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Good coating for aluminium injection mold for rubber?

January 4, 2011

I am looking for suggestions for coating material/solution for aluminium injection mold for rubber.
operating condition: 350 F

Current operation:
- No coating
- quick cleaning of mold after every single injection
- thorough cleaning of mold after 500 injections

I have tried using Electroless Nickel with PTFE in order to boost the mold release property but that did not turn out well. The coating was found peeled after 1 session.

Appreciate if anyone can advise or point me to the solution which works in this situation.

Regards,

Amir Setiawan

Amir Setiawan
Plating Shop Employee - Malaysia

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Hi,
When properly applied EN+PTFE will not come off under normal rubber molding conditions. Something went wrong during the surface preparation prior to the plating of your mold or perhaps you were using release agents containing silicone. Those are particularly tough to clean. Depending on geometry other options include PVD and chrome.
Good luck
G. Marrufo

Guillermo Marrufo
Monterrey, NL, Mexico
First of two simultaneous responses -- January 4, 2011

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It is quite possible that a used mold will not plate well. It definitely would require more preparation.

The EN Teflon should not have peeled. Possibly the part was not clean enough. More likely is the zincate was either too thin or too thick. It is also possible that the zincate was out of tolerance.
Acid / neutral EN will attack the zincate quite rapidly. I strongly recommend using an alkaline EN strike, a quick rinse and into the EN tank.

So, what was your steps for the EN-Teflon plating?

James Watts
- Navarre, Florida
Second of two simultaneous responses -- January 4, 2011