1. The shape and size of the workpiece structure. For example, complicated shapes and thin walls cannot be cast with metal molds; greater gluttonous blanks can often be cast by molding, die casting and precision casting. For another example, for some small parts with special shapes, due to the difficulty of processing, more precise rough manufacturing methods are often used, such as die -casting, melting mold casting, etc., to minimize the amount of processing.

   
   

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2. Requirements for parts of parts. The same material adopts different rough manufacturing methods, and its mechanical properties are often different. For example, the roughly cast blank is higher than the roughness of the sand -casting, and the roughness of centrifugal casting and pressure casting is higher than the rough strength of the metal -type. Most of the parts with high intensity requirements are mostly forged, and sometimes can be used to cast iron parts.

3. Consider feasibility and economics from the existing equipment and technical level of the factory. It should also be considered the possibility of precision casting, precision forging, cold rolling, cold squeeze, powder metallurgy, engineering plastics and other new technologies, new technologies, and new materials. After using these rough manufacturing methods, the amount of mechanical processing can be greatly reduced, and sometimes it can not even perform mechanical processing, and the economic effect is very significant.