Why Flashes are formed in the MIM Process? What are the improvements?

Date：2025-07-28   Views：0

In the MIM Process, flashes may be formed under some situations and such defects can be addressed.

Possible Causes:

In MIM processes, molds with multiple cavities require long runner systems and high molding pressure to deliver feedstock to each cavity. Due to variations in material properties and geometries of mold components, elevated molding pressure causes mold deformation. This deformation creates gaps between mold sections, allowing feedstock to penetrate and form flash.
*Flash severity increases when large molds (with numerous cavities) are used on small-tonnage molding machines.
Conclusion: High injection pressure → mold deformation → gap formation → flash.

Selectable Solutions:

• Employ Higher-Tonnage Injection Machines

Ensures sufficient clamping force to withstand mold dimensions, weight, and pressure, thereby mold separation during injection can be prevented.

Enhances dimensional stability and part quality.

• Optimize mold design and manufacturing

Rational layout of the runner system

Reinforcement of vulnerable mold sections

• Reduce injection speed and molding pressure

Prevents mold deformation and gap formation

Maintains consistent cavity sealing

(However, low speed and low pressure may cause the melt front to cool prematurely; thus, the temperature of the mold and the injection feedstock can be appropriately increased.)