The screw is the heart of an injection molding process. Over the past several decades, screw design for the injection molding process has played a vital role in delivering high quality and value added plastics parts. That’s where the story begins.
The origins of Injection Moulding
In 1868, John Wesley Hyatt invented a way to make billiard balls by injecting celluloid into a mold, perhaps in response to a request by billiard ball maker Phelan and Collander. By 1872, John and his brother Isaiah Hyatt patented the injection molding machine. This paper will discuss the evolution of the use of barrier / mixing screw technology in the injection molding process for the plasticating (melting and mixing) of polymers from early plunger machines to today’s sophisticated injection molding equipment. Although John and his brother Isaiah Hyatt patented the injection molding machine that was primitive yet it was quite suitable for their purposes. It contained a plunger to inject the plastic into a mold through a heated cylinder.




