Flow Time, Flow Rate, Inventory
2 people working - one at cashier, one in grill who are able to complete a customer's order from start to finish in 10 minutes. (flow rate)
At present, the flow time for a customer (Flow unit) to get his order is 10 minutes as the store is not busy and the 2 resources are able to process each order as it comes in.
Lunch hour hits and the customers coming into the store increase but the flow rate remains the same.
Customers now have wait longer to be served (flow time decreases - longer). Inventory increases as the unsatisified customers build up.
Manager adds two more people in both grill and customer check out. Flow rate triples as they can now process 3 customers in 10 minutes.
Flow rate increases, flow time goes back to normal and inventory (customers) decrease.