Site: Tokyo University
Institute of Industrial Science
22-1 Roppongi 7-chome, Minato-ku
Tokyo 106, Japan

Date Visited: 15 December 1995

JTEC/WTEC Attendees: K. Narayanan (report author), P. Fussell

Hosts:

Prof. Takeo Nakagawa

Prof. Takeshi Kishinami

Mr. Hayano

VISION

Prof. Nakagawa went over this in substantial detail at the afternoon general discussion. The notes here from the morning one-on-one meeting may repeat that discussion.

Prof. Nakagawa comes into rapid prototyping technology with a prior background in machining. He has extensive leading-edge research in high-speed machining pushing the CBN as a tool, and he also invented cast iron grinding wheels for novel electrolytic assist grinding. Consistent with his expertise, Prof. Nakagawa views future opportunities for rapid tooling to be in high-speed machining. He sees the difference of market forces between the U.S. aerospace/defense-driven and Japanese consumer products/mass production-driven forces leading to Japan needing rapid prototyping to keep up with rapid model changes in fields such as electronics. He does not see powder technology meeting the rapid tooling needs of higher than current machining accuracy.

ORGANIZATIONS

There are about 5 Japanese organizations with overlapping interests in rapid prototyping:

  1. The Die & Mold Industry Consortium on High-speed Milling, consisting of about 50 members with very little financial support.

  2. The MITI forging association, of which high-speed milling is a subset with about 15 members. One MITI-sponsored subgroup led by Ikegami Die & Mold Makers --representing about 20 small and medium companies, of whom half are RP makers -- is doing an accuracy and cost analysis.

  3. Niigata Prefecture Research supports new high-speed milling such as air bearing.

  4. Another competitive association that supports CBN milling.

  5. Japan Society for Precision Engineering Association.

MATERIALS

Polymer

A colleague of Prof. Kishinami, Narahara, does resin property characterization. No resin research is carried out by Prof. Nakagawa.

Metal

Prof. Nakagawa is interested in the area of auto body modeling. Laminated Al sheets brazed together is a material system that has appeal over zinc alloy because the product is stronger and lighter. Prof. Nakagawa has research interest in both simulation and modeling of sheet metal forming. He observed that MIT Prof. David Hardt's approach is interesting, and he sees the need to use sheets thicker than 5 mm for economy. He sees the limitations of the laminated rapid tooling approach being that cuts below 45° are not possible. He sees wire EDM as useful for blanking but too slow for forming tools. Over all lamination approaches it has advantages for permitting larger-size work, but it is not suited for sharp corner details like embossing.

Ceramic

Prof. Nakagawa sees ceramics as a niche market; however, he has brought a materials scientist into his group to come up with a rapid ceramic shell for a slip casting process. A traditional plaster mold can make 20 or 30 parts, but accuracy decreases with use. The competitive rapid rubber molds lack permeability for slip casting. He has developed a special ceramic, but due to its proprietary nature, he did not want to get into details.

SOFTWARE

Prof. Kishinami's research interest is primarily in the software area. He is active in ISO 184 automation. He is working with the STEP community on application protocols and shape models. He is interested in the data format to replace STL, which has many problems. Another area of research interest is deformation simulation RP-FEM, for example, shrinkage.

MACHINES

One of the original SOUP machines is in the lab used for research purposes, and there is a desktop machine at Rikken, the other campus. Due to U.S. patents there is a reluctance to do machine research. Prof. Nakagawa nevertheless has some ideas for a new machine, but he felt it was too early to discuss them; he hoped to present them in 1996.

We wish to thank Professors Nakagawa and Kishinami for their frank discussions and their generous hospitality.


Published: September 1996; WTEC Hyper-Librarian