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August 2000

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Subject:
From:
Jon Moore <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Mon, 21 Aug 2000 13:33:10 EDT
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Ed,
    I have done way more spray coating with acrylic than I would probably
like to admit.  Every time someone finds out you have experience with this
stuff, you become the assigned coating Process Engineer and you can never get
away from that job.  It's really not all that bad, though.  I have done my
curing process a couple of different ways.  My first ovens were IR lamps with
glass covers.  It got the job done, but it was difficult to get tight control
on the profile.  The last five or six lines that I put in were all standard
convection ovens, made for reflow soldering.  ( I can share brand if you want
- off TN)  The key is really stable temperature and high air flow, because
with acrylic you are really just driving off the solvent, or drying the
material as opposed to an actual cure as you would have with something like a
temperature cured silicone.  I know of one manufacturer of very good
selective spray coating equipment that also does a good oven.  But almost any
reflow / cure oven will do fine.  I typically set every zone at the same
temperature, in my case around 100 C, and set the conveyor speed for a total
time in the oven of around 6 - 8 minutes.  My exhaust system was drawing
about 1200-1500 cfm, which gave me enough airflow the meet the OSHA
requirements without the added expense of explosion-proof motors and wiring
throughout the oven.

Hope that helps!
Jon Moore

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