Flow Marks in Powder Injection Molding

Powder injection molding manufacture notes flow marks  is a common defect in MIM process. Let’ probe into the reason for flow marks defect based on past MIM parts experience.

Phenomenon:

The initial injected feedstock cool down rapidly, then generate interface with later injected feedstock, the flow marks refers to injection gate centered concentric circles mark.

The causes and treatment:
- the mold temperature is too low
- injection speed is too slow
-poor liquidity of raw material
- too small injection gate
-too low or uneven temperature for mould and feedstock
- no cold slug well or too small
-poor  product design,  thickness change big .

Original article link：http://www.zcmim.com/article/flowmarksinpowderinjectionmolding_1.html