How Additive Manufacturing Is Making A Difference In Sports

Additive Manufacturing

Additive manufacturing (AM) is also widely known as 3D printing. Through different processes (7 according to wikipedia), physical 3D parts get formed layer by layer, together with some joining, curing or fusing method. The 3 most common or popular approaches to 3D printing plastics include 1) the use of Filaments which typically comes in a roll, 2) the use of powder or fine beads and 3) the use of resin or liquid polymer. Over the years, organisations have worked on improving the 3D printers and processes so that we not only get higher quality prints in terms of better materials properties and finishes, the sizes (of the prints) have become larger and we can get them done in a shorter amount of time. 3D printing used to be (maybe even now) thought of as a great approach to building prototypes or proof-of-concepts, and they absolutely are. But with the improvements that have just been mentioned, they have brought us to a point where 3D printed parts (with a bit of finishing work) can be and ARE sold in various consumer markets as finished products.

So does that mean AM is the way forward for manufacturing? Well, not exactly. Lots of existing/traditional manufacturing processes are still really good and makes more economical sense for products made for the mass market. There are 2 (maybe 3) key advantages of using AM to make finished products:

1. Complex designs or geometries – 3D printing is able to fabricate complex internal or external functional structures that might be too complicated for traditional methods of manufacturing (e.g. injection moulding) or generate too much waste from subtractive methods of manufacturing (e.g. CNC machining).
2. Customisation – using 3D scanning or other means of capturing custom measures, 3D models of the product can be adjusted/customised to fit according to those measures, then processed to be 3D printed. The result is a rather efficient and scalable way of making custom fit products.
3. On demand production – as an extension from the above 2 points and as a result of this digital workflow, products/parts can be manufactured as and when required so there is no need to stock excessive quantities of finished products. Also, if we think of global distribution of products, it is possible to collaborate with overseas partners to get the part fabricated at a location closer to the end customer and save on shipping.

Do These Advantages In Additive Manufacturing Have Any Impact On Sports?

In many ways, yes. But if the question is more targeted at performance improvements, then we really need to look into what research tells us. For that, I lean on a paper by James and Andrew Novak. James is a Design and AM researcher while Andrew is a Sports Science researcher. They published a systematic review titled “Is Additive Manufacturing Improving Performance in Sports? A Systematic Review” in Nov 2020. The push for this systematic review (besides their personal interest) stems from the fact that lots of iconic sports brands are using AM to manufacture end-use sporting products* for the last few years. Therefore they hypothesise that there should be a growing amount of scientific evidence that shows AM products can boost performance in some way.

[* some examples include Nike VaporFly Elite FlyPrint, adidas FutureCraft & Carbon partnership, Riddell’s Precision Fit Helmet, Specialized’s S-Works Power Saddle with Mirror, etc]

For the rest of this article, I am going to summarise some interesting findings from that research paper and also look at some of the innovative products and developments in AM that I have come across in the last year or so.

Research Findings – Systematic Review

Quick Overview Of The Paper

A systematic review is one where the authors have looked through existing research, sifting through databases and identifying ones that meet their review objectives and answer their main research question – what scientific evidence is available that AM provides improved sporting products? The authors searched for publications between Jan 1984 to May 2019 where AM was applied to develop a functional sports product AND the product was used and tested AND has quantitative data. They filtered through 11,185 articles with related keywords, and after removing duplicates and applying their criteria, they got to 26 publications. From the 26 publications that investigated the benefits of using AM in sports products, there were 12 different sports with running/walking having the most number of publications (10) followed by cycling (4) and badminton (3). The other 9 sports had 1 research publication each.

Improvements Due To Additive Manufacturing

Out of the 26 publications that looked at the application of AM in sports products, the authors noted 10 of them had some form of improvements as a result of AM. The way I looked at it, 3 of the publications (about customised insoles) stemmed from the same research and the outcomes were more or less similar, so I combined them and listed them as 8 in the table below. If we look at the Outcome column (last column on the right), 3 outcomes were about better (improved & lighter) equipment, 1 was about better protection and 4 were about performance and comfort. Then if we look at the corresponding Input column (How AM was applied), we see that the equipment improvements are related to design optimisations that are possible through AM. While with improved performance and comfort, it was about customisation and fabrication that is made possible through AM and digital workflow. The publication that produced better protection kind of sits in between the two – there was a bit of optimisation and customisation.

We can see here that the key advantages of AM mentioned earlier (Complex designs/geometries + Customisation) reflect the Inputs that are listed in the table above. Some might argue that it is possible to achieve some of those with traditional manufacturing but it is much more efficient and effective with AM and the digital workflow process.

Again, all the noted improvements in those 8 studies listed ultimately lead to better or optimised performance for the athlete. The one thing the authors of the paper pointed out was – the number of publications were really limited (compared to industries such as medical, dental or aerospace) and also most of the research are once off without further continuation and without comparisons/validations from other research groups. The authors suggested that for AM to be more broadly adopted in the industry, there needs to be more robust research and reporting (publications). Especially ones that focus on improving safety, comfort and performance of athletes at various levels.

Research, Funding & Commercialisation

I would add that, at the end of the day, research does depend on funding. Research funding/grants are highly competitive and not easy to come by. On the other hand, funding that comes from commercial organisations may not lead to published research because the researched methodology might contain their ‘secret sauce’ that could give them a commercial advantage. Or some companies who have the resources might run in-house testing and validation to prove that their products (made by AM) do work and can benefit athletes.

Sometimes, some of the innovations we find in publications do translate to the commercial world. One example was the 3D printed titanium bike frame by Renishaw for Empire Cycles. Another one, though not explicitly stated, was the publication about the vortex generators reducing aerodynamic drag – they noted they had financial support from Nike. We can see that the shape and placement of the Nike AeroBlades look very similar to the vortex generators in the research paper. So it is quite possible that Nike’s AeroSwift technology that integrates Nike AeroBlades was an outcome from that research. Hopefully, some time into the future, we could see the other researched AM products mentioned above being commercialised.

AM Sports Products In The Market

From here, we are going to jump over and look at some of the current commercial products that are in the market. Though there are many different products that have been mentioned on 3D printing media websites, the ones that I have shortlisted below have met a few criteria: – 1) they are actually being made and sold to consumers, 2) there has to be some customisation involved to showcase the benefit of AM, and 3) the customisation would benefit the athlete whether its better fit, protection or performance.

Helmets

Starting from the top, we have the helmets. A good helmet should protect an athlete’s head and reduce the amount of impact that goes to it. Besides good structural design with impact absorbing or dissipating features, a good and proper fit to the athlete’s head is critical. A poorly fitting helmet not only means less comfort, it also substantially reduces the protective effect. The ill fit and discomfort could also cause distraction to the athlete, leading to poor performance and them being more prone to making mistakes.

Customisation :: So these three companies (HEXR, KAV and Riddell) have developed four custom fit helmets for three different sports – cycling, hockey and football. For their customisation, HEXR sends out a fitting cap to the athlete which they would use together with the HEXR app to scan their head (with the help of another person). The app provides guidance to ensure that a proper scan is completed. KAV sends their customers a fit kit and they organise a virtual fitting with one of KAV’s fit technician to complete the measures. KAV also relies on a database of head scans and machine learning algorithms to generate a 3D head rendering to design the custom helmet. For Riddell, they also have a 3D scanning process where the athlete puts on a head liner and is scanned by a Riddell team member using a tablet app. Riddell also takes any on-field impact data of the athlete (if available) and inputs it into Carbon’s design engine to create the custom helmet liner with optimised lattice structure.

Additive Manufacturing :: HEXR fabricates their helmet using Selective Laser Sintering (SLS) and Nylon 11. The core of the helmet is designed in a honeycomb structure that gives it its impact resistance as well as ventilation. Quite similar to HEXR, KAV’s design of its core consists of energy absorbing structures and it has channels to provide ventilation or cooling. The KAV helmets are produced using a Fused filament fabrication (FFF) process and a thermoplastic polyurethane. Riddell’s custom helmet liner, as mentioned, has an optimised lattice structure to fit the athlete’s head and playing requirements. The helmet liner sections are made using Carbon’s proprietary Digital Light Synthesis™ (DLS™).

Benefit/s :: Just reiterating some the points above: for all the helmets, the custom fit provides better comfort, better protection and the 3D printed structures allows for cooling the athlete through better ventilation.

Goggles

Next, we have swimming goggles. So often, people would get goggles that someone tried and recommended. The thing is, what works and fits someone else may not fit or work for you. There are typically only 2 things that can be adjusted to make standard goggles fit better – the head strap and the nose bridge. But sometimes, no matter how those 2 are adjusted or tightened, the fit just doesn’t feel right and water still gets into the goggles during a swim. Magic5 came up with a custom fit solution that aim to resolve that.

Customisation :: Magic5 allows swimmers to do a face scan using a smart phone app. The app requires the swimmer to use the front facing camera to capture images from the right side of their face to the left, taking some key measures of the swimmers eye socket and nose width. Once the scan is done, the swimmer can pick the preferred style and order a pair straight from the app.

Additive Manufacturing :: There isn’t any information on how the goggles are 3D printed or which parts are 3D printed or what material is used. It just says on their website that the googles are “produced by using 3D printing and advanced robotic technologies“. But logically the (3D printed) part would likely be the gasket seal portion that sits on the swimmers face. It is possible that they use robotic arm 3D printing or robotic additive manufacturing (RAM) because it allows printing in any angle which makes it good at achieving complex curved geometries. Based on a swimmer’s review, the gasket seal portion is not as soft as a silicone or foam seal.

Benefit/s :: As mentioned, the “custom fit” of the goggles should improve the comfort of wearing the goggles and also the seal around the eyes thereby preventing leaks. Magic5 has been around since 2017, and based on reviews, the good “fit and seal” is generally what most experienced. But there are also some swimmers who simply could not get the “fit” to work for them, sometimes even going through a few pairs.

Mouth Guards

Mouth Guards offer protection to the teeth, jaw and face, and it also reduces the risk of concussion (in contact sports). Custom fitted mouth guards (as evidence shows) could perform better than a standard off-the-shelf one. Getting a custom mouth guard is not new. But the traditional way using moulds and casts takes a long time while AM offers a quicker and yet effective solution.

Customisation :: The customisation is kicked off by 3D scanning the inside of an athlete’s mouth (mainly the upper jaw). The 3D scan of the gums and teeth is then processed to create a 3D model of the athlete’s teeth. Then a 3D model of the mouth guard is adjusted digitally to fit the 3D model of the teeth. The 3D scanning usually needs to be performed by a dental professional.

Additive Manufacturing :: Fused Deposition Modeling (FDM) or FFF is the process the Impact Gumshields and 3DMouthguard uses to produce their mouth guards, whereas GuardLab utilises Stereolithography (SLA). In terms of materials, 3DMouthGuard uses a bio-based material called Arnitel® by DSM. It is not know what material Impact Gumshields and GuardLab uses, but they would have to be non-toxic or biocompatible since they go in the mouth.

Benefit/s :: The benefit of AM custom mouth guard is that it provides a proper fit to the jaw which means it will stay in the mouth properly and do its job of protecting the athlete’s teeth/mouth, jaw and face. Also, as mentioned, AM is much faster than the traditional method of making custom mouth guards.

Surfboard

Wyve is startup based in Anglet (South West Coast of France) and they are using AM to produce surfboards. Their main motivation for doing that is an eco-friendly one – to reduce the environmental harm brought about from traditional manufacturing. Using their AM approach, they are able to rely on bio-based plastics and bio-epoxy which is less harmful to the environment. The longer term goal is to utilise recycled plastics that can be collected from waste. At the same time, their design does not neglect performance and what AM has allowed them to do, is to customise each board to the individual surfer.  

Customisation :: Ordering a custom board from Wyve requires the surfer to answer around 15 questions including the surfer’s height and weight, surfing abilities, surfing goals and preferences, and even their current fitness/strength level. Then Wyve uses a smart algorithm to digitally work out a high-performance surfboard shape that is adapted to the surfer’s requirements.

Additive Manufacturing :: From the digitally customised shape, the surfboards’s honeycomb (hexagonal) core structure is 3D printed using FDM (with a large build volume) and PLA filaments, a bio-based plastic made from corn starch. After some sanding, the structure is filled with bio-epoxy and covered with fibreglass or vegetal fibres as a coating to strengthen the board. And since Wyve has a eco-friendly mission, they are developing a process to recycle 100% of their surfboard plastic, and reuse this recycled plastic to build new surfboards.

Benefit/s :: The customisation based on the surfer’s abilities, preferences and goals is probably the main direct benefit to the surfer. Also, I guess as the surfer progresses and has new surfing goals, they can always return the old board and order a new custom board to suit their new goals. While Wyve can recycle the old board to make a new customised board.

Footwear

In this footwear section, we found ourselves insoles from Aetrex and ski boots by Tailored Fits. They both have a common objective – they support and protect the feet. Since everyone’s feet are different, having custom made insoles and ski boots will mean much better support. Consequently, the person wearing the custom footwear will experience better comfort, can have better control and thus better performance. In addition, both companies in some ways wanted to address pressure points felt in the feet. In the case of Tailored Fits, they really wanted to to get rid of the annoying pressure points from traditional ski competition boots through their customisation. On the other hand, Aetrex recognises that a lack of proper feet support can lead to various injuries such as arch pain or plantar fasciitis.

Customisation :: In terms of customisation, both footwear uses 3D scanning but there are some differences in their approach. For Aetrex, they use a purposed built scanner (the Albert Scanner) where the customer steps in with both feet and the scanning is completed in less than a minute. On top of 3D scanning, it also does a pressure scan of both feet. Then with both 3D and pressure data, Aetrex uses a software tool built with EOS to generate a digital insole with optimised structure to match the customer’s feet. Spread across the bottom of the insoles are different geometric shapes that act like springs and the different geometric shapes are placed in response to the pressure distribution of the customer’s feet. So not only does the insole match the shape of the feet, it provides more support at areas that need it more.

Tailored Fits utilises the Structure sensor together with an iPad app to 3D scan the skier from the feet to the calves because that is how high the ski-liner will go on the skier. They then take the scan and process it with a custom software developed together with Materialise to design a model of the ski boot liner.

Additive Manufacturing :: For Aetrex, After the digital insoles are generated, they are 3D printed via SLS using EOS’ machines. The material that is used is a Thermoplastic Polyurethane (TPU) which is a soft rubbery polymer. It’s been said that the whole process from scanning to receiving the custom insoles is within 2 weeks. For Tailored Fits, the model of the ski boot liner is 3D printed using FDM and a flexible plastic (possibly similar to TPU). It is not revealed what material is used but they had to pick one that will be able to stand the cold, be UV resistant and also be able to retain heat so as to keep the skier’s feet warm.

Benefit/s :: The main benefit of such customised insoles and ski boots is proper continual support and there is better transfer of energy and as mentioned earlier the removal of pressure points caused by inadequate fit.

AM In Elite Sports & Once-Off Customisations

At the elite sports level, lots of new innovations get tried/used because elite athletes (and coaches) want that extra bit of advantage and they are (sometimes) willing to take a bit of risk. That is assuming the new innovation is within the current rules and regulations of the sport. AM is one of those technology that has played a part in elite sports, especially in the Olympics and Paralympics level. We have seen in previous games, the customisation of equipment such as seats or grips or bike parts (frame/handle), and customisation of something wearable like shoes (midsoles), gloves, helmet and prosthetics. Quite often these customisations are too specialised and may not flow on to the wider sports community but it is still a really good validation for the AM technology and how they can be applied. As processes continue to improve and desktop AM machines become more affordable, I am sure there will be more. One example is this Paralympic athlete’s setup of a small factory 3D printing adaptive equipment for other athletes. Joe Townsend recognised the need not only for custom fitting equipment for adaptive athletes but also lighter and stronger materials for the competitive landscape. He found that Markforge’s carbon reinforced prints ticked many of those boxes he was after. When athletes order a custom handgrip, Joe sends out a kit to capture the athletes’ handgrip mould. Once Joe receives the moulds, he then digitises them, edits them, 3D prints the parts and does some post processing before sending them back out.

In another example of a once-off customisation, we see a custom 3D printed headgear that allowed this lady (Sarah) who had to get Cochlear Implants go back to doing Brazilian Jiu-jitsu safely without damaging the implant. Before Sarah got the 3D printed headgear, she tried different off-the-shelf headgears and helmet but they don’t fit and she would risk hitting her Cochlear. She contacted Eastpoint Prosthetics and they were able to do a 3D scan of her head and design a custom headgear that will meet her needs. The headgear was designed with a recess at the implant area and it was rigid at places where it needs strength and flexible at other areas. The headgear was 3D printed using HP’s Multi Jet Fusion technology and Nylon PA12. In the end, the digitisation (through 3D scanning), custom design and 3D printing methodology gave her the solution she needed. Do check out the full story on this cool parts episode on youtube.

In Closing

Additive Manufacturing opens up lots of opportunities for customisation and optimisation of sports equipment. The potential applications is really really vast as we have seen above. Though there isn’t too much research done that tested and quantified the actual improvement in using AM products, we can see the evidence is there. Even without published research, most companies who are producing products/parts using AM would have done their own testing to ensure that their products (e.g. helmets) would meet and exceed standards and perform as they had claimed.

There are still some shortfalls of AM products. There is only a certain degree a customised product can match the requirements of each individual. There is always some parameter or consideration that is left out in the (mass) customisation process and though it might work for most, it could still miss the mark for some (e.g. the custom Magic5 goggles that leaked for some). However, I believe this is something that can be improved over time with subsequent advances in 3D scanning technology (e.g. smart phones with lidar) and digital processes (and software) and greater adoption of AM.

Want To Customise Using Additive Manufacturing?

Lastly, with more and more on-demand 3D printing services flooding the market, it means (cheaper and) easier access to high quality 3D printed parts. Most 3D printing providers have an online portal where Product designers can easily upload a 3D part they designed and see the options available (materials & AM method) and cost of producing the part before ordering. Some platforms like Craftcloud or Treatstock have curated a whole list of 3D printing providers all over the world so we can compare prices from different providers or pick a provider that is local. So (theoretically) with a 3D scanning app on your latest smart phone, an open sourced cad software (e.g. FreeCad) and easy access to 3D printing providers, one could start customising their own sports equipment.

That’s all I have for this article. If you have any questions or interest in using 3D printing to customise something, feel free to reach out or leave a comment below. Thanks for reading!