At 01:44 PM 2/5/96 EST, you wrote:
>To all the SLA users out there and anyone else with any input....
>We have just started to see a very strange effect on our ACIS
>SLA parts. Many of the top skin fills are coming out with
>a textured pattern. It kind of looks like the textured plastic
>dashboard in a car - or an orange peel. It has a very intricate
>pattern that almost makes you think of Indian pyroglythics (yeah
>I know it is probably spelled wrong). We have seen it on all of
>our recent ACIS builds. Strangely enough different surfaces
>on the same part won't have it.
>We have a SLA 250 with a 30 mw laser (appears stable) and
>are using 5170 resin. Our system is in a controlled temperature/
>humidity environment and the laser does not appear to be
>fluctuating. I do not believe it is dewetting as this usually has
>a very different look. If you think you have seen this look - please
>let us know as these parts are for sand casting patterns and are
>not usable. If you have a mail account that handles attachments
>I can send several pictures of the effect. Any help/comments
>would be appreciated.
>Regards, Todd Stahlhut
What you have described sounds very much like what we have experienced on
DOWN FACING skins on our 250. I would describe it as wrinkled. The way we
overcame this was to slighytly increase the cure depths of the down facing
skin. You might try decreasing the hatch spacing a bit too. It could be
caused by some change in the laser beam profile. Of course the ACES
ADVANCED profile uses no skin fill at all, this is what we use most of the
Eastman Kodak Company
Rapid Prototyping Center
901 Elmgrove Rd.
Rochester, NY 14653-5315
Rapid Prototyping Center Established 1988
Selective Laser Sintering
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