CNC Machine Maintenance: Daily, Weekly and Monthly Checklist
CNC downtime rarely announces itself. It accumulates in skipped five-minute checks until a spindle bearing or a ball screw forces a five-figure repair. This checklist is the minimum cadence that keeps a production mill or lathe honest.
Every shift (5 minutes, operator-owned)
- Lube levels: way lube and hydraulic reservoirs at the marked level; top up with the specified grade only
- Air pressure: within the machine’s spec band; water traps drained
- Chips and coolant: clear chips from the enclosure, way covers and conveyor; check coolant concentration with a refractometer
- Unusual sounds: any new rattle, whine or chatter gets written down with the program number — memory is not a maintenance log
Weekly (30 minutes)
- Way covers and wipers: lift and inspect for trapped chips; a damaged wiper lets abrasive slurry reach the linear guide
- Filters: check coolant, air and hydraulic filter indicators; clean or swap as needed
- Tool changer: wipe the carousel and taper surfaces; inspect one toolholder taper for fretting
- Axis limits: jog each axis full travel at low override and listen; note any binding at the ends
Monthly (half day, technician-owned)
- Spindle runout: measure with a test bar and log the number — trending catches bearing wear months before failure
- Ball screws and ways: inspect for scoring, re-lubricate per the machine manual, check bellows integrity
- Electrical cabinet: verify cooling fans and filters; heat is the leading silent killer of drives and controllers
- Backup battery: check the absolute-encoder battery voltage; a dead battery during power-off loses machine zero
- Level and alignment: check machine level; foundation creep changes geometry gradually and invisibly
The economics of the checklist
A spindle rebuild runs five figures plus a week of lost production. A way cover wiper costs less than an hour of machine time. Every item on this list exists because somebody paid the full price of skipping it.
Log everything. A maintenance history is worth money at resale, and it is the only thing that turns “the machine sounds different” into a pattern you can act on before the failure.