Two actuators are typically employed on opposing sides of the rivet. LVER (low voltage electromagnetic riveting) is based on eddy current repulsion between a copper pancake coil and a copper driver plate. Rivet materials are selected which are ductile and tough, and the rivet dimensions are engineered to allow the “factory head” of the rivet to deform into shape without rupturing during this cold working process.Ī great example of this is the electromagnetic cold forming process which the company Electroimpact was founded on (good paper on this technology is located here, which is where the description and images below were taken from): Modern rivets exploit optimized geometry and careful material selection to avoid the necessity of heating the rivet to allow it to be formed into shape. ![]() The process required to buck a rivet into shape is significantly easier if the rivet does not need to be heated. Bolted connections (which do not require expensive skilled labor) have almost completely replaced riveting in structural steel construction for this reason… The hot-riveting process has become irrelevant enough that steel construction codes do not even contain design practice recommendation for riveting anymore. Largely a manual process… The process variables of heating time, differences in strength or ability across workers could affect the final upset shape of the rivets and the joint performance.This heating could alter the rivet metal microstructure and thus, the mechanical properties of the rivet. A solid understanding of the heating/cooling cycle during the installation of the rivet would be necessary.Things that I would be particularly concerned about if I had to design with this fastening method include: Pneumatic and hydraulic machines have been created to make hot-riveting (and cold-riveting, too) a much less labor-intensive process, but the nature of the hot-riveting process–having to run a rivet immediately from a hot furnace into the workpiece–does not make it easy to automate. I was kind of in awe of how much tedious riveting was required to assemble this immense ship (which is even larger than even some modern cruise liners image source): I recently visited the Queen Mary cruise ship (operated from 1936-1967, now docked in Long Beach California as a tourist attraction). Old bridges, boilers, and ships were made in this way. (And back in the day, a guy wouldn’t have had the benefit of a pneumatic hammer, either. One worker hammers on the rivet to create the “factory head” while another worker holds the factory head in place with a “bucking bar.”.One worker slides a red-hot rivet in place from the rivet furnace (occasionally, the “rivet catcher” is a completely different job from the worker tending to the furnace).A hole is drilled (or punched and/or reamed) if one hasn’t been already. The two components to be joined are fixtured in position.The process was labor-intensive, requiring several workers: Hot-forming of rivets is old-school, and rarely used now. Solid rivet after forming, joining two steel plates In hot-forming of “solid rivets,” the rivet is heated to a red-hot, malleable state, slid into the workpiece, and the end of the rivet composed of a cylindrical shaft is then “upset” into a headed shape. Which installation method is used on what rivet depends on the design of the rivet itself. There are three general types of rivet installation methods. Rivets come in many forms, and the different types will be described below in the “Rivet Designs” section. It is also permanent–unlike a threaded bolt, rivets are deformed into place in holes within the subcomponents to achieve a permanent connection (though some of them can be removed with relative difficulty). It is a fastener–unlike say, welding, it does not chemically merge the materials of the subcomponents. ![]()
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