Voumard 1000
Key Specifications
Max Workpiece ⌀
Accuracy
min bore diameter
max bore diameter
max workpiece length
grinding spindle speed
Overview
The Voumard 1000 is a CNC internal cylindrical grinding machine from Voumard, the United Grinding Group's specialist in internal grinding — the precision grinding of bores, holes, and internal features in hardened components. Internal grinding is the required process for hardened bearing bores, fuel injector nozzles, hydraulic valve bores, and precision spindle housings where the bore diameter, roundness, and surface finish cannot be achieved by honing, reaming, or boring alone.
The Voumard 1000 handles bore diameters from 1 mm to 100 mm in components up to 200 mm diameter on the universal grinding headstock. The machine accommodates both through-hole and blind-hole internal grinding geometries, including internal taper grinding and internal face grinding for component shoulders and seating surfaces adjacent to the bore. Voumard's universal internal grinding headstock concept enables multiple internal grinding operations (bore, face, taper) without workpiece repositioning.
Internal grinding spindle speeds are necessarily high — a small-diameter internal grinding wheel (3-15 mm diameter) must rotate at 50,000-100,000 RPM to achieve appropriate grinding wheel surface speeds. Voumard's high-frequency spindles provide the speed range required for small bore grinding while maintaining the dynamic balance and thermal stability required for consistent bore accuracy. The Voumard 1000's spindle options cover the full range from large bore (high torque, lower speed) through micro-bore (ultra-high speed) grinding configurations.
At $250,000-$400,000 new, the Voumard 1000 competes with Studer S141, Rollomatic GrindSmart bore options, and other internal grinding specialists. The Voumard line's focus on internal grinding applications provides application depth that general cylindrical grinders offering internal attachments cannot match.
Full Specifications
| Parameter | Value |
|---|---|
| Min Bore Diameter | 1 mm (0.04 in) |
| Max Bore Diameter | 100 mm (3.9 in) |
| Max Workpiece Diameter | 200 mm (7.9 in) |
| Max Workpiece Length | 200 mm (7.9 in) |
| Grinding Spindle Speed | Up to 100,000 RPM (spindle dependent) |
| Work Spindle Speed | Up to 3,000 RPM (workhead) |
| Positioning Accuracy | < 0.001 mm |
| Bore Roundness | < 0.001 mm |
| CNC Control | Fanuc with C.O.R.E. platform |
| Machine Weight | ~3,500 kg (7,716 lb) |
Strengths & Limitations
Strengths
- 1-100mm bore diameter range covers the full range from precision medical device bores through large industrial bearing races
- Up to 100,000 RPM spindle speed enables grinding of 1-3mm micro-bores at appropriate surface speed
- Universal internal grinding head enables bore, face, and taper grinding in a single workpiece clamping
- < 0.001 mm bore roundness and positioning accuracy meets the tightest bearing and fuel system bore specifications
- Voumard is dedicated to internal grinding — application depth exceeds general cylindrical grinders with internal attachments
Limitations
- Internal grinding is inherently slower than external grinding due to the small wheel diameter and limited wheel contact arc
- High-speed internal spindles have shorter service intervals than external grinding spindles — maintenance planning is essential
- Small internal grinding wheels are brittle and sensitive to collision — careful part loading and approach programming required
- Voumard's North American dealer presence is through United Grinding — fewer dedicated specialists than for Studer external grinding
Best For
Frequently Asked Questions
01
Grinding wheel surface speed (typically 25-45 m/s for conventional wheels, up to 60 m/s for CBN) determines the cutting action and surface finish of the grinding process. For an internal grinding wheel of 5 mm diameter to achieve 30 m/s surface speed, it must rotate at approximately 115,000 RPM. A 10 mm wheel needs 57,000 RPM for the same surface speed. Large bore wheels (80-100mm diameter) can achieve adequate surface speed at 8,000-12,000 RPM. This is why internal grinding spindles span from 5,000 RPM (large bore) to 100,000+ RPM (micro-bore) depending on the bore diameter being ground.
02
The Voumard 1000 achieves bore diameter tolerances of ±0.001 mm or better with active gauging control, bore roundness of < 0.001 mm, and cylindricity (bore straightness) of < 0.001 mm over the bore length. Surface finish of Ra 0.1-0.4 µm is standard; with CBN wheels and optimized parameters, Ra 0.05 µm is achievable for bearing bore applications. These tolerances meet ABEC-7 bearing bore requirements and most precision industrial bore specifications.
03
Internal grinding removes material by abrasive action with a high-speed grinding wheel, suitable for hardened materials (typically > 50 HRC) and producing bore accuracies in the ±0.001 mm range. Honing uses abrasive sticks at low surface speed to produce cross-hatch surface patterns and very fine bore size control, typically ±0.0005 mm. Honing is better than grinding for bore size accuracy but requires a pre-ground bore to start — grinding produces the accurate size and geometry that honing then fine-finishes if required. Most precision bore manufacturing sequences are: bore (lathe/mill) → grind (Voumard) → hone (Sunnen, Kadia) if Ra < 0.1 µm is required.
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