Episode 47: Celebrating National Composites Week - Interviews with Christopher Mims, Wall Street Journal; Joe Brennan, Joby Aviation

August 26-30, 2024 is National Composites Week. The theme of this year's NCW is "Composites Reinvent the World." In this episode of CW Talks we interview CW publisher and brand V.P. Jeff Sloan, Christopher Mims, technology columnist for the Wall Street Journal and Joe Brennan, manufacturing lead – composites, Joby Aviation. Join us for this exciting discussion of how composites are reshaping the world around us particularly in the mobility/transportation sectors.

Excerpts from the episode

Scott Francis  14:53

You've been writing about technology for a number of years, when you think about the future in terms of material science, what do you think we can expect to see in the next few years? What are your thoughts on the ways we design, manufacture and build things, and how is it going to continue to evolve?

Christopher Mims  15:13

One of the things that I'm the most interested in, because of my bias toward chips and all things digital, are what I think of as a class of composites known as metamaterials, which are built on microchips and and they're already showing up in sensors on our cell phones, new kinds of cameras. But any place where people are getting creative with, you know, how do we create materials where, you know, it's a combination of other materials, and not just like an alloy, like in metals, but a true composite. You're just getting really interesting results.

And so metamaterials are, to me, one of the most fascinating examples, because it has the potential to leverage existing microchip building technology, but create what are essentially nanoscale composites on chips. And then you just get to play with the whole universe of you know, everything we know about Nanotech and quantum effects and and kind of exotic physics. And I just think that what we're going to see as a result is electronics that are more and more sophisticated, more and more miniaturized, more and more interactive with their environment, because they're just going to be bristling with sensors and the ability to process that information.

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Scott Francis  20:21

In layman's terms, how would you describe the manufacture of one of these vehicles? I'm curious, roughly, how much of the structure is made of composites?

Joe Brennan  20:31

Sure, yeah. So the vast majority of the structure is made of carbon fiber composites. We have probably, I would say at least 90% of the structure made from composite materials, where we have some metallics, is where we have really concentrated loads coming into the vehicle.

So if you think about where loads get concentrated, like a landing gear, and where the landing gear attaches to the structure, we'll have a metallic fitting to attach the landing gear, or where the wing attaches to the fuselage we'll use metallic fittings to bolt those structures together. But outside of those kind of high load concentration areas, the vast, vast majority of it is carbon fiber composites, and again, we do that because of the weight efficiency, trying to save every gram we can across the entire airframe.

How it's made is fairly conventional prepreg manufacturing processes. So a lot of our parts have a fairly high amount of curvature and complexity to them, and so for those prepreg manufacturing processes, we primarily use hand layup processes. So it's a manual process of taking prepreg material that's been cut to a particular shape to fit a mold, placing that material into the mold by hand, we go through pretty rigorous inspection processes.

Even though it's a manual process, we need to have very tight controls over where every ply is placed, accounting for every ply, its orientation, making sure the material isn't deformed in any way. So every single layer that's put down is inspected by quality inspector, and its its position, and inspection is recorded, and we build up those layers manually by hand until the full thickness is achieved. And then it's a vacuum bag autoclave cure process to cure the prepreg material, and that's how we make the detailed parts.

Once we have parts, we join them into structures with assembly processes that include fastening as well as bonding. So we do do primary structural bonding using paste adhesives, and that is also a process that takes a really high degree of control to make sure it's happening correctly. So there's, there's a lot of quality inspection points along every step of the way for the bonding process. And it's a it's a mix of bonding and fastening, depending on joint loads, where we can bond and have lighter weight joints we do where we have, again, those high concentration of loads, such as like landing gear and wing attach points, we go with fastened joints. So basically, the parts are assembled through structural bonding and fastening until we have full structure, and then those structures are stuffed with a lot of wiring and electronics and systems and finished through final integration and assembly.

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About National Composites Week

The goal of National Composites Week (NCW) is to celebrate and bring attention to the ways that composite materials and composites manufacturing contribute to the products and structures that shape the American manufacturing landscape today.

NCW takes place each year in the final week of August and celebrates a specific theme.

The 2024 theme was Composites Reinvent the World. See what companies and individuals shared on LinkedIn and read more from the CW editorial team:

• Composites reinvent infrastructure 
• Composites reinvent transportation 
• Composites reinvent energy
• Composites reinvent aerospace, AAM and space
• Composites reinvent automotive