Posted by Gordon England on May 14, 2004 at 23:56:24:
In Reply to: Re: spraying on polycarbonate posted by Ben Nakhosteen on May 14, 2004 at 19:09:02:
: Hi Gordon,
: thanks for your immediate help.
: I did a quick coating test today and the results are quite promising. I compared smooth dry cleaned with ethanol cleaned substrates but could not see any significant difference in coating quality.
: However, I'm a little concerned about preparation of the plastic surface using chemicals since it may absorb liquid and may swell later on. I haven't tried sand blasting jet.
: I agree that cooling is a very important issue. The part I tried today was only 1mm thick and fixed to a piece of copper. Propably this resulted in insufficient cooling since the part was a little warped after the process.
: Another parameter is surface speed. I think I should try to increase from now 200mm/sec to about 2000mm/sec to reduce heat input in the part but for this I'll have to change the setup.
: Thanks once again
: Ben
Hi Ben
Increasing the surface speed dramatically will enable you to apply much thinner coating layers per pass, which should help keep temperature more even and lower. Additional air cooling jets may be useful if you are still struggling to control temperature.
A light grit blast etch will improve bonding greatly compared to just solvent cleaning.
Good luck, it sounds as though your on the right track.
Regards Gordon
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