Bruce H. Maddock
Union Carbide Corporation
Inducted 1997
Bruce Maddock (1911 – 1996) was a true pioneer in developing the fundamental processes and equipment for the extrusion of thermoplastics. When he began this work in 1936, the process was used primarily for thermoset rubber materials. He was instrumental in adapting the extrusion process to thermoplastics. His contributions include achieving more efficient heating, mixing, and metering or pumping capacities. His initial extrusion work focused on wire-coating with thermoplastics for electrical insulation.
Born and raised in Wyandotte, Michigan, Bruce H. Maddock received a bachelor’s degree from the University of Michigan in 1934 and joined the Bakelite Company in 1936. The company was acquired by Union Carbide Corporation in 1939. He worked for Union Carbide almost continuously until his retirement in 1974 (except a three-year interval). He retired with the title of Corporate Fellow.
From 1942 to 1945, he worked as chief engineer with the Intelin Division of Federal Telephone and Radio Corporation. He was responsible for designing and manufacturing thermoplastic-insulated coaxial cables for applications that included radar equipment developed during World War II.
Extrusion experts cite some of Maddock’s more significant contributions to include:
• Redesign the single-screw extruder to achieve the more efficient heating, mixing, and metering capacities required for thermoplastics relative to thermoset rubber.
• Developing processing methods for coating wire with thermoplastics.
• Techniques for extruding film, sheet, pipe, and other products from thermoplastics.
• Establishing a systematic body of knowledge about how productivity and product quality are affected by melt temperature, pressure, flow, mixing, and other process variables, making possible today’s computer modeling of extrusion.
Maddock is also credited with these inventions:
• The “push-out” or “screw-freeze” technique for analyzing the extrusion process by stopping the extruder, rapidly cooling molten polymer containing colored tracers, removing the polymer-filled screw from the extruder barrel, and unwrapping the plastic helix, which serves as the physical means for studying extrusion process variables.
• Development of a barrier mixing section, commonly named the Maddock Mixing Head or the Union Carbide Mixing Head, that helped eliminate gels and improve the thermal homogeneity of the melt.
Maddock produced many groundbreaking technical papers in the field of extrusion. He was active in the Society of Plastics Engineers (SPE) and, in 1957, helped establish its Extrusion Division. He received SPE’s Engineering and Technology Award in 1982 and its highest honor, the International Award, in 1988.
Areas of Expertise:
Plastics machinery