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B. Busetti, B. Steyrer, B. Lutzer, R. Reiter, J. Stampfl:
"A hybrid exposure concept for lithography-based additive manufacturing";
Additive Manufacturing, Volume 21 (2018), 21; S. 413 - 421.

Lithography-based Additive Manufacturing Technologies (L-AMT) exploit the curing of photosensitive materials upon light exposure. We developed a hybrid exposure concept. This system is able to overcome the challenge of providing good surface qualities and excellent feature resolution as well as a throughput similar to dynamic mask-based L-AMT systems by combining two light sources. A Digital Light Processing (DLP®) Light Engine (LE) with a building area of 144 x 90 mm² offers a pixelsize of 56 μm. In order to further improve the achievable resolution, a continuous laser-exposed contour line (spot size 20 μm) on the outside of the projected envelope can be written with an additional scanning laser-system. The matching of the DLP® projection mask and the laser-contour is crucial for accurate printing. Therefore a calibration tool was developed, which facilitates the alignment of the two light sources. A dichroic coated mirror enables a perpendicular alignment of the DLP® light beam and the laser beam.

Laser; Mask projection; Vat photopolymerization; Hybrid system; Throughput enhancement

http://dx.doi.org/10.1016/j.addma.2018.03.024