Shift cover depends on who is present: a fix for CNC shops

Twenty to ten on a Thursday night. The operator due on the turn-mill sends a message: fever, not coming. The night lead checks the list on the wall. It says three people can run that machine. One is on days. One left in the summer. The third is the night lead himself, already covering a VMC. The turn-mill sits dark until morning. At half past one the wire on the EDM snaps mid-cut. Nobody on shift can rethread it reliably, so that machine stops too.

Of the patterns on the CNC machining hub, this one bites hardest after dark. Night and second shifts run on whoever turns up, and a single gap becomes a dark spindle.

• One no-show on nights stops a machine, while the same no-show on days gets absorbed.
• The cross-trained list on the wall names people who have left or moved shifts.
• No-shows announce themselves as a phone message to the supervisor minutes before start.
• Unattended runs, such as long wire cuts, a loaded pallet pool or a bar feeder stocked for the night, begin with nobody named to check them.
• Day shift opens by restarting machines and sorting the night's doubtful parts.
• The same few operators land on nights every rotation.

An empty stool on nights costs more than its share. The machine loses a whole shift, not an hour. Bushes or brackets made by an uncleared stand-in need sorting at dawn, often on the surface plate using a height gauge. The morning setter spends his first hour on the night's trouble instead of his own changeovers. Delivery dates promised on three shifts quietly become two. Over months, the people who keep covering grow weary and start looking elsewhere.

• 'Cleared' was never defined. The wall list shows who the supervisor believes can run a machine, not who has been watched running it alone.
• No-shows follow no rule. There is no deadline for telling anyone, and no named person to tell.
• Leave goes to whoever asks first. Both cleared operators for one machine can be off in the same week.
• Nights carry blame, not reward. A thin night allowance and every morning complaint push good people towards days.
• The night lead has no authority. He cannot move someone between machines or halt a doubtful run without ringing the owner.

• Go through a month of second and night shift attendance, and mark every no-show that stopped a turn-mill, pallet machine or wire EDM.
• Against each machine, list who has actually run it unaided on that shift this quarter, including jaw changes and rethreading.
• Ask the night lead what he may decide without phoning anyone.
• Look at the past three months of rotation and count who did the most nights.

1. 1

   Draw the map

   One line per machine and one column per shift, holding the names of people cleared to run it alone. Circle any cell with fewer than two names.

2. 2

   Define cleared

   A person is cleared once a setter or supervisor has watched them run the job alone, handle a routine alarm and gauge to the sheet. Record the date.

3. 3

   Close single-name cells first

   Start with machines that have one name on nights. Train a second person on that shift using the grade card for the machine family.

4. 4

   Set one call-in rule

   Tell the night lead by a fixed time before the shift, by call rather than message. Late notice gets recorded, not shouted about.

5. 5

   Approve leave against the map

   Before saying yes to leave, check the map. Two cleared people for the same machine and shift are never off together.

6. 6

   Give the night lead real authority

   He may move people between machines, halt a run he doubts and call the setter under a written call-out rule.

7. 7

   Name the unattended-run check

   For every long cut or pallet run left overnight, one person signs that wire, coolant, filters and offsets were checked before it began.

Wire EDM two. Day cleared: two names. Second shift: two names. Night: one name. Gap, so train one more on nights.
VMC four. Day cleared: three names. Second shift: two names. Night: two names. No gap.
Turn-mill. Day cleared: two names. Second shift: one name. Night: none. Gap, top priority.
Last reviewed on a stated date, by the production head.
Rule: any cell holding fewer than two names is a gap and goes on the training plan.

Many night stoppages are not about people at all. They happen because the one spare part or tool that would have kept a spindle cutting is locked in the day crib. Give the night lead a small shelf of his own.

• Spare inserts for every repeat job on nights, labelled by machine.
• A wire spool, spare guide and nozzle for the EDM, plus a filter cartridge.
• Spare collets and a guide bush for the bar-fed lathes.
• A charged probe battery, a torque wrench and a chip hook.
• The alarm-code sheet for each controller, and the setter's call-out number.

A cover map holds when it connects to grading and pay. The 'cleared' mark should come from the same sign-off that moves a person up the machine grade. Someone cleared on more machines carries more cover value, and the grade ladder should show that. A visible night lead allowance, paid for responsibility rather than hours, makes nights a role people accept. That ladder is built through compensation and rewards design.

The day-to-day rules belong in your shift, leave and attendance rules. Wire EDM units, with their long overnight cuts, need their own version, set out on the wire EDM shift page. Lathe floors with heavy night volume get their own treatment on the turning shop shift page. For a full rule set, read shift and attendance rules that hold on a busy day.