Where does it go from here? – An AM Perspective (Part 6)

Several times in this series I’ve touched on the two core values in AM – design and supply chain.?I’ve talked about how the supply chain benefits have been the primary driver of polymer AM adoption while the flashier design benefits get more of the attention and shift focus toward metal.

Supply chain benefits will continue to be a massive driver for AM use in manufacturing, especially in polymer, but ultimately, the significant competitive advantage of additive technologies will prove to be in the new designs that can be unlocked or made cheaper and easier with printing.

I also touched briefly on the fact that one of the major drivers in aerospace is continuously pushing for lighter weight and mentioned that one of the major ways this is being accomplished is through the use of composites.?What I didn’t mention was that composites are not easy to work with.?Composite parts are very difficult to manufacture. ?The weight savings are worth it, but there is incredible opportunity in making composite parts easier, faster, and more cost effective.

But we can 3d print composites, so problem solved??Nope.?

Today, “composite 3d printers” are printing layers of fiber reinforced material.?Technically composites, yes, but with only a small fraction of the value those materials can offer.?3D printing composites utilize very short fibers that either need to be smaller than a powder particle for a powderbed system, or small enough to be compounded and extruded into an FDM filament.?When printed, the fibers in a powderbed can point in any direction and the fibers in an extrusion system will generally align with the extrudate path.?As a result, you get little to no reinforcement in a powderbed because of the tiny fiber size, or in extrusion, all your strength and stiffness gains are in-plane.?People already complain about the anisotropy of extrusion, which you are now making much worse because you are reinforcing X-Y and not adding any benefit to the already weaker Z direction.

Traditional composites are strong, stiff, and lightweight because they are made up of very long carbon fibers (or glass, or aramid fibers).?Those fibers are laid up in tapes or fabrics on a tool surface that gives the final part a shape once cured.?Or, flat plates are cured and then formed through a secondary process.?In either case, the final part has strength in the direction you need the strength rather than in a planar layer.?These are two things composite 3d printing lacks today – long fibers, and non-planar printing.

There are automated technologies that some consider 3d printing that overcome these limitations, but they have other limitations. Automated Tape Layup (ATP) and Automated Fiber Placement (AFP) deposit strips of composite tapes on a tool surface. This provides long fiber properties on a non-planar surface. The limitations come from the large size of the tape deposition heads which result in a great way to make a large, "swoopy" shape like a panel or wing skin, but there is no ability to add finer features, which come in highly manual secondary processes.

Several in aerospace have experimented with concepts to achieve true 3d printing of composites without the limitations of either 3d printing or AFP. When I was at Stratasys , we showed the Robotic Composite 3D Demonstrator at IMTS way back in 2016 as an example.?The purpose was to show that going to a multi-axis deposition strategy could allow us to create complex, light weight, true composite parts where we’ve aligned strength to our load path and turned anisotropy from a disadvantage into a light-weighting miracle worker. The continuous toolpath approach had a side benefit of a massive throughput improvement to boot.

This concept extends further, and I’ve had many conversations with visionary customers that recognize the value unlocked through the combination of 3d printing with processes like AFP. The combination can result in new classes of parts that are highly complex but light-weight and able to be produced faster and cheaper than current processes, if those processes can even create the envisioned part today. Using AFP to create a large simple structure and then FDM to add details and reinforcements in the same material system would be a powerful match.

Obviously, if it were easy, it would already be done.?There are significant challenges that remain including getting the final properties to what you want them to be without extra consolidation and curing processes.?Also, the software tools to design and simulate these parts, where they even exist, do not have the pedigree of similar tools for traditional technologies.?These are solvable problems, and I firmly believe that the long term competitive advantage of material extrusion 3d printing will be found exactly in the multi-axis printing of high value composite parts. This follows from the Part 4 hint that there are high value non-metallic part opportunities for AM that are ignored because of polymer's low criticality reputation.

But, we're not done yet.

Say you can wheel out your robotic 3d printer and set it to work on printing an ultra-efficient UAV structure.?How are you going to integrate wire harnesses through that design, and how will you install them??Here’s where I come back to the multi-functionality concept I mentioned way back in Part 2 – we need to be able to print, at a minimum, the electrical functionality directly into the part.?This means multi-material, and likely multi-deposition processes.?So now, those hard design and simulation challenges get even harder because we’ve gone cross disciplinary (do your ME's and EE's even speak the same technical language?).?This goes beyond composites at this stage, because you are printing in wires or traces or potentially other metallic functionality.?And maybe, now that you are truly in this hybrid concept, we’re not just printing, but automating assembling within the same cell as printing is happening - resulting in efficiencies that we can envision, but struggle to quantify at this point.

What we have in the end is the true promise of 3d printing realized – being able to create something that we haven’t been able to create before, and that we can produce wherever and in whatever quantity we need.?So ultimately, the design value leads and the supply chain values follow.??This flips us from even our most advanced applications today, like rocket motors that are being printed for their low volume economics and taking advantage of the increased complexity enabled by 3d printing as a secondary design benefit.

We don’t have to leap there.?There are dozens of possible steps along the way, and plenty of money to be made in the process.?There are applications today (which I’ve decided not to mention openly but would in appropriate conversations) that would immediately and directly benefit from taking even the first steps down this path.

#3dprinting ?#additivemanufacturing ?#aerospace ?#defense ?#aerospaceanddefense

Past Posts:

• Part 1 – Am I an Additive Manufacturing outsider yet?
• Part 2 – Where’s the real value in additive?
• Part 3 – Mass production or just production of mass?
• Part 4 – Polymer or Metal??Yes, please.
• Part 5 – The right type of supplier.