Cellular manufacturing
Cellular manufacturing describes a production management system in which the production steps are carried out in several subsystems which are called manufacturing cells. It is a subset of just in time and lean manufacturing where the use of cells in the manufacturing process makes it possible to combine the advantages of the other two production approaches. The flexibility in production is taken from job production, while the production rate and the effectiveness of the processes are taken from mass production [1].
Cellular Manufacturing System design
In order to be globally competitive within a production facility and to maximize its productivity, the manufacturing machines must be precisely placed an integrated into the production process. The use of a cellular manufacturing system can be used to keep fixed production costs as low as possible. However, before the cells themselves are considered, it is first necessary to analyze which products are produced and which resources and machines are used for them. With this information, parts with similar production steps or requiring the same resources and machines can be grouped into part families and manufacturing cells can be formed. It must always be taken into account that more than one cell can be needed for the manufacturing of a product [2].
Once it has been determined which machines will be placed in which cell, the layout within the cells must be defined. This intra-cellular layout specifies the order in which the machines are placed. To make this arrangement as efficient as possible, the transfer cost for the material flow within a cell (intra-cellular material flow) must be considered. But not only do intra-cellular transfer costs have to be considered, but also the inter-cellular transfer costs. These result from the material flow between two cells (inter-cellular material flow). The goal of every company is to minimize costs, which is why cell formation also aims to keep intra - and inter-cellular transaction costs as low as possible [3].
To finalize the design of the cellular manufacturing system, the part families must be scheduled for production and the resources have to be allocated. Resources include tools, humans, and materials. To achieve the best possible result, all decisions should be made simultaneously, but this is hardly possible. The reason for this is the NP-complete nature and complexity of the decisions, as well as the restrictions of traditional approaches [4].
Advantages and Disadvantages
The advantage of cellular manufacturing systems lies in the similarity of part families that are grouped for production. Thus, setup times and setup costs can be reduced:
- Setup time reduction
- Lead time reduction
- Decrease in work-in-process inventory
However, it should be noted that cellular manufacturing systems are most effective with stable part families, large production volumes, and flexible manufacturing machine stations [5].
This manufacturing system also has disadvantages [6]:
- It is not suitable for products with a short product life cycle
- Cannot adapt to short-term changes in demand
- The inflexibility of the production system to changes in the market situation
Virtual Cellular Manufacturing
Virtual cellular manufacturing is a further development of classic cellular manufacturing, for which the conversion of the production system to a classic cellular manufacturing system is not possible from a technical or financial point of view [7]. A virtual manufacturing cell, like a physical one, is a grouping of resources used for the manufacturing of a part family, but this grouping is not reflected in a physical structure. The grouping of the machines is only temporary, and the manufacturing cells only exist virtually, nevertheless the production schedule is based on this virtual structure. This system allows machines to be assigned to more than one cell, which makes it possible to organize production even more efficiently. Furthermore, production schedules can react better to changes in demand, as the virtual manufacturing cells can be reconstructed more quickly. However, the virtual cellular manufacturing system is also inefficient for constantly changing manufacturing conditions. The use of this system is not recommended for products with a short lifecycle and those with a constantly changing design [8].
Footnotes
- ↑ Chattopadhyay et al., 2013, p. 256; Delgoshaei et al., 2016, p. 132
- ↑ Delgoshaei et al., 2016, p. 131; Wu et al., 2007, p. 156
- ↑ Delgoshaei et al., 2016, p. 132; Wu et al., 2007, p. 156
- ↑ Wu et al., 2007, pp. 156-157
- ↑ Khilwani et al., 2011, p. 533
- ↑ Khilwani et al., 2011, p. 533; Süer & Gen, 2018, p. 12
- ↑ Nomden & van der Zee, 2008, p. 439
- ↑ Khilwani et al., 2011, pp. 533-534
| Cellular manufacturing — recommended articles |
| Dependent demand — MRP II — Pull system — Custom production — Material flow execution function — Interdepartmental planning — Target cost — Work cycle — Cycle time |
References
- Chattopadhyay, M., Sengupta, S., Ghosh, T., Dan, P. K., & Mazumdar, S. (2013). Neuro-genetic impact on cell formation methods of Cellular Manufacturing System design: A quantitative review and analysis. Computers & industrial engineering, 64, 272.
- Delgoshaei, A., Ariffin, M. K. A. M., Leman, Z., Baharudin, B. T. H. T. B., & Gomes, C. (2016). Review of Evolution of Cellular Manufacturing System’s Approaches: Material Transferring Models. International journal of precision engineering and manufacturing, 17, 149.
- Khilwani, N., Ulutas, B. H., Islier, A. A., & Tiwari, M. K. (2011). A methodology to design virtual cellular manufacturing systems. Journal of Intelligent Manufacturing, 22(4), 533-544.
- Nomden, G., & van der Zee, D.-J. (2008). Virtual cellular manufacturing: Configuring routing flexibility. International journal of production economics, 112, 451.
- Süer, G. A., & Gen, M. (2018). Cellular manufacturing systems: recent developments, analysis and case studies. Nova Science Publishers, Inc.
- Wu, X., Chu, C.-H., Wang, Y., & Yan, W. (2007). A genetic algorithm for cellular manufacturing design and layout. European journal of operational research, 181, 167.
Author: Janina Klüsch
