Alloy Titanium CNC Machining: Grades, Cuts, and Supplier Checks

Commercially pure grades TA1 and TA2 are the easiest titanium to cut. They are soft, formable, and used for chemical parts, brackets, and any place where corrosion resistance matters more than strength. Cutting speeds sit higher than for Ti-6Al-4V, but the material still galls on the tool, so sharp edges and a steady feed are not optional.

TC4, also called Ti-6Al-4V or Grade 5, is the alloy most drawings specify. It roughly doubles the yield strength of pure titanium and keeps it up to about 400 °C, which is why it shows up in airframe fittings, surgical instruments, and motorsport suspension. The trade-off is machinability. Expect cutting speeds around one third to one half of what you would use on 316 stainless, and expect tool life measured in minutes rather than hours on roughing passes.

We also run titanium in mixed-material assemblies where a titanium body meets an Inconel or stainless insert. That combination is common in aerospace and energy hardware. It needs separate tooling and separate fixturing plans, because the two materials do not share a workable surface speed.

If your part is a thin plate with a handful of holes, titanium is usually the wrong answer. Aluminum or 17-4PH stainless will cost less and machine faster. Titanium earns its place when weight, corrosion, or temperature rules out those options.

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  TA1 / TA2Pure grades, best machinability, for corrosion and chemical service.
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  TC4 (Ti-6Al-4V)The workhorse alloy. High strength, narrow cutting window, tool wear is the main cost driver.
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  Not for every partIf aluminum or stainless meets the spec, use it instead.

Titanium has low thermal conductivity, roughly a tenth of aluminum. Heat generated at the cutting edge has nowhere to go. It stays in the tool tip and the workpiece instead of leaving with the chip. Tool edges soften, wear accelerates, and the part surface can work-harden under a dull insert.

The material is also chemically reactive at cutting temperatures. Titanium tends to weld onto the tool edge, a condition called galling. Once a built-up edge forms, it breaks off and takes tool coating with it, so the next pass cuts with a damaged edge. This is why we run high-pressure coolant through the spindle and change inserts on a count rather than on a visual check.

Elastic modulus is low compared with steel, about half. A slender titanium rib or a thin wall deflects away from the cutter, then springs back. The result is chatter, poor finish, and a dimension that drifts. Fixturing and pass strategy solve most of this, not a change in feeds and speeds.

None of these problems is exotic. They are predictable, and a shop that runs titanium weekly plans for them before the first cut.

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  Heat stays in the cutLow conductivity concentrates temperature at the edge. Flood coolant or it wears fast.
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  GallingTitanium welds to the tool. Sharp edges, positive rake, and fresh inserts.
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  DeflectionLow modulus means thin walls move. Support the part, take lighter passes.

Workholding decides whether a titanium job succeeds. We prefer to hold on a thick sacrificial pad and machine the part in one five-axis setup where the geometry allows it, because every re-clamp risks a shift that you cannot inspect away. For thin ribs, we leave stock and remove it in a finishing pass with the part still supported by the parent material.

Tooling follows a simple rule: sharp, coated, and rigid. Solid carbide end mills with an AlTiN or AlCrN coating cover most work. Positive rake geometry keeps cutting forces down and reduces the tendency to rub. We avoid long reach tools unless the geometry forces it, and when it does, we reduce radial engagement and accept a slower cycle.

On speeds and feeds, the numbers matter less than the method. Radial engagement and feed per tooth control heat more than surface speed alone. A shallow radial cut with a full feed per tooth keeps the edge in the cut briefly and throws heat out with the chip. Deep radial engagement at low feed rubs the material and kills the insert.

Coolant selection follows the same logic. High-pressure through-spindle coolant, usually 50–70 bar, breaks the chip and reaches the cutting zone on deep pockets. On finishing passes where surface finish is the priority, we sometimes run a different strategy with lighter cuts and more passes to keep the tool cool and the finish consistent.

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  Single setupFive-axis access reduces re-clamping error on complex parts.
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  Leave stock for finishingThin walls stay supported until the last pass.
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  Shallow radial, full feedKeeps heat in the chip instead of the tool.

Ask what titanium grades they ran last month. A shop that machines aluminum all day can produce a titanium part, but the first article usually shows it: burned edges, chatter marks, or a finish that needs hand rework. Experience with the alloy shows up in cycle time and in how quickly they flag a geometry problem.

Look at the coolant system, not the machine brand. Through-spindle high-pressure coolant is the single most important capability for titanium. If a supplier cannot describe coolant pressure and chip evacuation, the process plan is thin.

Ask about tool life management. Titanium inserts wear predictably, and a shop tracking insert changes per part will hold tolerance across a 500-piece run. A shop changing tools when they look dull will not.

Finally, confirm the documentation trail. For aerospace, medical, and automotive work, you need material certificates, inspection reports, and a traceable route from raw stock to finished part. We hold ISO 9001:2015, IATF 16949:2016, ISO 13485:2016, and ISO 27001:2022, and issue inspection reports on request. Medical and aerospace programs also run under NDA when the drawing is customer-owned.

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  Recent titanium workAsk for the grades and part types from the last 30 days.
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  Coolant pressureHigh-pressure through-spindle is the baseline, not a bonus.
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  Tool life trackingPredictable insert changes keep long runs in tolerance.

Titanium part cost is dominated by cycle time and tool consumption, not by the raw bar. A geometry that needs many small tools, deep pockets, or long reach will cost multiples of a simple plate with the same envelope. If a design can be reworked to open up pocket corners and reduce depth-to-diameter ratios, the saving is often larger than any quote negotiation.

Raw material lead time also matters. Ti-6Al-4V bar and plate are stocked in common sizes, but large plate and near-net forgings can add weeks. Sending the drawing early, before the material is committed, lets us check stock and propose an alternative size.

We do not claim titanium is always the right answer. For a bracket that sees room temperature and no chlorides, aluminum does the job at a fraction of the cost. For a part that needs stiffness rather than strength, steel may be cheaper and easier to hold. Titanium pays off when weight, corrosion, or elevated temperature are real constraints in the application.

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  Design for the toolOpen corners and shorter reaches cut cycle time fast.
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  Material lead timeCommon bar sizes are stocked; large plate and forgings are not.
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  Wrong material testNo weight, corrosion, or heat requirement means titanium is likely overkill.