New drive system for molding machines

The machine design process in the past necessitated molding machines with hydraulics. Now the process uses mainly electric components, ball screws, and timing belts. This combination provides a higher efficiency and allows for precise movements. This article describes an electric injection unit using an eccentric crank to drive the forward motion of the injection screw. The problem with the current mold machines is that the timing belts create a lot of inertia, and the ball screws wear out and diminish in accuracy even before they need replacing. In contrast, the eccentric crank is constructed of steel and can last for as long as the machine itself. Additionally, the crank has better control of inertia. Normally, electric injectors do not match the power produced by a similar hydraulic unit; however, the injection power on the eccentric crank is 300 kW, which is comparable to hydraulics. This type of power would be acceptable for thin-walled, high-speed molding applications.   Read the full article at Design News.

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