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Spot Welding
A spot welder Spot welding (or resistance spot welding) is a type of electric resistance welding used to weld various sheet metal products, through a process in which contacting metal surface points are joined by the heat obtained from resistance to electric current. The process uses two shaped copper alloy electrodes to concentrate welding current into a small "spot" and to simultaneously clamp the sheets together. Work-pieces are held together under pressure exerted by electrodes. Typically the sheets are in the thickness range. Forcing a large current through the spot will melt the metal and form the weld. The attractive feature of spot welding is that a large amount of energy can be delivered to the spot in a very short time (approximately 10–100 milliseconds). This 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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spot Welder
A spot welder Spot welding (or resistance spot welding) is a type of electric resistance welding used to weld various sheet metal products, through a process in which contacting metal surface points are joined by the heat obtained from resistance to electric current. The process uses two shaped copper alloy electrodes to concentrate welding current into a small "spot" and to simultaneously clamp the sheets together. Work-pieces are held together under pressure exerted by electrodes. Typically the sheets are in the thickness range. Forcing a large current through the spot will melt the metal and form the weld. The attractive feature of spot welding is that a large amount of energy can be delivered to the spot in a very short time (approximately 10–100 milliseconds). This 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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Conductivity
The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by k, \lambda, or \kappa. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal conductivity. For instance, metals typically have high thermal conductivity and are very efficient at conducting heat, while the opposite is true for insulating materials like Rockwool or Styrofoam. Correspondingly, materials of high thermal conductivity are widely used in heat sink applications, and materials of low thermal conductivity are used as thermal insulation. The reciprocal of thermal conductivity is called thermal resistivity. The defining equation for thermal conductivity is \mathbf = - k \nabla T, where \mathbf is the heat flux, k is the thermal conductivity, and \nabla T is the temperature gradient. This is known as Fourier's Law for heat conduction. Although commonly expressed as a scalar, the most general form of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Welding Processes
This is a list of welding processes, separated into their respective categories. The associated ''N reference numbers'' (second column) are specified in ISO 4063 (in the European Union published as ''EN ISO 4063''). Numbers in parentheses are obsolete and were removed from the current (1998) version of ISO 4063. The AWS reference codes of the American Welding Society are commonly used in North America."Welding Inspection Handbook", 3rd edition, American Welding Society, , Miami, FL, pp. 10-11 (2000) Arc welding Oxyfuel gas welding Resistance welding Solid-state welding Other types of welding Notes and references *Cary, Howard B. and Scott C. Helzer (2005). Modern Welding Technology. Upper Saddle River, New Jersey: Pearson Education. . *Lincoln Electric (1994). The Procedure Handbook of Arc Welding. Cleveland: Lincoln Electric. . See also * Welding * List of welding codes This page lists published welding codes, procedures, and specifications. American Society of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clinching (metalworking)
In metalworking, clinching or press-joining is a bulk sheet metal forming process aimed at joining thin metal sheets 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stud Welding
Stud welding is a technique similar to flash welding where a fastener or specially formed nut is welded onto another metal part, typically a base metal or substrate. The fastener can take different forms, but typically fall under threaded, unthreaded, or tapped. The bolts may be automatically fed into the stud welder. Weld nuts generally have a flange with small nubs that melt to form the weld. ''Weld studs'' are used in stud welding systems. Manufacturers create weld studs for the two main forms of stud welding: capacitor discharge stud welding and drawn arc stud welding Drawn arc stud welding Drawn arc stud welding joins a stud and another piece of metal together by heating both parts with an arc. The stud is usually joined to a flat plate by using the stud as one of the electrodes. The polarity used in stud welding depends on the type of metal being used. Welding aluminium, for example, would usually require direct-current electrode positive (DCEP). Welding steel would requi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium-ion
A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also sees significant use for grid-scale energy storage and military and aerospace applications. Compared to other rechargeable battery technologies, Li-ion batteries have high energy densities, low self-discharge, and no memory effect (although a small memory effect reported in LFP cells has been traced to poorly made cells). Chemistry, performance, cost and safety characteristics vary across types of lithium-ion batteries. Most commercial Li-ion cells use intercalation compounds as the active materials. The anode or negative electrode is usually graphite, although silicon-carbon is also being increasingly used. Cells can be manufactured to prioritize either energy or power density. Handheld electronics mostly use lithium polymer batteries (w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel–metal Hydride Battery
A nickel metal hydride battery (NiMH or Ni–MH) is a type of rechargeable battery. The chemical reaction at the positive electrode is similar to that of the Nickel–cadmium battery, nickel–cadmium cell (NiCd), with both using nickel oxide hydroxide (NiOOH). However, the negative electrodes use a hydrogen-absorbing alloy instead of cadmium. NiMH batteries can have two to three times the capacity of Nickel–cadmium battery, NiCd batteries of the same size, with significantly higher energy density, although much less than Lithium-ion battery, lithium-ion batteries. They are typically used as a substitute for similarly shaped non-rechargeable Alkaline battery, alkaline batteries, as they feature a slightly lower but generally compatible cell voltage, and are less prone to leaking. History Work on NiMH batteries began at the Battelle Memorial Institute, Battelle-Geneva Research Center following the technology's invention in 1967. It was based on sintering, sintered Ti2N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel–cadmium Battery
The nickel–cadmium battery (Ni–Cd battery or NiCad battery) is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes. The abbreviation ''Ni-Cd'' is derived from the chemical symbols of nickel (Ni) and cadmium (Cd): the abbreviation ''NiCad'' is a registered trademark of SAFT Corporation, although this brand name is commonly used to describe all Ni–Cd batteries. Wet-cell nickel-cadmium batteries were invented in 1899. A Ni-Cd battery has a terminal voltage during discharge of around 1.2 volts which decreases little until nearly the end of discharge. The maximum electromotive force offered by a Ni-Cd cell is 1.3V. Ni-Cd batteries are made in a wide range of sizes and capacities, from portable sealed types interchangeable with carbon-zinc dry cells, to large ventilated cells used for standby power and motive power. Compared with other types of rechargeable cells they offer good cycle life and performance at low temperatures with a fai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthodontics
Orthodontics is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, and misaligned bite patterns. It may also address the modification of facial growth, known as dentofacial orthopedics. Abnormal alignment of the teeth and jaws is very common. Nearly 50% of the developed world's population, according to the American Association of Orthodontics, has malocclusions severe enough to benefit from orthodontic treatment: although this figure decreases to less than 10% according to the same AAO statement when referring to medically necessary orthodontics. However, conclusive scientific evidence for the health benefits of orthodontic treatment is lacking, although patients with completed orthodontic treatment have reported a higher quality of life than that of untreated patients undergoing orthodontic treatment. Treatment may require several months to a few years, and entails using dental braces and other appliances t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assembly Line
An assembly line is a manufacturing process (often called a ''progressive assembly'') in which parts (usually interchangeable parts) are added as the semi-finished assembly moves from workstation to workstation where the parts are added in sequence until the final assembly is produced. By mechanically moving the parts to the assembly work and moving the semi-finished assembly from work station to work station, a finished product can be assembled faster and with less labor than by having workers carry parts to a stationary piece for assembly. Assembly lines are common methods of assembling complex items such as automobiles and other transportation equipment, household appliances and electronic goods. Workers in charge of the works of assembly line are called assemblers. Concepts Assembly lines are designed for the sequential organization of workers, tools or machines, and parts. The motion of workers is minimized to the extent possible. All parts or assemblies are handled e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robot
A robot is a machine—especially one programmable by a computer—capable of carrying out a complex series of actions automatically. A robot can be guided by an external control device, or the control may be embedded within. Robots may be constructed to evoke human form, but most robots are task-performing machines, designed with an emphasis on stark functionality, rather than expressive aesthetics. Robots can be autonomous or semi-autonomous and range from humanoids such as Honda's ''Advanced Step in Innovative Mobility'' ( ASIMO) and TOSY's ''TOSY Ping Pong Playing Robot'' (TOPIO) to industrial robots, medical operating robots, patient assist robots, dog therapy robots, collectively programmed ''swarm'' robots, UAV drones such as General Atomics MQ-1 Predator, and even microscopic nano robots. By mimicking a lifelike appearance or automating movements, a robot may convey a sense of intelligence or thought of its own. Autonomous things are expected to proliferate in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robot Welding
Robot welding is the use of mechanized programmable tools (robots), which completely automate a welding process by both performing the weld and handling the part. Processes such as gas metal arc welding, while often automated, are not necessarily equivalent to robot welding, since a human operator sometimes prepares the materials to be welded. Robot welding is commonly used for resistance spot welding and arc welding in high production applications, such as the automotive industry. History Robot welding is a relatively new application of robotics, even though robots were first introduced into U.S. industry during the 1960s. The use of robots in welding did not take off until the 1980s, when the automotive industry began using robots extensively for spot welding. Since then, both the number of robots used in industry and the number of their applications has grown greatly. In 2005, more than 120,000 robots were in use in North American industry, about half of them for welding. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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