Titanium CNC Machining Services

• 1
  Key takeaways
• 2
  What to check before you send a titanium RFQ
• 3
  Why titanium CNC machining services behave differently from steel
• 4
  Grade and condition decide the cutting parameters
• 5
  Tolerance, surface finish and what they cost
• 6
  Certifications, confidentiality and the questions behind them
• 7
  Machine capability, part size and volume fit
• 8
  Reading the quotation and the lead time
• 9
  Step by step: how to screen a titanium supplier

Titanium has roughly one-seventh the thermal conductivity of steel. Heat from the cut does not leave through the chip, so it sits at the cutting edge. Edge temperature climbs, the tool dulls faster, and the dull edge rubs instead of shearing. That rubbing is what work hardens the surface, and the hardened layer is often harder than the cutter.

The second problem is stiffness. Titanium's modulus is about half that of steel, so a wall that would be rigid in 4140 will deflect in TC4. A 2 mm wall at 20 mm height can push away from the cutter, then spring back and cut oversize. You see this as taper or a wall that measures differently along its length.

Chip evacuation makes it worse. Titanium chips are thin, springy and tend to weld to the flute under heat. Once a chip welds, the next chip packs against it and the edge breaks down. Through-tool coolant at high pressure clears the flute and removes heat at the same time. Flood coolant alone often is not enough on deep pockets.

None of this makes titanium unmachinable. It makes the process less forgiving. A shop that cuts aluminium all day can quote titanium and still miss the tolerance, because the failure mode is different, not just the cutting speed.

• 1
  Heat goes into the toolOne-seventh the conductivity of steel means edge temperature is the limiting factor.
• 2
  Half the stiffnessThin walls deflect, spring back and finish oversize.
• 3
  Chips weld under heatHigh-pressure through-tool coolant is a process requirement, not an upgrade.

Commercially pure grades TA1 and TA2 have lower strength and cut closer to a 316 stainless job. Surface speeds stay moderate, tool life is reasonable, and the main risk is galling on the finished face rather than tool failure. If your part is a bracket or a spacer and corrosion resistance is the only requirement, these grades keep the cost down.

TC4, also written Ti-6Al-4V, is the grade most drawings specify. It responds to heat treatment, so the condition you buy changes the cut. Annealed stock machines predictably. Solution-treated and aged stock is stronger and less ductile, which shortens tool life and raises the risk of edge chipping on interrupted cuts.

The trap is specifying TC4 for a part that carries no load. You pay for the grade, the tooling and the slower cycle without using the strength. If the design allows TA2, say so on the drawing. If it does not, say which features need the strength, because the shop can then use different parameters on different faces of the same part.

Wall thickness sets the practical limit. Features below 1 mm in TC4 are possible, but they need light finishing passes and often a stress-relief step between roughing and finishing. Ask for that step explicitly. A shop that roughs and finishes in one continuous pass will hold the nominal dimension and lose the flatness.

• 1
  TA2 for corrosion-only partsCuts closer to stainless and costs less per part.
• 2
  TC4 condition mattersAnnealed is predictable; aged stock chips edges on interrupted cuts.
• 3
  Sub-1 mm wallsNeed light finishing passes and often a stress-relief step.

A ±0.005 mm tolerance on a titanium feature is achievable, but it is not a blanket number you apply to the whole drawing. It belongs on the two or three features that touch a mating part. Every additional tight callout adds inspection time, and inspection is often a larger share of a titanium job than the machining.

Surface finish follows the same logic. An as-machined face at Ra 1.6–3.2 μm is where most titanium parts sit, and that is what a standard cycle produces. Pushing to Ra 0.8–1.6 μm needs a separate finishing pass with a fresh edge. Ra 0.2–0.8 μm on titanium is a polishing operation, not a turning operation, and it should be quoted as such.

Beware of drawings that call out a tight finish on a face that will be painted, anodized or bonded. Anodizing adds a layer that changes the measured finish, and bonding responds to surface energy more than to roughness number. Specify the finish you need for function, not the tightest value you have seen used elsewhere.

The practical rule: mark critical dimensions and finish callouts, leave the rest at general tolerance. A drawing with forty tight callouts on a titanium part will be quoted high by every shop, and the quotes will not tell you which callouts drove the price.

• 1
  Tight tolerance is per featureApply ±0.005 mm where it mates, not across the whole drawing.
• 2
  Ra 0.8–1.6 μm needs a passA separate finishing cut with a fresh edge.
• 3
  Coating changes the readingAnodizing shifts the measured finish; specify for function.

ISO 9001:2015 covers the quality system. IATF 16949:2016 applies if your part ends up in a vehicle program. ISO 13485:2016 applies if it touches a medical device, and the audit trail requirements there are stricter than general machining. ISO 27001:2022 covers information security, which matters when you send drawings that are not public.

Certificates are a starting filter, not a proof of capability. Two shops can both hold ISO 9001 and produce very different titanium parts. The certificate tells you the shop has documented processes. It does not tell you whether the machinist running your job has cut TC4 before.

Ask how inspection data is recorded. A conformance certificate states that parts meet the drawing. A CMM report with datum callouts and the actual measured values tells you where the part sits inside tolerance. For titanium, where the cut pushes the part around, that difference matters on a first article.

Confidentiality works the same way. An NDA is available on request, and uploads are handled as confidential by default. If your drawing carries export-controlled geometry or a customer name, say so before you upload, because the handling rules change.

• 1
  Match the certificate to the marketIATF 16949 for automotive, ISO 13485 for medical.
• 2
  Certificate filters, data provesAsk for measured values, not just conformance.
• 3
  NDA on requestFlag controlled geometry before uploading files.

Titanium rewards rigidity, so the machine matters. Simultaneous 5-axis centers cut compound angles in one setup and avoid the re-fixturing that introduces position error. Mill-turn centers handle a turned body with milled features without a second operation. For a part with four sides of work, one 5-axis setup is usually cheaper than four vise setups, even at a higher hourly rate.

Size range sets the shortlist. GreatLight runs 127 high-precision CNC machines across three plants, including 16 simultaneous 5-axis centers, 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers. Maximum processing size is 4,000 mm, with travels at 4,000 × 400 × 150 mm, 750 × 1,150 × 550 mm, 600 × 600 × 600 mm, 500 × 500 × 450 mm and 500 × 310 × 200 mm, plus a Ø400 mm rotary table.

Volume fit is the other filter. Titanium jobs often start as one prototype and turn into a production run after testing. A shop with a minimum order quantity forces you to buy parts you have not validated. No minimum order quantity here, from one prototype to 10,000+ part runs, keeps the same process on both ends.

Ask what changes between the prototype and the production run. If the answer is nothing except batch size, the process is stable. If the answer is a new fixture, a new machine or a new supplier for the material, treat the prototype result as provisional.

• 1
  One 5-axis setup beats four vise setupsFewer fixturings means less position error on titanium.
• 2
  Size range narrows the listUp to 4,000 mm, with a Ø400 mm rotary table for round work.
• 3
  No MOQ keeps validation cheapOne piece or 10,000+, same process.

A titanium quotation that arrives as one number tells you nothing. Ask for the split: material, programming, fixturing, cycle time, finishing and inspection. The split lets you compare two shops on the same basis and shows which line item is driving the price. If a shop will not break it down, that is an answer too.

Material is usually the largest single line. Titanium stock is priced by grade and by certification. If the quote does not name the grade and the mill certification, you cannot tell whether the shop is buying TA2 or TC4 on your behalf.

Lead time should be stated as a start date, not a duration. A shop that can start production within 24 hours of drawing release has capacity and a prepared process. A quote of three to five days for parts is normal for this class of work, and a historical late-delivery probability below 2% is the kind of number worth asking about.

Watch for the hidden queue. Some quotes are fast because the shop does not actually cut titanium and plans to subcontract. Ask directly whether the machining happens in-house. If it does not, your tolerance and your lead time now depend on a supplier you never vetted.

• 1
  Ask for the cost splitMaterial, programming, fixturing, cycle time, finishing, inspection.
• 2
  Name the grade on the quoteGrade and mill certification should be written down.
• 3
  Start date beats durationProduction start within 24 hours signals a ready process.