Using an Assembly Sequencing Application to React to a Production Constraint: a Case Study 2017-01-0242

Ford Motor Company’s assembly plants build vehicles in a certain sequence. The planned sequence for the plant’s trim and final assembly area is developed centrally and is sent to the plant several days in advance. In this work we present the study of two cases where the plant changes the planned sequence to cope with production constraints. In one case, a plant pulls ahead two-tone orders that require two passes through the paint shop. This is further complicated by presence in the body shop area of a unidirectional rotating tool that allows efficient build of a sequence “A-B-C” but heavily penalizes a sequence “C-B-A”. The plant changes the original planned sequence in the body shop area to the one that satisfies both pull-ahead and rotating tool requirements. In the other case, a plant runs on lean inventories. Material consumption is tightly controlled down to the hour to match with planned material deliveries. When an inevitable delay of receipt of inbound shipment of a particular part is expected, the plant must somehow react to alleviate that part’s shortage and avoid assembly line stoppage. The plant reacts by changing the originally planned assembly sequence to the one that slows down the rate of installation of that part until the receipt of shipment from a supplier; afterwards, the plant accelerates the rate of installation of that part. We’ll briefly discuss the sequencing application that allows a plant to react to the ever changing production environment.