Why titanium is special
- Strength-to-weight: tensile strength ~900 MPa at 4.43 g/cm³ - stronger than 6061 aluminum at nearly half the density of steel
- Corrosion resistance: nearly immune to atmospheric and seawater corrosion
- Biocompatibility: Grade 23 (ELI) is implant-safe
- Temperature resistance: maintains strength to ~600°C
Why titanium machines slowly
- Poor thermal conductivity. Heat stays in the cutting edge instead of flowing into the chip. The tool tip runs hot and wears fast.
- High strength at temperature. Titanium does not soften when heated, so the tool is cutting strong material at high temperature.
- Work hardening. The surface hardens under the cutting edge, so the next pass cuts hardened material.
What this means for cost
|
Factor |
Aluminum 6061 |
Titanium Ti-6Al-4V |
|
Stock price per kg |
$5–7 |
$80–120 |
|
Machinability speed |
1x |
0.25–0.33x |
|
Tool wear rate |
Low |
3–5x higher |
|
Hourly rate surcharge |
Baseline |
1.3–1.5x |
|
Typical part cost ratio |
1x |
10–15x |
A 6061 bracket that costs \(50 at prototype might cost \)500–800 in titanium. That is not the shop being greedy - it is physics.
Design tips for titanium parts
Use conservative corner radii
Titanium tools deflect. Sharp internal corners require tiny tools that break. Design internal pocket corners at R1.5–R3 mm minimum.
Avoid thin walls
Titanium work-hardens and deflects. Walls below 1.5 mm chatter and deform. If you need thin walls, tell the shop - they will plan low-speed, light-cut strategies.
Use standard drill depths
Keep holes at 3–4× diameter. Deep holes in titanium are especially hard on tools.
Tolerance only the critical features
Tight tolerances in titanium cost more because cuts are slower. Apply ±0.005 mm only on bearing bores and mating faces.
Consider near-net shapes
For higher volumes, investment cast a near-net titanium shape and CNC machine only the critical faces. This cuts machining time (and cost) dramatically.
Where titanium is the right choice
- Humanoid robot wrist adapters and high-load finger bases
- Medical surgical instruments and implant components
- Aerospace structural brackets and engine mounts
- Marine hardware and underwater equipment
- High-performance sports equipment
Tolerance and surface finish
Titanium holds excellent tolerances when machined properly:
- Standard: ±0.01–0.025 mm
- Precision: ±0.005 mm on critical bores
- Surface finish: Ra 0.8–1.6 μm as-machined, better with grinding
Titanium anodizes (colorful, decorative) but the oxide is not as wear-resistant as hard anodize on aluminum. For wear surfaces, specify ground finish or DLC coating.
Lead time
Titanium parts take 10–15 working days for prototypes vs. 7–10 for aluminum, because feeds are conservative and inspection is careful.
FAQ
Q: Why is titanium so expensive to machine?
A: Three factors: expensive stock ($80–120/kg), slow feeds (1/3 of aluminum), and rapid tool wear. Combined, a titanium part costs 10–15× the equivalent aluminum part.
Q: When should I choose titanium over aluminum?
A: When strength-to-weight is critical, the part sees high cyclic loads, or it needs corrosion/biocompatibility. For brackets and covers, 7075-T6 is usually sufficient.
Q: Can you hold ±0.005 mm in titanium?
A: Yes. We routinely hold ±0.005 mm on bearing bores, with grinding for H5/H6 fits.
Q: Is titanium 3D printed better than CNC for titanium parts?
A: For very complex geometries with internal channels, metal 3D printing (SLM) wins. For structural parts with tight tolerances, CNC from forged billet is stronger and more repeatable.
Q: What is Grade 23 titanium?
A: Ti-6Al-4V ELI (Extra Low Interstitial) - purer, more ductile, used for medical implants. It machines similarly to Grade 5.
Send us your titanium part. We will quote realistically, flag features that will drive cost, and suggest design changes where aluminum would meet the load case. Contact Bella at yaqingliang277@gmail.com or WhatsApp 8614775540498.
