1, Definition of precision for CNC machine tools
The accuracy of a CNC machine tool refers to the degree to which the geometric parameters such as size, shape, and position of the parts processed by the machine tool are close to the theoretical values during the machining process. This includes multiple aspects such as positioning accuracy, repeated positioning accuracy, geometric accuracy, and machining accuracy. Among them, positioning accuracy refers to the positional accuracy that each coordinate axis of the machine tool can achieve under the control of the CNC system; Repetitive positioning accuracy refers to the magnitude of the position change when the machine tool moves multiple times to the same position under the same conditions; Geometric accuracy refers to the relative position and geometric shape errors between various components of a machine tool under no-load conditions; Machining accuracy refers to the degree of conformity between the actual size, shape, and position of the machined parts of the machine tool and the theoretical values during the cutting process.
2, The importance of precision in CNC machine tools
The accuracy of CNC machine tools is crucial for the manufacturing industry. Firstly, high-precision CNC machine tools can process parts with precise dimensions and complex shapes, meeting the needs of high-precision products. Secondly, high-precision machine tools can improve production efficiency, reduce scrap rates, and lower production costs. In addition, high-precision machine tools can also improve the assembly accuracy and performance stability of products, enhancing their market competitiveness.
3, Evaluation method for precision of CNC machine tools
The accuracy evaluation of CNC machine tools is mainly achieved through experiments and measurements. The commonly used evaluation methods include laser interferometer measurement method, ball and stick instrument measurement method, dual frequency laser interferometer measurement method, etc. These methods can measure key indicators such as positioning accuracy, repeated positioning accuracy, and geometric accuracy of machine tools. In the evaluation process, it is also necessary to consider the impact of factors such as the dynamic characteristics and thermal deformation of the machine tool on accuracy.
4, Factors affecting the accuracy of CNC machine tools
The accuracy of CNC machine tools is influenced by various factors, mainly including the following aspects:
Machine tool design: The structural design, transmission system, control system, etc. of a machine tool will have an impact on accuracy. Reasonable machine tool design can improve the rigidity and stability of the machine tool, thereby improving machining accuracy.
Manufacturing and assembly quality: The manufacturing and assembly quality of machine tools have a direct impact on accuracy. High quality manufacturing and assembly can reduce errors and deformations in machine tools, and improve their accuracy.
CNC system performance: The performance of CNC systems also has a significant impact on the accuracy of machine tools. A high-performance CNC system can achieve more precise control and higher machining speed, thereby improving machining accuracy.
Cutting parameters: The selection of cutting parameters directly affects factors such as cutting force and cutting heat during the cutting process, thereby affecting the accuracy of the machine tool. Reasonable cutting parameters can reduce the influence of cutting force and cutting heat, and improve machining accuracy.
Processing environment: Environmental factors such as temperature, humidity, and vibration can also affect the accuracy of machine tools. A stable machining environment can reduce machine errors and deformations, and improve machining accuracy.
