This work presents a method for extraction of the geometrical shape feature such as skeleton and unit normal vector field based the partial differential equations. Additionally, I discuss its expansion for reverse engineering. Finally, several numerical examples are demonstrated to confirm usefulness of the proposed method.

In this study, we attempted to fabricate highly functional sealing material by integrating fluoro-elastomer and thermoplastic. However, it is extremely difficult to join fluoro-elastomer and thermoplastic because they have different molecular structures, melting points, and curing temperatures. Control of the interface shape is also difficult. In order to realize integrated molding, advanced mold temperature control technologies are indispensable. For this reason, in this study, we investigated a multilayer compression molding process for joining fluoro-elastomer and thermoplastic using an induction heating and cooling multilayer compression mold capable of controlling the temperature of the upper and lower molds separately. We then carried out the two-step compression molding of high-density polyethylene molding plate and fluoro-elastomer, and succeeded in forming a multilayer molded product with a smooth linear interface. In addition, we confirmed that the two materials can be sufficiently joined due to the rise in mold temperature of the high-density polyethylene.

Fluoro-elastomer is often used as the sealing material of O-rings due to its excellent thermal resistance and oil resistance. As the quality of O-rings mostly depends on the skills of the manufacturing staff, measures to prevent decreased local strength of molded products and surface defects, etc. are often carried out by trial and error of engineers. For this reason, in reality, radical solutions for these problems are not being implemented. The main reason for this may be because, although knowledge on basic characteristics such as viscosity charactaristics, etc. is gradually being accumulated, because the series of phenomena occurring in the compression molding process from the melting, to flow and curing of the fluoro-elastomer in the mold have not been clarified, this has led to the delay in the empirical clarification of the compression molding phenomena of fluoro-elastomer. Thus in this study, we reviewed the behavior of fluoro-elastomer in the mold from melting to flow and curing, using an induction heating and cooling compression mold and colored marking method. As a result, we were able to confirm that the time elapsed from the setup of the fluoro-elastomer preform inside the mold to the start of compression affects resin flow and curing.

This research aimed to examine the additive manufacturing process based on the observation of the sintered maraging steel manufactured by the powder bed fusion method. A combined processing of metal laser sintering with high speed milling was used for manufacturing of the sintered objects. The sintered workpiece was manufactured by recycled maraging steel powder. An equiaxial crystal was observed from the outer periphery to the center in the melt pool. The hardness in the height direction of the sintered workpiece was measured, which was approximately 370 to 400 HV, but only the top surface was 320 to 340 HV. As a result of observing the structure in the sintered workpiece, round like and horned like shaped contamination that were different from the solidification structure of the maraging steel was confirmed. These contaminations were confirmed to be TiO2 and TiN based on the analysis by EDX, and it was estimated to originate from the metal powder and the coating layer of the cutting tool.