The accuracy of the processing of non-standard precision parts mentioned here must be strictly in accordance with the additional drawings, and the processing dimensions are all qualified parts within the allowable range of errors. Therefore, the requirement for processing precision parts is to process them strictly according to the theoretical dimensions.

The processing of precision parts is mainly based on size requirements, such as the diameter of the cylinder, there are strict requirements, and the positive and negative errors are qualified parts within the specified requirements, otherwise they are all unqualified parts; the length, width and height also have specific strict requirements, and the positive and negative errors are also stipulated. For example, if the diameter of a built-in cylinder is too large and exceeds the allowable error range, it will cause the insertion to fail. If the actual diameter is too small and exceeds the lower limit of the allowable negative error, it will cause the insertion to be too loose and not firm.

These are all substandard products that need to be scrapped or reprocessed, which will inevitably increase costs. Therefore, it is very important to ensure the accuracy of non-standard precision parts processing.