ADVANCED MATERIALS & PROCESSES | JULY/AUGUST 2024 29 Thixomolding is a method of molding thixotropic semi-solid magnesium alloy pellets in a machine that resembles an injection molding machine in physical appear- ance and operation. Thixomolding was derived from the basic studies of semi-solid metals in 1970 by David Spencer and Merton Flemings of MIT and was adapted to magnesium injection molding by Robert Busk, Norb Bradley, Regan Wieland, Bill Shafer, and Al Niemi at Dow Chemical in the 1980s. THIXOMOLDING DEVELOPMENTS Thixomolding’s commercial growth has been driven by its technical advantages, including enhanced precision, environmental cleanliness, and the ability to produce complex 3D shapes with high yields and minimal waste. Raymond Decker, FASM,* Stephen LeBeau, FASM,* and Tony Melkent, Thixomat/nanoMAG, Livonia, Michigan Gavin McGraw and Bill Wilson, Molded Magnesium Products, Jackson, Michigan *Member of ASM International to commercialize the practice, along with partners Dow Chemical (Arnie Geyser), Lindberg (George Bodeen, Leo Thompson and Bob Kilbert), Comalco (John Mihelich), and George Spalding. Later, Amptech (Ehor Babij) joined. Japan Steel Works (Kazuo Kitamura) was licensed to build and market thixomolders for many of Thixomat’s licensees, including those in the U.S.: Molded Magnesium Products (MMP), Parkway Products, and Phillips Medisize. Commercial development, appli- cations, and the market for thixo- The thixomolding process is illustrated in Fig. 1. Alloy chips are heated by barrel heaters and sheared by a rotating screw into a semi-solid state and then propelled by a driven screw at high velocity into a net-shape mold. In that semi-solid state of 5-15% solids, the metal presents a more viscous behavior for better filling of the die with low porosity. COMMERCIAL DEVELOPMENT In 1989, Ray Decker, Dave Dawson, and Bob Carnahan founded Thixomat Inc. TABLE 1 — APPLICATIONS OF THIXOMOLDING Electronics Automobile Sporting goods Handheld tools Medical Walkman Car tops Oakley sunglasses Drills Operating room equipment Laptops Brackets Shimano fishing reels Saws Don Joy ortho nano knee brace Digital cameras Boxes K-2 Snowboards Chain saws DLP projectors Liftgates Shaggy skis Nailers Cellphones Gear shifts Go-Cycle bicycles Boxes Child seats Bueller motorcycles Go Cycle Laptop DLP projector TTMP knee brace
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