[Back]

B. Busetti, B. Lutzer, J. Stampfl:
"Development of a hybrid exposure system for lithography-based additive manufacturing technologies";
Talk: SPIE Photonics West - LASE, San Francisco; 01-27-2018 - 02-01-2018; in: "SPIE Proceedings Vol. 10523: Laser 3D Manufacturing V", SPIE Digital Library, 1052305 (2018), ISBN: 9781510615311; 1 - 13.

Lithography-based Additive Manufacturing Technologies (AMT) exploit the curing of photosensitive materials upon light exposure. We developed a hybrid exposure concept, which is able to overcome the dilemma of providing high surfaces qualities and an enhanced throughput by combining two light sources. Digital Light Processing (DLP) Light Engine (LE) -exposure allows a rapid curing of extended areas. However, round envelopes are approximated by single pixels, which leads subsequently to a spatial approximation and thus to lower surface qualities, whereas laser-based AMT systems enable smooth structures. However, with increasing layer crosssection and smaller laser-spot size the exposure time increases, since single laser lines are applied next to each other in order to provide a fully cured layer. In our system, a laser focused to 20 μm shapes the outline of the item whereas a DLP LE, with a pixel-size of 56 μm, cures the inner area. A dichroic mirror, which reflects the wavelength of the laser and transmits the light of the DLP LE, facilitates the beam-alignment. An online-monitoring camera array guaranties the control of both light sources. Our new technology enables the production of parts which previously could not be produced with traditional manufacturing methods. The layer-by-layer approach enables highly complex structures, leading to a design oriented engineering of items. A system with these specifications provides an alternative to many microinjection molding or injection molding processes for complex structures and small lot sizes.
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Additive Manufacturing; Digital Light Processing; SLA; Projection system; Telecentric optics; Hybrid exposure;

http://dx.doi.org/10.1117/12.2286637