How to reduce the error of workpiece machining by vertical machining center

For any processing equipment, when there are problems with workpiece processing, such as processing route setting, processing program preparation, processing tool selection, machine tool problems, clamping problems and workpiece material, it will affect the processing accuracy and processing efficiency of the workpiece. As a high-precision processing equipment, the commonly used methods of reducing the machining error of the workpiece mainly include the original error reduction method, the error compensation method, the error transfer method, the error grouping method, the error average method and the error synthesis method.

1. Error synthesis method

Reducing the error of the machine tool itself is the main method to ensure the machining accuracy of the workpiece. The error synthesis method requires measuring the original errors of each axis of the machine tool. Laser interferometer is the main detection instrument of vertical machining center because of its high measurement accuracy and flexible use.

2. Error compensation method

The error compensation method is to artificially create an error to offset the original error inherent in the process system, or to use one original error to offset another original error, so as to achieve the purpose of improving the machining accuracy of the workpiece of the vertical machining center. Usually, by reducing the clearance of the machine tool, improving the rigidity of the machine tool, and using preload to generate a preload force for the relevant fit, the effect of the clearance is reduced. It can also improve the rigidity of the workpiece and the tool and reduce the overhang length of the tool and the workpiece to improve the rigidity of the process system. It is also possible to adopt reasonable clamping methods and processing methods, reduce cutting force and its changes, reasonably select tool materials, increase rake angle and main declination angle, and conduct reasonable heat treatment of workpiece materials to improve the processing performance of materials, etc. a method.

3. Directly reduce the original error method

The method of directly reducing the original error refers to trying to directly reduce or reduce the main original error factors that affect the machining accuracy after identifying the main original error factors. For example, after the vertical machining center is used for a long time, the positioning of the transmission system and the backlash caused by natural wear and tear are inaccurate.

Fourth, the error average method

The error average method is to use the mutual comparison and mutual correction between the closely related surfaces, or use the mutual benchmark for processing, so as to achieve the purpose of reducing the processing error of the vertical machining center.

5. Error transfer method

The essence of the error transfer method is the comprehensive error caused by the collective error, force deformation and thermal deformation of the transfer process system. For example, when a vertical machining center performs some hole processing, the coaxiality of the workpiece is not guaranteed by the rotation accuracy of the machine tool spindle, but by the fixture. When the machine tool spindle and the workpiece are connected by floating, the original error of the machine tool spindle will no longer be Affect the machining accuracy, and transfer to the fixture to ensure the machining accuracy.

6. Error grouping method

In the machining of vertical machining center, the machining error of this process is caused due to the existence of process blank error. The change of blank error has two main influences on this process: reaction error and positioning error. If the above error is too large, the machining accuracy cannot be guaranteed, and it is unrealistic to improve the blank accuracy or the machining accuracy of the previous process.

At this time, the error grouping method can be used, that is, the blank or the previous process size is divided into n groups according to the size of the error, the error of each group of blanks is reduced to the original 1/n, and then the relative position of the tool and the workpiece is adjusted according to each group. Adjust the positioning elements, so that the size dispersion range of the whole batch of workpieces can be greatly reduced. The essence of the error grouping method is to make up for the lack of machining accuracy by means of improving the measurement accuracy, so as to reduce the influence of machining errors.