Re: SLA - Part Building Issue

From: Steve Stewart (steve@protogenic.com)
Date: Fri Nov 20 1998 - 17:11:05 EET


Cheong Toh Kim Alvin wrote:
>
> Since 2 weeks ago, we started getting parts out from the SLA500 with
> undesirable results unseen before.
>
> >From the look of the part, it sure looks like after certain height of
> building, there was a shift of about 2mm in the X direction & this off-set
> position remained over the next 5mm build before it returned back to the
> original position. It remained so for a certain height before the same thing
> happened again with the literally same off-set & duration. This would self
> repeat over & over again throughout.
>
> The platform is well secured down & even if it's not, surely a mechanical
> shift if any would unlikley yield such a consistent pattern of steps on the
> part. It can't be the blade sweeping action along the Y axis either as the
> shift is along the X.
>
> I wonder has anyone out there observed this rather strange phenomenon & the
> solution??
>

Alvin -

We had a similar problem, not exactly the same, but found that "Smart
Laser" changes the power around depending on your draw speeds. If you
set Borders at 200 in./sec. and Hatch at 200 in./sec., and your laser is
relatively new, the software ups the current to 57 A to draw supports as
fast as it can, then maybe only needs 51 A to draw hatching on the
parts. As the laser tube is quite long, heat can significantly warp or
bend it. We wound up dropping the speed of Borders until the Amperage
requested by the software stayed stable, and have had no problems
since. I think in our case, we draw Borders about 35 in./sec. with
Hatch at 200.

Hope this helps,

-- 
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
 \_ Steve Stewart                          Phone: 303-252-0212 \_
  \_ protogenic, inc.                         FAX: 303-252-0223 \_
   \_ 1490 w. 121 ave., suite 101    WebSite:www.protogenic.com  \_
    \_ westminster, co  80234         e-mail:steve@protogenic.com \_
     \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

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