The customer bought this YLM new. It had been on continuous shift work for 15 years cutting mid-run production parts. Nothing had failed. The problem was subtler: cycle time on the reference part had crept from 3:12 to 3:55 over three years and management wanted to know why.
What we found
- Rapid rates on X and Y were down to 32 m/min from the rated 40. Servo tune had drifted with age.
- The tool magazine was firing slower than spec. Air pressure at the ATC was at 4.9 bar, not the required 6.
- Spindle warm-up was taking 40% longer to hit thermal equilibrium. Cooler had a slow leak.
What we did
No parts were failing, so nothing needed replacing outright. The job was tuning:
- Rebalanced the servo loops on X, Y and Z. Restored rapids to spec without going near the mechanical side.
- Replaced the ATC solenoid and repaired the air supply line. ATC time down from 4.1 s to 2.6 s per tool.
- Recharged the spindle cooler and replaced the flow switch. Warm-up back to under 20 minutes.
Result
Cycle time on the reference part came back to 3:16, four seconds off the day-one figure. On a run of 800 parts a shift, that is 27 minutes of recovered production per shift. Two shifts a day, 240 shifts a year: 108 hours of extra spindle time.
