How Precision Blanks Help This Aerospace Shop Build Better Parts

In the metallic hum of a California machine shop, a technician slides an aluminum part across a granite inspection table. The part, a precision-cut blank about a half-inch thick and 7 inches square, is literally floating untouched on a thin cushion of air trapped between two surfaces so true and so flat that there is little room for the air to escape. This invisible levitation is the result of equal parts skill and art — the art of achieving flatness — built on years of experience and millions of parts machined. And at TCI Precision Metals, a material supplier that deals largely in precision-ground blanks for flat parts, it is a daily achievement.  

About 400 miles east in Tempe, Arizona, another kind of floating is taking place. doesn’t build parts that glide so much as soar across the lower stratosphere. Among the parts and assemblies produced here are control panels for fighter jets, covers for satellite electronics, and aerospace components that require this same level of precise flatness and lack of residual stress. Both qualities are key to Matrix’s parts, and critical for retaining stability at altitude.

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Matrix Machine has spent decades mastering thin, flat, mission-critical parts for the defense and aerospace industries. But machining those parts from raw stock was a time-consuming and costly exercise in frustration. When clamped down for machining, residual stresses in the material — a result of forging processes, grain direction, thermal effects or numerous other reasons — can cause flat parts to warp and curl mid-cycle. This “potato-chip effect” is the last thing you want happening to a critical metal part at 38,000 feet.

That’s where TCI comes in.

From Aerospace Dreams to Material Realities

Matrix Machine began under founder Joel Young as a machine shop that slowly gravitated toward aerospace work. The current owner, Cable Morris, started with the company as a shop assistant before working his way to the top and eventually purchasing it with his wife Jennen Morris. The company boasts an on-time delivery rate over 98%, and it shoots for a zero defects per million parts. “We seek perfection,” Morris says.

Matrix Machine has spent decades producing avionics parts, mostly control panels and electrical covers for advanced fighter aircraft, as well as satellite parts. A major challenge the company faced came from producing so many thin, flat parts. Squaring material to the correct specifications can be a time-consuming process when working with the tight tolerances of aerospace parts, but the size and flatness made part deformation difficult to avoid.

While small areas of stress left over from the forging process are unlikely to cause major cracks or deformation in thicker parts, this is not the case for flat parts. Internal stresses in thin parts can cause materials to bend or bow (like a potato chip) during machining, especially if the thin part has a large surface area “We can machine parts that are 20 or 30 inches long that are glass flat,” Morris explains. With parts that size, stresses can cause scrapped parts much more easily.” And even before machining, the shop must be careful with workholding, as it can create pressure that causes flat parts to deform.

Additionally, the process of prepping blanks is simply time-consuming. “Doing this individually, squaring up your own material builds up a mountain of things to do,” says Morris. This takes time away from value-add work and eats up machine tool capacity.

For decades, the company has relied on a simple solution to this challenge: Let someone else do it.

Anatomy of a Perfect Blank

Back at TCI, stacks of metal form an answer to this industry-wide challenge. In the center of the facility, behind of row of traditional Blanchard grinders, are several duplex mills. Unlike standard CNC setups that typically square a single part at a time, the duplexes allow operators to not only stack multiple blanks at once, but also mill opposite sides of a blank simultaneously. The rotary table then turns so the remaining edges can be brought to tolerance. “We replaced 15 to 20 older mills with just four or five of these,” says TCI president and CEO Ben Belzer. “That’s how much more volume and accuracy we’re getting.” Customers often need dozens or even thousands of near-net-shaped parts ready to load into tombstones or pallets. Making this possible are TCI’s machine-ready blanks that arrive identically squared withing 0.0005".

TCI Precision Metals deals in high volumes of steel, stainless steel and aluminum, as well as nickel alloys, tool steel, titanium and plastic on request. The company uses precision saws and waterjet machines to cut the blanks to a basic shape, then grinds or mills them (in most cases) to a tolerance within 0.002 inches or tighter all around, including flatness. Additionally, the company can hold dimensional tolerances as tight as 0.0005 inches. “Our shop is designed to efficiently produce square, flat material at tight tolerances pre-machined to customer specifications,” says Belzer.

TCI’s array of Blanchard and double-disk grinding machines are used to achieve the appropriate tolerances without stress-related fractures or deformation. According to Belzer, the shop’s newer double-disk grinders help release the stress under controlled conditions. “The material floats between two grinding discs with material removed from the top and bottom equally,” he explains. This enables the company to relieve the stress carefully, without pressure from one side causing sudden deformation.

In a separate room across from TCI’s grinding department, a Keyence XM Series inspection system uses photo-based tracking and probe positioning to verify squareness, flatness and part dimensions. Designed to replace legacy CMMs, this portable 3D measurement device uses a camera-based probe and monitor to guide the operator through part inspections. The system works by mapping inspection points over a digital image of the part and tracking probe movement optically.

Not everything at TCI is automated, however. For the flattest parts — the ones that float like an air hockey puck —the finishing touches are made by skilled humans. To achieve this level of precision, technicians use feeler gauges and press brakes to remove microns of warp or bow. As seen in the video above, the operator slides the feeler gauge under the perimeter of the part, locates an area out of tolerance, then provides a “precision bump” on the press brake to flatten it. “It’s craftsmanship,” Belzer says. “You can’t automate your way into this kind of flatness, not really.”

For shops like Matrix, parts must maintain tolerances during deep pocketing or complex contour machining. And that means dealing with the residual stresses inherent to the material before making the first cut.

The Payoff of Precision

TCI began supplying materials to Matrix Machine in the late ‘80s, and the shop has since become one of its largest customers. “All of that prep work is gone,” Morris says. “They work with flat parts all day, and their process eliminates stresses in the blanks.” Because TCI intentionally releases material stress under careful conditions, the blanks have a much higher tendency to remain flat during machining. “Precision blanks are more expensive per weight of material, but it saves us so much in time and capacity,” Morris says. Additionally, by dramatically reducing the likelihood of material stresses causing scrapped parts, TCI enables Matrix Machine to dramatically reduce the amount of rework required, cutting down on both the material and energy used per part. This provides savings while providing a path toward more sustainable part production.

Of course, eliminating the time spent on prep work has freed up both capacity and time for Matrix Machine’s workers. “If we had an order of thin, but complex covers, we would save sixty hours of work on one order,” Morris says. “In a year, we save thousands.” This means the shop’s machinists and programmers get to spend more time on challenging part features. And because the blanks arrive ready to go, there are fewer opportunities for human error to creep into the machining process as operators load and transport parts. Eliminating prep work means eliminating the chance to screw up the prep work.

In fact, Morris feels spoiled by TCI at times. “When we have to source material elsewhere, it’s a problem,” he says. “It’s not plug-and-play like the precision blanks are.” Instead, the company must add multiple machining processes to square the material and reduce the effects of material stress on the final part. This adds hours to machining time. “Not to mention the time spent on workholding and dealing with stress related to workholding,” Morris says.

The biggest draw, however, is in knowing the material is reliable. “More important than the rest of this is peace of mind,” Morris explains. “It builds such a degree of confidence in our parts and our process that we never worry about whether we can get an order to the customer on time and in tolerance.”