CNC Aerospace Industry Services for Flight-Critical Parts

Aerospace parts rarely fail because the machine was too slow. They fail because the part moved between operations. Every re-fixture adds a datum shift, and datum shifts stack. A bracket with compound-angle faces, a rib web that thins toward the tip, a housing with ports on four sides: on a three-axis machine that is four setups and four chances to lose 0.02 mm. On a five-axis center the same part comes off one setup with the datums intact.

Our shop runs 16 simultaneous five-axis machining centers, 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers. The mix matters more than the headline count. A thin, flexible panel often machines better on a three-axis machine with a vacuum fixture than on a trunnion that has to clamp the edges. Pick the machine that holds the part, not the one with the most axes.

Simultaneous five-axis means the tool tip follows a true vector while the table tilts and rotates. That is what makes a compound-angle flange face flat instead of scalloped. It also lets us use a short, stiff tool on deep pockets, which is the difference between a chatter-free wall and a wall that needs hand blending. For a part that must hold Ra 0.8–1.6 μm across a contoured surface, this is not a convenience. It is the only practical route.

• 1
  One setup, one datumCompound angles and ported faces machined without re-fixturing.
• 2
  Short tools on deep pocketsLess deflection, better wall finish, longer tool life.
• 3
  Trunnion limitsVery thin panels may still prefer three-axis with vacuum workholding.

Aluminum is the easy one until it is not. 6061-T6 and 7075 cut fast, hold tolerance well, and take anodizing cleanly. The problem is thin walls. A 0.8 mm rib in 7075 will move after the clamps come off if the roughing pass left too much stress in the stock. We rough, let the part rest, then finish. That extra step costs a day on the schedule and saves the part.

Titanium Ti-6Al-4V is where tool life and heat decide the quote. It conducts heat poorly, so the cutting edge takes the temperature. Carbide grades and coating selection matter more than spindle speed. We run lower surface speeds, heavier feed per tooth, and high-pressure coolant aimed at the contact zone. A part in TC4 takes roughly three to four times the cycle time of the same geometry in 6061, and no amount of programming changes that ratio.

Inconel and other nickel alloys sit at the far end. They work-harden under a dull tool, so the cutting edge has to stay sharp and the machine has to be rigid enough to keep it engaged. We machine Inconel on the five-axis centers with the rotary table locked when possible, because a locked axis is a stiffer axis. For magnesium AZ31B and AZ91D, the constraint flips to chip control and fire safety. Fine magnesium chips need dedicated handling, and we keep those jobs on isolated machines.

Material choice is usually a design decision we cannot change. What we can change is the order of operations, the stock allowance, and the fixture. Those three things decide whether a titanium bracket arrives at final inspection at ±0.005 mm or needs a rework loop.

• 1
  Aluminum 6061 / 7075Fast cutting, but thin ribs need a stress-relief pause.
• 2
  Titanium TC4Heat goes into the tool; expect 3–4× the aluminum cycle time.
• 3
  InconelWork-hardens fast; sharp edges and rigid setups only.
• 4
  Magnesium AZ31B / AZ91DChip control and fire safety drive the process plan.

A tolerance of ±0.005 mm is not a machining problem on its own. It is a measurement problem first. If the shop cannot measure the feature reliably, the operator is guessing, and guessing produces scrap. We qualify the measuring method before the first cut: which CMM probe tip, which fixture for the part on the granite, what temperature the shop floor sits at. Aluminum grows about 23 μm per meter per degree Celsius, so a 300 mm part that warms 5 °C from handling moves 0.03 mm. That alone can eat the whole band.

In-process monitoring is where the tolerance is actually defended. We check the first article fully, then check critical features at set intervals while the run continues. If a boring tool starts to wear, the diameter drifts before the operator sees a bad part at final inspection. Catching it at the in-process check means one adjustment, not a batch of scrap.

Not every feature needs the tight band. A mounting hole pattern at ±0.05 mm is fine and cheap. The bore that carries a bearing, the sealing face, the mating spigot: those are where the tight tolerance belongs. Marking which is which on the drawing saves money and lets us plan the sequence around the hard features instead of the whole part.

Everything ships after 100% inspection. Raw material certificates, in-process records and final reports are available on request. For aerospace work, the paper trail is part of the product.

• 1
  Measure before machiningProbe tip and fixture qualified before the first cut.
• 2
  Thermal drift300 mm of aluminum moves 0.03 mm across a 5 °C shift.
• 3
  Tolerance where it countsTight bands on bores and sealing faces, not every hole.

An anodized surface on an aerospace part is usually there for a reason: wear resistance, corrosion protection, or electrical isolation. Hardcoat anodizing builds a thicker oxide layer and holds up on sliding surfaces, but it changes the dimension. A hardcoated bore grows. We mask critical diameters before the bath and note the build-up on the traveler so the machined size accounts for it.

Electroless nickel gives a uniform coating on complex geometry, which is why it shows up on valve bodies and connector housings. Silver and gold plating appear on RF and grounding paths where contact resistance matters. In each case the plating thickness has to be agreed before machining, because it is part of the tolerance stack, not an afterthought.

Bead blasting, tumbling and brushing even out tool marks and set a consistent surface for inspection. Laser marking handles part numbers and traceability codes down to 1.5 mm character height. Below that, the mark gets hard to read after plating or anodizing, so we push those marks to a larger area or use a different method.

Powder coating and black oxide cover the non-critical surfaces. Neither belongs on a mating face or a sealing land.

• 1
  Hardcoat anodizingWear resistance; mask critical diameters for coating build-up.
• 2
  Electroless nickelUniform on complex geometry; good for valve bodies.
• 3
  Silver / gold platingLow contact resistance on RF and grounding paths.
• 4
  Laser markingTraceability codes down to 1.5 mm character height.

Send a STEP file and a drawing with tolerances and finish callouts. Within 12 hours we return a quotation and a DFM analysis: features that will be hard to hold, radii that need a smaller tool than expected, thin walls that may deflect, and any tolerance that cannot be inspected with the equipment we have. That review is free and it happens before you commit to the order.

Once the order is placed, production can start within 24 hours if material is in stock. Standard parts ship in 3–5 days. We do not set a minimum order quantity, so a single prototype and a 10,000-part run go through the same first-article process. Prototypes are the right place to find a problem, not the production run.

Uploads are secure and confidential. An NDA is available on request before you send the first file. For defense-adjacent work, we agree on what can be discussed and what stays inside the project folder.

• 1
  12-hour responseQuote plus free DFM analysis on the first file.
• 2
  24-hour startProduction begins once material is released.
• 3
  No MOQOne prototype or 10,000+ parts, same process.
• 4
  NDA on requestSigned before files move.