe processing plant?

CNC lathe processing, first of all, determine the process requirements of parts, the batch of workpieces to be processed, draw up the functions that CNC lathe should have, make early preparations, and reasonably select the preconditions of CNC lathe to meet the process requirements of typical parts. The process requirements of typical parts are mainly the structural size, processing range and accuracy requirements of parts.

1, the initial steps of CNC lathe processing. First, determine the process requirements of the parts and the batch number of the workpiece to be processed, draw up the functions that the CNC lathe should have, and make good preparations in the early stage. The premise of reasonable selection of CNC lathe is to meet the technological requirements of typical parts. The process requirements of typical parts are mainly the structural size, processing range and accuracy requirements of parts.

2, according to the accuracy requirements, namely the workpiece size accuracy, positioning accuracy and surface roughness requirements to choose the control accuracy of CNC lathe. According to reliability, reliability is the guarantee to improve product quality and production efficiency.

3, the reliability of CNC machine tools refers to the machine tool to perform its functions under the prescribed conditions, long-term stable operation trouble-free. That is, the average time between failures is long, and even if something goes wrong, it can be recovered and put into use again in a short time. Choose a machine tool with reasonable structure, excellent manufacturing and mass production. Generally speaking, the more users, the higher the reliability of CNC system.

4, CNC lathe processing materials are: 304, 3 16 stainless steel, carbon steel, copper, aluminum, alloy, plastic, POM, etc. When turning products with different materials, it is necessary to use different quality tools to ensure the required accuracy of each product.

Machining accuracy is mainly used to characterize the fineness of the products produced, and it is a term to evaluate the geometric parameters of the machined surface. Machining accuracy is measured by tolerance grade, and the smaller the grade value, the higher its accuracy. There are 20 tolerance levels from IT0 1, IT0, IT 1, IT2, IT3 to IT 18 * *, in which IT0 1 indicates that the machining accuracy of the part is the highest and IT 18 indicates that the machining accuracy of the part is the lowest. Generally, factories and mines belong to IT7 level. When the workpiece rotates, the turning tool moves in a straight line or curve in the plane. Turning is generally carried out on a lathe to process the internal and external cylindrical surfaces, end surfaces, conical surfaces, molding surfaces and threads of the workpiece.

The turning accuracy is generally IT8—IT7, and the surface roughness is 1.6-0.8 micron. ..

1. Rough turning strives to improve turning efficiency by using large cutting depth and large feed rate without reducing cutting speed, but the machining accuracy can only reach IT 1 1, and the surface roughness is rα 20-10μ m. ..

2. Semi-finish turning and finish turning should adopt high speed and small feed and cutting depth as far as possible, and the machining accuracy can reach IT 10-IT7, and the surface roughness is rα10.16 μ m. ..

3. High-speed turning of non-ferrous metal parts on high-precision lathe with fine polishing diamond turning tool can make the machining accuracy reach IT7—IT5 and the surface roughness rα 0.04-0.01μ m+0μ m, which is called mirror turning.

In the actual production process, it will be found that the same CNC lathe is operated by different personnel, and the production efficiency varies greatly in the same working time, so the processing ability of many CNC lathes cannot be fully reflected and its best function cannot be exerted. In the process of use, only by fully considering various factors affecting the production efficiency of CNC lathes and striving to improve the production efficiency of CNC lathes can the production capacity of CNC lathes be fully exerted.

First of all, make a reasonable machining route to reduce the auxiliary time of NC milling.

In order to improve the production efficiency of CNC lathe, the parts processed by CNC lathe should be carefully analyzed to find out the technical requirements, structural characteristics, shape and position tolerance requirements, roughness, heat treatment and so on. Then on this basis, choose a reasonable milling process and a simple processing route.

Formulation of processing technology: Usually, a part can have several different processes, and there are often significant differences in production efficiency, processing cost and processing accuracy. Therefore, under the premise of ensuring the processing quality of parts, according to the specific conditions of production, we should try our best to improve production efficiency, reduce production costs and formulate reasonable processing technology.

Determination of processing route: Correct and concise processing route is the basis of ensuring processing quality and improving efficiency. When selecting the processing route of parts, the principle of determining the processing route must be followed to achieve the purpose of improving production efficiency. The principles of determining the machining route are: to ensure the machining accuracy and surface roughness of parts and high efficiency; The shortest machining route should be made as far as possible, which can not only reduce the program segment, but also reduce the blank cutting time of the tool; Numerical calculation should be simple, and the number of program segments should be less, so as to reduce the programming workload. In addition, when determining the machining route, we should also consider the machining allowance of the workpiece and the stiffness of the lathe and cutter, and determine whether the machining is completed by one pass or multiple passes. At the same time, try to achieve one-time clamping, multi-directional processing and one-time processing and molding. In this way, the installation times of the workpiece can be reduced, and the time for handling and clamping can be effectively shortened. This can not only effectively improve the machining efficiency, but also ensure the position accuracy requirements of the parts.

Second, choose the right tools.

When choosing tools, we should consider the processing capacity, process content, workpiece material and other factors of CNC lathe. The tools selected for CNC lathes require not only high hardness, high wear resistance, sufficient strength and toughness, high heat resistance and good manufacturability, but also stable dimensions and convenient installation and adjustment. Therefore, we should use new high-quality materials to manufacture NC machining tools, and optimize the tool parameters to make the size of the tool adapt to the surface size and shape of the machined workpiece. So, how to choose the right tool?

(1) Select the appropriate tool.

In the cutting process of CNC lathe, the role of metal tools is extremely important. The materials used to make tools must have high hardness, wear resistance and heat resistance, sufficient strength and toughness, good thermal conductivity and manufacturability, and good economy. In the process of selecting tools, on the premise of meeting the requirements of parts processing, try to choose tools with larger diameter, which have better strength and toughness; In the same process, the number of selected tools should be as small as possible to reduce the number of tool changes; Try to choose general standard tools, and don't use special non-standard tools or less.

(2) Reasonably determine the tool alignment point

Tool alignment point is the starting point of tool movement relative to workpiece when NC lathe processes parts. Also called "program starting point" or "starting point". The following principles must be followed when selecting the tool site: it is convenient to use digital processing and simplify programming; It is easy to find alignment on lathe and check machining; And the resulting machining error is small. The location of the tool alignment point can be selected on or outside the workpiece (such as fixture or lathe), but it must have a certain dimensional relationship with the positioning datum of the part. The tool setting point should be selected as far as possible on the design benchmark or process benchmark of the part. For example, the center of the hole can be selected as the tool set point of the workpiece positioned by the hole. The position of the tool is aligned with the hole, so the "on-site" and "tool alignment point" coincide. This can better improve the efficiency of tool setting and ensure the processing quality.

Thirdly, the clamping workpiece should be installed reasonably to improve the clamping speed.

When machining a workpiece on a CNC lathe, the positioning and installation of the workpiece should strive to unify the design benchmark, process benchmark and programming benchmark; Minimize the number of clamping, and process all the surfaces to be processed after one positioning and clamping as much as possible; Avoid manual adjustment of machining scheme and give full play to the efficiency of CNC lathe.

When CNC lathe cuts, the positioning and clamping design of parts, the selection and design of furniture should be considered comprehensively. When designing furniture, we must first ensure that the coordinate direction of furniture is relatively fixed with that of lathe. Secondly, it is necessary to coordinate the dimensional relationship between the parts and the lathe coordinate system. At the same time, you should also consider:

(1) When the production batch of parts is not large, combined fixture, adjustable fixture and universal fixture should be used as much as possible to shorten the production preparation time and save the production cost;

(2) Only special fixtures are considered for mass production, and the structure is simple;

(3) Parts should be loaded and unloaded quickly, conveniently and reliably, so as to shorten the downtime of the lathe;

(4) The parts on the fixture should not interfere with the surface processing of the parts by the lathe;

(5) When selecting tooling, it should be conducive to tool exchange and avoid interference and collision;

(6) Multi-station and multi-piece jigs can also be used for mass production to improve processing efficiency.

Fourthly, the cutting amount is reasonably selected to improve the cutting efficiency of machining allowance.

Cutting parameters include spindle speed, cutting depth and feed speed. When selecting cutting parameters of CNC milling machine, if it is rough machining, it is generally to improve productivity, but economy and processing cost should also be considered, and larger cutting depth and feed speed can be selected; In the case of semi-finishing and finishing, we should give consideration to efficiency, economy and processing cost on the premise of ensuring the processing quality; When the cutter moves in a short distance, the feed speed should be set as high as possible. The specific values should be determined according to the lathe manual, the cutting parameter manual and the experience.

Fifth, the tool pre-adjustment and automatic wolf measurement are implemented, which reduces the adjustment time of machine tools.

In the machining process of CNC lathe, many different tools are often used. If the cutters cannot be adjusted in advance, the operator needs to install each cutter on the spindle and slowly determine the exact length and diameter. Then, manually input through the buttons on the CNC control surface. If you use the tool alignment instrument, you can accurately measure the diameter and length of the tool, reduce the time occupied by the lathe, improve the first piece qualification rate, and greatly improve the production efficiency of the CNC milling machine.

Six, flexible use of various auxiliary functions and macro programs of CNC lathe

CNC lathe has the function of tool radius and length compensation. By changing the tool compensation method, the tool size error can be compensated, and the layered milling and rough finishing can be realized by the same machining program or used to improve the machining accuracy, and the matching parts can be machined by the same machining program.

The biggest feature of using macro programs is to express the shape or size of rules with the shortest program. Lathe is faster and more sensitive when executing such programs than when executing programs generated by CAD/CAM software. Macro programs can use variables and assign values to them. Variables can be manipulated, programs can jump, and modular processing programs can be formed. In application, only the part information and machining parameters need to be input into the call statements of the corresponding modules, which greatly shortens the programming and input time.

Numerical control lathe also has the functions of fixed cycle, subroutine, mirror processing, rotating lamp and so on. Using these functions can avoid the input of long programs, and can get twice the result with half the effort if used properly.