A flexible fastener manufacturing workstation was developed in the Automated Manufacturing Research Facility (AMRF) at the National Institute of Standards and Technology (NIST) to manufacture precision, threaded, metal fasteners. The workstation was then transferred to the machine shop at the Portsmouth Naval Shipyard in New Hampshire for making fasteners for submarines. The research and development project was a joint collaboration between the NIST, the Navy, and industry partners to advance the Naval shipyard's fastener manufacturing technology.
US naval shipyards manufacture threaded metal fasteners from the material K-monel and nickel-copper. These level-1, SUBSAFE fasteners are used for critical applications in nuclear submarines. They must meet stringent MIL-S-1222H, as well as ASME/ANSI specifications. Hence, an integrated turning/machining workstation was developed to meet the requirements of tight tolerances specified for the fasteners, material traceability, and fasteners on demand in small-lot sizes. Applying on-line gaging and closed-loop manufacturing process control techniques, through tool wear compensation, the workstation produces quality fasteners and minimizes scraps. The workstation has also incorporated in-station lot-ID marking to enhance material traceability and an integrated database to ensure manufacturing data integrity. As a result, the workstation has shown a very significant improvement in efficiency and productivity.