RE: Humidity study

Date: Thu Jun 17 1999 - 20:52:40 EEST


There has been a lot of study done on the topic and as soon as I can dig out
the printed reports I'd be more then happy to send you a copy.

We have been using SL5180 in our machines for some time (one machine we
just acquired) and have seen QuickCast patters swell as much as 0.100". The
real key is to prevent the moisture from getting to the part before you can
cure it!. We started to cure all of our patterns in plastic bags with
SilcaGel packs to give the pattern the best shot at curing dry. Also we
have learned (the hard way, several thousand $$ thrown in the trash) that
QuickCast patterns should NOT sit around for more then a couple of days in
any type of humidity! We have not had any swelling of solid builds,
although we normally don't track these as we do the QuickCast.

Hope this helps and send me your mailing address so I can send a copy of the
studies that I do have.

Karl Denton
Senior Engineer
Williams International

        -----Original Message-----
        From: Alta Precision []
        Sent: Thursday, June 17, 1999 5:07 PM
        Subject: Humidity study

        Good day all,
        Has anyone out there done any in-depth studies on how humidity
affects SLA patterns, more specifically on SL5180 resin. We all know that
the parts tend to swell when exposed to high levels of humidity, but does
anyone have hard data that they are willing to share? I'll even listen to
your worst horror stories. Thanks in advance.
        Bill Bernardo
        Alta Precision Prototypes
        Montreal, Qc., Canada <>

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