Internal Grinding Spindle
120MD45Y15
High-speed internal grinding spindle engineered for precision bore machining. 45,000 RPM with 15 kW power and P4 bearings for consistent sub-micron accuracy.
120MD45Y15 Internal Grinding Spindle
The 120MD45Y15 is a compact, high-speed internal grinding spindle engineered for precision bore grinding, hole machining, and bearing raceway grinding applications. Operating at 45,000 RPM with 15 kW of continuous power, this spindle delivers the speed and accuracy required for producing mirror-finish internal surfaces in hardened steels, ceramics, and advanced alloys. Its slim profile design allows access to small-diameter bores while maintaining the stiffness needed for high material removal rates.
Built around a matched set of P4 precision angular contact ball bearings in a permanent preload arrangement, the 120MD45Y15 maintains consistent geometric accuracy and vibration-free operation across its entire speed range. The oil-air micro-lubrication system delivers precisely metered lubricant to each bearing, extending service intervals and maintaining optimal oil film thickness at all speeds. A spiral water-cooling jacket integrated into the spindle housing ensures thermal stability during extended grinding cycles, preventing the thermal drift that can compromise bore roundness and dimensional accuracy. Every spindle is individually tested for runout using laser interferometry, with maximum runout guaranteed not to exceed 0.001mm at the grinding wheel interface.
Download Drawing Get a QuoteDetailed Parameters
| Speed (r/min) | 45000 |
| Power (kW) | 15 |
| Torque (Nm) | 3.2 |
| Tool Interface | Grinding wheel arbor (custom diameter) |
| Motor Type | High-frequency asynchronous motor |
| Bearing Type | P4 Precision Angular Contact Ball Bearings |
| Bearing Arrangement | Back-to-Back (DB) with spring preload |
| Runout Accuracy | ≤ 0.001mm at spindle nose |
| Cooling Method | Water-jacket cooling with liquid chiller |
| Lubrication | Oil-Air micro-lubrication (permanent grease optional) |
| Spindle Nose | Threaded arbor mount (custom sizes available) |
| Maximum Speed Factor (dmn) | 2.4 × 10⁶ mm·r/min |
| Housing Diameter | 120mm |
| Housing Length | ~460mm |
| Spindle Weight | ~38 kg |
| Sensor Integration | 2x PT100 temperature sensors at front & rear bearings |
| Protection Class | IP54 |
| Noise Level | ≤ 68 dB(A) |
| Balancing Grade | G0.4 per ISO 1940-1 |
| Mounting Orientation | Horizontal (standard) / vertical available |
| Application | Internal bore grinding, bearing race grinding, small hole precision grinding |
Available Options & Customizations
- Hybrid ceramic bearings (Si₃N₄ balls) for extended high-speed life
- Permanent grease lubrication for reduced maintenance
- Custom grinding wheel arbor diameter and thread specification
- Front & rear PT100 temperature sensor integration
- Increased IP protection for coolant-heavy grinding environments
- Custom mounting flange for specific grinder integration
Precision Engineering for Internal Grinding
The 120MD45Y15 is purpose-built for the unique demands of internal bore grinding, where speed, accuracy, and compact form factor are equally critical.
45,000 RPM High-Speed Operation
Optimized for the small-diameter grinding wheels used in internal bore work, delivering the surface speed needed for efficient material removal and fine finish quality.
P4 Precision Bearings
ABEC 7 / P4 grade angular contact ball bearings in a permanent preload configuration ensure minimal runout and maximum stiffness for precision bore geometry.
Oil-Air Micro-Lubrication
Precision oil-air delivery system meters exact lubricant quantities to each bearing, extending service life and maintaining optimal film thickness at high rotational speeds.
Integrated Water Cooling
Spiral water jacket design maintains stable operating temperature, preventing thermal drift that could compromise bore roundness during extended grinding cycles.
Dynamically Balanced Rotor
Each rotor assembly balanced to G0.4 grade for ultra-low vibration, essential for achieving mirror-quality surface finishes in bore grinding applications.
Compact Slim Design
Slim-profile spindle body allows access to small-diameter bores while maintaining the structural stiffness required for high material removal rates.
Individual Runout Verification
Every spindle undergoes laser interferometry testing before shipment, with a certified maximum runout of 0.001mm guaranteed at the grinding wheel mounting interface.
Custom Integration Support
Available with custom mounting flanges, shaft extensions, and sensor packages to match your specific grinding machine configuration.
Request a Quote for 120MD45Y15
Discuss your internal grinding requirements with our engineering team. We will provide a complete spindle solution with pricing, delivery timeline, and technical support. 24-hour response guaranteed.