Hardinge Kellenberger U300
Key Specifications
machine type
axes
atc spindle speed
b1 b2 axes
y axis
center drive
Overview
The Hardinge Kellenberger U300 is a 5-axis universal ID/OD grinding platform designed for high-precision applications that demand extreme flexibility and sub-micron tolerances. Unlike the K-series machines which follow a traditional cylindrical grinder architecture, the U300 features hydrostatic B1/B2 axes, a vertical Y-axis, and a tool-change spindle system that together enable grinding operations far beyond conventional cylindrical grinding.
The U300's defining feature is its automatic tool change (ATC) spindle system capable of speeds up to 60,000 RPM. This ATC approach allows the machine to automatically swap between different grinding spindles, dressing tools, and measuring probes, enabling complex multi-operation grinding cycles without operator intervention. The hydrostatic B1 and B2 axes provide vibration-free rotary motion for the wheelhead and workhead, delivering the stability required to consistently achieve sub-micron tolerances.
The vertical Y-axis expands the U300's capability beyond standard OD/ID grinding into face grinding, groove grinding, slot grinding, hole drilling, tapping, and automatic part centering. A center drive system enables grinding of IDs, ODs, and faces in a single clamping, which is critical for components where concentricity between features must be maintained to the tightest tolerances. The machine supports multiple CNC control options including Fanuc 32 Series, Fanuc 0i-F Plus, Mitsubishi M70V, or Siemens 840D.
New Kellenberger U300 machines price between $500,000 and $800,000 depending on axis configuration, spindle options, and control choice. The U300 competes with the Studer S151, Junker Lean Selection Allround, and Danobat LG-1000 in the high-end universal grinding platform segment. This is the machine grinding shops choose when a single platform must handle the widest possible range of precision grinding operations.
Full Specifications
| Parameter | Value |
|---|---|
| Machine Type | 5-axis universal ID/OD grinder |
| Axes | X, Z, Y (vertical), B1, B2 (hydrostatic) |
| Atc Spindle Speed | Up to 60,000 RPM |
| B1 B2 Axes | Hydrostatic bearing, CNC interpolation |
| Y Axis | Vertical axis for face/groove grinding |
| Center Drive | Yes (ID/OD/face in single clamping) |
| Tolerance Capability | Sub-micron |
| Control Options | Fanuc 32 Series, Fanuc 0i-F Plus, Mitsubishi M70V, or Siemens 840D |
| Automatic Tool Change | Yes (grinding spindles, dressing tools, probes) |
| Grinding Operations | OD, ID, face, groove, slot, taper, profile |
Specifications sourced from kellenberger.com — verified 2026-03-28
Strengths & Limitations
Strengths
- 5-axis architecture with hydrostatic B1/B2 axes enables the widest range of grinding operations on a single platform
- Automatic tool change spindle system eliminates manual spindle swaps, enabling complex multi-operation grinding cycles unattended
- Vertical Y-axis adds face grinding, groove grinding, and slot grinding capabilities beyond standard cylindrical grinders
- Center drive system maintains concentricity between ID, OD, and face features in a single clamping to sub-micron tolerances
- Multiple CNC control options (Fanuc, Siemens, Mitsubishi) provide flexibility to match existing shop floor standards
- Hydrostatic bearings on rotary axes provide vibration-free motion essential for achieving the tightest roundness specifications
Limitations
- Price range of $500,000-$800,000 makes the U300 a major capital investment requiring high-value precision grinding work
- 5-axis complexity requires skilled operators and programmers experienced with multi-axis grinding strategies
- Hydrostatic bearing systems require clean, temperature-controlled hydraulic fluid and regular maintenance
- The versatility premium means the U300 costs significantly more than a dedicated OD or ID grinder for shops with simpler needs
Best For
Frequently Asked Questions
01
New Kellenberger U300 machines price between $500,000 and $800,000 depending on axis configuration, spindle options, ATC capacity, gauging systems, and control choice. Base 5-axis configurations start near $500,000. Fully configured machines with maximum ATC capacity, in-process gauging, and Siemens 840D control approach $800,000.
02
The U300 is fundamentally different from the K-series. Where K-series machines follow traditional cylindrical grinder architecture with X/Z/B axes, the U300 adds hydrostatic B1/B2 rotary axes, a vertical Y-axis, and automatic tool change. This enables operations the K-series cannot perform: face grinding, groove grinding, slot grinding, and multi-operation cycles with automatic spindle changes.
03
Hydrostatic bearings use a thin film of pressurized oil between bearing surfaces, creating zero metal-to-metal contact. This eliminates friction, stick-slip, and vibration that limit precision in conventional bearings. On the U300, hydrostatic B1/B2 axes provide vibration-free rotary positioning that is essential for achieving sub-micron roundness and surface finish specifications.
04
The U300 supports four control options: Fanuc 32 Series (premium), Fanuc 0i-F Plus (standard), Mitsubishi M70V, and Siemens 840D. The Fanuc 32 Series and Siemens 840D offer the most advanced multi-axis interpolation and grinding cycle capabilities. Control choice typically depends on the shop's existing platform and operator training.
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