Aerospace machining is the precision cutting of aircraft and spacecraft parts from aluminum, titanium, and nickel alloys to drawing tolerances, with full material traceability and inspection records. Buyers judge an aerospace machining shop on three points: whether it can cut the alloy, hold the tolerance, and prove both through certifications such as AS9100D and AS9102 first article reports.

Picture a titanium bracket that passes every dimension on the CMM report. The quality engineer still rejects the lot. The heat number on the mill certificate does not match the number on the traveler, and nobody can show which bar the parts came from. The shop cut the metal correctly. In aerospace machining, that counts as a failure.

That gap between a good part and an accepted part sits at the center of aerospace machining. The cutting matters. In aerospace machining, the evidence matters just as much. This aerospace machining guide covers the alloys, tolerances, certifications, and sourcing choices that decide whether a program ships, and it is written for engineers and sourcing leads who want to know what to ask before they send a drawing.

What is aerospace machining, and how does it differ from general CNC work?

Aerospace machining removes material from billets, forgings, or castings to make airframe structures, engine hardware, landing gear parts, avionics housings, and satellite components. Most of the work runs on aerospace CNC machining equipment: 3-axis and 5-axis mills, turning centers, mill-turn machines, and wire or sinker EDM. A programmer writes the toolpath once, and the machine repeats it. That repeatability is why aerospace machining depends on CNC.

CNC machining for aerospace differs from a general job in the evidence it produces. Aerospace machining sells proof along with parts. A commercial shop proves a part with a certificate of conformance and a spot check. An aerospace buyer wants a chain of proof from raw bar to finished part.

Requirement General CNC job Aerospace machining job
Material proof Certificate of conformance Mill test report with a heat or lot number tied to each part
First parts Spot check AS9102 first article report on a representative part
Process changes Shop decides Controlled change, often a repeat first article
Heat treat, plating, NDT Any vendor Approved sources, often Nadcap accredited, as the contract requires
Records Kept for the job Kept for the retention period the contract sets

‍

If you want a broader view of machined components first, our CNC machined components page lists the processes and part families we handle.

Aircraft designers chase weight, so aerospace machining drawings call for thin walls, deep pockets, and curved contours. Those features slow cutting and make inspection harder. A wing rib can start as a solid block of aluminum and finish as a frame of thin webs, and every web can move when the last cut releases stress in the metal.

Which materials does aerospace machining use?

Strength per gram drives the material list for aerospace machining. Five families cover most parts that reach an aerospace machining shop.

Material Common grades Typical parts How it behaves on the machine
Aluminum 2024, 6061, 7075 Ribs, brackets, housings, fittings Cuts fast. Thin sections can bow after the final cut
Titanium Ti-6Al-4V Fasteners, engine casings, landing gear, structural fittings Heat stays at the tool. Slow speeds, short tool life
Nickel superalloy Inconel 718 Engine hot-section hardware, hinges, flaps Work hardens and wears tools quickly
Stainless and precipitation-hardening steel 304, 316, 15-5PH, 17-4PH Valve bodies, housings, hydraulic parts Gummy in the soft condition. Heat-treat state changes the cut
Composites and polymers CFRP, PEEK Panels, insulators, interior parts Fiber pull-out and delamination at hole edges

‍

The condition on the drawing matters as much as the alloy name. A 7075-T651 plate has been stress relieved by stretching. The same alloy in another temper cuts differently and moves differently. Read the callout before you compare quotes.

Aluminum alloys for aerospace machining

There's a reason aluminum is widely used in aerospace machining. It cuts more easily than the other metals discussed here, and machining mistakes don't usually cost as much to correct. That helps keep costs down. When fatigue resistance matters, 2024 is a common choice. For brackets and fittings, manufacturers often go with 6061. Parts in the wings and fuselage that take heavier loads are generally made from 7075.

One thing to watch with aluminum is how the material behaves as it’s being cut. Say you’re making a thin rib out of a thick 7075 plate. The part may start to bow as the last cuts release the stress locked in the plate.

Titanium machining: why heat decides the price

Heat is a major reason titanium machining takes longer than machining aluminum. It also has a significant effect on the cost of aerospace machining work. Ti-6Al-4V has a thermal conductivity of about 7 W/m·K. Much of the heat generated during cutting stays close to the tool edge rather than being carried away by the chip.

Tool life suffers when cutting speeds increase. In one published comparison, researchers limited the speed to 60 m/min after finding that higher speeds reduced tool life (IIETA study). Work hardening adds another problem. If the tool rubs against the titanium instead of cutting cleanly, it can leave a hardened surface that becomes more difficult to machine on the next pass.

So shops use sharp tools, steady chip loads, rigid fixtures, and heavy coolant flow. They accept longer cycle times, and buyers see that as a higher price per part. Few metals match titanium for strength at its weight. Aerospace machining uses it in fasteners, engine casings, and landing gear. Ti-6Al-4V is one of the 143 materials Wootz.work maps to machines.

Inconel and other superalloys in aerospace machining

Aerospace machining of engine hot sections uses nickel alloys such as Inconel 718. A published review of the alloy lists a tendency to form built-up edge, work hardening, rapid tool wear, and low thermal conductivity (Springer review). In practice, that means coated carbide or ceramic tooling, low cutting speeds, and a shop that has done it before. Ask for records of past Inconel work. A capability list proves nothing about aerospace machining skill.

Stainless steel, composites and polymers in aerospace machining

Aerospace machining of precipitation-hardening steels such as 15-5PH and 17-4PH ends up in housings, valve bodies, and hydraulic parts. Their heat-treat condition changes how they cut. Carbon fiber reinforced polymer brings a different problem: delamination and fiber pull-out at the edges of holes. Partners in the network machine CFRP structures for robotics programs, where edge delamination and fiber pull-out at holes are controlled by tooling and feed. PEEK covers insulators and high-temperature interior parts.

Which aerospace CNC machining processes do aerospace machining shops use?

Aerospace CNC machining relies on six main processes. Each one suits a different type of aerospace machining job.

Process Best for Watch for
3-axis milling Plates, brackets, prismatic parts Extra setups on complex shapes
5-axis milling Contoured structure, impellers, housings with features on many faces Programming time, tool reach, collision checks
Turning and mill-turn Shafts, fittings, bushings, pins Concentricity across operations
Wire and sinker EDM Hard alloys, sharp inside corners, small features Slow cutting, recast layer
Grinding and honing Bearing surfaces, tight bores Heat damage, added cost
Deburring and finishing Edge condition, corrosion protection Anodizing adds thickness, passivation does not

‍

Setups matter more in aerospace machining than most buyers expect. Each time a part moves to a new fixture, the datum can shift. A 5-axis machine reaches more faces in one clamp, so it removes chances to lose alignment. Design choices cut cost before any chip flies, too: corner radii, pocket depth, and rib thickness set cycle time. Our design capabilities team reviews every drawing before we quote.

Aerospace machining tolerances: what drawings ask for and how shops prove them

In aerospace machining, tolerances come from the engineering drawing, not from what a machine shop prefers to work with. Engineers use GD&T to define the limits for individual features and tolerance stack analysis to work out where tighter control is needed. But meeting a tolerance once isn’t enough. A shop needs to show that it can achieve the same result across repeated production runs. That’s where Cpk comes in. For critical features, we aim for a Cpk of at least 1.33 over repeat runs.

A part's temperature can affect its inspection results. Dimensional measurements use 20 °C as the reference, but a part that's still warm may have expanded enough to give an inaccurate reading. That's why shops doing aerospace machining usually let parts reach a stable temperature before measuring them.

Feature What makes it hard How shops verify it Held on Wootz.work programs
Overall dimensions Machine accuracy, temperature CMM ±0.005 mm on machined parts
Bore fits Tool wear, heat CMM or bore gauge H7 bore fits, press fits to H7/g6 in assembly
Hole position Fixturing, thermal growth CMM ±0.03 mm on a robot platform plate
Perpendicularity Machining stress warps thin plate CMM 0.03 mm bore perpendicularity on a 20 mm stainless plate
Surface finish Feed rate, tool condition Profilometer Ra down to 0.40 µm on turned brass parts

‍

Several of those figures come from non-aerospace programs. They show the discipline, and your drawing sets the target.

Every step toward a tighter tolerance adds aerospace machining work. A ±0.1 mm feature can leave the mill finished. A ±0.005 mm feature may need a second finishing pass, a grinding operation, a temperature-stable room, and a longer CMM program. Put tight limits where function demands them and nowhere else.

In one program for a European robotics OEM, bore alignment had to stay within 0.2 mm to a common datum over a 490 mm stainless arm, even after welding. The route used turned bar, a pre-milled blank, VMC finishing of the 28H7 holes, laser welding of the child part, and final machining, with a DFM drawing prepared in-house. It is not an aerospace part. It faces the problem a thin aerospace frame faces in aerospace machining, because process heat and clamping force both move the metal.

Want to check finish and tolerances yourself? Order a free sample box.

Aerospace machining certifications: AS9100D, AS9102 and Nadcap

Aerospace machining certifications answer a different question than tolerances do. Tolerances describe the part. Certifications describe the system that makes the part.

Credential Covers What it tells you What it leaves out
ISO 9001:2015 General quality management system The shop controls its processes No aerospace-specific controls
AS9100D ISO 9001 plus aviation, space and defense requirements The quality system meets aerospace machining expectations Does not approve a given part or special process
AS9102 First article inspection reporting Part-level evidence from the first production run Says nothing about the shop’s wider system
Nadcap Special processes such as heat treating, NDT, chemical processing, welding The process passed an industry audit Not a quality system certificate
ITAR registration Handling of US defense articles and technical data Legal standing for controlled work Says nothing about part quality

‍

AS9100D versus ISO 9001

AS9100D contains the ISO 9001:2015 requirements and adds aviation, space and defense requirements on top, according to SAE International. Its text also states that its requirements complement customer and regulatory requirements, and the latter win when they conflict. A shop can hold ISO 9001 and still fall short of what an aerospace machining buyer expects.

Wootz.work holds ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018, with NABCB-accredited certificates. Many aerospace machining buyers also ask for AS9100D at the facility that holds the machines. Treat that as a supplier-selection question, and ask for the certificate of the exact site. Our quality assurance and transparency page shows how we document every stage.

First article inspection under AS9102 in aerospace machining

AS9102 describes three forms. Form 1 identifies the part number. Form 2 records materials, special processes, and functional tests. Form 3 lists every drawing characteristic with its measured result, matched to numbered balloons on the drawing. The report covers a representative part from the first production run of a new part, and your contract says when to repeat it. Wootz.work ships FAI packages aligned to the AS9102 format, with CMM reports that compare actual values to nominal.

Nadcap and special processes in aerospace machining

In aerospace machining, special processes change a part in ways you cannot check by eye: heat treating, chemical processing, nondestructive testing, and welding. The Performance Review Institute runs Nadcap, and prime contractors sit on its committees (Boeing supplier FAQ). Many primes ask that these steps happen at accredited sources. The machine shop may not do them in-house, so ask where the part goes after machining.

Aerospace machining traceability: mill certs and heat numbers

Each shipment should carry a mill test report with the heat number, a dimensional report from the CMM and any compliance declarations the program needs, such as RoHS and REACH. Weld records join the package when the part has welds. The heat number on the report must match the heat number on the traveler. That one match prevents the rejection in the opening of this guide.

What drives the cost and lead time of aerospace machining?

Five factors set the price and the schedule of aerospace machining.

  • Material. Titanium and nickel alloys cost more to buy and take longer to cut.
  • Setups. Fewer clamps mean fewer chances for error and less labor.
  • Tolerance and inspection. Tight features add operations and CMM time.
  • Special-process queues. Heat treating, coating, and NDT often wait in line outside the machine shop.
  • Documentation level. A full first article package takes engineer hours.

Buyers who send an aerospace machining drawing with an alloy, a quantity, and a list of required certificates get a faster, more accurate quote. Wootz.work costs every part from first principles, including each operation and process time, and returns a first quote in under 24 hours. Send your drawing to see it.

Can you source aerospace machining offshore?

Sometimes. Offshore aerospace machining depends on the part, the contract, and the data attached to the drawing.

Where offshore aerospace machining fits

Commercial and aftermarket parts that carry no export control fit offshore aerospace machining well: brackets, housings, fittings, tooling and fixtures. Prototypes with flexible dates fit, and so do programs that need a second source. India and Southeast Asia offer engineering talent and cost advantage. Our global doorstep delivery page covers DAP and DDP shipping, and our IP protection page explains how supplier ecosystems stay controlled.

Where offshore aerospace machining does not fit

Some aerospace jobs are better kept closer to home. For example:

  • You're working with parts or drawings covered by the US Munitions List.
  • Your contract includes domestic-content or specialty-metal requirements.
  • You need a single part quickly and can't risk a delay.
  • Programs where the customer’s approved-source list excludes your supplier

What ITAR means for offshore work

The State Department’s Directorate of Defense Trade Controls administers ITAR, and the US Munitions List sits in section 121.1 of the regulation. Sending technical data for a listed defense article to a foreign person needs authorization. Disclosure counts as an export even when it happens inside the United States (University of Pittsburgh trade compliance). If your drawing might fall on the list, ask your export-compliance officer before any file leaves your network. Items off the list can still fall under the Export Administration Regulations. This is general information, not legal advice.

Qualification for aerospace machining takes time too. A new supplier often needs six to twelve months to clear an aerospace approval process, and your own procedure sets the real number.

How to vet a supplier for custom aerospace machining

Custom aerospace machining means parts built to your drawing, so the vetting questions come from your drawing. Ask these eight aerospace machining questions:

  1. Which certificates does the exact site with the machines hold, and when do they expire? Check the registrar’s database, such as OASIS for AS9100.
  2. Ask the shop about the alloys and tempers they've machined in the last 12 months. It's worth looking at a few actual parts they've produced.
  3. Find out how they maintain datum positions when a job requires more than one setup, especially how they hold thin-walled parts without bending them.
  4. What inspection equipment will they use to check your part's dimensions, and when was it last calibrated?
  5. How does the system tie the heat number to each part?
  6. Which special processes go to outside vendors, and which of them hold Nadcap accreditation?
  7. How does the shop notify you about a change in process, tooling, or material?
  8. Can it show a completed first article package in AS9102 format?

For a deeper approach to supplier checks, read our guide to factory audits in manufacturing.

How Wootz.work runs aerospace machining programs

Wootz.work handles manufacturing orders for OEMs, brands, and distributors, including companies that need aerospace machining services. We work with more than 400 suppliers across India and Southeast Asia rather than running our own factories. The actual machining takes place at qualified partner facilities, while our team manages the engineering, quality checks, and oversight of the work. We select partners based on their machining capabilities, quality systems, ability to trace materials, and compliance with export requirements.

When an aerospace machining inquiry comes in, we start by reviewing the drawing to see how the part can be manufactured. This DFM review is done before quoting, and we don't charge for it with the first quote. From there, we look at what the part needs and assign it to a suitable machine within our partner network, regardless of which factory is closest. We also track the drawing requirements as the job moves through production, recording checks at every stage. If something doesn't look right, the system can flag it before the part is shipped. The order includes mill test reports with heat numbers, CMM reports, and AS9102-aligned FAI packages.

Our network has delivered 60M+ parts and assemblies to 30+ global customers, with a 98%+ on-time delivery rate. Industries on our customer list include aerospace, defense, automotive, and robotics, and our aerospace machining work follows the same controls. For export-controlled programs, tell us early, and we will say plainly whether the work belongs in our network.

Choosing an aerospace machining partner

Good aerospace machining starts with an alloy the shop knows, a tolerance it can hold repeatedly, and a paper trail that survives an audit. Match each aerospace machining requirement on your drawing to a shop that can prove it, and treat export control as a gate you pass before the first file moves. If you want a partner that handles engineering, quality, and delivery under one contract, talk to us.

Send us your drawing. Your first quote comes with a free DFM review. Contact Wootz.work

FAQs

What tolerances does aerospace machining hold?

In aerospace machining, the drawing tells you how much variation is allowed for each feature. Some critical dimensions need to be held within just a few hundredths of a millimeter, sometimes even less. The Wootz.work network can machine parts to tolerances of ±0.005 mm. A CMM report shows whether the finished part meets those limits, while a Cpk study helps check if the same accuracy can be maintained throughout production.

Is AS9100 required for aerospace machining?

No law requires it for aerospace machining. Customer contracts and prime contractors do. AS9100D builds on ISO 9001 and adds aerospace requirements, so many buyers list it as a condition of approval. Read your purchase order and flow-down clauses to see which certificates apply, and ask for the certificate of the exact facility that will cut your parts.

Why is titanium machining slower than aluminum?

Titanium takes longer to machine because it doesn’t carry heat away very well. During aerospace machining, much of that heat stays near the cutting edge, causing the tool to wear faster. The metal can also harden if the tool rubs against it instead of cutting properly. To manage this, machinists use slower cutting speeds, sharp tools and plenty of coolant. Aluminum is easier to work with because more heat leaves with the chips, allowing it to be cut several times faster.

What is an AS9102 first article inspection?

An AS9102 first article inspection checks whether a shop can manufacture a new part according to its drawing and requirements. For aerospace machining work, the report has three forms. The first identifies the part, the second covers materials and special processes, and the third records the measured characteristics. The inspection is carried out on a representative part from the first production run. The contract determines when another inspection is needed.

Can aerospace parts be machined offshore?

Many non-controlled parts can go through offshore aerospace machining. Parts and technical data on the US Munitions List need State Department authorization before a foreign person sees them, and some contracts bar foreign sources. Check with your export-compliance officer first. Then match the part to a supplier that holds the certificates your program requires.

How do I get a quote for custom aerospace machining?

For custom aerospace machining, send the drawing, the material and temper, the quantity, and the list of required certificates. We review the drawing for manufacturability and return a first-principles quote in under 24 hours. List any special processes, finish callouts and documentation needs up front so the quote covers them.

‍