The Andon cord can be interpreted quite literally, as a manual pull chain, or an automated device, that halts a manufacturing line. Or, it can refer to a process, whereby any employee, anywhere on the ladder, can intervene to alert management of a manufacturing problem, thereby effectively stopping a line from finishing production and heading out the door, presumably with a fixable defect.
While a stopped line can initiate challenges, stymied production, costs, potential bottlenecks in other parts of the operation, the problems that ensue from a defective product making out the door can be much worse. Everything from customer service to reputation is on the line. So stopping it before it delivers a wonky product is always a good plan.