Re: thin layers

From: Dick Newton (Ford  Motor Company)
To: RP-ML, Elaine Hunt (Clemson  University)
Date: Sunday, January 22, 1995
Subject: Re: thin layers
> (1) What is the thinnest layer thickness that you can RELIABLY build in
> your technology?
  On the LOM .0038 inches
>
> (2) How  do you  accomplish this thinness?
Use a thiner paper. We could probably go slightly smaller than this if 
we wanted to look for an even thinner paper.

> 
>(3) What is the thinest layer you REALLY want to build?
I don't really know, every thing is a trade off and we don't normally
build parts that require that kind of resolution anyway. Most parts
that we see that require very fine z resolution also have very small
features. On the LOM, features that have small cross sectional areas in
the x-y plane (ie a small diameter pin pointing up in the Z) don't have
a lot of strength because of the laminating process.

>(4) What are the trade-off is any?  (slice time increase, file size
>increase?????)

The biggest trade off is build speed.  For a given part, build times
increase because of the increase in the number of layers that need to
be cut. Laser cutting speed and lamination speeds can be faster on
thinner papers, but not enough to make up for the increased number of
layers.

On some parts we will build certain areas at .0038, and then use double
layers through the rest of the part. Double layers laminate two layers 
before using the laser to cut through both, giving an effective layer
thickness of .0076.

The largest problem with going any thinner than what we currently use
is the strength of the paper. Very thin paper is easier to tear on the
take up rollers and feed mechanisms.

For most builds, we use paper that is around .0075 inch thick.

Dick