Impact of Interleaved Thermally Conductive Material with Conformal Fluid Channels on Tooling Thermal Response

Cooling time between plastic injection and part ejection in the injection molding tooling industry can account for 50-70% of the cycle time for molded components. It has been determined cooling time can be decreased by 35% with conformal cooling channels and 29% with copper inserts. The rapid development of commercially available hybrid machine tools with integrated additive and subtractive manufacturing capabilities enables the possibility of manufacturing high precision monolithic, multi-material components for the tool and die industry which utilize conformal fluid channels and copper; however, processing strategies to produce such components are not well established. This research investigates the use of interleaved conductive material, such as copper, within a monolithic mold with integrated conformal fluid channels for increased thermal performance of tooling. Enabled by hybrid manufacturing, the integration of additive and subtractive processing, allows the manufacture of complex shapes with multi-material structures which are traditionally unmanufacturable with improved surface finish required by tooling applications. While the potential implementation of hybrid directed energy deposition (DED) has been acknowledged to address this need, the manufacturability of a conductive and heat treatable material interface, process planning, and tool path design considerations for varied conformal fluid channel geometries, and bi-material monolithic structure manufacturing for enhanced thermal performance manufacturability is either under-developed or not yet fully understood. This investigation began with the process-structure-property analysis of 17-4PH, pure copper, and a mixture of the two at varied ratios. The investigation continued by evaluating the interface between the two materials when 17-4PH was deposited on top of pure copper and a copper mixture. The investigation was completed when various manufacturing strategies for conformal fluid channels were conducted. With the understanding developed through each step of this investigation, an analysis of an application of a multi-material conformal fluid channel mold insert was conducted.