Two scientists from Johns Hopkins University, Nathan C. Brown and Jochen Mueller, have developed a hybrid manufacturing technology they call HyFam, or Hybrid Formative Additive Manufacturing. Their work on this technology has led to a published paper in Advanced Materials. The team, from the Department of Civil and Systems Engineering (CaSE) in the Whiting School of Engineering, describes a technology that starts with contour printing first, followed by a filling-in process.
Mueller explains that,
“Instead of viewing additive and formative manufacturing as competing methods, we had the idea to marry the two. By combining the benefits of each, we created a new production method that also overcomes some of their major drawbacks…”
“HyFAM is less advantageous for highly intricate, uniform objects, but its strengths in combining speed, material flexibility, and design complexity make it a promising solution for a wide variety of industries, from construction to soft robotics.”
Brown stated,
“Additive manufacturing offers significant detail, but when you use a small nozzle to achieve it, the entire process slows down. This becomes a real hinderance in parts with large internal features and widely-varying feature sizes.”
The team essentially combined Material Extrusion with a filling nozzle. Outlines are finely 3D printed, and then internal structures are quickly filled by letting material flow into them. Now, this has been tried before in many different iterations. There have been different nozzle sizes tried for filling and printing contours, and adjustable nozzle diameters. Massivit has a similar process for thermosets, JuggerBot 3D is working on a Material Extrusion and DIW process, and the Z-Pinning approach is close as well; there are even more alternatives not listed. Many of us have also filled in open infill with epoxies and fillers as well. Legally, methinks this is going to be a bit of a mess.
The technology may still be very valuable though, because the duo says that they’ve fine tuned the rheology and bonding of the printing and forming liquid. That may give them better part properties. The scientists also explain that they’ve reduced “several typical AM flaws, such as bulging and internal voids, are eliminated, achieving exponentially faster production speeds for objects with varying feature sizes,” while they’ve tested the approach on “silicone, ceramics, metals, epoxy, cement, clay, and even chocolate.”
They also say that, “The process required precise control of how the material flowed and how thick it was to ensure even filling. It also relied on choosing materials that would behave similarly once solid, to avoid issues like shrinking and warping.”
I’m thoroughly confused by this. Is this a refinement of existing practices to the point that it is a useful technology? Similar to Rapid Liquid Print, or RLP (printing silicone into a bath of gel with a mixing nozzle), is this new because it works? With RLP, SLAM, and FRESH all the same process, the RLP team made it work for silicone and built a business off of it. Do we see this as a material-dependent thing where one gets a patent for chocolate but anyone can do this for PU? Do we need to consider HyFam as something similar? Or is this some kind of patent grab for a well known practice? To me, the Fab@Home team were doing this in 2008 and 2009. How is HyFam different from this 2012 paper that uses two nozzles to 3D print chocolate and jam?
Across many devices and parts, syringe-filling contour 3D printed parts is likely to become more prevalent. For many structures, this kind of an approach is much faster than the alternatives. I’m a huge fan of 3D printing a lattice structure and then covering it in plastic wrap before filling that with foam. In that kind of an approach, you end up having a strong skeleton, while most of the body comes from quickly adding the foam. This has been on a wish list of mine to do for some time, but I’m definitely not saving up money to patent it. Generally however, it is easy to see that for outdoor furniture, formwork, large structures, floors, and much more, this could be a very quick approach. I hope that I’m missing something here, and that this is a collective move forward for all of us.