RE: Using reused powder in SLS -reg

From: David K. Leigh (
Date: Wed Dec 18 2002 - 17:04:24 EET


Virgin Powder: Less Accurate
Used Powder: More Accurate

How do you define "less" accurate?
How many builds did you run with virgin powder?
Did you change any parameters from build to build?
How do you define virgin powder?
What was the makeup of your used powder?
Did you run this on more than one machine to verify results?
Were the powder lots the same?

Many questions to be answered before anyone can conjecture on the nature of
your results.
If you use the shrinkage values from used powder and run virgin powder - you
will not get accurate results.

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

  -----Original Message-----
  From: []On Behalf
Of ramanathan baranitharan
  Sent: Tuesday, December 17, 2002 10:25 PM
  Subject: Using reused powder in SLS -reg

  dear friends

  I am a post graduate student doing research in Selective Laser sintering
Polymer powders at PSG College of Technology

  Machine : Sinterstation 2500 plus

  material : Duraform PA (polyamide)

  In my experiments I infer that accuracy of exposed powder is better that
that of fresh powder with 11W laser power

  what may be the reason behind it?

  Before this experimentation we assumed that fresh powder may give better
dimensional accuracy and using only fresh powder for industrial projects.



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