In the past, the most common way to assemble a product (with some exceptions) was to place the product on a long, paced conveyor belt with workers standing off to one side. As the product reached the worker, they performed their function(s) and then waited for the next one to come down the line. In fact, Henry Ford utilized this type of manufacturing to build his Model-T. But, as times have changed, and as our understanding of how to manufacture has changed, we have found that there are better ways to layout process lines so that they are more efficient and much more flexible to customer demands.
The short answer as to whether you should use a u-shaped cell configuration is...it depends. There is a saying, "u-shaped cells work for everything, unless they don't." Auto manufactures to this day still use a paced line for their automobile construction, as it makes since for such a large product. But, there are areas where the u-shaped cell can be used, such as building up sub-assemblies, or for testing components.
The benefits of a U-shaped cell are many:
FLEXIBILITY. This is no small thing, especially in today's manufacturing environment where things change constantly and you have to be able to adapt and respond quickly. If the u-shaped cell is built out of modules, then you can bring in more modules and workers to meet an increase in demand / workload or remove them when things start to slow down. Also, the processes are usually closer together, so this allows workers to share operations or processes to help even out the flow through the cell.
RECLAIM FLOORSPACE. Typically, a u-shaped cell will take up less floorspace than a stretched out piece of conveyor. Since the input and out are closer together, you can usually use a smaller area to transport materials in and out of the cell.
EFFICIENT MATERIAL HANDLING. Since all of the process are done inside the cell, the parts can all be placed on the outside, where they can be more easily refilled from a nearby replenishment center. This also results in reducing a lot of waste from walking.
COMMUNICATION. Since the workers are closer together, they can address problems better and work together more as a unit than a bunch of separate entities.
Consider your facility layout and you will probably find that you would also benefit from going to u-shaped cells. There a lot of products out there that can help you with this. The best are modular in design so that you can make your cells very flexible. You will not reap all of the benefits by just jumping in with both feet. You will have to continuously improve the cells, but if you stick with it, you should see some real progress in you lean implementation.
