Value stream map

Process time is touch time. Wait is the queue in front of the step. Lead time is their sum, and process cycle efficiency is touch time divided by that lead. The machine in the example is the constraint. Most of the lead time is wait.

Supplier details sit on the left and customer details on the right, the way the map reads. Supplier lead time and shipping time are reported as door-to-door time and are not folded into the process lead time, so that result stays comparable.

Each step needs a name, a cycle time, and a wait. The map marks the longest cycle. Shortening a step that is not the constraint does not shorten the lead time.

Keep one time unit for the map. Mixing seconds of cycle with minutes of wait makes the lead time look like the wait disappeared. Inventory on a step is waiting product, counted in that same unit of time.