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.
Critical Ratio Dispatching
Meaning
Priority sequencing in production scheduling relies on the time remaining until a due date compared to the work remaining for a job. Scheduling logic ranks orders by the quotient of time until the deadline divided by the time required to complete the task. Using critical ratio dispatching allows a planner to identify which jobs are behind schedule or ahead of schedule in real time.
Equality occurs when the work remaining matches the time available, while a value below one signifies a late job.
Numeric Calculation
Calculation for the value is straightforward as time remaining is divided by work remaining. A value of 1.0 indicates that the job is on track. High numbers indicate slack, whereas lower numbers signal a need for immediate attention.
Workload Management
When multiple jobs compete for a single machine, the operator selects the one with the lowest score. Priority sequencing prevents a single long job from causing delays for multiple smaller orders.
Performance Outcome
Application of this method reduces the average lateness across the entire production facility. Logic functions best when processing times are predictable and the backlog is stable. Unexpected breakdowns or material shortages can distort the ratio if the data is not updated.