Development of an Automated Multiple Material Stereolithography Machine
Abstract
An automated Multiple Material Stereolithography (MMSL) machine was developed by
integrating components of a 3D Systems 250/50 stereolithography (SL) machine in a separate
stand-alone system and adapting them to function with additional components required for
MMSL operation. We previously reported retrofitting a 250/50 SL machine with multiple vats
to accommodate multiple material fabrication for building a wide variety of multi-material
models (Wicker et al., 2004). In the MMSL retrofit, spatial constraints limited the multiple vats
located circumferentially on a vertical rotating vat carousel to cross-sectional areas of
approximately 4.5-inches by 4.5-inches. The limited build size of the retrofitted 250/50
motivated the full development of a new system with multiple material build capabilities
comparable to the build envelope of the original 250/50 machine. The new MMSL machine
required fabrication of a large system frame, incorporating various 250/50 components and
software, and adding a variety of new components and software. By using many existing
components and software, the previous engineering development of 3D Systems could be
directly applied to this new technology. Components that were transferred from an existing
250/50 to the MMSL machine included the complete optical system (including the optics plate
with laser, mirrors, beam expander, scanning mirrors, and focusing lens), the rim assembly
(including the laser beam profilers), the associated controllers (computer system, scanning mirror
controller, power supply-vat controller) and the wiring harness. In addition to the new frame, the
MMSL machine required the development of a new rotating vat carousel system, platform
assembly, multi-pump filling/leveling system, and a custom LabVIEW® control system to
provide automated control over the MMSL process. The overall operation of the MMSL system
was managed using the LabVIEW® program, which also included controlling a new vat leveling
system and new linear and rotational stages, while the 3D Systems software (Buildstation 4.0)
was retained for controlling the laser scanning process. As a demonstration of MMSL
technology, simple multi material parts were fabricated with vertically and horizontally oriented
interfaces. The fully functional MMSL system offers enormous potential for fabricating a wide
variety of multiple material functional devices.