Routing (process plan)
A routing is the ordered list of operations a product goes through, each tied to a work centre and to the times it takes. It answers where each step is done and how long it runs.
A typical routing is a numbered queue of operations: cutting, bending, welding, machining, painting, inspection. Each operation names a work cell or a group of interchangeable machines and two times: setup time, the changeover, and run time per piece. External operations such as plating or heat treatment are written into the routing as well.
Capacity loading, delivery dates and labour cost all come out of the routing. Without one the schedule rests on the planner's instinct and the quote on a time somebody remembers. On short batches that can move the whole calculation, because the changeover then weighs more than the run itself.
The trap is standards nobody has checked in years. The machine has been replaced and the tooling is different, while the time in the system stayed the same. Once execution data comes off the floor, the standard can be compared against the measurement and corrected where the gap repeats on every order.
The signal that routings need attention is a production plan kept in a spreadsheet only one person understands, and parts run interchangeably on two machines with no recorded routing variant.