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  • Clinching

    serch.it?q=Clinching

    Clinching phasesClinching or press-joining is a bulk-sheet metal-forming process aimed at joining thin metal sheet without additional components, using special tools to plastically form an interlock between two or more sheets. The process is generally performed at room temperature but in some special cases the sheets can be pre-heated to improve the material ductility and thereby avoid the formation of cracks during the process. Clinching is characterized by a series of advantages over competitive technologies: Reduced joining time (the joining time is less than a second); Reduced cost and weight: the process does not involve additional elements such as screws, rivets or adhesives Reduced cost of the machine; No pre-holes are required; Can be adopted to join different materials including metals, polymers, wood, and composite materials; Can be easily automated and does not require qualified workers; Eco-friendly: it does not require pretreatments with solvents, acids, and other harmful liquids; The mechanical strength of the metal material near the joint is generally increased due to work-hardening; Cleanness: the process does not produce flashes or fumes; Repeatability; Flexibility: the same tools can be employed for a wide series of materials Reduced joining forces

  • Spot welding

    serch.it?q=Spot-welding

    A spot welder A spot welding robot Resistance spot welding (RSW) is a process in which contacting metal surface points are joined by the heat obtained from resistance to electric current. It is a subset of electric resistance welding. Work-pieces are held together under pressure exerted by electrodes. Typically the sheets are in the thickness range. The process uses two shaped copper alloy electrodes to concentrate welding current into a small "spot" and to simultaneously clamp the sheets together. Forcing a large current through the spot will melt the metal and form the weld. The attractive feature of spot welding is that a lot of energy can be delivered to the spot in a very short time (approximately 10–100 milliseconds). That permits the welding to occur without excessive heating of the remainder of the sheet. The amount of heat (energy) delivered to the spot is determined by the resistance between the electrodes and the magnitude and duration of the current. The amount of energy is chosen to match the sheet's material properties, its thickness, and type of electrodes. Applying too little energy will not melt the metal or will make a poor weld. Applying too much energy will melt too much metal, eject molten material, and make a hole rather than a weld. Another feature of spot welding is that the energy delivered to the spot can be controlled to produce reliable welds. ' is a modification of spot welding. In this process, the weld is localized by means of raised sections, or projections, on one or both of the workpieces to be joined. Heat is concentrated at the projections, which permits the welding of heavier sections or the closer spacing of welds. The projections can also serve as a means of positioning the workpieces. Projection welding is often used to weld studs, nuts, and other threaded machine parts to metal plate. It is also frequently used to join crossed wires and bars. This is another high-production process, and multiple projection welds can be arranged by suitable designing and jigging.

  • Rolling (metalworking)

    serch.it?q=Rolling-(metalworking)

    Rolling schematic view Rolling visualization. (Click on image to view animation.) In metalworking, rolling is a metal forming process in which metal stock is passed through one or more pairs of rolls to reduce the thickness and to make the thickness uniform. The concept is similar to the rolling of dough. Rolling is classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature, then the process is known as hot rolling. If the temperature of the metal is below its recrystallization temperature, the process is known as cold rolling. In terms of usage, hot rolling processes more tonnage than any other manufacturing process, and cold rolling processes the most tonnage out of all cold working processes. Roll stands holding pairs of rolls are grouped together into rolling mills that can quickly process metal, typically steel, into products such as structural steel (I-beams, angle stock, channel stock, and so on), bar stock, and rails. Most steel mills have rolling mill divisions that convert the semi-finished casting products into finished products. There are many types of rolling processes, including ring rolling, roll bending, roll forming, profile rolling, and controlled rolling.

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