Managing Shared Assembly Line Priority and Queue Allocation
Managing shared line priorities requires balancing station work content variance and commercial order margins to prevent bottleneck starvation.
Station Blockage
Meaning
Manufacturing delays occur when a completed unit cannot move to the next stage because that downstream area is already full. Flow disruption occurs when a finished part cannot exit a workstation because the subsequent area lacks storage space. Under station blockage, the upstream machine must stop operating even though it is fully functional and has material to process.
Faulty downstream flow or line imbalance typically causes this state.
Flow Disruption
Idle time accumulates at the blocked station, reducing the overall utilization of that resource. Operators may perform maintenance or cleaning while waiting for the line to clear. Loss of productive capacity at this stage cannot be recovered later in the shift.
Accumulation Source
Excess inventory in the downstream buffer is the primary driver of this condition. If the next station is slower or has encountered a breakdown, the parts have nowhere to go. High variation in task times often leads to these temporary stoppages in tightly coupled systems.
Buffer Provision
Increasing the size of the storage area between stations can reduce the frequency of these events. Buffers allow the upstream station to continue working while the downstream issue is resolved. Cost of carrying more inventory must be weighed against the benefit of higher machine uptime.