Maintenance, Troubleshooting, and Process Improvement
Preventive maintenance
Know the routine PM items: way lubrication and reservoir levels, way wipers and covers, ball screw and linear guide lubrication, coolant concentration and sump cleaning, chip conveyor and filtration, air line filters/regulators/lubricators, hydraulic oil and pressure, belts, spindle taper condition, and backup batteries for parameter memory. Spindle warm-up programs protect bearings and stabilize geometry. Leveling and alignment checks address geometry drift over time; backlash checks reveal wear in thrust bearings and screws.
Troubleshooting method
Work from simple to complex and gather evidence before changing anything: is the symptom dimensional, surface finish, or a control alarm? Dimensional drift often traces to tool wear, thermal growth, chips under the part, lost motion, or a shifted offset - not to a wrong program. Poor finish suggests runout, overhang, incorrect speed/feed, coolant starvation, or worn inserts. Verify with measurement, then act on the root cause.
Use structured tools: 5 Whys, fishbone (cause-and-effect) diagrams, PDCA, DMAIC, FMEA, poka-yoke (error proofing), and designed experiments when several factors interact. Kaizen and standard work sustain the gains; document the corrective action so the problem does not return.
Traps
Questions reward the person who edits the program or overrides an alarm rather than finding root cause, or who tightens a tolerance to 'fix' a capability problem.
Rule of thumb and worked example
Symptom → data → cause → countermeasure → verify. Worked example: dimensions creep 0.002 in over a two-hour run with stable tool life - check ambient/shop temperature rise and spindle thermal growth first, then confirm with a re-measured part before touching offsets.