What’s happen when the polymer of metal injection molding i

the problem of polymer melt
 

The metal injection molding manufacturer introduced that the molding of grain often does not seem have no need to pre-dry, but the excess water will be produce water vapor, it will lead to gap  etc problems when melting. Some moisture of polymer melt in molding work, the hydrolytic degradation will be more serious, caused crisp molding, the dry material of hydrolysis-sensitive polymers should insist on use desiccant or vacuum dry machine.
 

Thermal degradation rate of polymer melt increases, it will caused overheating, and caused crisp molding. Sizing glue can stay in the barrel for a long time, consume stabilizer of polymer melt. Because of the requests of high-pressure, the shape will happen defects when degradation of polymer, it will get into the trap of add temperature, decrease the viscosity of melt, the molding will be more slow.
 

Thus, when polymer degradation, it seem easy to make up, the viscosity cutting of polymer melt need more reaction temperature than it. So, a faster filling rate is more efficient for filling the cavity.
 

Metal injection molding manufacturer introduced that rapid cooling of the polymer melt can shorten the cycle, and also can improve production ability. It is a kind of simple way of realize precision parts, after release mould for a while, thermoplastic plastic will not rush and will cooling as fixed speed. Uniform cooling rate will cause shrink, and lead to wrong dimensions or high residual stress. If the temperature tool is low, the small dimensions gate will soon let melt to separation and free shrinkage from tool cavity. If it is this, molding cycle will have high pressure for a long time.