New Balance Uses Ultrasonic Equipment and Sieves to Ensure High Powder Throughput For 3D Printed Midsoles

Established in 1906, New Balance is one of the world’s largest shoe manufacturers. Way back in 2013, the company, which also makes athletic clothing, used 3D printing technology for the first time to create custom spike plates for track athlete Jack Bolas. The company continued to supply customized 3D printed spikes and cleats to its sponsored athletes, but in 2015, New Balance announced that it was teaming up with 3D Systems to release a limited edition high performance running shoe with a 3D printed midsole, made using 3D Systems’ DuraForm Flex TPU elastometric powder.

44 pairs of the New Balance Zante Generate, the first commercially available 3D printed running sneaker, were released last year.

“New Balance is at the forefront of 3D printing and has been utilizing this exciting and innovative technology to customize product for our athletes for a number of years,” Robert DeMartini, the President and CEO of New Balance, said last April. “Our unique position as both a manufacturer and retailer allows us to bring the world’s first 3D printed running midsole to market. The Zante Generate demonstrates the strength of New Balance design and innovation and will allow consumers to own a piece of running technology history.”

Each shoe takes several hours to complete. Traditional materials, such as an engineered mesh, are used to manufacture the rest of the shoe, while the soft yet strong midsole is 3D printed using a selective laser sintering (SLS) process.

Once the midsole, which features an internal honeycomb structure for maximum cushion and support, is 3D printed, it’s removed from the powder bed for cleaning and post processing, before being sent to New Balance’s Boston manufacturing facility for assembly and finishing.

During the actual SLS process, a laser is used to convert the powder into solid cross sections; this powder was actually the subject of a recent case study. During the initial stage of making the Zante Generate shoes, the New Balance laboratory began processing small batch work. However, once the company decided to take the process to the next level – large-scale commercialization – it asked fine mesh separation technology expert Russell Finex for help in finding a more efficient way to increase powder throughput and improve flowability for its prototypes.

The solution was to sieve the 3D printing powders with ultrasonic screening technology. After consultations and a product trial at the specialized Russell Finex test facility, New Balance made the decision to purchase a Russell Compact Sieve, as well as a Vibrasonic Deblinding System.

The versatile, high-capacity sieve is an industrial screener, and is about half the height of a traditional sieve. It comes with a solid rubber suspension, which brings the volume level down to as low as 70 dBA, and is designed to lower cleaning time as well. Because it can be easily stripped down without tools, operators can access the mesh screens easily, so New Balance can ensure the purity, and increase throughput, of its processed 3D printing powder.

Just like it invented the ultrasonic sieve deblinding technology, Russell Finex also developed the patented Vibrasonic Deblinding System, which upholds throughput rates, increases the service life of mesh screens, and lowers powder product loss.

“To put in numerical terms, to sieve 20 kg of material using the OEM provided equipment would take approximately eight hours,” explained Dr. Daniel Dempsey, Additive Manufacturing Engineer for New Balance. “With the [Russell Finex] sieve plus Vibrasonic, I can do the same amount in roughly ten minutes.”

The Vibrasonic System makes sure that the equipment runs continuously, at optimum performance, so it can quickly process the fragile, difficult powders that New Balance uses to 3D print the midsoles for its Zante Generate shoes.

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[Source: AZO Materials]