CHICAGO — Logic Devices Inc. of Sandy Hook, Conn., is promoting a patent-pending injection molding process called Incremental Cavity Ejection at its NPE booth, N4832. The process allows molded parts with heavy textured side walls, having a minimum draft angle of 0.78 degree, to have no external draft or scuffing. ICE eliminates the large draft angle requirements to ease the release from the cavity, and the large ejection force associated with pushing the part from the core.
There also is no relative movement between the outside of the part and the cavity when the mold first opens. Ejector pins and stripper rings are kept in the forward position as the mold opens only enough to allow the part to pull away from the cavity surface.
Initial breakaway ejection forces occur when the part is more uniformly supported by the cavity and core, minimizing the potential for part distortion. More-uniform distributed breakaway stress levels come about because the part is held in place by ejector pins and cavity undercuts.
When the part is free from the cavity, the force action on the ejectors is deactivated and the mold opens in the usual manner. Once open, the ejectors are reactivated to eject the part from the core, reducing the potential for part damage.
Other features include adding lettering and logos on side walls without adding costs, cutting costs of tooling on new molds, using the process on existing machines and faster cycle times.