| Fremont Plastic Molds in Fremont, Ohio, is now offering extrusion blow molds for large technical parts in which the mechanical knives required to cut, trim, and deflash parts are integrated into the mold. Fremont licensed the in-mold finishing (IMF) technology from Progressive Components in Wauconda, Ill., current owner of patents formerly held by the defunct Hobson Mould Works. "Putting blades in the mold and out of workers' hands can reduce injury rates and cut costs," states Glenn Starkey, Progressive Components president.
Fremont president Martin Cass says prototype IMF tools are already in development, an example being one for automotive washer bottles in which two containers blown mouth-to-mouth in one cavity are separated during ejection. In-mold guillotines can also be used to remove domes and slice off redundant features in molded parts. Since in-mold cutting is done prior to ejection, precise timing of the cutting step is critical.
Cass says one way IMF saves money is by increasing throughput. Secondary finishing of technical parts is often slowed down by the relative inaccessibility of external cutting points. He cites examples of automotive ducting, washer bottles, seating, and fuel filler pipes as well as appliance, furniture, and toy moldings. IMF also dispenses with costly and cumbersome nesting fixtures for post-mold finishing of large, technical parts. Their elimination helps compensate for the somewhat higher cost of IMF tools. Cass also argues that IMF tooling complements efforts to automate industrial blow molding. |
