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The Molding Cycle


Simplified molding cycle

Ever wonder how those "ejector pin marks" got on your parts? The animation above is a simplified version of the sequence of events for injection molding plastic parts.

1. The mold closes and builds pressure to keep it closed.
2. The plastic is injected into the mold under high pressure (up to 1000psi) to form the part to the cavity.
3. The mold stays closed while the injection unit refills, also allowing time for the part to cure.
4. The mold opens, with the part staying on one half of the mold.
5. When the mold opens, the ejector pins come forward to push the part off of the mold face.
6. The ejector pins retract, and it all starts again.


This is only a start, if demand warrants, I am going to be adding more information on injection molding.

Email me if you would like to see more


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