Additive Manufacturing

MAR 2018

ADDITIVE MANUFACTURING is the magazine devoted to industrial applications of 3D printing and digital layering technology. We cover the promise and the challenges of this technology for making functional tooling and end-use production parts.

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Page 15 of 67

MARCH 2018 Additive Manufacturing 14 TAKING SHAPE 3D-printed cavities was only two days. However, Lammon notes that while there was a significant amount of time saved during the tooling process, the opposite can be said during the molding process. The overall cycle time in PPT's case study was 175 seconds when using the 3D- prin ted cavities. With the aluminum mold, that time was only 44 seconds. This can be explained largely through the discrepancies between allowable heat and pressure. While the mold temperature was 70 degrees in the 3D-printed cavities, it was 125 degrees for the aluminum mold. The barrel temperatures reached 450 degrees with the 3D printed cavities, versus 520 degrees for the aluminum mold. And finally, the 3D-printed cavities required a 60-psi decrease on injection pressure, which represents a 10 percent reduc- tion on velocity and a 50 percent increase of fill time to that of the aluminum mold. While PPT's case study found overall savings in both cost (25 percent) and turnaround time (50 percent) when using the 3D-printed cavities, there are still limitations that need to be overcome. The plastic cavities used in PPT's study were printed with a proprietary digital ABS material from Stratasys, and finding the right mixture of materials that will increase the life of a 3D-printed mold will take time. Depending on the chosen resin, today each cavity set can produce between 50 and a few hundred shots—a small fraction of what's achievable with aluminum (not to mention steel). Success rates can be increased by experimenting with gate location and size, but Lammon notes that design details nearest the gate will be more susceptible to wear and/or damage. PPT is experimenting with other steps that can be taken to extend the life of the 3D-printed cavities, such as increasing gate and runner sizes well over what would be necessary in an aluminum mold. 3D-printed footwear is quickly becoming more readily available, with several major sports brands exploring additive manufacturing for running shoes. 3D printing supplier EOS North America Inc. and Under Armour have formed a partnership to advance commercial 3D-printed shoes. The two organizations will jointly work to scale Under Armour's 3D footwear business through the development of advanced laser sintering technology, and leveraging EOS's expertise in industrialized 3D production. Among the many aspects of the part- nership, Under Armour will utilize EOS 3D technology for printing powder-based parts, and the two companies will work in concert to develop polymer powder and advanced laser sintering. Under Armour will also collaborate with EOS's Additive Minds expert services to elevate its AM program. In 2017, Adidas announced it was partner- ing with Silicon Valley-based tech company Carbon to create Futurecraft 4D's midsole, a 3D-printed sole. Digital Light Synthesis (DLS) is a process from Carbon that uses digital light projection, oxygen-permeable optics and programmable liquid resins to gener- ate high-performance, durable polymeric products. Futurecraft 4D is Adidas's first application of DLS, and represents the brand's step into athlete-data driven design and 3D-Printed Sneakers Gaining Traction By Heather Caliendo Zante Generate, a running shoe from New Balance, features a full-length 3D-printed midsole through a collaboration with 3D Systems.

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