Resistance spot welding is a welding process that uses the resistance against electrical current to melt metal on a certain spot to join two pieces of metals together. This process calls for copper electrodes that are specially shaped to hold the pieces together and then to concentrate the electrical current into a small “spot”.
The high current passing through a relatively small area causes the metal to heat up and then to eventually melt the metal creating the weld that is going to join the two pieces together. The best thing about this form of welding is that it can deliver a tremendous amount of power in a very short period. This means that the power is expended onto the needed spot only and so there is no excessive heating of the metal pieces that you are working on. Different types of metals can offer different resistance to electricity so it necessary to make adjustments for every piece or different kind of metal that you are working on.
There are many applications for resistance spot welding but mostly it is utilized for sheet metal welding because it is ideal for working with thin sheets of metal. Resistance spot welding is used in the automotive industry where it is utilized in the construction of cars from sheet metal. The images that you have probably seen of automated arms moving in the assembly line of automobile manufacturing plants are actually spot welders that have been completely automated.
Another common application of resistance spot welding is in orthodontics where it is used to connect and reshape the bands used by orthodontists. It is also used in the manufacture of batteries where the use of ordinary soldering techniques might cause too much heat and damage. Here are some very simple and basic spot welding tips that you ought to keep in mind in order to stay safe and consistent with your quality.
1. When it comes to the metals that you can work on with resistance welding, steel and stainless steel are the only metal types that are recommended. Do not perform this form of welding with copper or copper alloys. Aluminium can be worked on as well but it requires a higher current which increases the risks and safety issues involved.
2. If you want to generate more heat use shorter tongs. In the same light the length of the tongs can be used to control the heat output. If you need lower energy output then you can use longer ones.
3. If you are using the longer type of tongs be careful that they do not get bent. If that happens then you are bound to lose pressure at the spot that you are working on.
4. Check the metal pieces that you are working on and make sure that there is no gap between them. A gap can cause the weld to weaken.
5. Keep the tips of the tongs that you are using straight to ensure that they touch each other at exactly the right spot. Keep the right pressure. It should not be too tight but it should not be too light as well.
6. Keep the tips of the tongs clean. Unclean tips can mean some power loss which will result in less heat produced and poorer quality welds. Once you have the basics down pat you’ll get a handle on the finesse and “feel” of it in no time.