02 April 2020
Back to nature
Hexr helmets began when co-founder, Jamie Cook, delved deep into the world of cycling helmets and their cellular structures under the watch of the acclaimed scientist and broadcaster, Mark Miodownik MBE, at University College London. Cook’s research continued at Oxford University, and it was here that the eureka moment arrived. Cook discovered that the EPS technology – the lid standard for over 40 years – isn’t the ideal material for impact control. So he set about creating an alternative inspired by nature: honeycomb.
“Every design method for energy absorption assumes that the contact area is constant, but that’s not the case for a curved surface,” states Cook. “We need to design for the head’s unique curvature. And the only way to make a curved honeycomb structure without distorting the mechanical properties is by 3D printing.”
And so began a five-year process involving countless hours researching head shapes and the optimum helmet fit, athlete feedback and 3,200 helmet tests. While not the first bike helmet to be 3D-printed, Hexr’s debut helmet is the first to utilise personal head measurements and Polyamide 11, a material usually found in the aerospace industry.
Protect your head, protect the planet
Because each Hexr is made up of hexagonal cells in a honeycomb structure, it spreads the energy over a larger area as more cells activate, softening to reduce pressure and the peak force. The force of impact and the chances of traumatic brain injury, therefore, are reduced – our helmet is 30% better at impact control than helmets constructed from EPS.
There are also the environmental benefits of custom-printed helmets. Firstly, there’s no possibility of overstock collecting on shelves, as each Hexr is printed on demand. Additionally, EPS foam is both non-biodegradable and produced using crude oil, compared to Hexr’s inner core which is made from 100% renewable raw materials and uses only castor bean oil. This bean is drought-resistant, doesn’t compete with other food chains, and thrives where other crops struggle to grow.
No two heads…
“No two heads are the same, so why should helmets be?” is our oft-repeated mantra. In contrast to the limited number of sizes provided by mainstream helmet brands, the creation of your own personal helmet begins with a scan of your head with our app, which harnesses a 30,000-point 3D mesh.
This data is then sent to our cloud servers, where a helmet is automatically generated. Next it is sent to our 3D printing facility where it is additively manufactured into a helmet with an accuracy of a fraction of a millimetre, but with an offset from our head to accommodate variations in hair length and the thermal expansion of our head while riding.
Our partners at 3T Additive Manufacturing Ltd in Newbury take care of this tightly controlled step of the process. Using a technology known as Laser Sintering, the helmet is produced layer upon layer by using high-powered and ultra-fine lasers to melt portions of consecutive layers of powder with a thickness of 0.1mm. The regions that have been melted later cool and solidify, forming a solid structure, whereas the surrounding areas remain in powder form which can be brushed away. The entire process takes approximately 36 hours for a batch of 6 helmets.
Gazing into the 183°C core of an EOSINT P 395 laser-sintering system, it’s easy to see that we’re witnessing the birth of something entirely new in the world of helmet design.
The personal touch
Having cooled for 72 hours following its 183°C build at 3T-AM, each helmet undergoes a rigorous finishing process to ensure optimal quality. First, all excess powder is removed using a combination of brushing by hand and blasting with tiny glass beads under high pressure. The powder removed in this step is recycled and will be used to print a future helmet.
Next, the honeycomb structure is dyed black using DyeMansion’s automated DM60 machine, before finally being visually inspected to verify its structural integrity and finish quality.
The future
The accessibility of custom products is set to open up due to rapidly advancing 3D printing technologies and the development of our own mobile scanning app.
“It was always the plan to make our scanning more accessible by building the 3D scan into phones, replacing the current need for ‘in-person’ scanning. We had originally hoped there would be a company with the scan technology we needed, but there was nothing in the market accurate to the level we require to produce a HEXR helmet” states Smithwick, HEXR co-founder.
Our present world of small, medium and large, sizing will soon feel antiquated in comparison.
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