Queue Time Between Operations
A job is not delayed only while a machine is running. In many fabrication shops, the largest delay happens while parts wait between operations.
Where the wait happens
Parts may sit between cutting and bending, bending and welding, welding and cleaning, or cleaning and finishing. The equipment may look busy, but the order is still waiting.
Why this matters
Queue time can make lead times longer, create rush work, and make good quotes harder to win. If one operation consistently creates a waiting line, that operation may be the real production constraint.