CNC Hard Turned Steel Inserts for the Plastic Injection Molding Industry

Precision Hard Turning for Injection Mold Components Tight tolerances. Hardened components. Consistent performance over thousands of cycles. A manufacturer of plastic injection molds needed a durable precision insert that would consistently align the upper and lower mold cavities. With the molds operating through thousands of production cycles, maintaining extremely tight tolerances was critical to both part quality and mold life. The manufacturer turned to Elge Precision Machining for our experience machining and hard turning precision components after heat treatment. Starting with 8620 steel, ELGE machined and threaded the 0.850″ long insert, then drilled and broached a small square used to drive the insert into the mold cavity. The components were subsequently heat treated to Rc 55 hardness. Following heat treatment, the parts were precision hard turned on a Hardinge CNC lathe. The ID was finished to 0.4377″, while critical dimensions were held to tolerances as tight as +0.0003″/-0.0000″. The head angle and face were also hard turned to achieve a surface finish exceeding the required 16 RMS specification. Each insert was then individually fitted and matched with its corresponding male component, also manufactured by ELGE, with each set identified and kept together throughout the process. The Result ELGE now produces approximately 1,000 matched sets per year, consistently delivering the dimensional accuracy, hardness, surface finish, and repeatability required for demanding injection-molding applications. Need a precision-machined component that requires tight tolerances after heat treatment? Contact Elge Precision Machining to discuss your application or request a quote.