Metal powder injection molding in order to obtain a desired shape of a defect-free, uniform particles of MIM shaped body. Firstly,Granular feed was heated to a certain temperature so that it has a high flowability,and then be cooled down to get the required of the injection mold cavity shape has certain rigid body, and then remove it from the mold to get the MIM billet.This process is consistent with the traditional plastic injection molding process,but due to high feed MIM powder content,making a big difference in injection process. improper control is easy to produce all kinds of defects.
Defects of most of metal powder injection molding products are formed in injection molding steps, such as crack, pore, weld, layered, powder and the binder separation phenomenon and so on.But these defects are often to find after debinding and sintering, therefore, control the injection molding process to improve product yield and material utilization is critical.
Injection molding defect control can be divided into two aspects,one is the function relations between the forming temperature, pressure, time setting, on the other hand is fill in feed flow in the cavity is involved in die design problems, including in the location of the inlet, the length of the flow channel, the setting of vent, etc, all these need to feed the rheological properties, cavity temperature and residual stress distribution in a clear understanding. Computer simulation technology will play an important role in metal powder injection molding mold design.