Site:               Daido Precision Parts Co. Ltd.
                    1642-144, Nasubigawa
                    Nakatsugawa City
                    Gifu 509, Japan

Date Visited:       January 11, 1996

WTEC Attendees:     T.S. Piwonka (report author), H.W. Hayden

Hosts:              T. Saito, General Manager, 
                      Precision Castings Division
                    T. So, Director, Tsukiji Plant
                    K. Tsushima, General Manager, 
                      Daido Precision Parts Co. Ltd.
                    J. Doinouchi, Manager, Marketing, 
                      Precision Casting Division
                    K. Kondo, Senior Staff, Contract Sect., 
                      Tech. Planning Admin. Dept.

BACKGROUND

Background on Daido Steel can be found in the brochures distributed at the meeting. Our hosts represented the steel casting division and the precision casting plant.

Daido Precision Parts Co. Ltd. occupies a recently built plant (1992). The plant, which cost ¥4.5 billion, employs 100 people -- 20 in technical and administrative positions and 80 production employees. The Nakatsugawa City plant occupies 8000 m2 of productive floor space on two levels. The plant was located there with the help of local authorities, who wished to persuade local young people to remain in Nakatsugawa, which is one hour by rail from Nagoya. The average age of the employees in the plant is 25 years. Annual sales are about ¥2.4 billion. Auto parts (mostly turbocharger wheels, of which 40,000 are shipped each month) make up 25% of the volume of the plant, electrical parts 20%, and the remainder are industrial products. Most parts are quite small and could fit into a 5 cm cube.

The steel foundry in Tsukiji has 300 employees, whose average age is 44. They use green sand and the V-process (V-process castings are used for railroad frogs) and have a centrifugal foundry for such products as hearth rollers. Induction and AOD melting are carried out.

Daido prepared extensive answers to the questions WTEC submitted to them, as well as extensive data on steel casting production in Japan. These are included in the references and will not be discussed at length in this report.

RESEARCH AND DEVELOPMENT

Research and development projects within the Daido foundries are initiated by individual engineers. The general manager decides whether it is worthwhile to pursue the project. If the project cannot be done in the casting plant, they may ask Daido R&D labs to carry it out. If so, the plant is charged ¥2 million/month for the use of a Daido researcher. Alternatively, they may choose to go outside to a professor at a university, which costs significantly less.

Daido representatives stated that most casting R&D is done within the research laboratories of large corporations. Daido spends 1.3% of its sales (presently about ¥270 billion total annually) on research and development. For instance, one project at Daido R&D is the evaluation of commercial solidification simulation programs. MITI gathers extensive statistics about the foundry industry, and this information is useful to the ministry in determining which foundry projects to pursue. MITI selects projects for partial funding influenced by the recommendations of the Steel Casting and Forgings Association of Japan. MITI is not considered to be very aggressive in supporting the foundry industry because the industry is not now perceived to be threatened by foreign competition. However, Daido representatives believe that if they were to ask MITI for help in developing a process or product, they would get it.

PRODUCTION APPLICATIONS

Daido Precision Products Co. Ltd. is clearly the most completely automated investment foundry in the world. Daido is the only Japanese licensee of the CLA and CLV process of Hitchener Corp., and this plant is dedicated entirely to that process. The wax room and finishing and inspection are located on the second floor, while dipping, de-waxing, pouring, ceramic removal, de-gating, and heat treating are on the first floor. The product is alloy steel and superalloy castings. The plant operates a five day week, with two shifts in cluster build (wax injection through de-waxing) and pouring and one shift in cleaning and inspection.

Daido operates its own tool and die shop, which is fully equipped with automated machine tools, and has a computerized die storage facility. Daido managers are particularly proud of their ability to find young people who are willing to learn die making.

Patterns are automatically injected and ejected from the pattern die. As soon as they are ejected, a pick-and-place robot carries them to a fixture where the wax gating is automatically cut off. Then another robot picks up the pattern, heats the gate area, and places it on the downsprue at a position which has just been heated by another robot. The downsprue indexes for the next pattern. Finished clusters are moved by conveyor to the two automated dip lines. Injection dies are moved by guided vehicles to the injection presses for installation.

Three hours of drying are required between dips as a fast drying binder is not used. A nine dip mold is built, using aqueous colloidal silica as a binder. Present drying time (including final dry) is about 70 hours per mold; the goal us to reduce that to 36 hours. There was no evidence during the WTEC visit of slurry control charts at the dip line, although information on slurry control may have been kept in another area of the plant.

Pouring is by the CLA or CLV process and is highly automated, with a computer-controlled melt station with graphics, which show the progress of the metal as it fills the mold. Because CLA/CLV castings do not require cut-off, gates are removed by grinding at automated stations.

Dimensional data for about 10% of turbocharger castings production is transmitted in digitized form, as is data for about 1% of the rest of the products. Daido offers to digitize customer data for its customers. Daido engineers do not presently use any of the available solidification software programs because they do not believe that any accurately represent fluid flow or are able to predict final casting dimensions. It is clear that they are particularly concerned with the dimensional accuracy of their parts; dimensional accuracy is as important as or perhaps more important than casting integrity.

In the past Daido has attempted to use rapid prototyping but found that it was very expensive, and not useful because the resins used in rapid prototyping were unable to replicate the thin cross-sections of Daido's castings. Daido may be willing to try rapid prototyping again now that the costs have decreased (now estimated to be about ¥30 to ¥40 million/part) and new resins have been developed

Daido has had no problem disposing of spent shell material, most of which goes to the building industry (cement plants) and the Nagoya pottery industry. Although the company previously had to pay to have it removed, it is now taken away free. The Tsukiji plant recycles 95% of its sand. The remainder, most of which is chromite sand, is disposed of for its chrome value.

REFERENCES

Answers to "Discussion Issues for ITRI." Daido Steel, January 11, 1996.
Data ("Deta"). Daido Steel, January, 1996.
Specialty Steel Technology. Daido Steel brochure.
Steel Castings Division - Meeting a Wide Range of Needs. Daido Steel brochure.


Published: March 1997; WTEC Hyper-Librarian