From our very own Miso Beno comes this amazing interview from Aero Precision.
The AR-15 platform was born of aerospace industry technology and design practices, so it's only fitting that Aero Precision, one of Boeing's leading OEMs (Original Equipment Manufacturers), is also a major OEM for some of the largest AR-15 vendors in the United States. Ten years ago, Scott Dover and Charlie Silkett expanded their company's product line beyond aerospace technology to include firearms manufacturing. The techniques and quality-control processes honed to perfection manufacturing jet engine components are now also applied to their line of firearms parts.
Scott Dover is the Vice President and lead of firearms production at Aero Precision. He agreed to give us a glimpse into what it takes to manufacture an AR-15 and show us around his production floor. Under his watchful eye, we managed to get some photographs of his facility and some of his products during their manufacture as well as a brief interview about his company and production process.
Left: A section of Aero Precision's production floor. Right: The back side of API's main cell loaded CNC machine.
Ben: How did your company [Aero Precision] make the leap from producing aircraft components to AR-15 components?
Scott: About 10 years ago we began looking into other types of work that fit into our core business of four axis horizontal machining. Both of us [Charlie Silkett] have the military in our backgrounds so we decided that getting into the AR-15 receiver producing market was a good idea. We looked into the major suppliers of “black rifles” and got a few contracts in the market.
Ben: Was transitioning from manufacturing aerospace components to firearms components a huge ordeal or are the two fairly similar?
Scott: Other than the high volume and focus on cycle time the two industries aren’t very different from each other. It’s the same type of core work, which is horizontal machining. Working with forgings is a bit of a different animal with calculating the center line of and thickness of each forging being a bit of a challenge but modern probing and dynamic comp techniques are available so its pretty easy to handle forging variations.
Ben: You touched a little bit on quality control and your quality control process before the interview, could you give our readers a brief explanation of your quality control process so they have a better understanding of how that works?
Scott: We break each run into lots of 50, be it uppers, lowers, and sight mounts. Then at the end of each run, we do our in process gauging where every part that comes off is checked against hard gauges and pins to check the parts for proper fitting. Then within that lot we will pull between four and twelve units where they have a full 100% inspection using a CMM [Coordinate Measuring Machine]. This will capture 150 features and correlate them against their “true position tolerance” which gives us the ability to take a snapshot of how all of the features are holding within our machining process. Our CMM is calibrated every twelve months and is only three years old. We’re probably going to upgrade our machine within the next couple years or as volume increases. We’re using our aerospace techniques of in process sampling and SPC Charts [Statistical Process Control explanation] and applying them to this type of work. We rarely get anything back.
Ben: Could you explain the SPC process to us?
Scott: Basically what SPC does is take all of the dimensions that were just measured on a part and shows how they compare on a range of tolerances. If all of your measurements are on one end of that range then that means the feature is within control while if the feature is bouncing around inside that tolerance then that means you don’t have control over that feature. You could have a bad lot of parts. Essentially it graphs how well your product and features of that product are in control.
You could have a run where all of your measurements are stacked on one end of the tolerance; you could even use up all of your tolerance but if they’re all just sitting at that end of the tolerance which would mean that the feature is under control. I could draw something back or forwards to keep the runs where we want them inside the tolerance range, or if we want we could simply leave it alone since its within our tolerance range. Boeing and all of the big OEM manufacturers like to see SPC Charts on what they call “key features.” Key features being those features that are critical to the functioning of that part.
Ben: Does your SPC/Quality Control Process vary from what other manufactures do?
Scott: I don’t know what other manufacturers do. I don’t even know if they use SPC. We’re just concerned that our products are right and we’re giving our customers the best possible product.
Left: The probe head on one of two automated CMMs waiting for instructions to begin checking tolerances on an AR-15 upper receiver. Center: In the foreground are two inspection windows for the main cell loaded mill. Right: Aluminum shaving bins from the the the three mills attached to the cell loader wait to be recycled as scrap metal.d
Ben: What are you most proud of in relation to your AR products?
Scott: It’s been a long process developing our tools and cycle programs. Anybody can make AR parts, but to do it in high volume and have the parts in print is what we’re most proud of. To create our parts in volume and still manufacturing a high quality product is what I would say.
Ben: Out of curiosity, would you mind sharing some of the names of your customers?
Scott: I'm actually very proud of who we deal with but we've signed NDA agreements so we can't reveal any of their names.
Ben: Before we close up where do you see your company in five years?
Scott: It would be nice to have five times the volume we have coming through here. We’d also like to be taking on military contracts, but that will remain to be seen depending on how the House, Senate, and executive branch change things around. We’ll still be here, that’s for sure, but we might be doing more aerospace and semiconductor work and less firearms work. We would love to continue to build our business and plan to do so since we just invested $2.5 million on new equipment this year alone. We definitely plan on sticking around.
Right and Center: Bare mill heads on 2 of the 2-axis milling machines lay silent while the wait for their attendants to load their next jobs into them. Left: AR-15 lower receiver forgings waiting to be machined.
Left: One of the 3 Axis CNC mills working on an aircraft components.Right: Another shot of AP's 4-Axis CNC Mills.
Left: Forgings for solid upper receivers being loaded onto a cell to be machined. Right:Warning, moving equipment may kill you.
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