Manufacturing Cell

Cellular manufacturing is a manufacturing process that produces families of parts within a single line or cell of machines operated by machinists who work only within the line or cell. A cell is a small scale, clearly-stated production unit within a larger factory. This unit has full responsibility for producing a family of like parts or a product. All necessary machines and manpower are enclosed within this cell, thus giving it a level of operational autonomy.

Cellular manufacturing, which is actually an application of group technology, has been described as a stepping stone to achieving world class manufacturing status. The objective of cellular manufacturing is to design cells in such a way that some measure of performance is optimized. This measure of performance could be productivity, cycle time, or some other logistics measure.

While its benefits have been well recognized, it should be noted that it might be difficult to develop a manufacturing cell. Some have argued that implementing cellular manufacturing could lead to a decrease in manufacturing flexibility. It is felt that conversion to cells may cause some loss in routing flexibility, which could then impact the viability of cell use. Obtaining balance among cells is also more difficult than for flow or job shops. Flow shops have moderately fixed capacity, and job shops can draw from a pool of skilled labour so balance isn’t that much of a problem. By contrast, with cells, if demand diminishes deeply, it may be essential to break up that cell and redistribute the equipment or reform the families. Furthermore, issues like placement of bottleneck machines are needed to be addressed during cell formation. Machines may require their own individual stocks of materials.

Inadequacies in employee education, training and involvement could come in the way of proper implementation. Also, some researchers have warned that the benefits of cellular manufacturing could deteriorate over time due to ongoing changes in the production environment. Finally, it must be noted that conversion to cellular manufacturing can involve the costly realignment of equipment. The burden lies with the manager to determine if the costs of switching from a process layout to a cellular one outweigh the costs of the inefficiencies and inflexibility of conventional plant layouts. Example 1

The Langston Company in Camden, New Jersey, a producer of semi-custom heavy machinery for the paper industry, manufactured a large range of parts in fairly small quantities. The plant was set up in a traditional job shop mode, where machines and processes were classified according to function (i.e. separate departments exist for milling operations, grinding etc.) and where each department was supervised by a foreman. Langston had experienced two major problems: (1) The planning and scheduling of the plant was complex, difficult and time -consuming and (2) the progression of parts through the plant was slow, mainly due to too much waiting and transportation time. In addition, the company was concerned with increasing labour costs and foreign competition.

Example 2
The implementation of cellular manufacturing for a small company usually requires the involvement of a bigger percentage of the total workforce than is needed in a large company. The layout and moving of equipment in a production area for cellular manufacturing in a small company can require the effort of most production employees. Cellular manufacturing implementation includes processes beyond the production area and a small company will need addition of a significant number of employees in other functions. The involvement of a greater percentage of the workforce in a common goal is a valuable mechanism for transformation. In effect, implementing cells creates a critical mass of support for change in small companies. In large companies, a transition to cellular manufacturing may not need a level of effort that supports transformation.

In companies A and B, almost all employees were involved in designing and
implementing cells. Everyone felt they had input in the cellular implementation. In contrast, company C designed cells using only supervisory and management level people. This company experienced a high level of resistance to cells. In fact, company C’s cellular effort failed after a period of six months.

(A Cross-Case Analysis of Small Companies Implementing Cellular Manufacturing D. Ryan Underdown, Ph.D., and Richard A. Leach Automation & Robotics Research Institute, The University of Texas at Arlington [email protected]/(817)272-5917/(817)272-5952 (fax))

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