Technology in Action
So he asked them for a tougher problem to solve. Smith offered the Pylon Interface Unit (PIU) for an attack helicopter. Tey were brazing the sides together and having a terrible time with distor- tion. (Tink of the PIU as a fancy aluminum box which will be stuffed with critical electronics and subjected to intense vibra- tions.) Braswell promised he could machine the components and then mechanically bond them together, which Smith’s engineers assured him wouldn’t work because the parts needed to adhere together such that the whole unit passed Electromagnetic Inter- ference (EMI) and continuity testing. Braswell said he could do it with glue. Tey were skeptical, but let him have his shot.
Defining a New Process Braswell had already been working with 3M on developing
specialized glues for a bomber project. In parallel to that R&D he also made a clever design change to the PIU: bonding pads. As Braswell explains, “Back in the old days bonding required large fixtures to hold the parts together until the glue set, and you’d have to use piano wire or glass beads in the bond to pre- vent the parts from squeezing out all the glue. So I thought, how can I make this thing more efficient and get rid of the fixtures? Tat’s when I came up with the concept of ‘glued and screwed.’ “I designed a 5 thousandths high bonding pad in the parts
where my screws would go, aligned with a tapped hole in the matching component. Tat would give me metal-to-metal contact for electrical continuity and would meet EMI require- ments. It also provides enough surface area with the right gap for the adhesive and achieves the required strength. Plus it’s easier. You just screw the thing together.”
also earned substantial business by taking on work that no one else wants to do. To be sure, this approach reflects Braswell’s intellectual curiosity and attitude, which in turn stems from his carpenter father. Te elder Braswell taught George to never give up and lived that motto himself, working into his 80s aſter los- ing all but a $26 monthly retirement payment. But “never give up” is also a strategic business decision. Braswell figures that if he embraces each new challenge and works through the kinks he’ll lock in a relationship. So even if the first job isn’t profitable (and it oſten isn’t), Command will emerge as the sole source for repeat work. When the job comes back they’ll be more efficient at it and profitable. It’s an approach they’ve repeated many times, most recently with tantalum.
Blocking Subatomic Particles with Heavy Metal Tantalum is a very heavy, hard, and rare metal, mostly used
in tiny capacitors; it has the highest known ability of any metal to store electricity. It’s also used in some coatings and superal- loys where its hardness and high melting point are needed. But it’s almost never used in the format faced by Command Technologies: sheets of pure tantalum, roughly 400 square inches in size, layering a block of aluminum. A customer wanted a layer of tantalum to function as a ra-
diation shield for a spacecraſt. Another firm solved the problem of imploding a layer of tantalum onto aluminum so that it forms a stable chemical bond, a process so specialized that one such implosion costs $125,000. But someone then has to machine the entire tantalum layer flat and cut all the necessary mount- ing forms, which are mostly in the aluminum side, but include
“It’s expensive to bring in all these processes in the beginning. But in the long run, once you’re approved by Lockheed, Northrop, Raytheon, you get a lot of that work.”
Not only did the part pass all Smith’s tests perfectly, they
rewrote their spec around the new approach. Braswell had turned the difficult black art of bonding into a relatively easy and repeatable process. Tis eliminated the need for brazing on a whole series of parts. Since then, the process has contributed both to Command’s
growth and to steady business in leaner times. Braswell adds that they’ve “never had a failure with a mechanically bonded assembly. It’s always passed the requirements for brazing and castings. We’re still making that original PIU, 30–40 different assemblies for a variety of customers, and now we have the first bonded assembly in space.”
Doing Work No One Else Wants to Do Besides revamping longstanding manufacturing processes, like replacing brazing with mechanical bonding, Command has
78 Aerospace & Defense Manufacturing 2014
some through-holes. Te first contractor failed. Command’s Sales Director, Lucy Boyd, didn’t want to touch it: “Too expen- sive. Too high risk.” Braswell, of course, accepted the challenge. “I said, ‘No, I want to machine it. I want to learn about it.’ ” It took two years of learning: Figuring out the best way to
hold the part and developing special machining processes. (Command dedicates several CNC machining centers to this kind of R&D, an investment few shops could afford.) A key part of the solution was partnering with Linley Patterson of DGI Supply. Patterson helped analyze the problem and recommended a specialized 3 flute solid-carbide end mill with variable helix, unequal indexing, and a staggered core. Great end mill or not, the parts are so expensive and hard to replace Command won’t machine one if there’s a threat of a thunder- storm and a possible loss of power that might interrupt the cut. And they teleconference with the customer every week,
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