Most Common Defects and Solutions on Automotive MIM Parts

With the constant development of MIM technology, it has been applied to more and more industries, and it is essential since been used in automotive. Whilst there are some common defects in the metal injection molding process.

1. Lack of Injection

Lack of injection is the phenomenon that mold cavity cannot be completely filled, the main reason is the stagnation. It occurs due to there is a relatively thin structure near the gate, and the melt encounters relatively large forward resistance during the injection molding process. If the melt does not flow at this point and there is no heat to replenish and have solidified, it will cause lack of Injection.



2. Jet Pattern
The jet pattern is the trails that stream from the gate along the flow direction, bending like a sneak trail. When this happens, we can apply an antiknock pin in front of the gate to prevent stream jets and also to enlarge the gate cross section.



3. Top Raised

When ejector ejecting parts, and the workpiece is not fully cooled solidification, mold release force, leading to parts in the mandrel head position is convex, higher than the normal surface of the workpiece. Under this circumstances, by reducing the ejection speed and mold temperature, to extend the cooling time could be working.