A CNC operator finishes Job 1152. He looks at the board. Three jobs are listed: Job 1156, Job 1158, Job 1160. He doesn't know which one is most urgent. He asks the supervisor. The supervisor checks the planner's desk. The planner is on a call with a customer. The supervisor makes a guess: 'Run 1156.' By the time the operator starts the setup, it is 11 am. He could have started at 10:30.
That 30 minutes of idle time happens three or four times a day at a typical custom manufacturer. It is the cost of unclear priority. The operator is waiting for information. The machine is spinning its wheels.
Why priority is unclear
Priority should be obvious. Job 1156 ships tomorrow, it is the most urgent. But the planner's priority list — if it exists — lives on his desk or in his head. The board shows jobs but not priority. The operator has to ask.
In a custom shop with 30 active jobs, priority changes hourly. A job finishes early, suddenly the next job is now the constraint. A customer calls with a rush, suddenly that job jumps the line. Material arrives early for a job that was three weeks out, suddenly that job can start. The board from this morning is obsolete by 10 am.
The cost of idle time
A 12-machine shop loses 30 minutes a day per machine to idle time waiting for priority. That is 6 machine-hours a day, or 30 machine-hours a week. If the shop makes 100k rupees of gross margin per machine-hour, that is 3 million rupees a week in lost utilization.
Most of that idle time is invisible. It is not tracked. You see 'idle time' in the logs but you do not see it as the cost of a priority system that is too slow to keep pace with reality.
What changes if the operator always knows
- The operator finishes Job 1152 and immediately knows Job 1156 is next — it is on his screen
- He sets up while the previous job is still cooling — no idle time between jobs
- If priority changes (material arrives, customer calls, supervisor has news), the board updates and he sees it in real time
- He does not have to ask. He does not have to wait. He does not have to guess.
Thirty minutes of idle time per operator per day sounds small. Over a month, on a 12-machine shop, that is 150 machine-hours of recovered capacity. That is real margin you get back.