Geometric roughness analysis in solid free-form manufacturing processes

Present day techniques of prototype manufacture based on computer-assisted design systems and material deposition processes have led to a considerable reduction in manufacturing time. However, numerous aspects of the use of these technologies have yet to be studied. One of these is characterisation of the surface roughness obtainable in layered manufacturing processes. To characterise effective roughness, a study of the roughness average (Ra) obtained through use of these manufacturing processes was carried out. This enabled us to establish two possible strategies for rapid prototype manufacture: manufacture at constant layer height, and manufacture with roughness confined within given limiting values. Prototype parts were manufactured using stereolithography technique and an experimental analysis of resulting surface roughness was carried out to enable us to compare the theoretical models proposed.