The Promise and the Hype of 3D Printing
“If all you have is a hammer, everything looks like a nail.”
“Just because you can doesn’t mean you should.”
I recently returned from RAPID + TCT, an event billed as North America’s largest 3D printing show. The trade show floor was mind-boggling. Some of the booths were as large as a one-bedroom apartment, and many of them featured machines printing objects in real-time.
Caracol’s huge robotic arm extruding lines of composite polymer might have been the most eye-catching display. The process is fascinating to watch.
Some booths displayed small, intricate parts, like printed components with functional ball bearings. Materials suppliers showcased everything from polymers in every color to metal powders from Al to Zn.
The engineer and materials geek in me loved this show. It was fun seeing everything that’s being printed and learning more about the latest trends. The runner in me wished I could buy a pair of Brooks shoes with a 3D-printed midsole that several employees in the HP booth were wearing, but they aren’t yet available to the public.
Beyond the Hype
3D printing has long been hyped as the next great thing for manufacturing. Although the technique has been used to make prototypes for decades, the industry is now struggling to gain wider acceptance as a manufacturing production method. The “cool” factor isn’t enough to achieve the vision of scaling that many in the industry wish would come true.
Hence the quotes at the beginning of this blog post. Materials innovations and advances in computing power mean that it’s possible to print nearly everything you can imagine, from cells to buildings, and it takes less time than you might expect. That doesn’t mean it’s always a good idea.
3D printing is best suited for use cases where the advantages of rapid customization make the most sense. For making millions of identical parts, methods other than printing will be faster, less expensive, and more energy efficient.
Useful Applications
Healthcare offers excellent opportunities for 3D printing to add value. Custom orthotics, eyewear, helmets, orthopedic braces, and prosthetics are more comfortable than off-the-shelf products because they are sized to the individual. Printing these items improves turnaround time and allows for flexibility in design and materials. Parts can be rigid where strength is needed and malleable when a softer surface increases patient comfort. Prosthetics can be colored to match skin tone.
Another example is printing replacement parts for equipment or appliances. That’s a win for productivity and sustainability for several reasons:
There is no need to scrap older equipment because a replacement part is unavailable, extending the equipment’s useful life
Replacement parts can be printed in a day or less, allowing factories to reduce downtime when something breaks
3D printing happens on demand, avoiding the wastefulness of stocking loads of spare parts just in case they are needed
Speaking of sustainability, 3D printing is not always the most environmentally friendly option. There is an energy cost to produce the raw materials (powders or filaments) and run the printers. Calculations of the emissions associated with manufacturing need to take this into account.
Recycling Plastics and Metals
During the RAPID + TCT event, I attended a panel about recycling in the additive manufacturing industry.
This panel was what drew me to the conference. Sherri Monroe, the Executive Director of the Additive Manufacturing Green Trade Association (AMGTA), moderated the panel, and Francois Minec from HP was one of the panelists. I interviewed them for Chapter 11 of my book Materials & Sustainability, “It Adds Up: 3D Printing and Sustainability.” It was great to finally meet them in person and hand them each a signed copy of the book.
Here are some of my takeaways from the panel:
Plastic recycling is problematic regardless of how plastic items are made. The additive manufacturing industry faces the familiar challenges of separating individual polymers, collecting them, and reprocessing them into recycled materials of high enough quality. Some materials can be recycled with the right infrastructure, and others—notably dental aligners—cannot.
For metals, it’s a different story. Specifications for metal powders are often quite stringent, and they vary for different metals and applications. Some people worry that used powder isn’t high enough quality for reuse in 3D printing, but replenishing the supply with spent powder can actually improve process stability.
Reducing Energy
One way to reduce the energy required to make materials for 3D printing is to change how materials, specifically metal powders, are made. Exhibitor 6K Additive uses short blasts of microwave plasma energy to create spherical powders from scrap, including both used powders from 3D printing and scraps from machining. The company claims that its method uses 75 to 90% less energy than standard powder production processes.
The 6K process can make lots of different metals and alloys. I picked up a bottle of tungsten powder and was surprised at how heavy it was. Perhaps I shouldn’t have been, knowing where tungsten sits on the periodic table, but it still felt heavier than I expected.
For applications where several materials could work equally well, choosing a powder or filament that melts at a lower temperature saves energy during printing. Optimizing materials and design to require fewer supports that later get discarded is another energy-saving approach. Sustainability-minded end users can add these to their list of considerations when designing 3D printed products.
My Take on Additive
I agree with keynote speaker Marie Langer, CEO of EOS, a company that makes 3D printers and materials. She said that the industry shouldn’t scale for the sake of scaling and should be patient when opportunities don’t come flooding in. (I believe the first part of that statement applies more generally, and that uncontrolled growth should never be the goal.)
To achieve additive manufacturing's promised performance and environmental sustainability benefits, focus on where it can add the most value and enable things that cannot be done otherwise.
Additive manufacturing needs to be a solution to known problems rather than a solution in search of a problem. The best tool isn’t always a hammer. Or a 3D printer. Fortunately for the engineers developing better materials and refining processes for 3D printing, there are lots of places where it can be an ideal solution.