RE: Info wanted on Quadrax

From: Lightman, Allan J (
Date: Mon Jun 30 1997 - 15:51:38 EEST

Looking at some of the original Quadrax slides, they show a curtain
recoater using resin pumped from a second vat below the build vat. In
their version of SL, the part is built attached to fixed platform,
necessitating that the laser focus recede as the volume in the build
chamber grows. They used a positive displacement pump to provide a
fixed volume of added resin during each cycle, thereby giving a fixed
layer thickness (without accounting for shrinkage of the cured section).
As I recall, they later went to a spray bar. At the end of their build
they drain the upper build vat into the lower resupply vat, exposing the
part for removal. They are then ready to build another part. For a
first hand account, contact Tim Heller, now at Stratasys
(+1-612-937-3000). He was involved with the development of the Quadrax

Allan Lightman
Allan J. Lightman, Ph.D.
University of Dayton Research Institute
Dayton, OH 45469-0150, USA

T: +1-937-229-3966

> -----Original Message-----
> From: John Male []
> Sent: Monday, June 30, 1997 5:16 AM
> To:
> Cc:
> Subject: Info wanted on Quadrax
> Dear All
> Does anyone out there have any information on the Quadrax Laser
> Technologies stereolithography machines? Were any machines sold
> commercially before their technology was acquired by 3D Systems?
> I'm especially interested in the recoating technique that they used.
> Did
> the recoating arm spray fresh resin onto the previous layer, or was it
> more of a 'curtain' of resin falling onto it? What were the layer
> thicknesses used?
> Any references with desciptions of the recoating mechanism would be
> greatly appreciated.
> Thanks
> John
> --
> John Male
> Research Student
> Centre for Rapid Design and Manufacture
> Buckinghamshire College of Higher Education
> Queen Alexandra Road
> High Wycombe
> Buckinghamshire
> England
> HP11 2JZ
> Tel 01494 605085
> Fax 01494 538593

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