Six methods to improve the quality of precision machining

Six methods to improve the quality of precision machining

In order to improve the quality of precision machining, identifying the main factors that cause machining errors (original errors) is crucial. However, how can corresponding process technology measures be taken to control or reduce the impact of these factors? Below, the editor will learn with you six effective methods to improve the quality of precision machining:

1、 Error grouping method

This method reports gross defects or the working dimensions processed in the previous process are measured and divided into n groups according to the error size, and the size error range of each group of workpieces is reduced to the original true/n; Then adjust the position of the tool relative to the workpiece according to the error range of each group, so that the center of the size dispersion range of the named group workpiece is basically consistent. To greatly reduce the size dispersion range of the entire batch of workpieces. This method is often more economical and feasible than increasing the accuracy of vigilance against gross errors. When precision machining tooth profiles, in order to ensure the coaxiality between the machined ring gear and the inner hole of the gear, the clearance between the gear and the spindle should be reduced. In production, gears are often grouped according to their internal dimensions and then matched with corresponding grouping mandrels, which evenly distributes the original errors caused by clearances and improves the accuracy of gear ring gear position.

2、 Error compensation method

This method is to artificially create a new original error to offset the inherent original error in the original process system, thereby achieving the goal of reducing machining errors and machining accuracy.

3、 Error transfer method

This method essentially transfers the geometric errors, stress deformation, and thermal deformation of the process system to a direction that does not affect the machining accuracy. For example, for multi station processes with indexing or indexing, or processes that use indexing tool holders for machining, the indexing and conversion errors of the entrepreneurs will directly affect the machining accuracy of the relevant surfaces of the parts.

4、 Error equalization method

This method utilizes closely related surfaces to mutually correct or use each other as benchmarks for processing. It can evenly affect the entire machining surface with larger local errors, making the machining errors transmitted to the workpiece surface more uniform, thus greatly improving the machining accuracy of the workpiece.

5、 On site processing method

Some precision in processing and equipment matching involves the interrelationships between components, which is quite complex. If we blindly improve the accuracy of the components themselves, sometimes it is not only difficult or even impossible, but using on-site processing can solve this problem. The key point of on-site processing is to ensure the positional relationship between components, and to use a cutting tool to process a component based on this positional relationship. For example, in the manufacturing of a hexagonal lathe, the axis of the six large holes for installing the tool holder on the turret must ensure that the machine tool and spindle rotation lines coincide, and the end faces of each large hole must be perpendicular to the spindle rotation line.

6、 Direct error reduction method

This method is a fundamental method widely used in production. This method aims to directly eliminate or reduce the main original error factors that affect machining accuracy after identifying them. For example, in the turning of slender shafts, bending deformation occurs due to the influence of force and heat. The "large straight blade reverse cutting method" is now adopted, which basically eliminates the bending caused by cutting force. Combined with spring tips, the harm of thermal elongation can be further eliminated.

Precision machining