Yes you can measure total time, and it's the sum of process time + queue time, they are equivalent. Below is a simple diagram depicting 2 steps. With a mismatch of process time of 10 min in step 2 vs 5 min in step 1, the total time balloons from 20 min without congestion to 45 min with full congestion. You can measure the queue time by either subtracting the process time (15 min) from the total time (45 min), or directly measure how long a car sits on the conveyor, both give the same #.
My point here is that if you can speed up step 2 process time by 5 min, you can eliminate the congestion and reduce the queue time from 30 min down to 5 min, it's a huge increase. So I hope by ramping up the robot speed, the total time a car stays in production can be reduced much more than just the improvements on the process time.
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