01
Holes drift out of tolerance
This alloy sits between 30 and 34 HRC. A drill that has already cut a few hundred holes wanders. Hole positions move 0.03 mm, dowel pins will not press in, and the whole batch needs rework or scrap.
Titanium Alloy Machining
Grade 6Al 4V ELI CNC Machining (Grade 23)
Machining of UNS R56401 titanium for medical, aerospace and subsea parts. 16 simultaneous 5-axis centers hold ±0.005 mm and Ra 0.2–0.8 μm on thin walls, deep pockets and long bores.
±0.005 mmRa 0.2–0.8 μm16 five-axis centersNo MOQISO 134853–5 day shipping
±0.005 mmAchievable tolerance on critical features
16Simultaneous 5-axis machining centers
99.99%Qualification rate across shipped parts
12 hQuote and free DFM analysis turnaround
Common problems
Where Titanium ELI Parts Go Wrong
Four failures we see quoted every week.
02
Thin walls spring back
A 0.8 mm medical housing wall cut with a heavy radial pass deflects under cutting load. It measures fine off the machine, then relaxes 0.05 mm after the fixture is released. Assembly finds it later.
03
Surface finish fails a spec callout
A Ra 0.4 μm seal face comes off the machine at Ra 1.2 μm because the finishing pass ran too fast. The part is dimensionally correct and still rejected. Polishing by hand adds days and risks the edge geometry.
04
Certificates do not match the lot
ELI grade is bought for its oxygen and iron limits. If the mill certificate is not traced to the bar that was actually cut, the finished implant or flight part has no paper trail, and the customer rejects it at receiving.
How we machine it
Cutting ELI Titanium Without Losing the Tolerance
Rigid setups, low cutting temperatures, and inspection that happens during the run, not after it.
Setup and strategy
Fixtures that hold the part still
Titanium moves when you cut it. We plan the fixture before the toolpath: soft jaws machined in place, vacuum plates for thin plates, and sacrificial tabs on parts that would otherwise lift. For long bores we use a Ø400 mm rotary table so the part is repositioned, not re-clamped.
Roughing runs at lower surface speed than aluminum with high-pressure coolant aimed at the cutting edge. That keeps heat in the chip instead of the workpiece. On a typical 5-axis medical housing we leave 0.3 mm for semi-finishing and 0.1 mm for the final pass.
- 1±0.005 mmHeld on bores, bearing seats and mating faces after finishing.
- 2Ra 0.2–0.8 μmAvailable on seal faces and sliding surfaces when called out.
- 34,000 mmMaximum part length on our largest traveling-column machines.
Inspection
Measuring while the spindle is still turning
A final inspection report tells you what went wrong. It does not save the batch. We probe critical features in-process on the 5-axis centers, log the offsets, and correct before the next part is cut. Wall thickness on thin sections gets checked with an ultrasonic gauge between operations.
Every shipment leaves with a full dimensional report when requested, plus material certificates traced to the heat number. Raw material is verified on arrival, monitored during the run, and inspected 100% before packing. That is how the qualification rate stays at 99.99%.
- 1Probing on the machineBore positions and datum faces verified before unclamping.
- 2Traceable paperworkMill certificates matched to the bar actually cut.
- 3Reports on requestDimensional data, material certs and finish measurements.
Selection guide
When ELI Grade Is the Right Call
The extra cost only pays off in specific conditions.
| Condition | Use grade 6Al 4V ELI | Use standard Ti-6Al-4V |
|---|---|---|
| Oxygen content | 0.13% max, better fracture toughness | 0.20% max is acceptable |
| Service temperature | Below –100 °C or cryogenic duty | Room temperature to 350 °C |
| Implant contact | Long-term bone or tissue contact | Fixtures, tooling, non-implant parts |
| Wall thickness | Under 1.5 mm with fatigue load | Thick sections, static loads |
| Cost position | Higher per kg, justified by risk | Lower cost, faster material supply |
| Typical parts | Bone screws, dental abutments, subsea stems | Brackets, housings, jigs |
What we run
CNC Services for UNS R56401 Parts
One shop for the whole part, from bar stock to finished surface.
01
5-Axis Milling
Impeller-like medical housings, angled ports and contoured bone plates cut in one setup. 16 simultaneous 5-axis centers available.
02
CNC Turning
Shafts, bone screws and bushings turned with live tooling for cross holes. Turning and milling in the same cycle reduces setups.
03
3- and 4-Axis Milling
Prismatic parts, plates and brackets. 27 three-axis and 12 four-axis machines handle the simpler geometry at lower cost.
04
Mill-Turn
16 mill-turn centers for parts that need turning, milling and drilling without losing concentricity between operations.
05
Surface Finishing
Bead blasting, tumbling, brushing and polishing. Laser marking with 1.5 mm minimum character height for traceability.
06
Rapid Prototyping
One-off ELI prototypes before tooling is committed. No minimum order quantity, from a single part to 10,000+ runs.
Capability range
Machine Capacity and Tolerances
Figures below are what we commit to, not catalogue maximums.
| Item | Range | Notes |
|---|---|---|
| Tolerance | ±0.005 mm (±0.0002 in) | On critical features after finishing |
| Surface finish | Ra 0.2–0.8 μm | Fine finish on request |
| As-machined finish | Ra 1.6–3.2 μm | Standard milled and turned surfaces |
| Maximum part size | 4,000 mm | Largest traveling-column machines |
| Large travel | 4,000 × 400 × 150 mm | Long, slim titanium parts |
| Medium travel | 750 × 1,150 × 550 mm | General 5-axis work |
| Compact travel | 500 × 500 × 450 mm | Small precision components |
| Rotary table | Ø400 mm | Multi-face work without re-clamping |
Why GreatLight
What You Get With the Quote
Numbers we can point to, not adjectives.
15Y
Machining since 2011
15 years in titanium and stainless, three wholly-owned plants covering 7,600 m² with 150 technicians.
127
High-precision CNC machines
127 machines in total, including 16 simultaneous 5-axis centers and 16 mill-turn centers under one roof.
99.99%
Qualification rate
Raw material check, in-process monitoring and 100% inspection before shipment keep rejections near zero.
12 h
Quote turnaround
Quotation and free DFM analysis within 12 hours. Production can start within 24 hours of approval.
4
Quality certifications
ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022 cover medical, automotive and data handling.
0
Minimum order quantity
No MOQ. One prototype or a 10,000-part run gets the same process control and the same inspection routine.
7,600 m²Manufacturing space across 3 plants
150Technicians on the floor
<2%Historical late-delivery probability
3–5 daysTypical shipping window for machined parts
Industry results
What Different Sectors Require, and What We Deliver
Medical implants
Bone screws and dental abutments in ELI grade. Surface finish on thread flanks and no contamination from tool steel contact.
- Ra 0.2–0.8 μm
- ISO 13485
- 100% inspection
Aerospace brackets
Thin-wall structural parts where weight is cut but fatigue life cannot drop. Wall thickness held to ±0.05 mm over long spans.
- ±0.005 mm
- 5-axis
- Mill certs traced
Subsea and energy
Valve stems and housings that see salt water and pressure cycles. Corrosion resistance comes from the alloy, not a coating.
- UNS R56401
- Up to 4,000 mm
- Passivation on request
Surgical instruments
Handles and mechanisms with fine features that must stay dimensionally stable after repeated autoclave cycles.
- No MOQ
- 3–5 day shipping
- Laser marked
FAQs
Questions Engineers Ask Before Ordering
What is the difference between grade 6Al 4V ELI and standard Ti-6Al-4V?
ELI stands for Extra Low Interstitial. Oxygen is capped at 0.13% instead of 0.20%, and iron and nitrogen limits are tighter. The result is higher fracture toughness and better ductility, which matters at cryogenic temperatures or in cyclic loading.
Mechanically the two alloys machine in a similar way. The difference shows up in the material certificate and in fatigue life, not on the machine tool.
Can you machine thin walls in this alloy without distortion?
Yes, within limits. Walls down to 0.8 mm are routine on small medical parts when the fixture supports the part and the finishing pass takes light radial cuts.
Below 0.5 mm the risk rises quickly. We will tell you at DFM stage if a wall is too thin to hold, rather than quoting it and hoping.
What tolerance can you actually hold on titanium?
±0.005 mm on critical features such as bores, bearing seats and mating faces. That figure applies after finishing, on the machine, with temperature-stable inspection.
General non-critical dimensions are usually held to ±0.05 mm, which keeps the part cost sensible.
Do you provide material certificates?
Yes. We check raw material on arrival and keep the mill certificate matched to the heat number and to the bar that was actually cut.
Certificates ship with the parts when you ask for them, together with dimensional reports.
How do you stop titanium from work hardening during cutting?
Keep the tool moving and never rub. We use sharp carbide with a positive rake, climb milling, and coolant directed at the edge so heat leaves with the chip.
Depth of cut stays above the work-hardened layer left by the previous pass. A light spring pass on hardened material is the fastest way to scrap a part.
What is the minimum order quantity?
There is no minimum. A single prototype and a 10,000-part run go through the same process control and the same inspection routine.
For one-off parts we still run a first-article check before shipping, because a single titanium part is expensive to replace.
How fast can I get parts?
Quotation and free DFM analysis come back within 12 hours. Production can start within 24 hours of approval, and machined parts typically ship in 3–5 days.
That window assumes the drawing is released and no new fixture design is needed. Complex 5-axis work with custom workholding takes longer, and we say so upfront.
Can you handle confidential designs?
Uploads are secure and confidential. We sign an NDA on request before drawings are shared.
ISO 27001:2022 covers how we store and handle customer data.
Send Your ELI Titanium Drawings
Upload the model and tolerances. You get a quote, a DFM note on the risky features, and a machine plan within 12 hours.
12-hour quote100% inspectionNo minimum orderNDA on request
