BMS Spindle Service

Precision CNC
electrospindle service

CNC electrospindle service – mechatronic precision and certified quality.
Electrospindles are integrated units combining spindle mechanics, electric drive, and control electronics – the heart of high-speed CNC systems. They require a specialized approach that merges mechatronic knowledge with hands-on repair experience.

At BMS Spindle Service, we offer comprehensive electrospindle repair, including advanced diagnostics, disassembly, cleaning, bearing and seal replacement, taper repair, precise dynamic balancing, and final performance tests. This allows us to restore full reliability to electrospindles used in woodworking, aluminum machining, and high-frequency systems.

Our services are backed by a 6-month warranty, and with certified procedures and components, we deliver operational parameters that meet or exceed OEM standards. It’s a service that truly extends CNC machine lifespan and minimizes production downtime.

Why CNC electrospindle service
is essential for reliability and efficiency

The electrospindle is the heart of a modern CNC machine – combining a motor, tool clamping system, and control electronics. Its failure affects not only rotation, but also heat dissipation, machining accuracy, encoder signals, and synchronization.

Timely electrospindle service allows you to:

  • Eliminate overheating and electrical short circuits – protection against winding and insulation damage.
  • Restore accurate encoder signal – crucial for precise positioning.
  • Avoid costly, unplanned downtime – efficient service minimizes failure risk.
  • Extend the lifespan of rotor, stator, and ceramic bearings – saving on parts and repairs.
  • Reduce noise and vibration – refurbishment and balancing improve machine performance.
  • Save on OEM electrospindle replacement – service offers faster turnaround and significantly lower cost.

Professional electrospindle repair restores factory parameters and prepares the system for continued, safe operation.

Electrospindle balancing after refurbishment

CNC electrospindle service
step by step

Electrospindle refurbishment requires a precise approach – it covers both mechanical and electrical components. Thanks to our repair procedures, we can restore full functionality and durability of high-frequency spindles.

1. Initial diagnostics and spindle removal

We begin with a detailed diagnostic of the electrospindle and its safe removal from the CNC machine – either on-site or after it has been delivered to our service center.

The initial diagnostics include:

  • measurement of tool clamping force, noise, vibration, axial and radial runout,
  • preliminary temperature and thermal behavior analysis,
  • inspection of encoder, sensors, and wiring,
  • verification of malfunction symptoms reported by the machine operator.

Thanks to precise analysis at this stage, we can identify the potential causes of failure and plan further repair actions.

2. Technical disassembly and cleaning

After diagnostics, the spindle is transferred to the service zone, where it is fully disassembled under ESD-safe conditions with complete technical documentation.

This stage includes:

  • disassembly of rotor, stator, bearings, sensors, and encoder,
  • ultrasonic cleaning of components and removal of grease and coolant residues,
  • disinfection, drying, and inspection of each part under a microscope,
  • labeling and preparation of components for further analysis.

At this point, the spindle components are ready for detailed wear assessment and planning of possible refurbishment or replacement.

3. Damage analysis and service report

After cleaning and preparation, the electrospindle undergoes a complete electrical and mechanical diagnosis.

During the analysis, we perform:

  • resistance and impedance measurements, as well as winding insulation tests,
  • encoder operation and signal verification,
  • clearance checks and preliminary bearing wear assessment,
  • identification of tool clamping system failures (if present).

Based on the measurements, we prepare a detailed service report that defines the scope of further repair steps.

4. Stator rewinding (if required)

If the motor windings are damaged, we perform a complete revision and rewinding in controlled laboratory conditions.

The rewinding process includes:

  • removal of old windings and core preparation,
  • winding of new copper wire according to OEM specifications,
  • impregnation of windings with resin and thermal oven curing,
  • testing of phasing, resistance, and insulation integrity.

The rewinding process complies with standards for high-frequency electrospindles and ensures original performance parameters.

5. Mechanical refurbishment and component replacement

After completing the winding tests, we proceed with the mechanical rebuilding of the spindle – replacing or refurbishing all worn components.

The scope of work includes:

  • replacement or refurbishment of sleeves, bearing seats, flanges, and rings,
  • installation of new seals, bushings, and tool clamping elements,
  • assembly of spindle bearings in accordance with the manufacturer’s specifications,
  • precise fitting of components according to OEM documentation.

All components are assembled in controlled conditions, maintaining tolerances compliant with industrial standards.

6. Spindle taper refurbishment

A critical element for machining precision – the tool taper – is thoroughly restored in our grinding department.

As part of the refurbishment, we perform:

  • precision grinding to remove microdamage and restore geometry,
  • chrome plating of the taper surface to improve wear resistance,
  • adjustment of taper angles in accordance with tool specifications,
  • restoration of taper alignment and concentricity with the spindle axis.

Proper taper refurbishment ensures stable and precise tool clamping, which is crucial for CNC machining quality.

7. Dynamic balancing of the rotating assembly

Once the rotating assembly is assembled, we perform dynamic balancing to eliminate vibration and increase spindle longevity.

This stage includes:

  • balancing the rotor across full speed range – low, medium, and high RPMs,
  • using CIMAT stations for real-time vibration analysis,
  • achieving ISO balance class G0.4 or better,
  • minimizing vibration and noise caused by imbalance.

A properly balanced assembly ensures stable operation even above 30,000 RPM.

8. Encoder setup and sensor calibration

For electrospindles equipped with encoders, we perform precise alignment and signal phasing to ensure full compatibility with the CNC system.

The procedure includes:

  • positioning the encoder (optical or magnetic) relative to the spindle axis,
  • phasing the encoder with the stator windings,
  • signal testing – phase alignment, waveform, and readings across full RPM range,
  • calibrating temperature, speed, and clamping force sensors (if present).

Proper encoder setup ensures accurate spindle control and full synchronization with the machine drive system.

9. Functional load testing (burn-in)

Before returning the electrospindle, we perform a long-term test under real operating conditions, monitoring all key parameters.

During the test, we check:

  • electrospindle operation at different speeds and temperatures,
  • vibration amplitude and noise level,
  • encoder signal quality and phase alignment accuracy,
  • clamping force and stability of all sensor systems.

This stage confirms that the electrospindle is fully ready for production use and all systems function according to specification.

10. Final inspection, report, and documentation

Before the electrospindle is returned to the customer, it undergoes a final quality inspection and complete documentation is prepared.

The full set of documents and protection includes:

  • dynamic balancing certificate (ISO G0.4 or better),
  • electrical and mechanical test report,
  • measurement charts and calibration reports,
  • confirmation of compliance with OEM parameters,
  • warranty card – 6 months on all replaced components and performed work,
  • electrospindle transport protection (bubble wrap, foam, reinforced box or crate).

The electrospindle is now ready for safe transport – with full documentation and service warranty.

11. Spindle geometry alignment to the machine

After delivering the electrospindle to the customer, we can perform precise alignment of the spindle axis with the machine guides and worktable.

During the geometry calibration, we perform:

  • measurement and correction of spindle axis position relative to the machine’s guide system,
  • alignment of the spindle angle relative to the working table surface,
  • verification of coaxiality and proper tool engagement angle,
  • axial accuracy tests to ensure precision machining operations.

Thanks to this calibration, the electrospindle operates in line with the machine’s geometry, ensuring maximum CNC machining accuracy.

Precise CNC electrospindle refurbishment with restored factory parametersCNC electrospindle repair for DOOSAN lathe – disassembly, diagnostics, and reassemblySpecialized CNC electrospindle service – disassembly, measurement, repair
Runout measurement of CNC electrospindle during repair processComprehensive HSD electrospindle service with full documentationHOMAG SKF electrospindle service – disassembly and component check
HITECO electrospindle service – diagnostics, repair and post-refurbishment testsDisassembly of OKUMA electrospindle before repair and refurbishment

Most common electrospindle problems
and how we solve them

Electrospindle vibrations at high speeds

Worn spindle bearings, incorrect balancing, or improper assembly of rotating components.

Solution – Dynamic balancing and bearing replacement effectively eliminate vibrations and restore operating stability.

Electrospindle overheating

Inefficient lubrication system, damaged seals, or malfunctioning coil cooling mechanism.

Solution – Seal replacement, lubrication system refurbishment, cleaning of cooling channels, and temperature sensor inspection.

Loss of torque / unstable motor operation

Motor winding damage, overheating, short circuits, or encoder issues.

Solution – Electrospindle rewinding according to the original specification and post-repair testing.

Uneven tool runout

Worn spindle taper, misaligned tool mounting, or weakened clamping force.

Solution – Spindle taper grinding and clamping force calibration restore mounting precision and eliminate runout.

Frequently
Asked Questions

Vibrations, overheating, torque loss, noise, and uneven tool runout are the most common signs that the electrospindle requires servicing.
Yes. Electrospindle repair can be several times cheaper than purchasing a new unit while retaining original performance specifications.
The service includes diagnostics, cleaning, bearing and seal replacement, electrospindle rewinding, dynamic balancing, and final testing.
The standard lead time is 5–7 business days. In case of major damage (e.g., need for rewinding), it may take longer.
Yes – with regular inspections, clamping force measurements, and spindle alignment, you can significantly extend spindle life.

Trust the electrospindle experts
and restore full performance

We repair electrospindles quickly, precisely, and with a warranty – regardless of the brand or machine type.

  • 12-month service warranty

  • Express turnaround times

  • Serving customers across Europe

CONTACT

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