Error control method for machining

Due to the inherent precision error of mechanical manufacturing equipment, and the process of mechanical processing, machining error is inevitable in the process of machining. In this paper, the causes of machining errors are analyzed and discussed, and some feasible, effective and reliable error control methods are given.

One, the cause analysis of machining error

As is known to all, machining is almost inseparable from machining machine tools, no matter how high the precision of machining machine tools, it is inevitable to produce machining errors. Before using machine tools for machining, first of all to process the workpiece clamping positioning, fixture positioning will produce errors. On the other hand, machining machine tools in the process of realizing transverse feed and longitudinal feed, because of the guide rail, screw and other transmission components themselves have design and processing error and transmission accuracy error, therefore, machine tool processing process will also produce machining error.

1. Adjust the error

Mechanical processing is composed of a series of different processes and steps, in the process of mechanical processing, often need after each step, to fine-tune the process, such as re knife, or workpiece positioning contact or re-clamping and so on, in this process will inevitably produce new errors.

Therefore, when other mechanical processing conditions are certain or no longer change, the adjustment error for the error precision of the processed workpiece will play a decisive role.

2. Positioning error

In machining, the workpiece needs to be positioned and clamped, and only the fixed workpiece can be successfully completed. In the process of positioning and clamping of the workpiece, it is often people to complete the process, which will inevitably lead to the production of processing errors, even for the fully automated machining center, its positioning clamping all automatically completed by the control system, it is still inevitable to produce positioning errors. The accuracy of the workpiece is located and clamped will directly affect the geometry of the surface shape of the workpiece, which has an important influence on the completion of assembly.

Discussion on the control measures of machining error

According to the above analysis, although machining error is inevitable, the cause of the error can be found through specific analysis in the process of machining. Therefore, machining error can still be strictly controlled. Some feasible and effective error control measures are discussed below.

1. Local assembly and processing

For some machining precision requirements are higher, or repositioning, assembly will produce large positioning and assembly errors of machining process system, often can use a assembly, on-site processing method, can avoid the repetition of secondary errors, is conducive to improve the surface quality and precision requirements of machining.

2, reduce the original error

So-called primitive error, is mainly refers to in the process of machining, because of the machine tool positioning, a mechanical error caused by the factors such as cutting tools, is to eliminate the error, so must be before machining, to test the mechanical processing of various work step, find out the error of each link to produce and use a certain method to eliminate the original error, In order to obtain higher quality machining accuracy. For example, in the process of long axis axial turning, the axial cutting force is easy to cause the axial deformation and produce machining error. In the actual machining process, the method of large cutter reverse turning can be used to eliminate the axial deformation error caused by the axial cutting force, so as to improve the machining accuracy and surface quality.

3. Error compensation

Some errors can not be reduced or reduced, in this case, it is necessary to artificially create new processing errors, to offset the impact of the original error on the machining system, so that the two kinds of errors offset each other, eliminate the impact of the error on the machining workpiece. It must be noted that the man-made error must be equal to and opposite to the original machining system error. Only in this way can the original original error completely eliminate the influence of the machining system, in order to obtain high quality machining surface.