A NEW METHODOLOGY XSPEC AND PROTOTYPING TOOL XFAST HAVE BEEN DEVELOPED TO SUPPORT THE CONCURRENT DESIGN OF MANUFACTURING SYSTEMS. THE METHODOLOGY INTEGRATES THE DESIGN EFFORTS IN THE HARDWARE, ELECTRICAL, AND SOFTWARE DOMAINS. THE TOOL INTEGRATES SEVERAL COMMERCIALLY AVAILABLE DESIGN PACKAGES FROM DIFFERENT DOMAINS INTO A SINGLE SYSTEM UNIFIED BY THE METHODOLOGY. THIS PAPER ALSO PRESENTS TWO CASE STUDIES USING THE METHODOLOGY AND TOOL IN THE DESIGN OF ACTUAL FACTORY SYSTEMS: A FLEXIBLE MATERIAL TRANSPORT SYSTEM, AND AN ASYNCHRONOUS GEAR WELD LINE. THESE STUDIES CLEARLY IDENTIFY THE BENEFITS OF USING XSPEC AND XFAST.