How Does It Work? Spot Welding Machine Basics
Spot welding can be used when you need small cross section welds performed on a particular spot. Welders are able to repeat the process as many times as possible without having to change the same area over. They just need to concentrate on the correct size of their workplace. Spot welding can also strengthen the weld puddle by reinforcing weak areas.
Spot Welding machines use an electrical current to fuse the two sheets of metal together. The electrical current that is used is not enough to melt or even vaporize the metal sheet that is holding the two sheets together; the electrical current actually just breaks the surface tension of the metal sheet in question. Instead of melting or even vaporizing the sheet metal, the electric current heats it up just enough to allow a localized heating agent to bond with the outer surface of the sheet metal. The bonding of the heat with the sheet metal allows it to become rigid, just as the paper or plastic does when it is heated up from the heat source. This in turn makes the sheet metal harder to remove from the spot.
This spot welding machine differs from a typical arc welding process in that there is no direct heat input. The electrical current merely breaks down the metal to a physical state where it can be welded. The electrical current is however applied with enough pressure so that the fusing of the metal takes place at a temperature that is consistent with the melting point of the steel. Because of this consistent heat source, a pressure is applied so that the weld is strong enough to stay together.
As the heat from the electrodes is applied, the steel becomes soft and pliable. This allows the user to move the electrodes around in order to maintain the exact thickness. Because the heat does not uniformly distribute throughout the width of the sheet, small irregularities in the weld are not obvious. This is one of the main benefits of using a spot welding machine. The filler metal will be joined together with greater consistency than if you used pneumatic or gravity-fed electrodes.
The filler metal also has the ability to be positioned into a variety of shapes. The electrodes that are used in the process can be positioned into hollow tubes. These tubes are known as cup shaped because they contain an interior pinch of air that acts as a filler in the process of forming the metal sheets. When a pinch of air is present, it pulls on the two sides of the sheet that is joined together. This creates a consistent level of electrode force along the length of the cup. This is one of the main benefits of using the spot welding machine over other methods.
In the process of forming a metal sheet with the use of a spot welding machine, you can control the resistance offered by the system. You will be able to increase the electrode force and reduce the time of the filler pulse or vice versa. If you need to increase the speed in the welding process, you can do so by reducing the time of the pulse or vice versa.