Technical essentials for precision parts processing types and guarantees

Author: Xueqin Yang

The development level of the manufacturing industry is related to the economic development of the entire country. Over the past 30 years, China’s manufacturing technology and capabilities have undergone major changes. However, there is still a long way to go for some high-tech and high-precision products compared with European and American countries. Only in the next 30 years can it be fully developed. This is a problem related to the prospects of China's manufacturing industry. Chinese entrepreneurs have seen the opportunities and challenges in the market. If China cnc machining industry cannot develop to a higher level, there will be no chance of relying on the demographic dividend to develop. Because Central and South Asia and Indian countries are vigorously carrying out infrastructure construction and deployment, their labor costs will be more than half of that in China. It is clear that China has no advantage at all for the initial processing and processing with supplied materials. If a company wants to have a position on the international stage, it must use high-tech and high-precision products.

How can companies that process precision parts ensure the precision of their products? First, let's analyze the classification of precision parts:

Production type of precision parts processing:

  1. Single-piece production: produce products of different structures and sizes individually, and rarely repeat.
  2. Mass production: The same products are manufactured in batches throughout the year, and the manufacturing process has a certain degree of repetition.
  3. Mass production: The number of products manufactured is very large, and most work sites often repeat a certain process of a certain part.

Technical essentials for guaranteeing precision in machining of precision parts:

  1. Machining the reference surface first: During the processing of the part, the surface as the positioning reference should be processed first, so as to provide a precise reference for the subsequent processing as soon as possible. Called "benchmark first."
  2. Dividing the processing stages: the surfaces with high processing quality requirements are divided into processing stages, which can generally be divided into three stages: rough machining, semi-finishing and finishing. Mainly to ensure the processing quality; to facilitate the rational use of equipment; to facilitate the arrangement of the heat treatment process; and to facilitate the discovery of blank defects.
  3. Face before hole: For parts such as box body, bracket and connecting rod, the plane should be processed first and then the hole should be processed. In this way, the holes can be positioned on the plane to ensure the position accuracy of the plane and the holes, and it is convenient to process the holes on the plane.

4. Finishing processing: The finishing cnc machining japan of the main surface (such as grinding, honing, precision grinding and rolling processing, etc.) should be carried out at the last stage of the process route. The surface finish after processing is above Ra0.8um, and slight collisions will Damage to the surface. In Japan, Germany and other countries, after the finishing process, you must use flannel to protect it. Never touch the workpiece directly with your hands or other objects, so as to avoid the finishing surface due to the transfer and installation between processes. Be injured.

The processing of precision parts is mainly based on the size requirements, such as the diameter of the cylinder, there are strict requirements, and the positive and negative errors are within the specified requirements are qualified parts, otherwise they are unqualified parts; the length, width and height are also specific Strict requirements, plus and minus errors are also specified. For example, if the diameter of an in-line cylinder is too large and exceeds the allowable error range, it will not be able to be inserted. If the actual diameter is too small, it will exceed the lower limit of the allowable negative error. If it is not inserted, it will cause the problem of too loose and weak insertion. These are all unqualified products, which are to be scrapped or reprocessed. This will inevitably increase the cost. Therefore, it is very important to ensure the accuracy of precision parts processing.