WEEK THREE OPERATIONS CONTENT

Demand vs Capacity Mismatch

When incoming demand rate exceeds system capacity rate, causing inventory to continuously build up in queues or buffers.

Inventory Buildup Rate

The rate at which backlog accumulates per unit of time, calculated as Demand Rate minus Capacity Rate.

Inventory Buildup Rate Formula

Buildup Rate = Demand Rate - Capacity Rate

Peak Inventory

The maximum inventory or backlog accumulated in a system, occurring at the exact moment incoming deliveries or arrivals stop.

Peak Inventory Formula

Peak Inventory = Inventory Buildup Rate x Duration of Inflow (hours).

Clearing Time

The time required to process the remaining accumulated backlog after new arrivals have stopped.

Clearing Time Formula

Clearing Time = Peak Inventory / Processing Capacity Rate.

Makespan

The total elapsed time from when a facility opens for incoming jobs to when all processing finishes and inventory reaches zero.

Makespan Formula

Makespan = Inflow Duration + Clearing Time.

Holding Bin Capacity Limit

The fixed maximum storage capacity of an internal buffer; once full, inventory shifts to external waiting lines (like truck queues).

Truck Queue Start Time

The point in time when internal storage becomes 100% full, forcing arriving vehicles to wait outside in line.

Average Queue Length (Triangle Rule)

For a linearly growing line that builds from 0 to a maximum (Peak Queue), the average queue length is equal to 1/2 of the peak queue height.

Total Wait Time (Vehicle-Hours)

The cumulative waiting time experienced by all vehicles, calculated as Average Queue Length x Duration of Queue.

Longest Waiting Vehicle

The vehicle that arrives at the exact moment inflow stops, sitting at the end of the maximum queue and waiting for the full clearing time.

Elevating a Bottleneck

Taking targeted operational actions to increase the processing capacity of the system's slowest constraint.

Bottleneck Elevation Tactics

Adding parallel processors, reducing step processing time, staggering operator breaks, ensuring preventive maintenance, and keeping spare parts ready.

Non Bottleneck Capital Trap

Spending money or adding machinery upstream or downstream of a bottleneck, which fails to increase system throughput and only increases WIP.

Quality Check Placement Rule

Locating quality inspections immediately before a bottleneck so the constrained resource never wastes time on defective parts.

Mixed Product Flow Rule

Tracing distinct product flows separately through shared and unique steps to isolate individual product bottlenecks.