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In laser welding of thermoplastic resin plates, the periphery of the welded portion is deformed after cooling. This deformation makes the surface undulate, thus creating residual stress, as shown in Fig.3. Furthermore, because strain is generated due to thermal contraction when laser welding, this stress, to a greater or lesser extent, inevitable remains. This residual stress has an influence on welding joint strength; therefore the degree of strain becomes a welding joint quality issue in laser welding. In this paper, as shown in Fig.3, strain is studied using the finite element method analysis software,ANSYS ED 9.0. Model behavior of joint strain is analyzed by applying normal load in place of thermal contraction.

This study proposes a new method on 3D micro fabrication using a combination technique of nano-scale processing and wet chemical etching. The (100) surface of single crystal silicon was processed by using the mechanism of friction force microscope (FFM). A processed area was protuberated in the condition where normal load is less than 372μN. The sample processed in this condition was etched by KOH solution. After the etching process, convex structure was made on processed area. The effect of processing condition on etch rate of processed area was studied. It was found that etch rate was changed with normal load, pitch of processing line and number of processing. Also, mechanism of height change was investigated under those conditions and some 3D microstructure were fabricated by these results.