3D printing is taking the manufacturing world by storm; this article covers what nanotechnology is delivering in the world of additive manufacturing.
We have all heard of the revolutionary capabilities of additive manufacturing / 3D printing. Adoption of 3D printing technology has been enabled by the recent improvements in speed, reliability, and access. So much so, that the market is expected to grow to $5 billion, with a 21% CAGR, through 2017. The combined innovations around nozzle design, CAD software, and speed are what have driven the wide-spread adoption of 3D printed machines. With the recent adoption of additive manufacturing equipment, wide-spread supply chain disruptions are already hitting the market. Here, we discuss how additive manufacturing is impacting the industry and how nanotechnology is playing a role in pushing the application envelope.
To date, additive manufacturing has predominantly focused on rapid prototyping. And we are not just talking about tinker-toys. Prototype materials include glass, plastics, ceramics, stainless steel, and titanium. Advanced prototypes with industrial applications are already being manufactured regularly. For example, Ford Motor Company 3D prints the intake manifold of their test engines. Normally, an intake manifold takes up to four months and half a million dollars to make, but 3D printing takes only four days and $3,000. Looking forward, additive manufacturing will move from prototypes to full-scale production.
There are a variety of different types of additive manufacturing techniques; fused deposition modeling (FDM), selective laser sintering (SLS), and stereolithography (see wiki processes for additional details). While the most common technique is polymer FDM, each technique locally layers material to produce almost any shape device. This process delivers value in two ways: 1) nearly any geometry can be produced, including designs that were previously not possible through stamping, casting, or milling operations, and 2) there is less waste because you are only putting material where you need it, which is particularly exciting parts made from high-cost alloy/specialty materials. These two value propositions are particularly appealing to manufacturers of low volume, high value parts.
Additive manufacturing continues to grow its capabilities across a wide range of applications, including: batteries, sensors, and aerospace parts. A great demonstration of this is a recent GE Engine Bracket Challenge. After filtering through 697 entries, many not from the aviation industry, the top prototype was 80 percent lighter than the traditional design (see the Free Complexity article). Looking forward GE announced that they plan to use 3D printed parts in jet engines by 2020. In fact, Valve magazine recently asked when we will start to see seals, gaskets, or specialty valves 3D printed. Through a combination of additive manufacturing and machine finishing, certified parts are being produced even today; for fun, check out the 3ders.com applications site for a rolling list of recent innovations (link).
Additive manufacturing has also been demonstrated on the nanoscale. Using a technique called two-photon stereolithography, manufacturers are able to produce micron sized devices within minutes. Here, two laser beams are manipulated with mirrors to photochemically react specific regions of a photoactive polymer. When the two laser beams cross, that point is reacted into an insoluble solid. The system is so sensitive that it only takes 2 photons to induce this change. This improves not only resolution but speed. In fact Nanoscribe, a recent spin-off from the Karlsruhe Institute of Technology in Germany, is selling the Photonic Professional GT with 30 nm resolution. They have already demonstrated an impressive set of 3D structured, made from an SU-8, Ormocomp, or IP resists. The process is so fast, check out this video of them printing a micron-sized spaceship in less than a minute.
Nanomaterials, however, are making a much larger impact on additive manufacturing. Polymers, such as ABS blends, still dominate the space. New materials are slow to be adopted by additive manufacturing technology because of a number of operational challenges, including; specific melting point, material viscosity, no-solvent being allowed in the ink, and controlled cooling process. To overcome these challenges, nanomaterial additives are being integrated into FDM inks. Most common additives include graphene, carbon nanotubes, and metallic nanoparticles. These nanomaterial-enhanced inks enable advanced material properties that operate within the FDM nozzle operating conditions. For example, Graphene Lab Inc use graphene infused polymers to build polymer-based devices with enhanced mechanical, thermal, and conductive properties. Here, the sheets of graphene work like rebar in the polymer structure to make the material stronger. But because graphene has extremely high in-plane conduction capabilities, the polymer devices can be made electrically or thermally conductive. Current applications include printed electronic circuits, sensors, or batteries.
In the like, nanoparticle silver ink has been printed onto curved substrates producing an order of magnitude improvement in monopole antenna performance. Alternatively, Nano Sun has printed a titanium dioxide infused membrane for water filtration. Here, the nanoparticles entrained in the membrane focus UV light to kill waterborne bacteria. Researchers have also been able to tune the mechanical properties of 3D printed epoxy-based devices by varying the amount of carbon fiber.
For broad adoption of 3D printed devices in the industrial sector additive manufacturing processes need to offer more than just parity with current manufacturing techniques. Certification methods and quality standards for 3D printed devices need to be clarified by leading organizations such as ASME or ISO. Even with standards, however, customer confidence in 3D printed devices still rely on the combination of 3rd party testing, manufacturer confidence, and iterative success stories. Perhaps it is the conservative nature of the process control industry or perhaps it is simply the pace of innovation but additive manufacturing will be a slow progression into the automation industry.
Nanotechnology brings a few promising innovations to the field but the depth of offering still trails the robust quality measures required for wide-spread adoption. A lot of work needs to be done before we see nanotechnology push the world of additive manufacturing. Instead, nanotechnology can enhance the offering of the 3D printed devices. The good news is that 3D printing is a new tool in the manufacturers’ toolbox and it is only a matter of time before we see that problem be solved with a nanotech solution.
Stay tuned: My next post will be about the challenges of verifying manufacturing quality of nanomaterials.
Robert Ferris, Ph.D. is a strategic planner with Emerson Process Managements. He holds a bachelors and masters in chemical engineering, an MBA in new technology commercialization, and a Ph.D. in Mechanical Engineering and Materials Science. He has an extensive background in nanotechnology development and advanced process control.
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