Site:               Toyota Motor Corporation

                    Tahara Plant
                    3-1 Midorigahama Tahara
                    Aichi 441-34, Japan

                    Head Office
                    1, Toyota-cho, Toyota, 
                    Aichi 471-71, Japan

                    Myochi Plant
                    1, Nishiyama, Myochi
                    Miyoshi, Nishikamo-gun
                    Aichi 470-02, Japan

Date Visited:       January 11, 1996

WTEC Attendees:     P.H. Mikkola (report author), M.C. Flemings, C. Uyehara

Hosts:              Organizer
                    Tetsuya Suganuma, Project General Mgr., Technical Admin. Division

                    Guest Accompaniment
	                 Dr. Kiyoshi Funatani, retired Toyota,  
                      Associate Director, Nihon Parkerizing

                    Tahara Plant
                    Hiromitsu Hayashida, General Manager, Tahara Plant, Admin. Division
                    Shinobu Sasaki, Deputy General Mgr., Tahara Plant, Machining Division
                    Tadashi Fujimoto, Project Manager, Engineering Services,
                      Tahara Plant, Machining Division
                    Syunichi Fujio, General Manager, Aluminum Casting, 
                      Engineering Foundry Division

Head Office Akiyoshi Morita, Director, Member of the Board, Materials R&D Yasuhito Yamauchi, Director, Member of the Board, Production Engineering Division and General Manager, Myochi Plant Dr. Yukio Ohtsuka, Project General Manager, Foundry Engineering Division Shigeki Sugimoto, General Manager, Metallic Material Department, Materials R&D Division Masami Suzuki, Manager, Development Department No. 2, Foundry Engineering Group, Production Engineering Development Division Myochi Plant Masakatsu Yamato, General Manager, Administrative Division Yoshiro Hayashi, General Manager, Foundry Division Akira Fujii, General Manager, Manufacturing Engineering Department Makoto Waniguchi, Assist. Mgr., Production, Engineering Service Dept. Etsushi Hayashi, Manager, Iron Casting, Engineering Department, Foundry Engineering Division Other Participants: Dr. Itaru Niimi, Honorary Professor, Toyota Technological Institute Hiroyuki Syamoto, Assistant Manager, Metallic Materials Group, Materials R&D, Division III


Toyota operates both iron and aluminum casting operations. It operates both sand cast and die cast operations to produce parts for its auto manufacturing. Cast components are for chassis, powertrain, and body. The focus of Toyota's casting operation is to meet the challenges for casting technology of the 21st century. Toyota has three principles for corporate activities: (1) taking advantage of high value-added casting products, (2) developing a production preparation system readily responsive to market needs, and (3) developing a casting technology good for human and global environment.

Toyota does apply technology to all aspects of its operations. Continued improvement is the general theme, but the company has started innovative processes, such as the new differential pressure casting process to manufacture V-8 engine blocks.


Major casting technology development is handled by the Foundry Engineering Division which is outside the production group but works very closely with the plants. This group plays the following roles: process planning, facility and mold design, facilities and molds purchase, process tryout, technical development, prototype part casting and related plant support. In addition there are two groups that support the Foundry Engineering Division, the Machinery Group and its affiliates, which are involved with facilities preparation and mold manufacturing. There is no question that the customer for the Foundry Engineering Division is the production group, made up of casting, machining, painting and assembly. The Foundry Engineering Division has 546 employees working in seven departments or areas:

  1. Assistant to the general manager: handles general administration
  2. Engineering Administration: handles technical planning, technical control, development and prototype design
  3. Iron Casting Department: handles facilities planning for iron production
  4. Aluminum Casting Department: handles facilities planning for aluminum production
  5. Die Casting Department: handles facilities planning for die casting which includes gravity, low pressure, and high pressure systems
  6. Prototype Casting Section: handles manufacturing of wood patterns and prototype casting parts manufacturing
  7. Experiment Duties Section: handles experiments and analysis of production and process tryout

Many advances in both product and process have resulted from the work at Toyota Foundry Engineering. Some of the most recent are the total differential pressure (TDP) aluminum cylinder block production (using Toyota's new differential pressure casting process), production of aluminum suspension members by low pressure die casting and aluminum wheels by high pressure casting, automatic core transfer and setting, automatic core delivery, plus automatic coating of investment casting molds.

The Toyota casting group has the latest tools to do casting solidification and fill analysis. It also uses CT and X-ray to inspect for internal casting defects. Coordinate measurement (CMM) machines are used to measure product dimensions.

The effort Toyota is making to help preserve the global environment is a model for the industry. Toyota is particularly careful in four areas:

  1. Friendly working environment (dust protection, heat protection, and noise protection)
  2. Quantitative control (low odor resins, reduced production of mold releasing agents and slag)
  3. Recycling (re-use of dust, recycling of waste sand, expansion of return scrap, dezincification of shredded steel)
  4. Prevention of greenhouse effect (energy-saving production processes, alternative fuels)


Tahara Plant

The Tahara plant complex is located on recovered land on Mikawa Bay. The entire complex is on 925 acres with 213 acres in buildings. The site contains two casting shops in addition to machining, body, and assembly shops. On the same site are a test course, a shipping dock, and a recreation area.

The casting plant is a state-of-the-art aluminum casting plant that produces engine blocks and heads using metal mold processes. The plant uses shell core, fast aluminum secondary melting, molten metal conditioning and handling, metal pouring using low pressure plus vacuum where required, and casting cleaning and processing. This highly productive plant is very clean with good lighting and quiet, dust-free work environments. Most applications of automation are designed to reduce labor requirements and improve working conditions. The plant even uses a robot to coat molds for low pressure die casting. Light currents are used to keep employees out of the way of moving equipment. Dies for the casting plant are made at the Teiho plant.

Computers are used at various locations in the plant, but the entire design cycle using computers had not been implemented at the time of the WTEC visit.

Myochi Plant

The Myochi plant was completed in June 1973. It employs 1900 people with floor space of 197,000 m2. It operates on a two-shift, three operating crew concept to manufacture both iron and aluminum castings. The site has three different casting plants: two produce iron castings, and plant number three produces aluminum. Products of the casting complex are cylinder blocks, differential carriers, cylinder heads, and cross members. The cylinder heads and cross members are made from aluminum. Ductile iron is the largest production at the site. Both cupola and induction furnaces are used to melt iron, and the Georg Fischer treatment technique is used to produce ductile iron. A large percent of the ductile iron is heat treated. The green sand ductile iron mold line indexes at a rate of 140 molds/hour.


Toyota continues to have a strong commitment to metals and metal casting. It does much process development and implementation of technology to improve cost and quality. The company is a world leader in the area of reducing pollution from casting operations. Toyota removes zinc from automobile body scrap prior to melting and also reduces noise in the casting environment. The plants have outstanding lighting, and the company continues to work to reduce gas, dust, and odor in its plants. All sand is reconditioned and recycled into either green sand molds or shell cores.

In all cases casting plants are located next door to machining operations, but some parts are shipped by truck to other locations to be machined. The outside and yard areas of the casting plants are very orderly and clean.


Okada, Y., Y. Takeuchi, and S. Fjio. 1994. "Development of Methods for Removal of Zinc from Automobile Body Scraps," by Toyota Motor Corp., reference US Patent 5,350,438.

Outline of Myochi Plant. Brochure.

Toyota. Brochure.

Toyota Foundry Engineering Division. Brochure.

Welcome to Tahara Plant. Brochure.

Published: March 1997; WTEC Hyper-Librarian