On-line layer profile dimensions measurement of model maker rapid prototyping using vision technology

The key principle of rapid prototyping (RP) is to fabricate a 3D object, la yer by layer, which is a 2D fabrication process. Vision technology is being successfully applied in general industry to inspect object dimensions on-l ine, but most of the applications are limited to objects with 2D patterns. Hence, it should be possible to apply vision technology to inspect RP layer profile dimensions on-line. A CCD camera was employed to capture the layer profile image of the Model Maker (MM) RP system layer by layer. The captur ed image was processed to identify the RP profiles and further to calculate the real profile dimensions of the fabricated layer. The experimental resu lts demonstrate that the dimensions of an RP part could be measured in situ , layer by layer, and could, potentially, be real-time monitored. This pape r presents the vision calibration and the detailed image processing algorit hms for the single layer profile identification and dimensions measurement. The results show that the measurement accuracy of the layer profile was ab out 98%.