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Spot Welding

Spot welding is one of the most important type in welding. This welding is a process in which contacting metal surfaces are joined by the heat obtained from resistance to electric current flow. Work-pieces are detained together under pressure exerted by electrodes. Spot welding sheets are in the 0.5-3.0 mm thickness range.

This spot welding method uses two shaped copper alloy electrodes to think about the welding current into a little "spot" and to at the same time clamp the sheets together. Forcing a big current through the spot welding will melt the metal surface and form the weld.

The attractive features of spot welding is a lot of energy can be delivered to the spot in a extremely small time (ten to one hundred milliseconds.) That permits the welding to happen without too much heating to the rest of the sheet.

Applications Of Spot Welding

Spot welding is classically used when welding important types of sheet metal. Thicker stock welding types is more difficult to spot weld because the heat up flows into the nearby metal more easily. It can be easily well-known on many sheet metal goods, such as aluminum alloys and metal buckets. Aluminum alloys can also be referred as a spot welded. However, their much upper thermal conductivity and electrical conductivity mean that up to three times upper welding currents are needed. This spot welding requires bigger, more powerful, and more expensive welding transformers.

The most common application of spot welding is in the automobile company and manufacturing industry, where it is used exactly generally to weld the sheet metal to form a car. Spot welders can also be entirely automated, and many of the spot welding industrial robots found on assembly lines are spot welders (the other major use for robots being painting).

Spot welding is also used is in the orthodontist's clinic, where small size of scale spot welding equipment is used when resizing metal "molar bands" used in orthodontics.

Another application is spot welding straps to nickel-cadmium or nickel-metal-hydride cells in sort to make batteries. These cells are joined by spot welding lean nickel straps to the battery terminals. Spot welding can maintain the battery from getting moreover hot, as might happen if conservative soldering were done.

This welding is a good design put into practice must always allow for sufficient accessibility. Spot welding connecting surfaces should be free of contaminants, such as dirt, oil and scale with quality welds. Metal thickness is commonly not a issue in determining good welds.

Tool Styles

Electrodes used in spot welding can differ greatly with different welding applications. Each and every tool style has a different purpose. Radius style electrodes are used for electrodes and high heat applications, with a condensed tip for high pressure, unconventional electrodes for welding corners, offset unconventional tips for reaching into corners and small spaces, and finally offset truncated for reaching into the workpiece itself.


The spot welding method tends to harden the material, cause it to warp, decrease the material's fatigue power, and may stretch the material as well as anneal it. The Physical effects of spot welding include interior cracking, metal surface cracks and a terrible appearance. The chemical properties exaggerated include the metal's interior resistance and its corrosive properties.

Time Calculation

Spot welding set of connections can be calculated using the following equation:

        Total weld time = (L + W + U) x N

Where L is the load time in seconds, N is the number of welds, U is the unload time in seconds, and W is the weld time in seconds.





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