On-line force monitoring of platform ascending rapid prototyping system

In the processing of the bottom-exposure stereolithography system, the curing photopolymer will connect to the resin tank as well as the upper layer. After the exposure of each layer, the forming platform has to be levered up and resin can flow into the gap between the completed layers and the resin tank. During the pulling up stage, the cured layer might not levitate together with the above layers but break-and stay on the bottom of the resin tank. In order to conquer the pulling failure. a great amount of over curing is necessary to gain enough bonding force between the new exposure layer and the above layers. This over curing will cause decline of accurary. In this paper. a super elastic intermediate material has been introduced to minimize the pulling force. The super elastic and shear strength property can help to break the vacuum between the new exposure layer and the resin tank. By the reduction of the pulling force. the amount of over curing requirement can also be reduced. Formulation of the cured forming shape and the pulling force has been proposed. The result shows that only area size is important. Hence, the pulling force can be predicted and used in on-line monitoring of the fabrication process. (C) 2004 Elsevier B.V. All rights reserved.