Chaos and Convergence on Bucket Brigade Assembly Lines

One way to coördinate the efforts of workers along an assembly line that has fewer workers than work stations is to form a bucket brigade. Each worker in a bucket brigade simultaneously assembles a single item (an instance of the product) along the line. The worker carries the item from work station to work station until either he hands off his item to a downstream co-worker or he completes the work for his item. The worker then walks back to get another item, either from his co-worker upstream or from a buffer at the beginning of the line. The most notable application of bucket brigades is to coördinate workers to pick products for customer orders in distribution centers, as reported in Bartholdi and Eisenstein (1996b) and Bartholdi et al. (2001). Bucket brigades have also been used in the production of garments, the packaging of cellular phones, and the assembly of tractors, large-screen televisions, and automotive electrical harnesses (see Bartholdi and Eisenstein (1996a,b, 2005), and Villalobos et al. (1999a,b)). In the Normative Model of bucket brigades (Bartholdi and Eisenstein 1996a) the work content of the product is assumed to be deterministic and to be continuously and evenly

Deterministic Chaos in a Model of Discrete Manufacturing

Abstract: A natural extension of the bucket brigade model of manufacturing is capable of chaotic behavior in which the product intercompletion times are, in effect, random, even though the model is completely deterministic. This is, we believe, the first proven instance of chaos in discrete manufacturing. Chaotic behavior represents a new challenge to the traditional tools of engineering management to reduce variability in production lines. Fortunately, if configured correctly, a bucket brigade assembly line can avoi

Design and Control of Warehouse Order Picking: a literature review

Order picking has long been identified as the most labour-intensive and costly activity for almost every warehouse; the cost of order picking is estimated to be as much as 55% of the total warehouse operating expense. Any underperformance in order picking can lead to unsatisfactory service and high operational cost for its warehouse, and consequently for the whole supply chain. In order to operate efficiently, the orderpicking process needs to be robustly designed and optimally controlled. This paper gives a literature overview on typical decision problems in design and control of manual order-picking processes. We focus on optimal (internal) layout design, storage assignment methods, routing methods, order batching and zoning. The research in this area has grown rapidly recently. Still, combinations of the above areas have hardly been explored. Order-picking system developments in practice lead to promising new research directions.Order picking;Logistics;Warehouse Management

Dynamic Quay Crane Allocation

We introduce simple rules for quay cranes to handle containers along a berth where vessels arrive continuously in time. We first analyze a model where workload is continuous. Our analysis shows that if the system is configured properly, it will always converge to a state with the maximum possible throughput regardless of external disruptions or changes in workload. Numerical simulations based on a discrete workload model suggest that, by following the same rules, the system can still converge to state with throughput that is very close to its upper bound

Design and Control of Warehouse Order Picking: a literature review

Order picking has long been identified as the most labour-intensive and costly activity for almost every warehouse; the cost of order picking is estimated to be as much as 55% of the total warehouse operating expense. Any underperformance in order picking can lead to unsatisfactory service and high operational cost for its warehouse, and consequently for the whole supply chain. In order to operate efficiently, the orderpicking process needs to be robustly designed and optimally controlled. This paper gives a literature overview on typical decision problems in design and control of manual order-picking processes. We focus on optimal (internal) layout design, storage assignment methods, routing methods, order batching and zoning. The research in this area has grown rapidly recently. Still, combinations of the above areas have hardly been explored. Order-picking system developments in practice lead to promising new research directions

Using Bucket Brigades to Migrate from Craft Manufacturing to Assembly Lines

One way to organize workers that lies between traditional assembly lines, where workers are specialists, and craft assembly, where workers are generalists, are "bucket brigades." We describe how one firm used bucket brigades as an intermediate strategy to migrate from craft assembly to assembly lines. The adoption of bucket brigades led to a narrowing of tasks for each worker and thus accelerated learning. The increased production more than compensated for the time lost when workers walk back to get more work, which was significant in this implementation. To understand the trade-offs in migrating from craft to assembly lines, we extend the standard model of bucket brigades to capture hand-off and walk-back times.bucket brigades, assembly line, work sharing, dynamical system, self-organizing system

Using Bucket Brigades to Migrate from Craft Manufacturing to Assembly Lines

One way to organize workers that lies between traditional assembly lines, where workers are specialists, and craft assembly, where workers are generalists, are “bucket brigades. ” We describe how one firm used bucket brigades as an intermediate strategy to migrate from craft assembly to assembly lines. The adoption of bucket brigades led to a narrowing of tasks for each worker and thus accelerated learning. The increased production more than compensated for the time lost when workers walk back to get more work, which was significant in this implementation. To understand the trade-offs in migrating from craft to assembly lines, we extend the standard model of bucket brigades to capture hand-off and walk-back times. Key words: bucket brigades; assembly line; work sharing; dynamical system; self-organizing system History: Received: August 27, 2002; accepted: November 1, 2004. This paper was with the authors 16 months for 2 revisions. TUG ™ is a company that assembles about 10 models of industrial tractor of the type commonly used at airports to pull luggage trains. Initially, the company was small and privately held but, when the founde