During the pressing process of powder metallurgy parts, compaction defects will occur due to various reasons, resulting in the scrapping of powder metallurgy parts. In the production of powder metallurgy parts, the higher the density of the material, the higher its physical and mechanical properties. That is to say, the density and distribution of the green compact of powder metallurgy parts will determine the performance of the product.
Therefore, in the process of powder metallurgy mold debugging and pressing, the density of the green compact is an item to be detected. When testing the density, it should be noted that the compacts with different structures and requirements should be treated differently. There may be a problem with the mold design or manufacturing, if the error can be eliminated by adjusting the process. It can also be remedied, otherwise only the mold will be scrapped.
For the no-step cylindrical compact, the axial dimension can be adjusted and stabilized by adjusting the powder loading, changing the pressing pressure or prolonging the holding time. For stepped green compacts, the height of the steps can be changed by adjusting the forming position of the combined die punch, the powder loading ratio of each table, and the running speed of the floating die punch.
It is found from the processed finished products that the shapes of the products produced by CNC machining and powder metallurgy are similar, but it is obvious that the price of CNC machining is more expensive than that of powder metallurgy. Powder metallurgy is a process technology for preparing metal powder or using metal powder as raw material, after forming and sintering, to manufacture metal materials, composite materials and various types of products.
CNC machining refers to a process method for machining parts on a CNC machine tool. Since digital information is used to control the displacement of parts and tools in the entire machining process, this method can solve the problem of changing parts varieties, small batches, complex shapes, etc. The problem of high precision is also realized at the same time.