3D-PRINTED METAL INSERTS FOR EFFECTIVE MOLD BUILDING by Liz Stevens, writer, The American Mold Builder injection mold builders and their plastics processor customers. With a background as a traditional mold builder, RJG-certified master molder, injection molding plant manager and owner of a traditional mold building shop, Murphy first gave additive manufacturing a whirl 24 years ago and has kept his eye on it ever since. “I always saw 3D printing as an option,” he said, “ for something like cooling, where it needs to be in a mold, and to get good part quality over what was conventionally available, such as milling and drilling a water line.” Until recently, additive technology, however, was not yet fully capable and reliable. “There were a lot of cracking issues,” he explained. “It was not capable of producing really good, porous vents. And there was leaking and other problems that you really don’t want in a cooling part.” Murphy said that it wasn’t until the last five to seven years that things improved enough for additive to be reliable for tooling. As he watched the technology improve, Murphy developed tool steel powder recipes specifically for 3D production of injection molding components. Variable Density Inserts help eliminate downtime and missed deliveries by preventing clogged vents
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dditive manufacturing is growing steadily, having evolved beyond its initial applications for creating 3D models and producing specialized, very low-volume parts. For mold builders, 3D metal printing now offers components for conformal cooling, venting and hot runner manifolds, with more developments on the horizon. The American Mold Builder talked with Jason Murphy, president of the additive tooling company Next Chapter Manufacturing (NXC), Grand Rapids, Michigan, about the current state of 3D metal printing. Marcin Zajac, engineering manager at A1 Tool Corporation, Melrose Park, Illinois, and Steve Michon, owner of Zero Tolerance, LLC, Clinton, Township, Michigan, also were interviewed about their experiences with NXC to design and build conformal cooling components. Jason Murphy founded NXC five years ago to apply the special qualities of 3D metal printing for the benefit of plastic
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the american MOLD BUILDER | Issue 4 2021
NXC uses directmetal laser sintering (DMLS) additive technology, a process that Murphy described as one of the oldest, most mature and refined 3D metal printing processes. The company’s additive printers build layer by layer, laying down and laser sintering metal powder to produce very hard, fully dense and solid steel components that are finished with heat treatment and stress relief. The metal powders in use are current-day incarnations of MIM powders – previously used for metal injection molding – which are created through gas atomization. The largest printer at NXC can produce 12” x 12” x 16” components, and Murphy is awaiting delivery of a new machine for producing even larger parts. CONFORMAL COOLING – MADE FOR COMPLEX GEOMETRY As the designs for parts have become more complex, including more structural details and features such as ribbing, conventional cooling componets now often are inadequate to the task. Complex geometries and very tight spacing often cannot be effectively cooled with traditional line-of-sight milling and drilling. “What 3D printing does over conventional
