Updated: Feb 26
The preferred shape of the lean workcell is U-shaped. Each subprocess is connected to the next in order of process. With the worker in the interior of the U, minimum movement is required to move the workpiece or assembly from one workstation to the next.
Ultimately, one of the goals of the lean workcell is to eliminate all non-value-added movement; hence its U-shape. When the worker has finished the process, he simply turns around and is back at step one.
The workpiece may be carried from one value-added operation to the next. However, there are times when the workpiece or the fixture holding the workpiece is too heavy and must be transferred mechanically between workstations.
Although very heavy parts may be transported on belt conveyors, manual push or gravity conveyors are ideal for moving parts between workstations. Their minimum complexity makes them easy to service and minimizes downtime. In addition, they are easy to connect end-to-end, which makes it easy to move workstations within a workcell. The curved “corners” of the U-shaped workcell can pose a problem. As potential dead space, they may act as a mini-storage area, thereby encouraging a return to batch processing. Instead, the use of a ball roller transfer should facilitate part movement through the corners of the U-shape.