All of the big sportswear brands have been investigating the possibility of printing high-performance footwear. And they have been supported by the manufacturers of materials and printing equipment.
Adidas set up a strategic partnership with Redwood City, Calif.-based 3D printing specialist Carbon to create its Futurecraft 4D high-performance footwear. The German sportswear brand says it used 17 years of running data to design the new midsole. This was made using a digital footwear component creation process that removed the need for traditional prototyping or molding.
It uses Carbon's Digital Light Synthesis (DLS) process. This employs digital light projection, oxygen-permeable optics and programmable liquid resins to create high-performance, durable polymeric products.
The running data in Adidas's library was used to shape functional zones into a midsole design. Using the data allowed Adidas to design midsoles which combined movement, cushioning, stability and comfort.
In contrast to standard 3D printing manufacturing methods, the DLS process is claimed to overcome issues such as low production speed and scale, poor surface quality and restrictions in color and material.
The midsoles are grown from liquid, and Adidas says the lattice network that is formed has 20,000 individual struts that can be adapted to optimise energy return.
Nike has started printing the uppers, too, and Eluid Kipchoke ran to victory in the 2018 Virgin London Marathon in a pair of shoes with uppers 3D printed out of TPU. The company claims this is the first time the uppers of performance footwear have been created in this way.
The uppers are made using solid deposit modeling. In this method, filament is unwound from a coil, melted, and then laid down in layers. The company claims printing allows prototypes to be created 16 times faster than other production processes.
Nike also is using the technique to incorporate athlete-specific data into the textile geometry. Nike uses data captured from the athlete and this is analyzed to confirm the material's ideal composition. That analysis is used to design the textile.
The company claims that 3D printed fabrics are more dynamic than traditionally woven fabrics. This is because the warp and weft fibers are connected.