Extra-low-interstitial titanium is specified here for fatigue life inside the body, not for machinability — it work-hardens quickly, so every pass has to actually remove material rather than rub the surface, or the next pass is cutting a harder skin than the one before it. Thread milling instead of tapping means the internal thread can be probed the same way as every other feature on the part, rather than trusted to the tap’s own geometry.
Part
Orthopedic Bone Screw
A cannulated fixation screw turned from titanium bar, thread-milled rather than tapped so the thread form is verifiable feature by feature on the CMM.
Part
Orthopedic Bone Screw
Rev
Rev B
Year
2025
Material
Ti-6Al-4V ELI
Tightest tolerance
±0.005mm (5 µm) major diameter
Lot
500-off, per lot
Lead time
21 days
Route sheet
How this part actually got made.
| Op | Stage | Machine | Tool | Result |
|---|---|---|---|---|
| 01 | Stock | Material stores | — | Saw-cut billet, certificate matched to the traveler. |
| 02 | Turn | Okuma LB3000, 2-axis CNC lathe | CNMG 432 insert, 0.4mm nose radius | Ra ≈ 1.13 µm |
| 03 | Thread mill | Haas VF-2, 3-axis vertical mill | M6x1.0 single-point thread mill | — |
| 04 | Heat treat | Outside process — subcontracted | — | Certificate returned with the lot; hardness re-verified on receipt. |
| 05 | Inspect | Zeiss Contura CMM | — | First-article report against the drawing's GD&T callouts. |
Finish
Specified surface finish.
What the drawing calls out — verified on receipt with a profilometer, not assumed from the tool that made it.
Ra0.40 µm