Site:               Ahresty Corporation (Tochigi Plant)
                    4060 Otsu, Mibu-Machi
                    Tochigi 321 02, Japan

Date Visited:       January 9, 1996

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

Hosts:              Shinsuke Nanko, President
                    Suguru Takeda, Manager, Technical Engineering Dept.


Ahresty Corp. is an integrated die casting company. Before 1988 the name was Fuso Light Alloy Co. The name "Ahresty" is the symbol of the direction the company wants to follow -- rigorous pursuit of the integration of "Research, Service, and Technology." Its principal products are aluminum die castings, secondary aluminum ingot, free access floors, garden tools, and peripheral equipment for die casting machines. The company operates six casting plants, five sites for die manufacturing and a secondary aluminum operation.

Ahresty has a die casting operation in Wilmington, Ohio, which supplies products to Ford, GM, Honda of America, Aisin USA, Nissan Mexicana, plus others. All of its U.S.- produced parts are for the automotive industry.


Ahresty research activities are related to the die cast process and to products that can be manufactured using aluminum. At the various die cast sites Ahresty has evaluated various technological advances in high pressure die cast systems. It has developed processes that improve the quality of high pressure die casting. None of this is basic research, but application of technology to the manufacturing operation. Examples are rapid melting furnace technology, automated aluminum scrap sorting, launder molten metal handling, CAD systems for die design, CT scanners to measure interior casting dimensions, and infrared temperature sensing devices.

Ahresty applies the technology required to assure that customer requirements are met. It employs a technology called PASOP which reduces the solidification of molten metal in shot sleeves, increasing the tensile strength and elongation of die cast parts. The PAC technique uses a powder lubrication to improve soundness of heavy section castings.

Ahresty uses sand cores in selected applications in its high pressure die cast operations to cast in features not possible with metal cores. The Ube gas free (GF) system is used on most machines to reduce the amount of entrained air in the die cast products. APE pins are used as required to assure soundness of isolated heavy section castings. Timing to activate these pins is determined by experience and casting solidification simulation.

To achieve heat treatable high pressure die casting, Ahresty uses a technique called pore free (PF). The PF system fills the mold with oxygen before pouring in molten aluminum. The oxygen then reacts with the incoming molten aluminum, forming solid aluminum oxide. This reaction results in a vacuum in the die casting and reduces the gas entrained in the castings. The result is a casting that can be heat treated or welded without blisters.

Another technique developed by Ahresty R&D and installed in manufacturing is a jet cooling system for core pins. This eliminates costly downtime caused by core pin breakage and die polishing.

Ahresty does offer its advanced engineering services to other companies in the form of casting analysis and simulation techniques for die design.


Ahresty operates mostly in the cell configuration. The castings are moved from die cast machines of varied size with overhead or floor mounted robots or extractors. These control the complete cycle, from casting design via computer work station to die construction on site. Coordinate measurement machines with computer-aided tomography (CAT) are used to measure internal wall thickness calculate the dimensional tolerancing of castings.

Molten metal is transferred to each die cast machine with either metal launder systems or ladles. After castings are made, an automatic extractor places it into a trim press to remove flash. Some parts are given added machining prior to shipment. Ahresty has the world's largest die cast machine -- a 4000 ton Ube machine at the Tochigi plant. A very large oil pan made from this machine was shown in the casting display area. Ahresty's major products use the JIS-ADC12 (AA-384.0) alloy.

The Tochigi plant produces engine blocks with cast-in-place iron liners. Liners are not heated and are cast both by using mandrels in the liners and by placing liners into the die onto locators in the die. The process engineering appeared to be well thought out. There were no statistical process control (SPC) charts at machines, but there were job instructions on how jobs were to be performed and checked for quality.

The plant lighting, workspace, and housekeeping were all well above average for a casting operation.


Ahresty is a leader in the application of technology to high pressure metal mold casting operations. Its business has been reduced as a result of the increase in automotive production outside Japan. As a result it has located plants in the United States to manufacture castings. Company managers also are looking to new markets to sell die castings, floor panels and escalator steps being two examples. They continue also to work on several applications of technology to improve high pressure die cast operations. These innovative approaches are used where they make sense to improve the operation. The company won the Deming award in 1989.


We're Ahresty: Research, Service, Technology. Brochure.
Ahresty R&D Corporation. Brochure.
Ahresty. History and sales volumes brochure.
Corporate Outline Ahresty Tochigi. Brochure.
Ahresty of America Corp. Copy of equipment, sales, and customers information.
Corporate Outline. Ahresty Corp. Brochure.

Published: March 1997; WTEC Hyper-Librarian