Wind turbine flanges, shafts and hubs: large-format lathe or double column machining centre?
It depends on the geometry: rotor shafts and flanges that fit within the swing go on a large-format CNC lathe, while hubs, housings and other non-rotational parts go on a double column machining centre. The Vurcon PL140/5000 swings Ø1,440 mm over bed with 5,000 mm between centres and 30 kW, and the PL180/8000 reaches Ø1,850 mm, 8,000 mm and 37 kW; the DC1020 and DC1330 double column centres travel 2,050 to 3,100 mm in X with a BT50 taper. Many flanges use both: turned on the lathe, bolt circle drilled on the double column — or everything on the lathe if it has live tooling.
The quick rule: does the part rotate or sit?
The first question is not size but how the geometry is generated. If almost every surface is a diameter, a face square to the axis, a taper or a thread, it is a lathe part. If it has flat faces in several orientations, off-centre bores and holes that do not follow a rotation axis, it is a machining centre part.
- Rotor and main shafts: lathe, between centres. Bearing seats, tapers and threads in one set-up with good concentricity.
- Flanges: lathe for facing and turning diameters; the bolt circle on the same lathe with live tooling, or on the double column.
- Slewing rings: raceways and faces on the lathe; drilling and tapping wherever it is most cost-effective.
- Hubs: castings with blade faces and bores in several orientations; double column, in few set-ups.
- Turbine and gearbox housings: facing joint planes and boring bearing housings; double column.
When the large-format lathe is the answer
For shafts and flanges that fit the machine, the lathe is faster and gives better concentricity, because every rotational surface comes from the same spindle. Check three figures:
- Swing over carriage, not just over bed: Ø920 mm on the PL140/5000 and Ø1,340 mm on the PL180/8000. That is what really limits the diameter you can turn.
- Distance between centres longer than your longest shaft, with tailstock and, if needed, steady rest: 5,000 or 8,000 mm.
- Low-speed torque for forgings with uneven stock: the PL140/5000 runs from 12 to 600 rpm with 30 kW; the PL180/8000 has 37 kW.
Check weight too: the PL series takes up to 15 t between centres and 20 t in reinforced versions. And if the shaft has keyways or radial holes, the Y-axis on the PL140/5000 or the optional driven turret on the PL180/8000 saves unloading it.
When the double column centre pays off
The double column wins when the part is not rotational, or when milling and drilling outweigh turning. Its gantry structure with a BT50 taper gives the rigidity to rough cast iron and steel, and the table takes bulky parts.
- DC1020: 2,050 × 1,100 × 600 mm travel, BT50, 6,000 rpm and 15/18.5 kW. In stock in Spain.
- DC1330: 3,100 × 1,400 × 800 mm, with the same spindle.
On a hub, the figure people forget is Z: vertical travel has to cover the clamped part height plus tool and holder. On housings, measure the largest face you need to mill and compare it with X and Y.
Typical mistakes
- Trying to do everything on one machine. A lathe with live tooling can drill a bolt circle, but it does not replace a double column on a cast hub.
- Choosing on swing over bed without looking at swing over carriage.
- Checking only X and Y on the machining centre and running short in Z.
- Leaving transport and foundations to the end — on machines this size they need planning well ahead.
Part-by-part comparison
| Part | Main machine | Deciding figure |
|---|---|---|
| Rotor shaft | PL140/5000 or PL180/8000 | Distance between centres: 5,000 or 8,000 mm |
| Flange | Large-format lathe, plus double column for holes | Swing over carriage: Ø920 or Ø1,340 mm |
| Slewing ring | Large-format lathe | Swing and driven turret |
| Hub | DC1020 or DC1330 | Z travel: 600 or 800 mm |
| Gearbox housing | DC1020 or DC1330 | X and Y travel: up to 3,100 × 1,400 mm |
Frequently asked questions
Can I drill a flange bolt circle on the lathe?
Yes, with live tooling and a C-axis: the PL140/5000 has a 4-station turret with Y-axis and the PL180/8000 takes a driven turret. If the flange has a lot of tapped holes, it usually pays to move it to the double column.
What if the flange is larger than the lathe's swing?
Flanges and rings above Ø1,850 mm are handled as a bespoke project: the large-format range goes up to Ø3,150 mm swing in the RT series. Send us the drawing and we will propose a configuration.
Are wind-sector machines in stock?
Yes: the PL140/5000 lathe and the DC1020 double column centre are in stock in Spain. The PL180/8000 and DC1330 are configured to your part.
If you have shafts, flanges or hubs to machine, send us diameter, length, weight, material and operations for your largest part. We will propose a lathe, a double column or both, with installation and commissioning, training, service and spare parts within Grupo Ferrotall. Find out more on our energy and wind page, in large-format lathes and double column machining centres, or reach us through our contact page.