On the improvement of the stereolithography (SL) process

The successful control and operation of the stereolithograpy (SL) process depends on many parameters. These can be categorized systematically into: hardware, i.e., the construction and mode of operation of the machine; the controlling software such as the hatching pattern, error compensation and part orientation; and the material properties of the photo-polymer. The improvement of the current SL process is approached from both the software and hardware viewpoints. In the software study, the following issues are considered: (a) a correction table for compensating on the positioning accuracy; (b) STL slicing software with an editing and automatic error-correction function; (c) a direct slicing algorithm to be used on commercial CAD software; (d) the optimal part orientation software and (e) a variable slicing algorithm. For hardware and material studies, a novel process using a mixture of Aerosil silica powder and photo-polymer was developed. The resulting mixture not only reduces the requirement for support structures fur the model hence shortening the model-building time, but also improves the properties of the model, such as tensile strength, shrinkage rate, etc. (C) 2001 Elsevier Science B.V. All rights reserved.