RE: Sla 250 Parts build when machine is having a good day

From: Blasch, Larry (
Date: Mon Jul 03 2000 - 16:42:52 EEST

Hello John,

First, how clean is your vat?

The first thing I would suspect is blade crash and layer damage due to
floating threads that can accumulate from multi-object laser hopping and
stray vectors.

These will normally sink to the bottom and create a sludge/slime layer that
can sometimes be dislodged by a deep build. All it takes is a little damage
and you can have a total failure. Cleaning the tank out is not as tough a
job as it may seem, but it will make a huge difference. If you have had a
number of crashes and you are only using a fishnet to get the big stuff,
then you really need to filter the entire tank.

If you have never drained and filtered the tank, I would be happy to offer
you some suggestions on how to do it without the need for a HAZ-MAT team or
a chiropractor on hand.

Second, it could be a power problem... low voltage (sag) can cause recoater
problems as well as dramatic changes in laser power. Since the SLA-250 only
reads the laser power between layers, if the layer section is large, you can
have a substantial variation in cure depth during a long layer trace.
You could try a run with the /diag option set to create a diagnostics log
that will record the laser power at each re-coat to see if you have a
fluctuation in the power during the build. This could be a symptom of
impending laser and/or power supply failure also.
(Call 3D's hotline and they can talk you through it.)

I would suggest that you look into a filtered power supply or UPS if that is
a potential problem.

Third, power down the entire machine (Not just the computer) and do a cold
restart. It's not Windows (no offense Bill), but I've found that goofy
problems can crop up after months of continuous run time.

Good luck,


Lawrence R. Blasch
Design Engineer
CAE Systems Administrator
"A decade of RP experience"

OPW Fueling Components
P.O. Box 405003
Cincinnati, OH 45240-5003 USA
Voice: (513) 870-3356
Fax: (513) 870-3338

* "Always remember you're unique,*
* just like everyone else." *

-----Original Message-----
From: John Curran []
Sent: Monday, July 03, 2000 1:59 PM
Subject: RE: Sla 250 Parts build when machine is having a good day

hello everyone

I'am new to the list and this is my first enquiry.

I run a 3D 250 and have done for nearly two years
I am having trouble with parts failing part way during a build. the layers
do not seem to be bonding together. I have not changed any settings.
I am still using Maestro for set up. the laser is at 24 Mw and vat temp is
I can build a part perfectly and then build the exact same part using the
same file and it will fail. Does anybody have any ideas before I call out
and engineer

thanks in advance John Curran

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