Paul, another factor that we have seen that I believe is more critical
the geometry is the material. David Leigh from Harvest Technologies did
a presentation at the SLS User's group on material recycling that gave a
very good concept to keep material consistent across many builds.
We had seen our shrinkages vary widely from build to build before we
instituted a rigid recycling program. It is important to mix used
from multiple builds together before adding virgin powder. This takes
the variable of large/hot build material versus small cross section/cool
builds. Basically, mix used material in large batches to take out
build variations due to temperature exposure differences.
Since that time our shrinkage values have been very tight. Obviously, if
you are using 100 percent virgin material this should not be an issue.
However, I assume that you are trying to run as high a percentage of
used material as possible without degrading the material properties.
-- Tim Gornet Computer Aided Engineering Consultant INTERNET: firstname.lastname@example.org SLUGNET: Vogt Bldg. Rm 101, University of Louisville, Louisville, KY 40292 PHONENET: (502)852-0714 FAXNET: (502)852-8890
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