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Machines used or welding are categorized into constant voltage or constant current. A constant voltage welding machine oscillates the output current in order to preserve a certain or set voltage while a constant current welding machine conserve sturdy current. This kind of machines is proposed to be mainly used by trained individuals like welders.

 

Spot welder is a machine that is used in the process of joining metal surfaces by the use of heat acquired from resistance to electric current. In spot welding usually three stages are involved. In the first step the electrodes should be brought close to the surface of the metal slightly applying pressure on it. After that a current is applied briefly then removed but the electrodes should be left not until the metal surface to cool down. The time taken for this type of welding ranges from 0.1 to 0.63 seconds, this time will be dependent with the force of the electrode, metal thickness and the electrode diameter.

 

The apparatus used in this field of welding practice comprise of electrodes and tool holders. The function of tool holders is to hold electrodes in their place firmly they also give support to the optional water hoses which are used to cool down the electrodes in the welding process. The methods used in tool holding comprises of regular offset, paddle-type, universal and light duty. Electrodes are made in many unlike sizes and shapes depending on the desired application and are made mainly of low resistance alloy commonly copper.

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The two surfaces that are to be joined or welded together are called workpieces. These workpieces should be good conductors of electricity. The welding apparatus  throat length limits the width of the workpieces which varies from five inches to fifty inches.

 

After welding, that is when the current is removed; cooling process begins through the coolant holes at the center of the electrodes. The coolant may be both brine solution and water.Spot welder machine has way mode advantages over other types of welder machines. Here are some advantages of sport welder machine; there is no need of wire or any filter metal or welding materials such as acetylene, oxygen or argon. It also has a short heating time and is concentrated in a particular area hence stress and deformation are minimal.

 

Spot welding is efficient it produces less noise and has no harmful gases. It has a simple operation and it is laid-back to recognize automation and mechanization.  When the core is molten, it I surrounded by a plastic ring, therefore the molten metal is separated from the atmosphere air and the metallurgical procedure is modest.

 

The drawback of spot welder is that the joints made on the surfaces increases the mass of the component. There is no dependable non-destructive testing technique; it can only be tested through destructive testing of the welded parts. Spot welder creates localizes joints only that may not be that strong, the strength depends on the temperature, the force applied and how clean the workpieces were.