Also called routings, process routing, operation sequence, work instructions
What is a routing?
The ordered list of operations a part goes through, with the work centre and the time allowed for each.
What else it is called
- Other names
- routings, process routing, operation sequence, work instructions
- In French
- gamme de fabrication
Related entries
Understanding routing
The sequence of operations a part passes through, naming the work centre for each, the setup time it needs and the run time per piece. It is the operational half of the product definition, the bill of materials being the other.
It also carries more weight than it looks. Capacity planning multiplies routing times by scheduled quantities. Quoting adds routing times to material cost. Standard costing values work in process by the operations completed. Every one of those inherits whatever is in the routing, so stale times propagate into quotes, promises and reported margins simultaneously.
The maintenance problem is real. Routings get written when a part is introduced, improved on the floor over the following year, and never updated - so the quote reflects a process that has been superseded. When quoted hours and actual hours diverge persistently, the routing is the first place to look, and it is almost never the floor’s fault.
In practice
When quoted hours and actual hours diverge, the routing is usually the culprit rather than the floor.
Frequently asked
How often should routings be reviewed?
Annually for active parts, and immediately after any process change or tooling change. A cheaper trigger is variance: review any routing where actual hours differ from standard by more than about 15 per cent over a reasonable number of jobs.
Should routing times be the best case or the realistic case?
Realistic, including the setup and the normal interruptions, because the number is used for promising dates as well as for costing. Optimistic routings produce quotes you win and lead times you miss.