Brett Casson

For years, thongs have been footwear constructed from a slab of foam that has been cut to shape and a Y-shaped strap attached with plugs.

The design is ubiquitous, but it has drawbacks, including that the foam readily absorbs water, making it slippery when wet and not durable.

Because the process to make thongs is a subtractive manufacturing process, producing them also generates significant waste.

With his company Retraction Footwear, engineer Brett Casson MIEAust is taking a new approach. Casson has designed the world’s first commercially available fully 3D-printed thong – additive manufacturing provides everything but the glue.

“The mission of the company is to create the most comfortable pair of thongs in the world,” he says.

“We believe that 3D printing provides a revolutionary change in the way that thongs are manufactured.”

The 3D-printing process allows the thong to be constructed using a complex geometry that incorporates hundreds of tiny air pockets to provide cushioning and support.

The size of these air pockets can be adjusted, Casson explains, and the thongs can be customised to suit each customer’s foot length, width, arch height and weight, along with colour preferences.

Since the thongs are printed using additive manufacturing, the process leaves no waste behind, since the machine only places material where it is needed rather than cutting away excess material.

“A hard-wearing sole is incorporated into the design, which does not absorb water and provides much more grip in the wet,” Casson adds.

“The sole is also much more hard wearing meaning each pair lasts longer — another environmental benefit.”

Judges’ comments:

“A really innovative approach to manufacturing a well-established product. This makes a strong case for the no-waste additive manufacturing approach versus the traditional subtractive approach.”