Operational reliability and quality loss of diversely configurated manufacturing cells with heterogeneous feedstocks

Machine reliability in cellular manufacturing is a challenging engineering problem in the formation and design of manufacturing cells. The heterogeneity of feedstock quality is also common in manufacturing industry. However, so far, no work has been done to investigate the performance of diversely configurated manufacturing cells under the heterogeneous feedstocks. In this paper, considering the actual engineering condition, the uniformly random arrival and the clustered arrival of low-quality feedstocks are proposed and modeled by the homogeneous Poisson process and Hawkes process, respectively. Also, to study the mixed reliability of a machine under the impact of heterogeneous feedstocks, a mixed failure-rate model is constructed by the mixture of exponential and Weibull distributions, and the processing quality is modeled by a non-homogeneous Poisson process with a dynamic intensity function. Then, we achieve a contrastive analysis for operational reliability and quality loss of manufacturing cells with basic serial and parallel configurations under the impact of heterogeneous feedstocks. At last, the designed simulation illustrates the effectiveness of our proposed models, and some results are concluded to provide some guidelines for the design of manufacturing cells.

Melhoria na flexibilização e aumento de produtividade de uma linha de montagem de uma empresa do setor de autopeças através da alteração do arranjo físico do processo

Due to the constant competitiveness among the multinational companies nowadays, these companies intensely seek agility and flexibility in their production processes, so that they can respond quickly to variations in their demands, eliminating waste and making their processes leaner and more competitive. Following this trend, the present work had as a proposal and purpose to restructure the layout of a conventional assembly line (linear layout) for U-shaped manufacturing cells, and it is intended in this way to obtain flexibility improvement and productivity increase of the process. The applied methodology was developed from bibliographical research and analysis of the current situation, where a mapping of the processes was done in order to identify the wastes that had a negative impact on the production line. As for the factors that had a negative impact to the process, it was found that there was a need to change the layout of the production line. As the main results related to the restructuring, there is an increase of 6% in productivity per person, a reduction of approximately 30% in the movements of operators in the process, and an improvement in the flexibility of the assembly line, adapting it according to the variation in customer demand.

Algorithm for workcells design

The paper presents a methodology for the design of the manufacturing cells, covering all the necessary steps, from the analysis of the customers’ needs, to part families for group technologies, process engineering, control procedures, production rate, production planning (push or pull workflow), supply in the manufacturing cell, workcell configuration, work standardisation. The necessary tools through each stage are presented. Also, there are presented links to major company systems. For each design stage, deliverables are specified. this design approach is not linear. At each stage it is possible (and indicated) to go back and analyse the previously established parameters. The methodology is a complex one, and in a wider space the detailed parameters will be presented in extenso.

Concurrent scheduling and layout of virtual manufacturing cells considering assembly aspects

Cell formation, scheduling, and facility layout are three main decisions in designing manufacturing cells. In this paper, we address the integration of these decisions in virtual manufacturing cells considering assembly aspects and process routing. We develop a mathematical model to determine the machine cells, the layout of machines and workstations on the shop floor, the processing route of parts, and the production sequence of operations on the machines. In this mathematical model, material handling costs and cycle time are minimized. To the best of our knowledge, this is the first paper that concurrently addresses the scheduling and layout of virtual manufacturing cells with assembly aspects and so-called criteria. To effectively solve the problem, a Population-based Simulated Annealing (PSA) combined with linear programming is proposed. The practical usability of the developed model is demonstrated in a case study. Finally, instances from the literature are solved to evaluate the performance of the PSA. The comparison results showed the superior performance of the PSA in comparison with CPLEX solver and standard simulated annealing.