In the processing of China custom turning parts for automotive factory precision parts, the main dimension requirements are such as cylinder diameter, which is a strict requirement. The positive and negative differences are only qualified parts within the required scope, otherwise they are irrelevant parts. The size is also strictly required. Negative and positive differences also require embedded cylinders (such as very simple basic components). When the diameter beyond the tolerance range is large enough, it cannot be inserted. If the specific diameter is small enough to exceed the negative limit of the allowable error, insertion looseness and instability problems will occur. These are nonconforming products. The length of steel cylinders is too long or too short, which is beyond the allowable range. They are irrelevant goods and need to be scrapped or reprocessed, which will inevitably lead to increased costs.

In fact, the machining requirement of precision parts is an important dimension problem of Z. Processing must be carried out in strict accordance with the attached drawings. The specific size of the processing is difficult to be consistent with the basic theoretical size of the drawing. Only the machined dimensions meet the benchmark within the allowable deviation range. Therefore, the requirements for precision parts processing are strictly in accordance with the basic theoretical dimensions. Secondly, sophisticated precision parts processing machinery, inspection tools and sophisticated production equipment make it easier to process precision parts with higher precision and stronger actual effect. The testing instrument can detect unqualified parts, and all goods sent to customers can truly meet the requirements.