New 3D-printed athletic shoes from New Balance (Boston, MA) and EOS (Krailling, Germany) have hit the ground running! Custom running shoes are perfectly suited for the individual runner because everyone's foot- strike pattern, degree of pronation (the amount a runner's foot rolls inward with each step), and braking and propulsion forces are all unique. However, the extent to which most running shoe models vary is rather limited in comparison.

As a result, there are some who believe that personalizing a runner's shoes, specifically the spike plate that provides traction on the underside of the shoe, can help athletes become faster on the track. New Balance Athletic Shoe Inc. is a big proponent of this trend. So it should be no surprise that New Balance has turned to design-driven manufacturing to 3D print custom spike plates, based on biomechanics and personal inputs, for elite athletes.

A proprietary process is used to collect race simulation data from Team New Balance runners. Using a motion-capture system to determine the relationship of the foot to the force plate, a three-dimensional vector is recreated of the foot strike. The Sports Research Lab then applies advanced algorithms to translate this information into an optimized design that can be additively manufactured on an EOSINT P385 system, plastic laser-sintering technology from EOS that allows designers to produce, or "grow," complex geometries that can't be created using traditional manufacturing techniques.

The spike plates are grown in the EOS system from a custom-blend nylon powder, coupled with tailored laser conditions, yielding maximum engineering properties such as tensile and flex moduli while minimizing build time. The developer of the spike plate material is Advanced Laser Materials of Temple, TX, a developer of high-performance materials that collaborated with New Balance on this project.

Katherine Petrecca, business manager of New Balance Studio Innovation, commented, "By laser sintering our customized spike plates we can manufacture on demand, fluidly adjust our process to accommodate different sizes and widths, and update designs without the continuing capital investment required by injection molding."

The incorporation of the laser-sintered spike plate also resulted in a five percent weight reduction compared to traditionally manufactured versions.

"There are so many great things that came out of this process, compared to the methods we used in the past to develop and manufacture products," said Sean Murphy, Senior Manager, Innovation and Engineering, at New Balance. "This is a totally unique situation where we come away with the runners' data, generate multiple plates we feel will meet their needs, and actually provide several pairs of track spikes for them to try simultaneously. It's great to be able to have them identify and respond to each different variation that we product."
While the runner-specific spike plates are currently only available for Team New Balance athletes, Petrecca noted that this will eventually change and be made available to other runners as well to enhance the individual's performance and comfort.