Comparative models for minimizing ergonomic risk in assembly lines

We present a new mathematical model for the assembly line balancing problem with the objective of maximizing the line comfort to operators. Besides minimizing discrepancies between the ergonomic risks of workstations, balancing is subject to temporal and spatial conditions for the workstations. To evaluate the performance of the proposed model, we compare it with other mathematical model whose objective is minimizing the maximum ergonomic risk of a mixed-model assembly line. To compare the models, a case study linked to Nissan’s engine plant in Barcelona (NMISA, Nissan Motor Ibérica – BCN).Postprint (published version

The multi-objective assembly line worker integration and balancing problem of type-2

[EN] The consideration of worker heterogeneity in assembly lines has received a fair amount of attention in the literature in the past decade. Most of this exploration uses as motivation the example of assembly lines in sheltered work centers for the disabled. Only recently has the community started looking at the situation faced in assembly lines in the general industrial park, when in the presence of worker heterogeneity. This step raises a number of questions around the best way to incorporate heterogeneous workers in the line, maximizing their integration while maintaining productivity levels. In this paper we propose the use of Miltenburg's regularity criterion and cycle time as metrics for integration of workers and productivity, respectively. We then define, model and develop heuristics for a line balancing problem with these two goals. Results obtained through an extensive set of computational experiments indicate that a good planning can obtain trade-off solutions that perform well in both objectives.This research was supported by CAPES -Brazil and MEC-Spain (coordinated project CAPES DGU 258-12/PHB2011-0012-PC ) and by FAPESP -Brazil (grant number: 2010/19983-6 ).Moreira, MC.; Pastor, R.; Costa, A.; Miralles Insa, CJ. (2017). The multi-objective assembly line worker integration and balancing problem of type-2. Computers & Operations Research. 82:114-125. https://doi.org/10.1016/j.cor.2017.01.003S1141258

A Dynamic Approach to Multi-stage Job Shop Scheduling in an Industry 4.0-Based Flexible Assembly System

Part 7: Operations Planning, Scheduling and ControlInternational audienceIndustry 4.0 technology is based on the concepts of flexibility and dynamic assembly system design. This enables new production strategies and creates new challenges for job shop scheduling. In particular, manufacturing processes for different customer orders may have individual machine structures whereas the flexible stations are able to execute different functions subject to individual sets of operations within the jobs. This study develops a control approach to job shop scheduling in a customized manufacturing process and job sequencing of operations within the jobs. The developed approach presents a contribution to flexible distributed scheduling in the emerging field of Industry 4.0-based innovative production systems

Including ergonomics aspects into mixed-model assembly line balancing problem

Not considering ergonomics in the assembly systems can bring to sub-optimal solutions and, in case of high levels of ergonomics risk in the tasks execution, several musculoskeletal disorders affecting the global performance of the assembly line. Several papers have been developed in the last years about how to integrate the ergonomics aspects into traditional Single Assembly Line Balancing Problems (SALBP). In this paper, we have extended our recent integrated ergonomics approach to the Mixed-model ALBP (MALBP), where many products are processed in the assembly system in the same period. First, a theoretical model has been developed in order to simplify the MALBP into SALBP, under time and ergonomic approaches. Then the behavior of the assembly system with the real products has been evaluated in terms of time smoothness and ergonomics levels. General discussions and future agenda will be introduced at the end of the paper

Incorporating Ergonomics Factors into the TSALBP

Part 2: Design, Manufacturing and Production ManagementInternational audienceMixed-product assembly lines have ergonomic risks that can affect the worker productivity and lines. This work proposes to incorporate ergonomic factors to the TSALBP (Time and Space constrained Assembly Line Balancing Problem). Therefore, we present several elements for new models to assign the tasks to a workstation considering technological, management and ergonomic factors

Reconfiguration of Machining Transfer Lines

International audienceIn this chapter, we introduce a new optimization problem that aims at minimizing the reconfiguration cost of a transfer line. A line has to be reconfigured if a new product must be produced by an existing line or any changes in product characteristics occur. In such cases, new operations have to be integrated on existing equipment while some previously assigned operations are deleted. Since transfer lines consist of a sequence of unit head machines, their reconfiguration is not an easy issue because of numerous constraints on compatibility between old and new operations to be taken into account. Therefore, a compromise between introducing new equipment and reusing old one should be found. In this chapter, a Mixed Integer Program is proposed for solving this problem with objective to minimize the cost of the final line configuration. An illustrative example is presented