Re: SGC Rapid Prototyping

From: Brad W. Wright, Ph.D., P.E. (
Date: Sat Aug 01 1998 - 01:58:34 EEST


The SOLIDER system was developed and commercialized by Cubital, Ltd. Like
Stereolithography, solid ground curing (SGC) also uses a liquid plastic
resin that is solidified when exposed to UV light. However, the actual
solidification of each slice is significantly different from
SGC consists of a four step process to solidify each slice. First, (like
the SLA), an elevator is positioned under the surface of the resin, at a
depth equal to just over the first slice thickness. Then, an image of the
slice is produced on an electrostatically-charged erasable glass plate using
ionographic printing techniques. That image, serving as a photo-mask, is
positioned over the elevator, and the surface is flooded with UV light. All
of the cross-section that is to be solid is fully cured at that time. In
the second step, the liquid resin remaining on the elevator is removed,
leaving the hardened areas intact.
In the third step, melted wax is spread over the workspace, filling in all
of the areas that are not occupied by solidified resin. After the wax is
cooled and hardened, the fourth step consists of an action by what is
effectively a milling machine. In this step, the surface of the wax/resin
is milled flat, resulting in an accurate slice thickness. These four steps
are then repeated to solidify the next slice, and so on, until the model is
At the end of the build, the workspace is full of hardened wax, containing
within the completed prototype. The wax is then melted and washed away,
leaving the completed prototype. One advantage of SGC is that the wax
provides an ongoing support structure; thus, no additional time or effort is
required for complex geometries.

Hope this helps

Brad Wright
Wright Engineering and Applied Technologies

Jeff Markus wrote:

> Can someone please explain to me what SGC is and how it compares to SLA,
> SLS and FDM?
> Thanks,
> Jeff
> --
> Jeff Markus
> Mechanical Design Engineer Fax: (613) 969-8191
> Autosystems Design Centre Tel: (613) 969-1122 Ext. 4414
> Belleville, Ontario, Canada email:
> For more information about the rp-ml, see

For more information about the rp-ml, see

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