Re: Re - bad surface on top facing part with holes/protrusions

From: Scott \ (
Date: Thu Sep 18 1997 - 23:45:32 EEST


Great idea! I guess the reason the your text did not show up without
playing with the beam comp, is because the width of certain areas of
the text was smaller then the laser beam. One way to check this is pull
up the slice file in view. It will show you if the laser is going to
scan (or miss) the feature before you build the part. You can also pull
the .stl into SOLID View and measure the feature to check if it is
bigger then your laser width.

Stahlhut, Todd A. wrote:

> I posted a message last week concerning bad top facing surfaces on
> parts
> with protrusions and openings such as text, bosses, and holes. It is
> theorized that the bad surface finish is due to the drawing method
> where the laser sweeps between features rather than clear across the
> part - skipping openings/protrusions. I have a front panel mockup
> with
> a lot of raised text. The resulting top surface was quite bad due to
> all of the surface interruptions. After inputs from several RP mail
> users, a call to the 3D hotline (yea its a problem on the 250 - hope
> they fix it someday - maybe NT.....) and some actual thought on my
> part
> (some would say a rarity) - I came up with a half way solution that
> is
> a pain - but helped. Hopefully others can use this trick also. What
> I
> did was went back to the ProEngineer model and cut the text off at the
> top surface and wrote this out as a STL file. Then I cut the part off
> even with the bottom of the text and wrote that out as an STL file. I
> then located these STL files in the build set so the text lined up
> properly (but moved down a layer thickness to ensure bonding) and
> build
> the part. Because they are two separate parts it completes the bottom
> part first - sweeping clear across the part - leaving a nice surface,
> then it draws part two - the text. The resulting part was
> significantly
> better than the first attempt at building it as a single part.
> This was a pain - but was worth the effort to get a better product to
> my
> customer. If you are listening 3D - please fix this bug (yes I
> realize
> this falls in the product enhancement category - but I consider it a
> bug....)
> Regards, Todd Stahlhut
> P.S. - Another lesson that I learned in building this part was that
> at
> least with ProE text (about .1 tall) was that beam comp needs to be
> significantly reduced or turned off completely. With my method above,
> you can leave beam comp on for the main part and turn it off for the
> text part.


Scott "Scooter" Sutterer Premier Design & Mfg. Co. Phone: (314) 936-1288 Fax: (314) 936-2528 _________________________________ NOTE: I am not responsabel for speling; puntuasion nor grammer!

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