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Machine brand
Mitsubishi Spindle Repair and Rewind
We repair spindles and spindle motors from Mitsubishi machines and from machines fitted with Mitsubishi Electric drives. CNC Spindle Service is an independent workshop in Sankt Augustin, Germany, with no authorisation from or affiliation with any Mitsubishi company. Units are normally shipped in to us; removal or refitting on site abroad is possible only by prior technical arrangement.
Scope
Mitsubishi spindle systems we work on
Mitsubishi is not one builder. Mitsubishi Electric makes spindle motors, drives and controls fitted in other companies' machines; Mitsubishi Heavy Industries and the various Mitsubishi machine tool operations build machining centres, gear machines and EDM. So the first job is identification: we work from the nameplate on the actual spindle unit, not from the badge on the machine, and quote once we know what is in front of us.
Spindle motors fitted in other machines
Mitsubishi Electric spindle motors turn up in machines carrying a completely different badge. Work on these is motor work: bearings, shaft, fan and encoder, with a rewind where the winding has failed. We test the insulation and report the winding condition before anything is committed to.
Machining centre motor spindles
Built-in motor spindles from Mitsubishi machining centres are stripped completely, because a winding fault, a bearing fault and a cooling problem look alike from the outside. Bearings are replaced as a matched set with the preload determined for that spindle type, and the unit is run and measured after assembly.
EDM quill and rotary head assemblies
Sinker and wire EDM machines have no cutting spindle in the milling sense, but the quill, the C-axis rotary head and their bearings wear in the same way. These are dismantled, cleaned of dielectric residue, rebuilt with new bearings and seals, and checked for concentricity on the electrode mount.
Belt-driven and geared heads
Larger boring, milling and gear-cutting machines drive the spindle through a belt or a gear train from a separate motor. The fault often sits in the drive line rather than the cartridge, so pulleys, couplings and gear backlash are checked alongside the spindle bearings before parts are ordered.
The exact configuration depends on the machine model and the year of manufacture. Two machines with the same model designation can carry different spindle units, so we confirm the build from your nameplate photograph before quoting.
Symptoms
Faults we see most often on Mitsubishi spindles
Noise and rising vibration
Bearing noise on a spindle motor is easy to confuse with a drive tuning problem. We run the unit on our own test setup, measure vibration, then strip it and report the bearing condition.
Overheating and thermal drift
Motors that run hot are often blamed on bearings when the cooling fan, a blocked jacket or a failing winding is the cause. Insulation resistance is measured before the unit is reassembled.
Runout at the taper
Crash damage and worn tool changes leave the taper out of true. It is reground and the runout corrected against the bearing journals; a bent shaft is reported first, because that decides whether a rebuild is worth it.
Tool clamping problems
Weak drawbar force shows up as chatter and marked tapers. Clamping force is measured, the collet set and disc springs replaced, and the release cylinder checked, since a leaking piston mimics a worn clamp.
Encoder and orientation faults
Mitsubishi spindle motors carry their own speed and position encoder, and orientation faults often trace back to it or to its cable rather than to the mechanics. We check the encoder before opening the bearings.
Coolant or grease ingress
Coolant past a front seal, or dielectric and swarf on an EDM head, reaches the bearings and the winding. We report how far the contamination has travelled, because that decides between a rebuild and a rewind.
Process
What a repair looks like
The spindle is logged in and inspected on arrival, then dismantled completely. We measure shaft and housing geometry, check the bearing seats, inspect windings and encoder, and photograph what we find. You receive a written quotation with the scope of work before anything is repaired. After the work is done the unit is dynamically balanced, run-in tested and shipped with a test report containing the measured values.
The individual operations — bearing replacement, rotor and stator rewinding, taper regrinding, drawbar and clamping repair, encoder work, seal and cooling circuit overhaul — are described on the services section of our homepage. On a Mitsubishi spindle they are usually combined into one rebuild rather than ordered separately.
What to send with your enquiry
- Photographs of the spindle nameplate and of the tool interface
- Machine model, spindle type and year of manufacture
- A short description of the symptoms and when they appear
- Any measurements you already have — runout, temperature, vibration, current draw
- Whether the machine is still assembled or the spindle is already removed
Removal should be carried out by qualified personnel following the machine documentation. If that is not possible on site, ask us about removal and refitting as part of an on-site visit.
Shipping and on-site service
Our workshop is in Germany and we have no branch, warehouse or permanent staff in other countries. Customers outside Germany send the spindle to us by freight forwarder; we inspect, repair, test and return it. On-site work — removal, installation, alignment and commissioning — is possible internationally, but only after the job has been agreed technically in advance, so that the right parts and instruments travel with the technician.
Questions
Mitsubishi spindle repair — frequently asked
Yes. Send the unit straight to the workshop; no dealer has to sit in between, and we are not tied to a single parts catalogue. We hold no Mitsubishi authorisation of any kind and make no claim to one. If a fault turns out to sit in the drive or control rather than the spindle, we say that instead of selling a rebuild.
Two groups. Mitsubishi Electric spindle motors arrive out of machines built by other companies entirely. The rest come from Mitsubishi machining centres, horizontal boring and gear-cutting machines, and from sinker and wire EDM. Because the badge alone does not identify the unit, send a nameplate photograph with the enquiry.
Both are possible. Where the winding has failed, the motor is rewound to the original data and the insulation tested afterwards; where it is sound, the job stays mechanical. Which route applies is decided after the unit is stripped and tested, not from the fault description on the phone.
Typically 5 to 10 working days from arrival, depending on parts availability and what the teardown reveals. That is an estimate, not a committed date; a binding date is only valid if confirmed in writing. A rewind adds time, because winding, impregnation and drying cannot be shortened without spoiling the result.
Diagnosis is chargeable work, not a giveaway. The unit is dismantled, measured and electrically tested, and you then receive a written quotation setting out the findings and the proposed repair before any repair work starts. Nothing is machined or ordered until that quotation is accepted in writing.
Send us the spindle details
Tell us the machine model, the spindle type and what the machine is doing wrong. We come back with an initial assessment and a written quote before any work begins.