Throughput,” he says, “is the rate at which the system generates money through sales. - Eliyahu M. Goldratt

Flow means that inventories in the operation are moving. When inventory is not moving, inventory accumulates. Accumulation of inventory takes up space. Therefore, an intuitive way to achieve better flow is to limit the space allowed for inventory to accumulate. To achieve better flow, Ford limited the space allotted for work-in-process between each two work centers.

I write down the three measurements which Lou and I agreed are central to knowing if the company is making money: net profit, ROI and cash flow.

STEP 1. Identify the system’s bottlenecks. (After all it wasn’t too difficult to identify the oven and the NCX10 as the bottlenecks of the plant.)
STEP 2. Decide how to exploit the bottlenecks. (That was fun. Realizing that those machines should not take a lunch break, etc.)
STEP 3. Subordinate everything else to the above decision. (Making sure that everything marches to the tune of the constraints. The red and green tags.)
STEP 4. Elevate the system’s bottlenecks. (Bringing back the old Zmegma, switching back to old, less “effective” routings. . . .)
STEP 5. If, in a previous step, a bottleneck has been broken go back to step 1.