RE: ACES and EOS

From: Bronson R. Hokuf 302-328-5635, FAX 302-328-5693 (Bronson.R.Hokuf@usa.dupont.com)
Date: Wed Aug 06 1997 - 21:44:43 EEST


Hello,
You wrote:
> I heard a lot about ACES hatching technique, and wondered if this is a
> process by 3D Systems or a technique that can be chosen before building
> the part. That is, I have an EOS Stereos MAX, can I use ACES?
>
> Thank you all!
>
> --
> * Christian Antoniutti
> * email: mailto:antoniutti@uniud.it

ACES(tm) stands for Accurate Clear Epoxy Style. This is 3D Systems'
trademarked name used to represent a way of writing vectors in
photopolymer.

This drawing style (or something similar) has been in use for many years at
various locations; it was not desirable for acrylate resins because of the
high shrinkage factors associated with those materials.

The goal of this build style is to write layers with closely spaced lines
resulting in very uniform UV laser exposure across the layer. It results
in smoother up and down facing surfaces and usually produces clear parts.
Typically the line spacing should be ~40% of the beam diameter For a beam
diameter of 0.25 mm (0.010 in.), you should select a hatch spacing of 0.1mm
(0.004 in.). 3D recommends using both X & Y hatch vectors, however using
only X or Y hatch vectors will also work provided the exposure given to
each layer is correct.

Many users have begun building epoxy models with a wider hatch spacing.
When combined with so called "skin-fills" (tightly spaced hatching on up
and downfacing layers), this generally results in substantially faster
build speeds and parts that look much the same with only a marginal
reduction in material properties. To try this approach, you might try
hatch spacings of 0.229 mm or 0.3 mm and find a substantial speed increase
in your builds. For this wider hatch spacing, you should use both X & Y
hatch vectors and higher overcures when drawing. (Note: With epoxy resins
it may be undesirable to increase the hatch spacing beyond 0.3mm (0.012
in.); wider spacing may expose unreacted resin to the vat leading to resin
instability.) Some epoxies may not be able to support a wide range of
build styles, you should consult with the material vendor if you have any
questions in this regard.

This was longer than I expected, I hope it helps,
Bronson
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Bronson R. Hokuf USMail: DuPont Company
DuPont Company (NCCC/Penn's) 2 Penn's Way, Suite 401
Photopolymers & Electronic Materials New Castle, DE 19720
Somos(r) Solid Imaging Materials Tel: 302-328-5635
E-Mail: hokufbr@esvax.dnet.dupont.com Fax: 302-328-5693
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