Rugged Interconnects for Harsh Environments eBook

Molds are routinely manufactured in halves to facilitate the removal of the overmold once the plastic has cooled. These molds serve specific purposes: The A side faces the cavity (front half of the mold) and the B side faces the core (back half of the mold). • The A side, often called the “cosmetic side” will be smooth or textured. • The B side, referred to as the “functional side,” typically contains the structural elements of the part. This side has a rough finish and ejector pin marks. Lastly, molten overmold plastic is injected into the mold to fill all cavities caused by the automated milling process and to encapsulate the interconnect within. The mold is then cooled, and overmolded parts are ejected by pins. Final finishing is frequently accomplished by hand. This step includes deburring (removal of rough/irregular edges) and flashing (removal of excess plastic that forms on the surface of injection molded assemblies resulting from the mating of the mold halves). Cryogenic and thermal deflashing are popular methods of finishing molded rubber or plastic devices but are not applicable to overmolded interconnects or cable assemblies.

Overmolding ruggedizes most any interconnect configuration, including split-cable designs.

Subsequent steps in the process include the determination of precise dimensions and shape of the interconnect that delivers optimum functionality, namely seal, strain relief, and cable union. The molds’ mechanical dimensions are then generated by 3D computer-aided design (CAD) modeling software and translated into manufacturing instructions via computer-aided manufacturing (CAM) software. CNC (computer numerical control) post processor software next converts toolpaths created by the CAM system into NC programs. These programs are read by a machine’s controller, which moves the cutting tool along the programmed paths in a safe, consistent, and predictable manner. The resulting molds are liquid-tight cavities usually constructed from hardened/pre-hardened steel, aluminum, Teflon, or beryllium-copper alloy.

Molds are engineered utilizing software-driven automated machining processes.

Programmable ovens are requred to ensure the integity of some overmold plastic materials.


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