The Pros and Cons of Cellular Manufacturing

The other day I was asked about the benefit of cellular manufacturing so I thought I would share some of my thoughts with you.

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-defined production unit within a larger factory. This unit has complete responsibility for producing a family of like parts or a product. All necessary machines and manpower are contained within this cell, thus giving it a degree of operational autonomy.

Benefits ofcellular assembly include shorter lead times, higher productivity, decreased throughput time, increased flexibility, improved quality and increased output. In addition, communication is usually enhanced, because operators work closer to each other. Assemblers can see each process-what is coming and how fast-and one person can perform multiple operations. Also, multiple cells can easily produce multiple product designs simultaneously, making the assembly line more flexible.

Cells help eliminate waste, especially:

Excess Inventory—A cell will generate inventory only for the output being achieved. Because of a manufacturing cell's layout, excess inventory cannot be tolerated, as there is no place to put it.

Waiting—Operators do not have to wait for supplies or tools as they are all kept in the cell ready for use.

Motion—Workers need not move throughout the plant because everything they need to do their job is kept in the cell.

Part Transportation—In-plant transportation is reduced, as there is no need to truck parts from department to department.

Over-processing—Unnecessary operations (such as packing and unpacking for in-plant transportation) are eliminated in a cellular structure.

Despite numerous advantages, workcells are not always the best solution. In fact, some assembly applications aren't conducive to cells. For instance, cells are often incompatible with low-volume, high-mix production and applications that involve high-cost capital equipment. Equipment utilization rates are generally lower in cells, and if capital costs are high, this can be a detriment.

 

http://www.simsconsult.com/ProsConsLeanManuf/FORMFAB2.pdf 

Assembly cells make sense in certain situations, but they don't work in all plants. When deciding whether or not to use cells, manufacturing engineers must consider factors such as assembly processes and the product being produced. If a part has a short build time with many components, a cell may not be more productive than a progressive assembly line.

Just like anything else, cellular manufacturing is no panacea. It is an operational strategy that, if implemented properly, will provide a new dimension to competing: quickly introducing high quality products and delivering them with unprecedented lead times, swift decisions, and manufacturing products with high velocity.