(Straight-Talk Q&A for Buyers Who Sign POs)
Q1: We’re holding ±0.005 mm on a part with pockets, threads, and a keyed bore. Can a lathe carry the whole job?
A: Not without help.
A lathe owns round-bar stock—perfect for shafts, sleeves, or flanges. Add live tooling, and you pick up cross-holes or milled flats. However, the moment you need angled pockets or multi-axis contours, the part must travel to a mill.
Real-world snag: Every transfer means new fixtures, new zero points, and a fresh chance for concentricity drift. One high-mix aerospace shop we know scrapped 14 % of turned-then-milled housings until they switched to single-setup mill-turn.
Q2: Our current vendor quotes 5 weeks. We need 10,000 pcs in 2 weeks. Process choice or just fantasy?
A: Process choice.
|
Route |
Setups |
Cycle (Ø45 mm valve body) |
First pallet out |
|
Lathe → mill → bench |
4 |
9 min + 11 min + deburr |
18 days |
|
Mill-turn center |
1 |
16 min |
9 days |
How it works: One chuck grip, one program, one inspection sheet. The same shop above cut lead time from 38 days to 11 calendar days after investing in two new Doosan Puma MX machines.
Q3: Material cost is 42 % of our landed price. Where do the chips really go?
A: Mostly to the bin on pure turning jobs.
• Bar-to-part on lathe: 60–70 % buy-to-fly for complex rotors.
• Forging + 5-axis mill: 88–94 % buy-to-fly.
Field example: A 17-4 PH impeller dropped from 1.9 kg blank to 0.58 kg finished—same strength, 69 % less swarf, $18 saved per unit.
Q4: Surface finish keeps bouncing between Ra 0.5 and 0.7. We spec Ra 0.4 max. What actually delivers?
A: Controlled chipload + spindle stiffness.
|
Variable |
Typical Lathe |
High-End Mill |
|
Runout |
3–5 μm |
0.8 μm |
|
Chipload swing |
300 % in grooves |
< 8 % trochoidal |
|
In-cycle finish pass |
Hard to index |
0.1 mm step-over, 12 krpm |
Result: Mills hit Ra 0.25 in 316L without hand polishing; lathes rarely break Ra 0.45 on interrupted cuts.
Q5: My boss wants one supplier, one PO, one throat to choke. Possible?
A: Yes—if the shop lives on mill-turn platforms.
What we run at Simituo:
• 12 x Okuma Multus & DMG CTX (Ø600 mm x 1500 mm swing)
• Night-shift CAM team writes single-operation G-code while you sleep
• First article in 4 working days, full PPAP in 9
Ready to shave weeks, kilos, and headaches?
Submit your RFQ at www.simituo.com—quotes will be returned within 4 hours.