Queue Control is an optional shop control feature that enables you to establish a target queue size for space-constrained or bottleneck work centers.
Work Center Types
Queue Control is used against two types of work centers:
Space-Constrained Work Center
When a work center has limited staging space for items in its queue, Queue Control can be used to place a limit on queue size to prevent overcrowding of the staging area.
Bottleneck Work Center
A “bottleneck” work center is a key machine or process with limited capacity through which most jobs must pass, either directly or indirectly. No matter how efficient your other work centers are, it is the bottleneck work center(s) that limits the pace at which jobs can get through the shop. To maximize shop throughput, it is vital to keep the bottleneck work center(s) fully utilized with a target queue size.
Activating Queue Control
Queue Control is activated on the Schedule tab within the Work Center Schedule screen. Select the Queue Control checkbox and then enter a Buffer Days amount to establish the target queue size.
Establishing the Buffer Days
The appropriate Buffer Days amount depends on the work center type.
Space-Constrained Work Center
Set a Buffer Days amount that appropriately limits the amount of material that can accumulate in the available staging area.
Bottleneck Work Center
In general, the Buffer Days amount for a bottleneck work center will be relatively large because the intent is to provide a backlog of work that keeps the work center fully utilized at all times. Set the amount high enough to insure a steady backlog of work, but not so high as to exceed available staging space or to create excessive waiting time.
Using Queue Control at shop level
In the opening tab of the Work Center Schedule screen, the Q-Control checkbox column identifies all work centers that are subject to Queue Control.
If a work center’s Queue Days amount is displayed in green, it is less than its target Buffer Days setting. If the Queue Days amount is displayed in red, it is greater than its target Buffer Days setting. Color coding helps as follows:
•When a space-constrained work center has a red Queue Days, it means that the work center staging area is full and measures should be taken to temporarily stop giving it more work.
•When a bottleneck work center has a green Queue Days, it means that the queue is below its target size and measure should be taken to temporarily give it more work to prevent it from being idle.
Using Queue Control at job sequence level
In the Schedule tab within the Work Center Schedule screen, the Next WC field can be used to assess queue conditions and alter worker assignment selection, if needed.
The down arrow in the Next WC field displays the Buffer Days and Queue Days associated with the job’s next sequence. If the next work center is subject to Queue Control, color coding is applied to these two fields. If the Queue Days amount is displayed in green, it is less than the target Buffer Days setting. If the Queue Days amount is displayed in red, it is greater than the target Buffer Days setting. Color coding helps as follows:
•When the next work center is a space-constrained work center with a red Queue Days, it means that the work center staging area is full. If you assign this job sequence, it may not have space available in the next work center for staging completed items. In that case, you may wish to assign a lower priority sequence instead that has no such constraint in its next work center.
•When the next work center is a bottleneck work center with a green Queue Days, it means that the next queue is below its target size. In that case, you may wish to instead assign a lower priority job sequence destined for the bottleneck work center so that the bottleneck work center stays busy and avoids being idle.
