CNC machine tools will inevitably be affected by various factors during processing, causing certain deviations in processing accuracy and bringing certain inconveniences to production and life. How to improve the processing precision of CNC machine tools is a thing that gold fans are very concerned about.
1. Precision problems in CNC machine tool processing
1.1 The impact of position errors in CNC machine tool processing on processing accuracy
Position error refers to the magnitude of change or deviation in the mutual position of the actual surface, axis or plane of symmetry of the processed part from its ideal position, such as the verticality, position, symmetry, etc. Position error in CNC machine tool processing generally refers to dead zone error. The main reasons for the position error are that the gap and elastic deformation generated during the transmission of machine tool parts lead to errors in processing and during processing of the machine tool. the head must overcome friction and other factors lead to position errors. In the open-loop system, the position accuracy is greatly affected, while in the closed-loop tracking system, it mainly depends on the accuracy of the displacement detection device and the speed amplification factor of the system , and the impact is generally small.
1.2 Machining precision errors caused by geometric errors in CNC machine tool processing
In the processing of CNC machine tools, because the cutting tools and accessories are affected by external factors such as external forces and heat generated during processing, the geometric accuracy of the machine tool is affected and the Parts processed on the machine tool undergo geometric deformation, which results in geometric errors. According to research, the main causes of geometric errors in CNC machine tools are none other than the following two: internal factors and external factors. Internal factors that cause geometric errors in machine tools refer to geometric errors caused by the factors of the machine tool itself, such as the flatness of the machine tool working surface, flatness and straightness of machine tool guide rails, geometric accuracy of machine tools and accessories, etc. External factors mainly refer to geometric errors caused by factors such as external environment and thermal deformation during processing. For example, during the cutting process, tools or parts expand and deform due to heat, leading to geometric errors that affect machine tool processing. . Precision and precision in machining of parts.
1.3 Machining precision errors caused by machine tool positioning in CNC machine tool processing
Through long-term data analysis and practical workpiece processing operations, it can be found that the positioning of machine tools has a great impact on the processing accuracy of CNC machine tools. From a structural point of view, the machining errors of CNC machine tools are mainly caused by the positioning accuracy, among which the power system of the machine tool is the main link that affects the positioning accuracy. The power system of CNC machine tools generally consists of a mechanical transmission system and an electrical control system. Positioning accuracy is related to the mechanical transmission system in structural design. In a closed-loop system, CNC machine tools can generally prevent position deviations of major power system components, such as ballscrews and other components, through positioning detection devices. As for the open-loop system, due to the many influencing factors and the complexity of the situation, positioning monitoring cannot be carried out, so it has a greater impact on the machining accuracy of machine tools CNC.
2. Countermeasures to improve the machining precision of CNC machine tools
When processing CNC machine tools, the precision of the processed parts directly affects the quality of the product. Some mechanical parts and precision equipment parts have very high requirements for processing precision. Improving the processing precision of CNC machine tools is the solution. the problem. The fact is. Through extensive research and analysis, it is concluded that strategies to improve the machining accuracy of CNC machine tools generally include the following methods:
2.1 Improve machining precision by controlling the original error of CNC machine tools
When processing CNC machine tools, errors themselves are inevitable. There are certain errors between processed parts and CNC machine tools. This unavoidable error is called the original error.
Therefore, to improve the processing precision of CNC machine tools, controlling the original error of CNC machine tools is one of the important countermeasures. A systematic analysis should be carried out on the possibility of initial errors and corresponding improvement measures should be formulated based on the causes and types of errors. When processing mechanical parts, the positional accuracy and geometric accuracy of CNC machine tools have a great impact on the processing accuracy of parts. Position control and geometric precision control should be used to reduce the impact of position errors and geometric errors on parts. . At the same time, for deformation errors generated during processing, air cooling, water cooling and other methods should be used to control thermal deformation during processing to reduce the impact of deformation errors thermal on the precision of the treatment. At the same time, regarding the position error, it is necessary to reasonably select a tool suitable for the workpiece material to avoid tool deformation. At the same time, a reasonable fixture should be selected according to the shape of the workpiece blank. part to be treated. If necessary, the luminaire should be specially designed according to the shape and size of the room to avoid the occurrence of position error.
2.2 Reasonably design the basic components of machine tools to avoid positioning errors
The positioning accuracy of machine tools has a significant impact on the accuracy of parts. The essential components that affect the positioning accuracy of machine tools such as the straightness and flatness of the feeding system, guide rails, worktables, etc. When designing CNC machine tools, the basic components should be selected reasonably. For example, when selecting ball screws currently widely used in machine tools, the precision of ball screws should be fully considered, and relatively mature ball screw technology should be selected and. installed. Ball screw support cannot be ignored. The support of the ball screw is closely related to the precision of the system transmission. The support of the ball screw is mainly determined by the axial load and rotation speed. the machining precision of the CNC lathe. It is generally selected with high precision fixing and supporting methods. And the bearing capacity of the ball screw should be strictly checked during the design process.
Energy chains, as part of the external protection of machine tools, are now essential for machine tools. Due to its chain link structure, it will also produce a certain amount of vibration when following the movement of the tool holder. This vibration will be directly transmitted to the tool, and will ultimately have a certain impact on the precision of the machining.
Therefore, the performance of the energy chain greatly determines the precision of the machine tool. The igus E6 series energy chain is specially designed to significantly reduce vibration and noise, minimizing the impact of energy chain movement on machine tool accuracy.
In addition, the igus E6 series energy chain adopts small-pitch polymer springs and hole-free pin connection method, which has no wear and is suitable for high-speed and high-acceleration applications. When the speed V=1.8 m/s, the noise is only 37 Db(A) and can also be used in industries such as clean rooms.
2.3 Improve the processing precision of CNC machine tools through real-time monitoring technology
With the continuous improvement of CNC technology, the entire processing process of CNC machine tools is monitored in real time, the error links in the processing process are adjusted timely, and the error data of each link in the processing process is collected and returned to the control terminal, and through the error data adopts a corresponding error compensation mechanism to carry out timely error compensation, which can effectively improve the accuracy processing of parts.
Daguang focuses on providing solutions such as precision CNC machining services (3-axis, 4-axis, 5-axis machining), CNC milling, 3D printing and rapid prototyping services.
