1、 Several errors in the fixture.
The effect of the fixture is to make the workpiece correspond to the precise direction of the tool and machine tool, so several errors in the fixture have a significant impact on mechanical processing errors (especially directional errors).
2、 Positioning error.
Positioning errors mainly include benchmark non overlapping errors and inaccurate positioning secondary production errors. When machining a workpiece on a machine tool, a mechanical processing factory must select several elements on the workpiece as positioning benchmarks during the machining process. If the selected positioning benchmark does not overlap with the design benchmark (used to determine the appearance scale and orientation benchmark on the part drawing), then the benchmark does not overlap error.
The workpiece positioning surface forms a positioning pair with the fixture positioning component. Due to the inaccuracy of positioning secondary production and the cooperation gap between positioning secondary production, the direction change of the workpiece is called an inaccurate error in positioning secondary production. The inaccuracy in positioning the secondary production only occurs when selecting the adjustment method for processing, and does not occur in the trial cutting method for processing.
3、 Machine tool production error.
The production errors of machine tools mainly include spindle rotation errors, guide rail errors, and transmission chain errors.
Spindle rotation error refers to the change in the actual rotation axis relative to the uniform rotation axis of the spindle, which directly affects the accuracy of the workpiece. The main reasons for spindle reversal errors are the coaxiality of the spindle, the bearings themselves, the coaxiality between bearings, and the spindle winding. The guide rail is the reference for determining the relative direction of machine tool components and also the reference for machine tool movement. The production errors of the guide rail itself, uneven wear of the guide rail, and installation quality are important factors that contribute to the formation of guide rail errors. Transmission chain error refers to the relative motion error between the transmission components at both ends of the transmission chain. It is caused by production and assembly errors in the transmission chain, as well as wear and tear during use.
4、 Several errors with the tool.
Any cutting tool inevitably wears out during the cutting process, resulting in changes in the size and shape of the workpiece. The impact of several tool errors on mechanical machining errors varies due to the impact of tool errors: when selecting a fixed scale tool for machining, the production error of the tool will directly affect the machining accuracy of the workpiece; For general cutting tools (such as turning tools), production errors will not directly affect mechanical machining errors.
