Book: 3D Printing For Product Designers

I’m extremely excited to share some news with you all! For the past 2 years I’ve been writing a book that is specifically focussed on 3D printing strategies and case studies for product designers. I’ve been lucky enough to work with Prof. Jennifer Loy and Prof. Olaf Diegel, both very well known leaders in the field. The book is called 3D Printing for Product Designers: Innovative Strategies Using Additive Manufacturing, and is now available for pre-orders direct from the publisher Routledge (at a discounted price!).

In many ways this book closes my personal first chapter in the 3D printing industry, which began in 2009, and brings together experiences and lessons learned working in industry, with industry, and on cutting-edge research projects at several of Australia’s leading universities specialising in 3D printing. Of course, my 3D printed bicycle has been a big part of that journey, and was selected by the team for the front cover, which is a real privilege. And yes, there is a detailed case study in the book that explores this project in more detail for anyone interested.

Obviously there are already some fantastic books on 3D printing, with Ian Gibson et al.’s book Additive Manufacturing Technologies probably the most well known, originally published in 2015. Our co-author Olaf Diegel also led writing a more recent book called A Practical Guide to Design for Additive Manufacturing, and 3D Hubs have a nicely illustrated book called The 3D Printing Handbook. There are others, but one thing most of these books have in common is that they’re particularly written for engineers, with lots of technical guidelines and explanations of the different 3D print technologies (which can date quickly given the rapid pace of technology developments). There isn’t a book written specifically for product and industrial designers using 3D printing, and there isn’t one that helps companies understand how to effectively adopt the technology. That’s where our book fills the gap.

The book revolves around 3 overarching strategies that can be followed chronologically, or selectively chosen depending on a company’s specific needs:

• Strategy 1: Working with existing production – includes rapid prototyping, bridge manufacturing, fixtures, jigs, enhanced tooling and agile manufacturing.
• Strategy 2: Product redesign and new product design – includes part consolidation, light weighting, customisation, form follows function and product innovation.
• Strategy 3: Digital business innovation – includes digital inventory, distribution, personalisation, scalable systems of supply and digital business innovation.

The goal is to help designers and engineers lead their company or client through a process of incremental change. This is particularly important for established companies with a workforce (or management) resistant to change. It can also be used to inform new entrepreneurial activity, allowing startups to begin at the cutting edge of digital business innovation.

Real-world case studies used to illustrate these strategies include bicycles (of course!) and other sports products, guitars, furniture, medical devices and prosthetics, jewellery, heat exchangers and more. Many of these have come from our friends and colleagues around the world, and the book features over 100 high quality colour photos to illustrate these.

The book is currently in production, so I can’t share a lot more right now, but I look forward to sharing some more detailed posts soon to give previews of different sections of the book. Stay tuned!

– Posted by James Novak

From bespoke seats to titanium arms, 3D printing is helping Paralympians gain an edge

Jeff Crow/AAP Image

Authors: James Novak, The University of Queensland | Andrew Novak, The University of Technology Sydney

** Please note: this is a copy of an article I wrote for The Conversation, published on 3rd September, 2021, and is shared under a CC-BY-ND license. You can access the original article by clicking here.**

Major sporting events like the Paralympics are a breeding ground for technological innovation. Athletes, coaches, designers, engineers and sports scientists are constantly looking for the next improvement that will give them the edge. Over the past decade, 3D printing has become a tool to drive improvements in sports like running and cycling, and is increasingly used by paralympic athletes.

The Paralympics features athletes with a diverse range of abilities, competing in a wide range of different categories. Many competitors use prosthetics, wheelchairs or other specialised components to enable them to perform at their best.

One interesting question is whether 3D printing widens or narrows the divide between athletes with access to specialised technologies, and those without. To put it another way, does the widespread availability of 3D printers — which can now be found in many homes, schools, universities and makerspaces — help to level the playing field?

Forget mass production

Mass-manufactured equipment, such as gloves, shoes and bicycles, is generally designed to suit typical able-bodied body shapes and playing styles. As such, it may not be suitable for many paralympians. But one-off, bespoke equipment is expensive and time-consuming to produce. This can limit access for some athletes, or require them to come up with their own “do-it-yourself” solutions, which may not be as advanced as professionally produced equipment.

3D printing can deliver bespoke equipment at a more affordable price. Several former paralympians, such as British triathlete Joe Townsend and US track athlete Arielle Rausin, now use 3D printing to create personalised gloves for themselves and their fellow wheelchair athletes. These gloves fit as if they were moulded over the athlete’s hands, and can be printed in different materials for different conditions. For example, Townsend uses stiff materials for maximum performance in competition, and softer gloves for training that are comfortable and less likely to cause injury.

3D-printed gloves are inexpensive, rapidly produced, and can be reprinted whenever they break. Because the design is digital, just like a photo or video, it can be modified based on the athlete’s feedback, or even sent to the nearest 3D printer when parts are urgently needed.

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Read more: Paralympians still don’t get the kind of media attention they deserve as elite athletes

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Harder, better, faster, stronger

An elite athlete might be concerned about whether 3D-printed parts will be strong enough to withstand the required performance demands. Fortunately, materials for 3D printing have come a long way, with many 3D printing companies developing their own formulas to suit applications in various industries – from medical to aerospace.

Back in 2016, we saw the first 3D-printed prosthetic leg used in the Paralympics by German track cyclist Denise Schindler. Made of polycarbonate, it was lighter than her previous carbon-fibre prosthetic, but just as strong and better-fitting.

With research showing sprint cyclists can generate more than 1,000 Newtons of force during acceleration (the same force you would feel if a 100-kilogram person were to stand on top of you!), such prosthetics need to be incredibly strong and durable. Schindler’s helped her win a bronze medal at the Tokyo games.

Denise Schindler on her way to a medal in Tokyo. Thomas Lovelock

More advanced materials being 3D printed for Paralympic equipment include carbon fibre, with Townsend using it to produce the perfect crank arms for his handbike. 3D printing allows reinforced carbon fibre to be placed exactly where it is needed to improve the stiffness of a part, while remaining lightweight. This results in a better-performing part than one made from aluminium.

3D-printed titanium is also being used for custom prosthetic arms, such as those that allow New Zealand paralympian Anna Grimaldi to securely grip 50kg weights, in a way a standard prosthetic couldn’t achieve.

Different technologies working together

For 3D printing to deliver maximum results, it needs to be used in conjunction with other technologies. For example, 3D scanning is often an important part of the design process, using a collection of photographs, or dedicated 3D scanners, to digitise part of an athlete’s body.

Such technology has been used to 3D-scan a seat mould for Australian wheelchair tennis champion Dylan Alcott, allowing engineers to manufacture a seat that gives him maximum comfort, stability and performance.

3D scanning was also used to create the perfect-fitting grip for Australian archer Taymon Kenton-Smith, who was born with a partial left hand. The grip was then 3D-printed in both hard and soft materials at the Australian Institute of Sport, providing a more reliable bow grip with shock-absorbing abilities. If the grip breaks, an identical one can be easily reprinted, rather than relying on someone to hand-craft a new one that might have slight variations and take a long time to produce.

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Read more: 3 reasons why Paralympic powerlifters shift seemingly impossible weights

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All these technologies are increasingly accessible, meaning more non-elite athletes can experiment with unique parts. Amateurs and professionals alike can already buy running shoes with 3D-printed soles, and 3D-printed custom bike frames. For those with access to their own 3D printer, surf fins, cycling accessories and more can be downloaded for free and printed for just a few dollars.

However, don’t expect your home 3D printer to be making titanium parts anytime soon. While the technology is levelling the playing field to a certain extent, elite athletes still have access to specialised materials and engineering expertise, giving them the technological edge.

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This article was co-authored by Julian Chua, a sports technology consultant at ReEngineering Labs and author of the Sports Technology Blog.

3D Printed Toys with Moving Parts

My desk is covered with 3D prints, some of them my own designs, and others are just cool examples of what can be done with a home 3D printer. This is one of those examples.

Stian Ervik Wahlvaag (@agepbiz) has created a clever range of 3D printed vehicles known as “Tiny Surprise Eggs” – why? Well, because they fit within an egg of course! The unique feature of each toy (and egg) is that they feature moving parts printed in place, without the need for any support material. Once the toy is taken off the printer, it is ready to go. The example pictured above is “Surprise Egg #7 – Tiny Car Carrier” and all the vehicle wheels rotate, and the car carrier itself can raise and lower the ramps.

While I didn’t print the egg, I did scale these prints up 200% to have something a little bit more child-friendly. Unfortunately I enjoy them so much they have permanently stayed on my desk, but I promise I’ll print my son another set! The moving parts still work really well at this increased scale and provide some clever design tricks to ensure multiple parts can be printed as an assembly. As an example, above is a cross section through one of the cars showing how the wheels and axels are designed within the main body of the car. Some simple angled details mean that no support material is needed when printed in this orientation, yet from the outside the car just looks like it has normal cylindrical wheels. Great example of how to design for additive manufacturing (DfAM) as it’s known.

Following the vehicle carrier, I’ve also 3D printed “Surprise Egg # 6 – Tiny Jet Fighter” which features wings which fold out, again at 200% scale and with no support material. Both of these designs, as well as at least 8 more surprise egg vehicles, are free to download from Thingiverse, and highly recommended as a way to test your print settings (if there are any issues the moving parts may end up fused together), and learn a few of the tricks for designing assemblies for 3D printing.

If you print these yourself, or have any other recommended prints that include clever design details like moving parts, please share them in the comments section.

– Posted by James Novak

3D Printing Build Farms

3D printing is a slooooow process. While 3D printing geeks like me can spend hours watching a printer lay down layers of plastic, it often turns manufacturers off who are used to rapid manufacturing process like injection moulding where parts can be pumped out every few seconds. However, there is a way to produce products en masse and it’s called the 3D printing build farm.

Perhaps you’ve already seen images like the ones above – these are well known examples of 3D printing build farms at Ultimaker (left) and Prusa (right) that illustrate what they’re all about: Lots and lots of 3D printers! A 3D printing build farm is basically just a collection of several 3D printers, or many hundreds of 3D printers, that can significantly scale up the production of parts. These can often be networked together as part of a single management system, meaning only a small number of workers are needed to keep an eye on things. The benefit over other mass production technologies is that you still retain the benefits of 3D printing a unique item on every 3D printer, rather than just producing thousands of exactly the same product. Of course, you can also produce thousands of the same part, for example the Prusa build farm is made up of over 500 of their own 3D printers, which are used to print many of the parts to assemble new 3D printers.

A centralised build farm (left) and a decentralised, geographically dispersed build farm (right)

Recently I published a book chapter analysing 3D printing build farms in the context of work and the future. Titled ‘3D Printing Build Farms: The Rise of a Distributed Manufacturing Workforce,’ one of the main opportunities we discuss that has not yet been exploited is for 3D printing build farms to be geographically distributed, rather than centralised within a single facility (illustrated above). If all the 3D printers within the build farm are connected to a central management system, then they do not actually need to be located in the same physical location.

Obviously there are some benefits to having all the machines located together, particularly for maintenance and monitoring. However, there may also be several benefits to distributing the 3D printers domestically or internationally, particularly in light of the COVID-19 pandemic and the longer-term changes we may now enjoy working from home, or at least working in a more decentralised manner:

• 3D printers can be located closer to customers. Centralised 3D printing build farms must still ship products around the world, just like conventional manufacturers, which costs time and money.
• Distributed farms may better suit new flexible working conditions, allowing people to work the hours they want, from a location they want.
• New jobs in regional areas with smart regions connected to smart cities. 3D printers may be distributed in regional areas, as well as cities, reducing the need for people to relocate to overcrowded cities in order to find work.
• Businesses may join forces and utilise shared “nodes” of the 3D printing build farm.

Time will tell if this provides businesses with new advantages, but it is clear that build farms, whether centralised or distributed, are a growing trend with real commercial value. Some of the biggest adopters are in the dental industry, for example SmileDirectClub which uses 49 multi jet fusion 3D printers from HP to manufacture moulds for up to 49,000 clear aligners each day. This is big business, driven by 3D printing and build farm systems.

– Posted by James Novak

3D Printing in Sport – Hit or Hype?

If you’re into 3D printing, no doubt you are familiar with some of the ways it is being used in sports. Some of my own products (above) have included a 3D printed bicycle frame, smart bicycle helmet and surf fins, while in the media products have included shoes, golf clubs and shin pads.

However, as a researcher, I was interested to know how this translates into academic research. How many research studies have been looking at 3D printing for sports products? How much improvement does a 3D printed product offer over a conventional one? Which sports are adopting 3D printing? Working with my brother, Dr Andrew Novak, we hypothesized that given the amount of coverage in 3D printing media, there should be quite a large amount of research supporting the developments of iconic 3D printed sports products, as well as novel developments that haven’t even made it into the media yet. The results – published in a paper titled ‘Is additive manufacturing improving performance in Sports? A systematic review‘ – were surprising (preprint version freely available).

Up until May 2019, we found only 26 academic studies that provided any empirical evidence related to 3D printing for sports products. The graph above shows which sports, and how many articles have been published. The first of these appeared in 2010. Running/walking was the most popular sport with 10 articles (38%), followed by cycling with 4 articles (15%) and badminton with 3 articles (12%). All other sports – baseball, climbing, cricket, football (soccer), golf, hurling, in-line skating, rowing and surfing – had only been assessed in single studies. This means that a lot of research into 3D printing of sports products are just one-off projects, and indicates that there may be very little funding/interest to continue building larger projects.

It also suggests that any research being done to support mainstream commercial applications of 3D printing, for example for brands like Adidas and Specialized, is protected by intellectual property (IP) and not being published.

10 articles (38%) observed improvements in performance of products developed via 3D printing compared to conventionally manufactured products, 8 articles (31%) found a similar performance, and 5 articles (19%) found a lower performance.

From a technical perspective, powder bed fusion technologies were the most utilized with 50% of articles using either selective laser sintering (SLS) or selective laser melting (SLM), although 52% of articles did not name the 3D printer used and 36% did not name any software used to design or optimize products. 3D scanning technology was also utilized in 11 articles (42%).

So, is 3D printing in sport a hit or hype? Based on this research it is clear that within academia, 3D printing is still in the very early phases of consideration, and seems to be significantly behind industry. While you may be able to go and buy some 3D printed running shoes or insoles, or cycle on a 3D printed saddle, you won’t find any objective data in journal articles on these products or much research to suggest that 3D printed products are any better than conventionally manufacture products.

– Posted by James Novak

3D Printing and COVID-19 in Data

Following my previous post discussing some of the opportunities and challenges of using 3D printing to fill supply chain holes during COVID-19, I’m pleased to share the more detailed research I’ve been working on that supported my article in The Conversation.

Published here in an open access journal is an analysis of all 3D printing projects that were initiated during the first months of the pandemic. As a summary, the image above shows the timeline of these projects, and the types of products that were being produced. In total, 91 projects were documented in my research, with only 7 of these occurring before the World Health Organization (WHO) declaration of a pandemic on March 11. Most of these were based in Asia. The remaining 84 projects (92%) followed the declaration as the pandemic spread around the world and health systems rapidly struggled to meet the demand.

The figure above also shows that 60% of projects were for personal protective equipment (PPE) such as face shields and goggles, while 20% were for ventilator components, and a further 20% were for miscellaneous projects such as hands-free door openers.

Of the PPE projects, 62% were for face shields as shown above in the left chart. This includes the popular Prusa RC3 face shield pictured in my previous post, although the first documented face shield actually occurred on February 25 from The Hong Kong Polytechnic University. Obviously face shields are a relatively low risk product compared to components for a ventilators, and makers could easily 3D print these on desktop 3D printers.

The chart on the right above documents the types of 3D printing technologies used for each of the 91 projects. Perhaps it is no surprise that fused filament fabrication (FFF) was the most used, accounting for 62% of projects. Resin printing with stereolithography (SLA) or digital light processing (DLP) was the next most popular for 10% of projects, followed by multi jet fusion (MJF=9%), selective laser sintering (SLS=8%), continuous liquid interface production (CLIP=2%), and concrete was used in one project in China to 3D print concrete isolation houses for Xianning Central Hospital in Hubei. Interestingly, 8% of projects did not specify the 3D printing technology being utilised, suggesting that some projects lacked documentation or were reported by the media simply as “3D printing.”

While this review provides an overview of the broad trends related to the 3D printing of health and medical products during the first months of the COVID-19 pandemic, ongoing research is needed to continue monitoring 3D printed products throughout the pandemic to understand longitudinal trends. For example, does the initial hype from March subside and a more stable pattern of research and collaboration continue through April and the following months? Do projects consolidate and merge, with others ending as regulations tighten, or traditional supply chains stabilise?

It will also be necessary to analyse 3D printed products and validate them, particularly as the health crisis continues for months or even years. Initial 3D printing projects, while well intentioned, were largely unregulated and a reflexive response to direct and immediate needs. As supplies stabilise, and the infection curve flattens, more time and resources can be devoted to research, building upon the NIH 3D Print Exchange database of approved designs, perhaps developing an approved FDA or TGA database of designs as well as 3D print technologies and materials. These may be necessary for any future outbreaks of the virus, as well as allowing for better preparation for future health, humanitarian and natural disaster crises that may require a similarly rapid response to equipment shortages.

If you want to find more of the data and read the detailed analysis, please read the article here. Additionally, you can freely access all of the data I collected for this research, and continue building off it, by accessing it on Figshare. I hope it is useful for building our understanding of how 3D printing can be deployed during a health crisis.

– Posted by James Novak

3D Printed Sea Urchin Light

This project has been a little while in the making and it’s exciting to finally be writing about it. About a year ago I posted about 3D scanning some shells, and as part of the scanning I captured a sea urchin shell. At the time I didn’t know what I’d do with it, but fast forward a year and I’ve found a perfect application; turning the sea urchin shell into ceiling light covers in my house.

In this post I’ll go over the main processes and experiments I went through to get the finished product, but in case you’re just here for the big finale, here’s the link so you can download the final Sea Urchin Light exclusively from my Pinshape account and 3D print as many as you like!

3D Scanning

As explained in further detail in my previous post, I used an EinScan Pro 2X Plus 3D scanner, which included a turntable to automatically capture all angles of the sea urchin shell. This resulted in a full-colour, highly detailed model of the shell, as shown to the right. However, as anyone familiar with 3D scanning will know, this model is just a skin with no thickness or solid geometry, and was just the starting point for the design process.

Design

If you don’t have access to expensive CAD programs, good news; this project was completely designed in free software! I’ve used Autodesk Meshmixer for many of my tutorials and posts, it’s a surprisingly powerful tool and a must for anyone involved in 3D printing. Additionally, it’s quite useful when you are working with 3D scan files, which are typically a mesh like a STL or OBJ. The process took a little time, but has been outlined in 6 basic steps below:

1. Fill any holes and errors in the 3D scanned sea urchin shell. In Meshmixer, this simply involves using the “Inspector” tool under the “Analysis” menu.
2. Scale up the shell to the appropriate size, then use the “Extrusion” tool to thicken the skin into a solid shell. So that the shell would allow a lot of light through, I used a 0.7mm thickness for the overall design.
3. I wanted to create an interesting pattern when the light was turned on, so separated several areas of a copy of the original mesh to be used to create thicker sections. This was a slow process of using the brush selection tool to remove areas, before repeating step 2 with slightly thicker geometry. For this design I ended up with 3 different thicknesses around the shell.
4. To allow the light fitting within the shell, a larger opening was needed at the top. A cylinder was added from the “Meshmix” menu and placed in the centre.
5. By selecting both the shell and the cylinder together, the “Boolean Difference” command became available, subtracting the cylinder section from the shell.
6. Lastly, a neck section measured off the original light fitting was added. I cheated slightly and modelled this in Autodesk Fusion 360 (also free if you’re a student), but you could use Meshmixer – it would just take a bit longer to get accurate measurements. Then the separate parts are joined together using Boolean Union, and the design is finished.

3D Printing

As well as the new design needing to fit the geometry of the existing light fixture, it also needed to fit the build volume of the 3D printer – in this case a Prusa i3 MK3S. As you can see below, the shell is only slightly smaller in the X and Y dimensions than the build plate.

In terms of print settings, I stuck with some pretty typical settings for PLA, including a 0.2mm layer height. Support material is necessary with the light printed with the neck down – this is the best orientation in terms of ensuring the surfaces visible when standing below the light (remember, it is ceiling mounted) are the best. Where support material is removed is always going to be messy, and you wouldn’t want to have these surfaces being the most visible. Overall, this meant that each light took ~32 hours to print.

Material & Finishing

One of the steps that took a bit of experimentation was choosing the right material in order to look good when the light was both on and off. Each of these lights are the main, or only, sources of light in the spaces they are installed, so they need to provide a good amount of light.

As shown above, 3 different materials/finishes were trialled. Initially I began with a Natural PLA from eSUN, which is a bit like frosted glass when printed. While this allowed all the light to escape and illuminate the room, most of the detail was difficult to see in both the on and off settings. It was just like a random glowing blob. I then tried pure white PLA, hoping that the print would be thin enough to allow a reasonable amount of light out. Unfortunately very little light escaped, however, the shadows from the different thicknesses looked excellent, and when the lights was off, it was very clear this was a sea urchin shell. Perhaps this would be a good option for a decorative lamp, but not so good for lighting a whole room.

So the “Goldilocks” solution ended up being in the middle – I 3D printed the shells in the translucent Natural PLA, and then very lightly spray painted the exterior with a matt white paint. Just enough to clearly see that it is a sea urchin shell when the light is off, and translucent enough to allow a lot of light out. Perhaps there is a material/colour of filament that would achieve this with needing to paint, but I didn’t want to have to buy rolls and rolls in order to find it. PETG would be interesting to try, and if you have any other suggestions, please leave them in the comments section.

The Result

To the right are the dimensions of the ceiling light fixture within which the sea urchin light comfortably fits. The light itself is a standard B22 fitting, so the sea urchin can comfortably fit most standard interior lights. However, if you have a different sized fitting, or want to fit it over an existing lamp, you can easily scale the design up or down to suit your needs. I’ve already fitted one of the early small test prints over an old Ikea lamp, it just sits over the top of the existing frame. In total I’ve now installed 5 of the large ceiling light covers in my house, and am planning a new design to replace some of the others (my house is full of this terrible cheap fitting!).

As mentioned at the beginning of this post, I have made this design exclusively available on Pinshape – it’s just a few dollars to download the file, and then you can print as many as you like! If you 3D print one, please share a photo back onto Pinshape, I love seeing where my designs end up and what people do with them.

– Posted by James Novak

3D Printed Flexible Lens Cover

I’ve said it countless times before, and I’ll say it again – some of my favourite 3D printing projects are the ones which are quick, easy, and either add value to an existing product (e.g. see my 3D printed webcam mount or lucky bamboo holder), replace something broken or lost (e.g. my SUP paddle lock),  or in this case, something missing.

I recently bought an old pair of binoculars (or is it just a binocular?) from an antique store. They came in a pretty beaten up case, and were missing two of the protective lens covers, but overall worked nicely with lenses that weren’t scratched. The lens covers that did come with the binocular were cracking and didn’t really stay in place any more, so it was 3D printing to the rescue.

Planning to use some PolyFlex TPU95 filament from Polymaker to create a soft, rubber-like lens cover, I ended up designing the lens covers to be just slightly smaller than the measured diameter of each lens, 0.25mm smaller to be specific, with the intent of creating a secure friction fit, but not so tight they had to be stretched over the lenses. The design is very simple, a couple of extrudes in Fusion 360, before adding the circular pattern detail around the outside (which was not part of the original lens caps!) to add a personal touch. Now that they’re printed they remind me of beer bottle caps, but the intent was just something a bit rugged and easy to grip without spending a long time trying to be too clever in CAD.

These were 3D printed on a Wanaho Duplicator i3 Plus with an upgraded Flexion Extruder. What’s a Flexion Extruder? Well, you can read my whole series documenting early experiments trying to 3D print flexible materials here, but long story short, a Flexion Extruder is the ultimate upgrade for cheap desktop FDM machines that allows you to successfully and reliably 3D print with soft TPU materials. If you don’t have a Flexion, or a good quality system like the Prusa MK3S which has been designed to print a whole range of materials including TPU, chances are you will end up with a tangled mess of filament coming out the side of your extruder, or worse! They’re just too soft to be forced down into the hotend and come out of a tiny nozzle.

The other trick is getting the right settings to print with – you will find loads of different theories and recommendations online, 3D printing TPU is a bit of a dark art and there are many different types of flexible TPU that require different settings. So getting things right will take some time. This is a good general guide to follow, and I’d reiterate that you MUST print extremely slow – I used 20mm/s for the lens caps. Also, follow the recommendations from your filament supplier, this material from Polymaker was printed at 220°C with the build plate at 50°C. Seemed to be about perfect.

Above you can see just how flexible the end result is, the lens caps easily bend and squash without permanent deformation. If you’ve got any settings you’ve found are reliable, or just general tips and tricks for 3D printing TPU, please comment below to build up some resources for others to find.

Happy 3D printing.

– Posted by James Novak

3D Printed Knits

Did you know it’s possible to knit using a desktop 3D printer?

This has been some work I’ve been doing in the background for a little while now and combines all the benefits of digital design with craft-based hand assembly. OK, so you can’t print with soft yarn (yet), but by printing thin geometry you can create some relatively soft and flexible knits that are unlike the typical chainmail assemblies often used in 3D printed fashion/textiles.

The trick to this is to simplify the knit into individual pieces, which can be 3D printed flat on the build plate. This makes printing extremely fast, also known as a 2.5D print which I’ve written about in a previous blog post. While one of the benefits often discussed about 3D printing is the ability to produce complex assemblies as a single part, in the case of a knit, this will result in significant amounts of support material, and the need for quite bulky geometry to ensure the knit geometry is strong enough. However, by printing separate components, these problems are avoided, and you can have some fun manually connecting the loops together while you wait for the next print.

Additionally, the new opportunity of 3D printed knits is to create completely new patterns and geometries in CAD software. This has been the focus of my newly published paper called A Boolean Method to Model Knit Geometries with Conditional Logic for Additive Manufacturing (free to access). In it I detail how to set up an algorithm in Rhino with  Grasshopper that will allow customisation of loop and float structures for a knit, the sort shown in the top picture. If you have some experience with the software, you can follow the process outlined in the paper to set up a similar system, and begin modifying parameters and geometry to create completely new knits that would not be possible using traditional knitting techniques.

As shown above, the Grasshopper code gets quite complex so is not for the feint of heart, but if you understand boolean logic, and have used Grasshopper, I’m sure you can build this! And if not, have a go at modelling some knit geometry in your favourite CAD package and print it out – you can keep printing on repeat to extend the size of your “knitted” textile, this is how some of my early tests were done. If you start by modelling some rows of circles, then connect them together, this will get you close to a knit structure.

Happy 3D knitting.

– Posted by James Novak

Fingerprint Stool 3D Printed on a BigRep ONE

Size matters!

I’ve been throwing out teasers about this project on social media for over a year, and with my research just published in the Rapid Prototyping Journal, it is very exciting to finally be at the finish line and able to share it – all of it! So what exactly is it?

Well, it’s a 3D printed stool. But more than that, it’s the outcome of a design for additive manufacturing case study using the new BigRep ONE 3D printers, housed in the ProtoSpace facility at the University of Technology Sydney. The BigRep ONE is essentially a desktop FDM 3D printer on steroids, with a build volume measuring 1005 x 1005 x 1005mm, that’s over 1 cubic meter of space to 3D print! And much like a desktop FDM printer it uses filaments like PLA, PETG, TPU and realistically just about any other filament material, as well as using a Simplify3D profile for slicing, so designing for the printer and operating it is identical to many common desktop 3D printers.

Given the newness of these machines when they were installed in ProtoSpace in early 2018, my job was to test the capabilities of them whilst developing a showcase product to highlight how they can be used to develop new types of products, and with such a large build volume, furniture was an obvious choice. However, my budget was not unlimited ($1500 AUD) and nor was the time I was allowed to run the printer, which was capped at 5 days so that it was not taken out of commission for other users for more than one working week. Sounds like a generous timeframe unless you’re familiar with just how slow FDM printing is even at the desktop scale, and while this printer is bigger, it is certainly not any faster. And when you are printing for 5 days, this machine will really chew through filament, so that $1500 budget quickly runs out.

In terms of the fingerprint concept, the stool was designed when I was newly engaged and uses a fingerprint from my (now wife’s) ring finger, and my own. Awwwwe… There are few features more unique to each human than a fingerprint, so this concept was also chosen as a truly unique feature that highlights the capacity for 3D printing to be used for one-off personalised products.

The above video helps explain the design and printing process, which essentially involved:

1. Ink used to take impressions of fingerprints on paper.
2. Fingerprints digitised using a flatbed scanner.
3. Fingerprints vectorised in Adobe Illustrator. Exported as DXF files.
4. DXF files imported into Solidworks CAD software and oriented 420mm apart for the height of the stool.
5. Manual creation of the 3D geometry.
6. Export to STL.
7. Slice in Simplify3D.
8. 3D print on the BigRep ONE [1mm nozzle diameter, 0.5mm layer height, 5% infill, 2 walls, 3000mm/min print speed]

Sounds nice and straight forward. However, I must admit things did not go this smoothly: Firstly, designing to fit a specific budget and print time required several iterations, with an early version of the design twice as large as the design pictured here. This meant initial cost estimates were in the range of $2194-3882 and print times 117.5-216.1hours – talk about variation! All of this variation is due to experimenting with process parameters like layer height and nozzle diameter for the same design, and was an important learning process that could be taken back into later iterations of the design, which ultimately became smaller.

Secondly, another obstacle we struggled with was bed adhesion. This is a common problem with desktop machines, however, not normally when printing with PLA. We quickly found that during the first layers, a slight warp or piece of material sticking up would get knocked by the extruder, causing a knock-on effect as the extruder and any material it had collected quickly cause all of the individual sections of the fingerprint to dislodge. Pictured above on the left is the largest section that printed before some material snapped off and somehow caused the nozzle to become entombed in PLA, pictured above on the right. That was an expensive error, new nozzles for the BigRep ONE do not come cheap!

Given the design was intended to print without any need for support material, we eventually had to concede defeat and add a raft. This had the effect of linking all of the initially individual sections of fingerprint together during the first layers, and provided a strong adhesion to the bed. While we could’ve tried all sorts of glues, tapes and other hacks, we didn’t want to resort to these on such a new machine until we had more time to test settings and work with BigRep on a solution. The good news: the raft worked and after 113 hours, and at a cost of $1634 (only slightly over budget), the Fingerprint Stool was complete. The raft did take 1 hour to remove with a hammer and chisel (with a 1mm nozzle there is so much material it cannot be removed by hand), and the surface finish is quite rough – but in my mind this is the charm of FDM, just like a piece of timber has grain and knots that are simply part of the material.

Overall the BigRep ONE is an exciting technology, you just need to keep in mind that due to the scale, all of the small issues you can experience on a cheap desktop machine are also magnified. However, it is great for producing large-scale functional parts like furniture, or any of the other examples you may have seen from BigRep in 3D printing news over recent months.

This is a brief overview of the project, there is much more technical information and analysis in my paper in the Rapid Prototyping Journal, including metrology data of the final design compared with the 3D file, as well as surface roughness data. I’d love to hear your feedback on the project or your own experiences with the printer if you’ve been lucky enough to use one. And keep an eye out for updates about the stool appearing in an exhibition later in the year 😉

UPDATE: Thank you to BigRep for taking an interest in this project and writing their own story about it here, and to 3D Printing Industry for also sharing this story.

– Posted by James Novak