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Additive Manufacturing 20 MoldMaking Technology —— JANUARY 2018 can also be completed on each object one at a time. This helps to minimize distortion and residual stress of the object and the mold. These features and functions enable the multilayer robotic depo- sition system to deposit up to 2.5 pounds of tool steel alloy per hour, creating consistent and reproducible beads, while eliminating defects and reducing issues related to extreme temperatures. Through his past expe- rience, Zaffino claims that in manual TIG welding, the welder tends to con- taminate the tungsten as many as six times per hour by touching the steel, which affects quality and cost. With the robotic deposition system, a single sharpening of the tungsten electrode has been able to endure up to 8 hours of depositing tool steel alloys. Application Evolution "Once we were able to create near- net-shaped objects on an existing 3D surface, we started to develop the tech- nology further to produce conformal cooling water circuits using the same 3D format," Zaffino says. Current mold cooling technology for a bumper mold This part-deflection study of the conventionally cooled bumper mold shows the deflection of the molded part in the various planes. The X plane shows more uneven shrinkage at the ends of the part, which are typically difficult to cool. Note the uneven shrink- age across the part face, which could show as a wave pattern in the finished part. The Y plane shows the part deflecting along the bottom edge, causing the part to frown. The Z plane shows the ends being pushed inward in the midsection and outward at the ends. This condition will make installation more difficult during assembly. Conventional Cooling — Deflection Results show the mold surface temperature after a 30-second cycle time. Note the average temperature delta between the conventional and conformal methods is 9.3°F, allowing more even heat distribution and faster part cooling. Mold Temperature Comparison Using this robotic multilayer deposition system for conformal cooling can eliminate the majority of the baffles or bubbler systems, which in turn, reduces gun drilling and tapping by 75 percent.