With the development of machinery manufacturing industry, the emergence of CNC machine tools is an innovation in the machinery manufacturing industry. As an advanced processing instrument, CNC machine tools are widely used in the manufacturing industry.
It is widely used in the manufacturing industry, not only brings convenience to the manufacturing industry, but also saves a lot of human resources, while creating a richer social and economic value. At the same time, in order to ensure the quality of the parts, also put forward higher requirements for CNC machine tool technology. CNC machine tools as the core technology in the manufacturing industry, the control of its processing accuracy directly affects the quality of products. As the manufacturing process continues to be automated, the entire industry has put forward higher demand for manufacturing products, to ensure the quality of products, it is necessary to improve the machining accuracy of CNC machine tools.
CNC machine tools in the manufacturing process of parts, its processing factors are mainly by the machine precision, programming processing technology, servo systems and interpolation accuracy and other factors
Factors together to determine. In addition to these factors, CNC machine tool manufacturing and processing impact factors are also affected by other external factors, such as the texture of the material, manufacturing process, installation level, control means. Whether external factors or internal factors, are the impact of machine tool processing factors, the quality of manufacturing products have an immeasurable impact.
CNC machine tool programmers to determine the compilation point of origin and programming processing technology have an impact on machine tool processing.
(1) the compile origin of the machine tool to confirm will affect
Affect the processing of CNC machine tools. CNC machine tools need to work by the programmer according to the shape and characteristics of the processed parts for coordinate compilation, if the origin compilation is not accurate, it will lead to errors in the entire processing program, thus affecting the quality of workpiece processing. In this way, in the processing process, the CNC machine tool programmer should focus on the CNC machine tool to confirm the compilation origin, and to check the process of the machined parts, so as to effectively avoid the corresponding errors brought about by the inaccuracy of the compilation origin.
(2) programming data processing technology will also affect the processing quality of CNC machine tools.
If the data processing is not accurate, it will lead to errors in the production process of the workpiece, affecting the quality of the workpiece processing. For example, the relevant personnel in the processing process does not take into account the shape and size of the workpiece itself, it will lead to the generation of processing errors, and even lead to the scrapping of the entire workpiece. For some workpieces with high precision and complex shapes, the programmer should check the
The machining reference and calculation reference to ensure that the accuracy of CNC machine tools to improve the quality of the workpiece.
CNC machine tool machining process is a variety of factors, mainly including the geometric error of the machine tool, machine tool thermal deformation error, servo-feed system error. From these influencing factors, the servo feed system error as well as the machine tool geometry error is a common influencing factor, to a certain extent, affects the quality of the product.
(1) CNC machine tool processing is mainly through the servo motor drive ball screw control processing position, if the screw drive error, it will affect the accuracy of the entire machine positioning. In practice, if the servo motor screw movement in the opposite direction, not only will affect the processing accuracy, but also due to the appearance of the gap will lead to CNC machine tools idle phenomenon, thus causing errors.
(2) CNC machine tools are also susceptible to the role of external forces, which makes its moving parts appear elastic deformation, making the CNC machine tool error problem aggravated. For example, CNC machine tools in the process of processing, the tool is affected by external forces, will appear deformation, which will cause the geometric accuracy of the machine tool to reduce, resulting in its processing out of the parts do not meet the specifications, which is called "let the knife", which is also one of the reasons for the problem of machine accuracy.
(3) CNC machine tool geometric error is determined by the machine tool guide and machine base and other structures of the machine. If the design of the machine tool is not accurate enough, it will lead to the machine tool in the operation process to increase the self-weight, thus affecting the accuracy of the product. For example, in the design process, the choice of a weak load capacity of the guide rail will lead to the machine tool machining process at high speed moving conditions in the accuracy of the problem .
In the machining process of CNC machine tools, the factors that affect the quality of machining are the turning tool tip, radius of the arc, the main offset angle and the deviation of the turning tool tip from the center of the part
Geometric parameters such as; these factors will affect the roughness of the part, but also affect the tool life. For example, when the main deflection angle is large, it will affect the accuracy of the entire CNC machine tool processing. So in the operation of CNC machine tools, for the main deviation angle, radius of the arc, height and other parameters to control, is very necessary.
In the programming, you need to use the appropriate methods and techniques in order to improve the programming data processing technology of CNC machine tools. To eliminate the influence of tolerance zone position
Impact, CNC program is generally according to the contour of the part, according to the basic size of the part for programming, which undoubtedly ignored the impact of the tolerance zone position, making CNC machine tools, although the precision is very high, but the processed parts do not meet the needs of the dimensional tolerance.
(1) should analyze the part diagram, determine the process, and the need to analyze the part drawing, shape, size, accuracy, clear processing content and requirements, determine the processing program, processing route, cutting parameters and the choice of tools and fixtures.
(2) Relevant numerical calculation. To calculate the geometric elements, base points, end points and arcs on the contour of the part according to the geometric dimensions of the part and the machining route.
coordinates of the part contour. In the process of writing the program, the corresponding values are calculated, the machining trajectory is calculated and the corresponding data are obtained according to the geometry and the process route and the set coordinate system.
(3) Production control mechanism. The program finished programming is applied to the CNC machine as parameters, relevant information is entered, and the program is properly calibrated and the first item is tested. The program written and the control mechanism prepared must be proofread and test cutter before it can be officially used.
Tool is the most important tool of CNC machine tools in processing parts, the choice of tool must take into account its wear resistance, high temperature resistance and other parameters, but also requires the tool must be able to carry a certain pressure, impact and vibration, so in the choice of tool must consider the quality of the parts and the use of production processes. Common machine tools are mainly made of high-speed steel, carbide, ceramic materials, different materials have different characteristics of the knife, to choose the tool according to the corresponding requirements. In addition to the selection of a good tool, but also reasonable control of the tool and the geometric angle in the processing, the geometric angle of the tool including the arc radius of the tip, the main deviation angle, edge inclination angle, front foot, back foot, vice rear angle, etc., need to control the tool from multiple angles, that is, the main deviation angle will directly affect the strength of the tip and the shape of the cutting surface. For the arc radius of the tool tip, the larger the arc radius, the lower the roughness of the machined part surface; for the front and rear foot of the tool, the sharper the front and rear foot of the machine tool, then the more delicate its surface is.
In this way, CNC machine tool processing accuracy and tool has a strong relationship, in the selection of tools must be precision, wear degree to grasp, so as to effectively improve the geometric accuracy of the tool. In addition, the geometric accuracy of CNC machine tools are also affected by the cutting speed, too fast will lead to vibration of CNC machine tools, which will have an impact on the geometric accuracy of CNC machine tools. In response to such problems, the requirements in the design of CNC machine tools, must use treated steel sliding guide material, and in the installation to make the steel sliding guide in the plane below, and then fill the gap between the guide and the base with filler, so as to improve the geometric accuracy of the machine tool.
To the angle of the tool and the material for the appropriate choice. In the case of industrialization continues to deepen, the characteristics between the parts also changed from unification to standardization, and the tools used in CNC machine tools must also have these characteristics in order to improve the tool bearing machining accuracy. Although the tool itself has a more perfect material, but to ensure the machining accuracy of CNC machine tools, the tool must be selected scientifically; in the process of processing should also take into account the hardness of the tool as well as wear resistance, such as the most widely used tool material is now alloy and high-speed steel. Want to improve the tool bearing machining accuracy, you need to try to use some parts to control the sliding bearing; also choose a better wear resistance of the bearing, so as to ensure the accuracy of the machine tool. And to minimize the heat source in the machine tool, and make the heat source away from the spindle of the machine tool; at the same time, the machine tool should be set up to dissipate heat, such as the use of metal working fluid for lubrication and take away the heat of the process, and thus reduce the degree of deformation of equipment and parts.
In addition, we must pay attention to the bearing speed and adjustment problems, such as adjusting the middle and small slide inserts, so that the middle gap is less than 0.04mm, and to ensure that it moves smoothly and lightly; choose the right power machine tool, to enhance the stability of the machine tool installation. In the processing of CNC machine tools also take into account the tool point, tool point is the point on the coordinate system tool movement begins, pay attention to the tooling process, if the tooling problems, not only will affect the accuracy of the processed parts, and will threaten the safety of employees.
The accuracy of CNC machine tools is directly linked to the quality of production, production efficiency, high precision CNC machine tools is the premise of China's CNC machining to internationalization. Therefore
Therefore, the management and maintenance of CNC machine tools is also very important.
(1) CNC machine tools are a prerequisite for creating value, so the relevant enterprises must recognize the importance of maintaining equipment, maintenance equipment. Machine management directly affects the normal operation of CNC machine tools, but also affect the accuracy and utility of CNC machine tools.
(2) the relevant personnel to ensure the reasonable use of CNC machine tools. CNC machine tools play an important role in modern manufacturing, it improves the productivity of machinery and equipment, but in the use of the process will be affected by the environment, air, heat sources, so you must use CNC machine tools reasonably in the daily work, so as to avoid machine failure. In the use of the process, but also to strengthen the importance of CNC machine tools to ensure the correct use, and choose the right site. CNC machine tools are susceptible to external influences, thus, to effectively avoid its high temperature conditions and humid environment, and the relevant personnel should be familiar with the relevant operating specifications before use.
(3) the relevant personnel should regularly do a good job of machine level and mechanical accuracy of the inspection, and do the correction work. There are two methods of correction of mechanical accuracy.
The first method is to compensate the parameters of the system, such as screw backlash compensation, each coordinate positioning accuracy of the fixed point compensation, the machine back to the reference point position correction; the second method is to repair the machine tool, guide repair, ball screw nut vice preload to adjust the backlash.
To improve the quality of products produced by CNC machine tools, we must pay attention to the accuracy of CNC machine tools. CNC machine tools as an important tool in the manufacturing industry, its own parts system will also affect the accuracy. Therefore, we must do a good job of preventive and control measures from programming design, programming data processing technology, and regular maintenance of equipment to make it run normally, but also reasonable analysis of the equipment in the application process of the accuracy of the problem, and effective correction, so as to ensure that the product qualification rate.
