Hull Corp

A new option for micromolders is an injection machine that replaces the traditional screw with a motor-driven plunger. Named for the part sizes it produces, the Sesame is a small electropneumatic micromolding machine made by Hull Corp. (Warminster, PA). The machine can mold 20 thermoplastic sesame seeds from a single pellet. Instead of a screwing action, the Sesame uses a tiny plunger to push material into the mold. This plunger, that can be as small as 1.5 mm in diameter, is... 

Fig. 6-2. Front view of a 64-capacity (integrated circuits) mold, showing layout, top-transfer pot, and plunger used in a transfer molding system. (Courtesy of Hull Corp.)...

Hull, J. L., Injection Molding Thermosets Seminar, Hull Corp., 1986. 

Fig. 9-27. Simplified encapsulating procedure. Courtesy Hull Corp.)...

During the 1930s gradual improvements in the product and processing overcame some of the drawbacks of this material. Nonetheless, the apphcations were limited and Thiokol Corp. stmggled to remain solvent. The first year Thiokol reported a profit was in 1941, 13 years after its foundation. This was realized when the U.S. Air Force discovered that the aUphatic polysulftdes were usehil as a fuel-resistant sealant for aircraft tanks and hoses. Polysulftdes also began to be used as sealants for boat hulls and decks. 

Major suppliers for organic fillers include GCA Chemical Corp. and Composition Materials of America (com cobs) Akrochem Corp., American Fillers Abrasives, and James River Corp. (flock and fiber) Agrashell Inc. and Composition Materials of America (nutshell and hull flours) Composition Materials of America (rice hulls) and Akrochem, American Wood Fiber, and Smith Chemical Color (wood flour). 

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