Black Specks in MIM Machining Process

MIM process manufacture notes that black specks is a common defect in MIM process. Today we would like to discuss the reason for black specks based on our last experience of Unmanned Aircraft parts machining project.

Phenomenon:
Finish products’ surface with black spots

Causes :
-mixed paper scrap, lines, or dust into material when pour material into the cylinder
-not clean up the material barrel, screw, feed tube, nozzle  during refueling
- improper process lead to mix with foreign matter

- the mold surface is not clean
- choose wrong pigment (cracking)

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