3D Printed Footwear
Shoe 3D printing was probably the very first application to drive the imagination of a wider demographic of people, envisioning the idea of ready-to-wear 3D-printed products. Led by Janne Kyttanen over a decade ago, visionaries, designers and artists have experimented with 3D printed footwear at many levels, using a variety of technologies, since the early 2010s (some even earlier). At the same time, the use of 3D printing for shoe prototyping is a well-established practice in the footwear industry and has recently been booming in Asia, as has the use of AM for producing molds, patterns and even lasts used in shoe parts production.
However, it was not until recently that AM technologies became productive and cost-effective enough to enable mass production of accessible end-use products. In fact, mid-soles are the very first consumer product that is already being mass-produced today while in-soles are the first product that—to a certain extent—is being mass customized. These two main trends—along with explosive adoption of AM in prototyping and mold production—are going to be the key elements driving the industry for the foreseeable future, as 3D printing makes its way in the $400-billion global footwear market.
The global footwear industry generated revenues of about $260 billion in 2018 and is expected to grow at around 4% CAGR for the next ten years, totaling around $400 billion by 2029. The segment is mature and growing steadily as hundreds of millions of people around the world—especially in emerging economies—are now able to afford quality footwear.
Within this scenario, AM is expected to play an increasingly important role on several fronts. These include increased adoption in segments where the benefits of AM are consolidated, such as prototyping and indirect manufacturing (i.e. 3D printing of molds and cast patterns for mold production), as well as increased automation for mass production of shoes and other footwear products.
Key 3D printed footwear trends
The trends that are driving the footwear industry toward a larger adoption of additive manufacturing are first and foremost tied to the idea of the underlying macrotrend of increased personalization of all consumer products, from automobiles to jewelry. Today, this is still in a very early phase, where brands—thus uniformity—are still considered more valuable than custom-made products by the majority of global consumers. Younger and future generations are now beginning to place more value on custom-made products, especially as these become actually available.
At the same time, AM is also driving a push toward increased automation by further digitalizing the current high-labor intensive shoe-making process. As these two trends—customization and digital automation—come together, they will usher in the macrotrend of mass customization. Footwear is expected to be one of the first family of consumer products where this transition will take place.
Mass customized orthopedic insoles and sandals
The first footwear products to be produced by additive manufacturing were orthopedic insoles. These are insoles for shoes, boots and even sporting footwear products, that ensure increased comfort by perfectly adapting to the foot’s geometry and the user’s gait. Evolution of basic insole products led a number of companies to introduce 3D-printed orthotics, ensuring even more accurate and effective support, or 3D-printed custom sandals.
Midsoles became one of the most significant cases of mass production via additive manufacturing. After a number of attempts and R&D experiments, adidas and Carbon developed a workflow for cost-effectively 3D printing hundreds of thousands of footwear midsoles. These currently leverage lattice geometries that are optimized for AM but in the future could also integrate a degree of customization.
While large batch production remains a long-term goal, short batch production for limited editions is already increasingly possible through AM. This takes place both through direct additive manufacturing of shoe final parts or through accelerating traditional workflows by adding AM for faster and more cost-effective prototyping and mold-making.
Designer and luxury products
Similarly, 3D printing has already been used for a number of highly experimental and artistic designer footwear products, ranging from entire shoes to custom sculpted heels. Fashion designer Iris Van Herpen has often used 3D printing for both clothing and footwear as have a number of other designers such as Zaha Hadid, Ben van Berkel, Fernando Romero, Ross Lovegrove, Michael Young, Bryan Oknyansky, Gait Goldstein, Cristina Franceschini and several more.
A few major firms are also working to implement 3D printing technologies in the production of footwear uppers, which is the most labor-intensive in the entire footwear production workflow. This is generally achieved through the extrusion of polyurethane materials along with automated knitting or textile cutting process.
Fast prototyping and molding
Finally, it should be always considered that, for the short and medium-term, AM is used as a key technology to obtain faster and more cost-effective prototypes and tools (in footwear this segment includes molds, patterns and lasts), to be used in traditional footwear manufacturing processes.