design for the right mix of products must be coupled with the technical capabilities that allow for quick changeover of product mix and quantities that might vary dramatically, even on a monthly basis. Reconfigurable manufacturing systems have these capabilities. RMS System Architecture and Operation The system architecture of a typical RMS is shown below. The system is composed of stages: 10, 20, 30, 40, etc. Each stage consists of identical machines, such as CNC milling machines, or RMT machines. The system produces one product, for example, an automotive engine block or a cylinder head. The manufactured product moves on the horizontal conveyor. Then Gantry-10 grips the product and brings it to one of CNC-10. When CNC-10 finishes the processing, Gantry-10 moves it back to the conveyor. The conveyor moves the product to Gantry-20, which grips the product and load it on the RMT-20, and so on. Inspection machines are placed at several stages, and at the end of the manufacturing system. RMS is defined as a “system designed at the outset for rapid changes in its structure.” In practice this feature is implemented by designing an open space with an access to the gantry at each stage. These spaces enable matching rapidly higher market demand by adding machines in these spaces, which increases production rate to match the demand. The product may move during its production in many production paths. Three paths are shown in the figure. Although the CNC machines at each stage are identical, in practice there are small variations in the precision of identical machines, which create accumulated errors in the manufactured product. The magnitude of the error depends on the path in which the product moved; each path has its own “stream-of-variations” (a term coined by Y. Koren). RMS characteristics Ideal reconfigurable manufacturing systems possess six core characteristics: modularity, integrability, customized flexibility, scalability, convertibility, and diagnosability. These characteristics, which were introduced by professor Yoram Koren in 1995, apply to the design of whole manufacturing systems, as well as to some of its components: reconfigurable machines, their controllers, and system control software. Modularity refers to the modules that reconfigurable manufacturing systems consist of. At the system level the machines are modules. At the machine level the axes of motion are modules (see the RMT Figure). The system control may be composed of control modules. Modules are easier to maintain and update. Integrability is the ability to rapidly