Automated fluid handling and leveling system for multiple material stereolithography

This work addresses the development of an automated multiple material fluid handling and leveling system for its implementation into a Multiple-Material Stereolithography (MMSL) apparatus. A patent filed by Wicker et al. (US Patent 7,556,490) disclosing a MMSL apparatus served as the basis for the development of this work. The system is designed to operate in a variety of MMSL apparatus configurations. Fluid vats are designed to meet the enclosure constraints, facilitate the interface to the pump and sensor, and support the handling of the fluids. Due to its fluid isolation and bi-directional flow capabilities, a digital drive peristaltic pump is used as the key fluid handling element. A laser triangulation displacement sensor is used as the live feedback for the control system. Communication and control software routines are developed to operate the control system and support the system implementation flexibility. A basic mathematical model of the control system and the individual physical elements is presented. A PID technique is employed as the control strategy. Satisfactory operation is demonstrated by incorporating the system into an automated MMSL machine able to produce simple multiple material SL samples.