1. Accuracy modeling of five-axis CNC machine tools
In order to further understand the machining accuracy modeling of five-axis CNC machine tools, this article selects a five-axis CNC machine tool produced by a machine tool group as the research object, including bed, worktable, workpiece, horizontal slide, vertical slide, and axis Swing the head and other parts. Firstly, we abstract the layer into a fiber multi-body system and then understand the error amount of each part of the base layer, and know the error amount between each part, so as to provide a theoretical basis for the specific proposal of the precision model of the five-axis CNC machine tool. Features of five-axis CNC machine tools: Five-axis CNC machine tools have strong geometric characteristics, which are mainly reflected in the geometric error term, that is, when taking an axis as an example, moving along the axis will produce a corresponding positioning error-(), direction generation Straightness error-(), straightness error caused by direction-(); In addition, when rolling, the corresponding position also produces errors, that is, roll error-(), yaw error-(), pitch error-( ). Therefore, it is necessary to analyze the axis and the geometric error of the axis before establishing the machining accuracy model of the five-axis CNC machine tool, so as to better grasp the movement relationship between the various parts, so as to determine the correct spatial point, and finally establish a standard model.
2. Establishment of machining accuracy model of five-axis CNC machine tools
According to the five-axis CNC machine tool structure design accuracy model, and establish the corresponding control coordinate system, then according to the five-axis CNC machine tool characteristics analysis and determine the rotating Carr coordinate, and finally set the Carr coordinate system, namely "(,,...)". Set the coordinates of the tool, and then establish a coordinate system based on points, that is, the point coordinate axis system function analysis result formed by the tool is: Through the analysis of the above coordinates, the actual forming movement of the machine tool will focus on the point Form the corresponding coordinates, that is:, from the above data coordinate relationship, we understand that when building a machine tool machining accuracy model, we must pay attention to the model's coordinate range, and clarify the transformation relationship between the tool formation point and the displacement point to ensure the measurement effect . In addition, it is also necessary to control the position of the tool forming point. It is best to set the tool position according to the coordinates in advance, and then strictly control the position of the tool within the preset position range when building the model to minimize the tool assembly error distance. Finally, it is necessary to determine the measurement standards and requirements according to the tool application requirements, and then build a five-axis tool accuracy model based on the requirements and standards, and analyze the data coordinate position relationship of the accuracy model control elements to ensure that the coordinate model is efficiently used.
3. Geometric error analysis of five-axis CNC machine tools
In the process of establishing the machining accuracy model of five-axis CNC machine tools, it is necessary to analyze the geometric errors of the five-axis CNC machine tools, including geometric errors, thermal errors, load errors and servo system errors. Among them, geometric error is the easiest to measure, and any geometric error can be analyzed by the method of motion modeling, and the impact of environmental factors is the least. However, the measurement and analysis of thermal error, load error and servo system error are more difficult, so in comparison, this article chooses geometric error for analysis. The five-axis gantry CNC machine tool selected in this article has a key moving part, and each key part may have static and motion errors. The motion error is divided into term linear displacement and term angular displacement error. Here it can be based on the six degrees of freedom of the rigid body. Suppose that the theory analyzes that each axis movement will produce various errors, so each axis has a movement error. based on this analysis, the five-axis CNC machine tool geometric coordinate system is analyzed between the axis and the axis, the axis and the axis, and the axis and the axis. , Perpendicularity error and static error have terms and terms respectively, so the geometric error parameters of five-axis CNC machine tools have a common term.
4. Research on precision prediction of five-axis CNC machine tools
After establishing the machining accuracy model of the five-axis CNC machine tool and analyzing its geometric errors, it is also necessary to predict the model, mainly through experimental analysis. The specific predictions are as follows: Carry out precision error control on the coordinate modeling in the application process of CNC machine tools, and control the error within a certain range as much as possible; then set the error range to,, etc.; then analyze according to the experimental results and distinguish The machining accuracy and experimental results of the five-axis CNC machine tool are presented; finally, on this basis, the machining accuracy is set and selected according to the specific CNC machine application effect to improve the efficiency of machine tool application.
5. Conclusion
The establishment of the machining accuracy model of five-axis CNC machine tools can not only improve the structure of five-axis CNC machine tools, but also improve the application efficiency and machining accuracy of five-axis CNC machine tools. This article analyzes the machining accuracy modeling of five-axis CNC machine tools in detail, hoping to play a positive role in improving the accuracy of five-axis CNC machine tools.
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