USING THE SLP METHOD IN THE DESIGN OF FLEXIBLE MANUFACTURING CELLS

Flexible manufacturing systems are becoming increasingly important as customers increasingly want customized products. Also, the trend of the product life cycles to become shorter and shorter causes the proliferation of flexible manufacturing systems. Proper layout is key to making the manufacturing system truly flexible. Novel research and this article show how the Systematic Layout Planning method can be applied to the design of flexible manufacturing systems and, going further, how the design process can be supported by manufacturing process simulation.

Layout Optimization of Flexible Manufacturing Cells Based on Fuzzy Demand and Machine Flexibility

Layout flexibility is critical for the performance of flexible manufacturing cells, especially in dynamic production environment. To improve layout flexibility, layout optimization should consider more flexible factors based on existed models. On the one hand, not only should the current production demands be covered, but also the future uncertain demands should be considered so that the cell can adapt to the dynamic changes in a long term. On the other hand, the flexibility of machines should be balanced in the layout in order to guarantee that the cell can deal with dynamic new product introduction. Starting from these two points, we formulate a layout optimization model based on fuzzy demand and machine flexibility and then develop a genetic algorithm with bilayer chromosome to solve the model. We apply this new model to a flexible cell of shell products and test its performance by comparing it with the classical two-stage model. The total logistics path of the new model is shown to be significantly shorter than the classical model. Then we carry out adaptability experiments to test the flexibility of the new model. For the dynamic situation of both the fluctuation of production demands and the introduction of new products, the new model shows obvious advantages to the classical model. The results indicate that this advantage becomes greater as the dynamics becomes greater, which implies that considering fuzzy demand and machine flexibility is necessary and reasonable in layout optimization, especially when the dynamics of the production environment is dramatic.

Layout design for flexible machining systems in FCIPS and convertibility to CPS module in smart factory

Although being not in accordance with the original concept proposed in the “Industrie 4.0”, the smart factory has been gradually applied to the practice. In contrast, we can observe that nearly all discourses, suggestions and discussions have been carried out without considering the convertibility of flexible manufacturing in FCIPS (Flexible Computer-Integrated Production Structure), which is the utmost leading facility within the industrial nation, to the CPS (Cyber Physical Systems) module in the smart factory. Admitting the powerful potentiality of the smart factory, at crucial issue is to discuss to what extent and how the technological and human resources so far accumulated in FCIPS are available for the smart factory. This paper proposes, first, the conceptual drawing of the smart factory on the basis of the concept of FCIPS, and then suggests the similarity of both the concepts. In fact, the smart factory consists of cloud computing, information communication network and CPS modules, whereas FCIPS consists of CIM, information communication network and a group of FMCs (Flexible Manufacturing Cells). Then, the paper describes the present and near future perspectives of the CPS module and FMC, especially placing the stress on machining, and asserts the convertibility of FMC for “One-off Production with Keen Machining Cost” to the CPS module. Finally, the paper summarizes the research and engineering development subjects in FCIPS and the smart factory necessary to be investigated hereafter together with detailing one leading subject, i.e. methodology to incorporate the human-intelligence into CIM.

Simulated Annealing Applied to Optimize the Efficiency of Flexible Manufacturing Cells

This work proposes a new methodology to optimize flexible manufacturing cells applying Simulated Annealing and Contribution Margin concepts. This methodology helps to determine the number of extra products that could be sold and manufactured while taking advantage of this idleness. The price formation to sell the extra products was based on contribution margin concepts. The main concept is to use cell idleness to increase profits while the costs are already paid. Equipment and workers have their fixed costs paid regardless of whether they are active or not. When they are not active, all of their costs are considered to be losses. What motivated the present work was the fact that, in general, the idleness detected in manufacturing processes does not receive adequate attention in the sense of taking advantage of it. To achieve this purpose, a program was developed to implement the methodology. This program generates user interfaces that allow the prediction of daily scheduling parts production. The first interface identifies only bottlenecks and idleness. The second interface, based on the Simulated Annealing (SA) metaheuristic technique, was designed to perform the management of idleness. A database was organized to present current and future daily scheduling parts production. Based on the volume of sales and the lead time of sold products, sellers are always able to update this database. Thus, the program can provide through its user interface, at any time, all of the information about production data for a specific schedule day that comes from the database. The user mentioned here is expected to be an industry salesman. Thus, it will always be possible to have previous knowledge about the bottlenecks and idleness that exist for any scheduled day in the future. This knowledge allows for planning the process of selling extra products made from the existing idleness. Two aspects were considered with respect to selling extra products that are produced via taking advantage of the idleness: the delivery time and the contribution margin of each product. To validate the program, a simulation was performed to determine which products should be produced during a scheduled day to ensure the delivery times or to ensure the maximum contribution margin, while considering the delivery time that is available. As a final consideration, the software can be considered to be functional and responsive to the possibility of profit maximization from the use of cell idleness.

Augmented reality in error troubleshooting inside flexible manufacturing cells

A new type of software framework for error troubleshooting in flexible manufacturing systems using a frame marker device. Our framework system meant to resolve the failures originated from the human-machine interface and to generate self-training from previous experience.