Dear KL:
The only person that I know for sure that has done a home-brew RP machine is Aad Van
der Geest from the Netherlands. He started with an HP inkjet and modified that to print in
color on top of starch or a plaster-like powder. The purported difference between his
approach and Z-Corp is that the layer adhering material is within the powder bed. His
original price was going to be around $7K as I recall, but since about a year ago, the
development was taken over by TNO and subsequently licensed to BMT in Germany. Their
intended price was around $15K and the machine made it to beta test. Aad has an EPO patent,
however a patent fight with MIT resulted in the demise of the project.
You can find links to these developments on the WWGRP commercial systems pages, and
possibly in the Digest area, as well.
The elusive $1K machine may come to exist at some point, but it awaits 2 things: An
audience big enough to support applications that result in a massive engineering
investment, and perfection of materials and technology to address those larger market
segments. Remember that a $1K selling price implies a manufacturing cost of about $250
which is not a trivial exercise.
On the up side, think about what's in a VCR or a small copier. I think the technical
task is on the same order so there's no inherent reason why it cannot be done. Ask first:
What market would support that investment?
There's been considerable thinking about this, at any rate, by a group at Harvard and by
Koshnevis at Univ of Southern CA. Both groups have written quite a bit about such
applications, although the approaches are more like FDM with big trowels and robotic
heads. This avoids having to remove a large powder bed, or getting it rained on and having
it harden into a mass. Koshnevis calls his approach "Contour Crafting" and he has a number
of patents. There are other groups working on structures such as sailing vessels, etc.
Look at the Univ listings on the WWGRP to uncover more info; also on the
art/architecture pages and in the bibliography.
These are good questions to pose to the RPML. They come up periodically there with an
ensuing storm of replies, but that's good - They should! Consider being an instigator.
Best regards,
Ed Grenda
Castle Island Co.
