GRASP for sequencing mixed models in an assembly line with work overload, useless time and production regularity

Peer ReviewedPostprint (published version

Free and regular mixed-model sequences by a linear program-assisted hybrid algorithm GRASP-LP

A linear program-assisted hybrid algorithm (GRASP-LP) is presented to solve a mixed-model sequencing problem in an assembly line. The issue of the problem is to obtain manufacturing sequences of product models with the minimum work overload, allowing the free interruption of operations at workstations and preserving the production mix. The implemented GRASP-LP is compared with other procedures through a case study linked with the Nissan’ Engine Plant from Barcelona.Peer ReviewedPostprint (author's final draft

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

In this article, we propose a hybrid procedure based on bounded dynamic programming assisted by linear programming to solve the mixed-model sequencing problem with workload minimization with serial workstations, free interruption of the operations and with production mix restrictions. We performed a computational experiment with 23 instances related to a case study of the Nissan powertrain plant located in Barcelona. The results of our proposal are compared with those obtained by mixed integer linear programming.Peer ReviewedPostprint (author's final draft

An expert system to minimize operational costs in mixed-model sequencing problems with activity factor

One of the major issues in industrial environments is currently maximizing productivity while reducing manufacturing cost. This can be seen clearly reflected in mixed-model assembly lines based systems, where obtaining efficient manufacturing sequences is a key to be competitive in a dynamic and globalized market. However, this continuous cost reduction and productivity growth should not penalize the welfare of employees. This work is intended to address this lack of compatibility between the economic and social objectives through the study of the mixed-model sequencing problem from both the business and labor perspective. This is done by considering the possibility of reducing or increasing processing times of operations by varying the work pace of line's operators within the permissible legal boundaries. Thus, depending on this flexible activation time of operators, the amount of completed work and idle time will be one or the other and, consequently, the productivity of the line will also improve or get worse. In this regard, we propose new approach to the sequencing problem without incurring cost increases and providing a safe working environment, in accordance with applicable law. This new approach leads to obtain efficient manufacturing sequences, in terms of both productivity and labor conditions. Specifically, the objective of the new problem is minimizing the unproductive costs of the line by incorporating the possibility of increasing production through the variation of the work pace of line's operators. Increasing the work pace of operators, the amount of non-completed work or the preventable idle time can be reduced and therefore, their associated costs too. In addition, and without losing sight of the effort involved in working with a work pace above the normal, we propose several economic criteria to compensate the activation of workers where necessaryPeer ReviewedPostprint (author's final draft

Mejores soluciones del conjunto de instancias Nissan-9Eng.I para el problema MMSP-W/pmr/free

Estado del arte 2016/06 MMSP-W/pmr/freeEn este documento se recogen las mejores soluciones actuales de las instancias Nissan-9Ing.I, para el problema de secuenciación de modelos mixtos con mínima sobrecarga, restricciones sobre el mix de producción y libre interrupción de operaciones. Dichas soluciones proceden de 3 fuentes: programación dinámica acotada mediante programación lineal, programación lineal entera mixta y algoritmos GRASP hibridizados con programación lineal (GRASP-LP). El documento recoge también las 23 mejores secuencias, correspondientes a las instancias Nissan-9Ing.I, que ofrecen los algoritmos híbridos GRASP-LP.Postprint (published version

GRASP for sequencing mixed models in an assembly line with work overload, useless time and production regularity

Peer Reviewe