In the photofabrication system a UV laser scans liquid resin to cure it into thin plates which are then stacked together to fabricate any shape of plastic model. The development of photofabrication has now reached on the brink of achieving a break-through for practical application: a mechanical fabrication accuracy of 0.1mm. However, the photofabrication system is making it impossible to achieve high accuracy in the cured resin model, because of the liquid solid phase change.
Warpage is mainly produced by shape factors, and no method for evaluation has been established. In addition, warpage increases significantly except under optimum fabrication conditions. In this paper, we studied the fabrication conditions for DMEC SCR 100 and SCR 200 resin using a simple model.
Conventionally fabrication conditions have been determined from the cross-sectional shape of the cured resin obtained from the laser scans. This study investigates the following two points: (1) With regard to the structural and volume changes of the polymerized resin, the density of the UV-cured resin is measured. (2) With regard to the curing and shrinkage phenomena, warpage is measured.
It has been established that the photofabrication system requires an optimum laser intensity of light 2.3 to 3 times larger than that of the conventional level. A fabrication condition has been determined which minimizes the warpage of the cured resin.

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Composite plastics reinforced with fibers preserve the resin matrix features such as corrosion resistance and light weight, while improving the material strength. Reinforced plastics are thus widely used. Many studies have been done on composites but the effects of processing conditions on the variability of strength have not been sufficiently studied. Minute accumulating data analysis method can detect the changes in patterns and distribution of strength. This method is applied to investigate the tensile strength behavior of polypropylene reinforced with mica and potassium titanate fibers.

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