Michihiko Hoshino

Research on the Influence of Die Shape in Complex Extrusion of Multi Billets

Multi-billet extrusion has been developed for a novel process in manufacturing of shapes with complex cross-section, for example a side-door impact beam for automobile. And furthermore, very wide shapes for roofs of railroad vehicles may be able to be manufactured. In this paper, fundamental experiment carried out by using modeling material and knowledge about bonding of some separated parts was obtained. It is clear that a unification angle is important for bonding intensity. The unification angle was adjusted by flow guides. It is success to manufacture a round pipe with inner liv.

Investigation of Conclad Extrusion and Multi-Billet Extrusion

In Nihon University, Conform continuous extrusion and new extrusion processes which are called multi-billet extrusion have been investigated last ten years. Conclad extrusion which was developed from Conform continuous extrusion[1], is applied to manufacturing trolley wire for train in Japan. The trolley wire which is copper covered steel wire has shorter life cycle than expected one because of corrosion for acid rain. The quality of welding part of copper must be improved. In this paper, it is investigated how to decrease involving oxide films in welding part by experimental method. On the other hand, the multi-billet extrusion[2] is applied to manufacturing automotive frames, especially impact attenuators. The developed extrusion process has been done under experimental condition. However, it is capable to vary geometries of rib which is in the inside of closed profile extruded products by this process.

Effect of Dummy Block Shape on Deformation of Oxide Film of Billet in Copper Extrusion

There are some problems in the copper hot extrusion. One is the mixture of impurities in the product, for example, the oxide film in the side of billet comes to the outer of product and the oxide film in the back‐end of billet is inserted in the material and extruded into the center of product, which is called as “piping”. Then, it has been investigated that dummy block shape effects on deformation of oxide film by experiment and numerical simulation.

Manufacturing of Carbon/Resin Separator by Die Sliding Extrusion

A fuel cell will play a part of a module of power generator instead of an internal- combustion engine. It is required to improve the productivity and miniaturizing of the fuel cell. The separator in the fuel cell is an important part. The manufacturing process of carbon/resin separators usually is injection molding or compression forming. On the other hand, the authors have developed die sliding extrusion based on the friction extrusion [1] and side flow extrusion [2]. The die sliding extrusion is a kind of valuable shape extrusion [3,4]. It is applied to manufacturing fuel cell separators which have linear channels on its upper and lower surfaces in the orthogonal direction.