RE: SLS Duraform features with 100watt lasers

From: David K. Leigh (dkleigh@harvest-tech.com)
Date: Thu Oct 10 2002 - 19:37:41 EEST


We do fine features on all of our systems. I don't see a significant
difference between running a 25W Laser and a 100W Laser. We have 25W, 50W,
and 100W systems (Vanguard equiv.) and a 100W Vanguard HS. We also have
some older systems with 50W and 100W lasers. If you are truly interested in
a benchmark, let me know. I can run the same geometry in each of the 4
systems (25W Vanuard, 50W Vanguard, 100W Vanguard, and 100W Vanguard HS).

The issue I have seen with differences in sidewall quality has been more
with our HS system than it has been with the wattage of the laser. I think
the rate at which the laser scans coupled with a slightly different slicing
algorithm have introduced an instability in the accuracy of x and y wall
thicknesses.

********************************************************************
David K. Leigh (254) 933-1000
Harvest Technologies, Inc. fax (254) 298-0125
Rapid Prototyping Services www.harvest-tech.com

-----Original Message-----
From: owner-rp-ml@rapid.lpt.fi [mailto:owner-rp-ml@rapid.lpt.fi]On
Behalf Of Scott Tilton
Sent: Thursday, October 10, 2002 10:02 AM
To: rp-ml@rapid.lpt.fi
Subject: SLS Duraform features with 100watt lasers

Hello again to everyone.

Thanks to all for the responses to my last question.
What a good resource this list can be!

I have another question that has come up.

I have been informed of some the negative aspects of upgrading to a 100 watt
laser, which is required to make metal parts in a Sinterstation.

Specifically, that when making parts in normal Duraform material, the 100
watt laser is operating at such a low duty cycle that thin walls in the X
direction will suffer. Essentially, asking the laser to blink on and off
for such a short period of time is hard enough without asking it to blink on
at such a low percentage of its maximum power.

Can anyone quantify the difference in performance?
Perhaps with examples of parts they have built?

For example if you were building a top and bottom shell for a round
electronics enclosure.
What would be the thinnest "tongue" feature to fit in the matching groove
feature on the other half of the assembly?

For my own personal experience with this type of feature, I get very
hesitant when someone comes to me with a wall thickness of .020" or less.
I've gotten them to build successfully, but I don't make promises that it
will be right on the first try. We are currently using a 25 watt laser.

Also . .how badly is the outline scan quality affected?
I imagine if a 100watt laser is having trouble running at 12% for normal
fill scans, the 7% required for an outline is going to have problems too?

Or maybe I'm wrong.

Any "Been There Done That" experiences welcomed.

Thanks again.

Scott Tilton

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