CNC machines are the most valuable and complex equipment in most small manufacturing shops — and they require consistent, systematic maintenance to deliver the accuracy and uptime you depend on. A neglected CNC machine doesn't just break down; it gradually drifts out of tolerance, produces scrap, and eventually fails catastrophically.
This checklist is based on manufacturer recommendations from Mazak, Haas, DMG Mori, Okuma, and Fanuc, combined with real-world experience from maintenance technicians at over 200 small manufacturing shops. It covers mills, lathes, and machining centers with Fanuc, Siemens, and Mitsubishi controls.
⚠️Important safety note
Always follow lockout/tagout (LOTO) procedures before performing any maintenance that requires accessing electrical, hydraulic, or pneumatic systems. Never perform maintenance on a running machine.
📅 Daily Maintenance Checklist
These tasks should be performed at the start of every shift, or at minimum once per day. They take approximately 30–40 minutes total and prevent the majority of CNC failures.
CRITICALTASKTIME
Critical
Check coolant level and top off if below MIN line 2 minCritical
Check coolant concentration (should be 6–10% for most applications) 3 minStandard
Inspect coolant for contamination, smell, or discoloration 1 minCritical
Clean chip conveyor and chip collection area 10 minStandard
Wipe down exterior surfaces and control panel 5 minCritical
Check lubrication system oil level (way lube) 2 minCritical
Inspect all axes for smooth movement (jog each axis) 3 minCritical
Check for any unusual noises or vibration during warm-up 5 minStandard
Verify tool holders are properly seated and clean 3 minCritical
Clean and inspect spindle taper 3 minCritical
Check air pressure at machine inlet (should be 80–100 PSI) 1 minStandard
Drain water separator on air line 1 min8 critical tasks · 12 total tasksEst. total: 39 min
📆 Weekly Maintenance Checklist
Weekly tasks go deeper than daily checks and address components that degrade over days rather than hours. Budget 60–90 minutes per machine per week.
CRITICALTASKTIME
Critical
Lubricate all greased points per manufacturer spec 15 minCritical
Clean and inspect linear guide rails and ball screws 20 minCritical
Check and clean coolant tank strainer/filter 10 minStandard
Inspect all coolant lines and nozzles for blockage 10 minCritical
Check hydraulic fluid level (if applicable) 3 minStandard
Inspect all electrical connections in control cabinet (visual only) 10 minCritical
Clean control cabinet air filters 10 minCritical
Inspect tool changer mechanism and clean as needed 15 minStandard
Check all limit switches and home position sensors 10 minStandard
Verify spindle orientation and reference positions 5 min6 critical tasks · 10 total tasksEst. total: 108 min
🗓️ Monthly Maintenance Checklist
Monthly maintenance addresses system-level components and requires more time and some specialized knowledge. Budget 3–4 hours per machine per month.
CRITICALTASKTIME
Critical
Replace coolant if contaminated or pH out of range 60 minCritical
Full lubrication of all axes — check auto-lube pump function 30 minStandard
Inspect and clean spindle air purge ports 15 minCritical
Check spindle bearing temperature during operation 10 minCritical
Inspect all belts for wear, cracking, or proper tension 20 minStandard
Check and adjust axis backlash if needed 30 minCritical
Inspect all safety guards and interlocks 15 minStandard
Clean and inspect chip auger motor 20 minCritical
Check hydraulic system pressure and filter condition 15 minCritical
Inspect all hoses and fittings for leaks or wear 20 minCritical
Back up machine parameters and programs 15 minStandard
Clean and lubricate pallet changer (if equipped) 20 min8 critical tasks · 12 total tasksEst. total: 270 min
📊 Quarterly Maintenance Checklist
Quarterly tasks typically require a full or half-day per machine and may need a qualified CNC technician. Plan these during scheduled downtime periods.
CRITICALTASKTIME
Critical
Replace spindle oil (if oil-lubricated spindle) 45 minCritical
Perform geometric accuracy check (squareness, flatness) 60 minStandard
Calibrate tool length measurement system 30 minStandard
Inspect and repack ball screw nuts if needed 90 minCritical
Replace hydraulic filter (check pressure differential first) 30 minStandard
Inspect all motor brushes (if brush-type servo motors) 45 minStandard
Clean and inspect rotary encoder seals 30 minCritical
Check axis drive amplifier cooling fans 15 min4 critical tasks · 8 total tasksEst. total: 345 min
📅 Annual Maintenance Checklist
Annual maintenance is a major service event. Plan for 1–2 days of downtime per machine and consider engaging the machine manufacturer's service team.
CRITICALTASKTIME
Critical
Complete way lube oil system flush and refill 90 minCritical
Replace all coolant — full tank clean and flush 120 minCritical
Full spindle inspection (runout, taper contact, bearing play) 120 minCritical
Replace all air filters in control cabinet 30 minStandard
Inspect and clean all electrical terminals for corrosion 60 minCritical
Replace backup battery in CNC controller 15 minCritical
Full geometric and volumetric accuracy calibration 180 minStandard
Inspect all linear rails for wear and replace if needed 120 minStandard
Professional spindle repair/rebuild assessment Schedule6 critical tasks · 9 total tasksEst. total: 735 min
5 Most Common CNC Maintenance Mistakes
1
Ignoring coolant management
Contaminated coolant is the #1 cause of preventable CNC problems. It causes corrosion, spindle bearing damage, and biological growth that clogs filters and lines. Check concentration and pH weekly.
2
Skipping the daily warm-up routine
CNC machines need thermal stabilization before cutting to achieve dimensional accuracy. Skipping warm-up leads to size variation in the first parts of the day and premature thermal stress on spindle bearings.
3
Over-greasing or under-greasing
More grease is not better. Over-greasing linear guides causes heat buildup and premature wear. Always use the manufacturer-specified grease type and quantity. The right amount is usually a very small bead.
4
Delaying battery replacement
The CNC controller battery maintains memory for machine parameters and programs when power is off. Most batteries last 3–5 years. A failed battery means lost parameters — and a service call to reload them.
5
Not backing up programs and parameters
Every machine should have its parameters backed up monthly. If the controller fails or the battery dies, you can restore from backup in minutes instead of days.
Track all these tasks automatically
Stop relying on paper checklists. Myncel automatically schedules your CNC maintenance, sends alerts when tasks are due, and tracks completion — for every machine in your shop.