Sequencing to Minimize Work Overload in Assembly Lines with Product Options

Abstract

We address the problem of sequencing jobs, each of which is characterized by one of a large number of possible combinations of customer-specified options, on a paced assembly line. These problems arise frequently in the automotive industry. One job must be launched into the system at equal time intervals, where the time interval (or cycle time) is prespecified. The problem is to sequence the jobs to maximize the total amount of work completed, or equivalently, to minimize the total amount of incomplete work (or work overload). Since there is a large number of option combinations, each job is almost unique. This fact precludes the use of existing mixed model assembly line sequencing techniques. We first consider the sequencing problem for a single station which can perform two different sets of operations. We characterize the optimal solution for this problem and use the results as the basis for a heuristic procedure for multiple stations. Computational results with data from a major automobile company are reported.assembly lines, sequencing, dynamic programming, heuristics

A hybrid dynamic programming for solving a mixed-model sequencing problem with production mix restriction and free interruptions

“…The original problem, MMSP-W, is an NP-hard problem [3] for which several alternative procedures have been proposed. These solutions include exact procedures based on branchand-bound ( [16]), dynamic programming ( [3], [17], [18]), heuristic procedures based on local search ( [19]), greedy algorithms with priority rules ( [19], [20]), metaheuristics ( [21]) and beam search ( [22]). Several studies have also considered the multi-criteria option (( [23], [24], [25], [26]).…”

“…Constraint (2) requires that the programmed demand to be satisfied. Constraint (3) indicates that only one product unit can be assigned to each position of the sequence. Constraint (4) establishes the relation between the processing times applied to each unit at each workstation and the work overload generated by each unit at each workstation.…”

Consideration of human resources in the Mixed-model Sequencing Problem with Work Overload Minimization: Legal provisions and productivity improvement

“…Process variables Note that 3 and 4 models are an extension from the models proposed by Yano and Rachamadugu (1991) and Scholl et al (1998). Likewise, the 3 ∪ 4 and 4 ∪ 3 models are an extension from 3 and 4, respectively.…”

“…In this case, the objective is to minimize the uncompleted work, which is also known as work overload. One example of this type of problems is the Mixed-Model Sequencing Problem with Workload Minimization (MMSP-W) both the original version, Yano and Rachamadugu (1991), and its variants Bautista, Cano and Alfaro (2012a, b).c) Minimization of the number of subsequences with special options. These problems are focused on avoiding blockages caused by products that require additional work C onsideration of human resources in the Mixed-Model Sequencing Problem with Work O verload M inimization: Legal provisions and productivity improvement J. Bautista, R. Alfaro-Pozo, C. Batalla-García 3 by offering special options.…”

“…; (4) the maximum time that the processors of workstations can work on the last product unit = ; (5) the range of the number of processors ! by workstation; (6) the consideration of links between serial stations.Process variables Note that 3 and 4 models are an extension from the models proposed by Yano and Rachamadugu (1991) and Scholl et al (1998). Likewise, the 3 ∪ 4 and 4 ∪ 3 models are an extension from 3 and 4, respectively.…”