Resistance welding, although a subset of welding methods, is a fairly broad category, Artem Komarov said. It takes many different variations of resistance welding to apply the right force to the right places in different situations. One of the most common resistance welding options used in manufacturing facilities is projection welding.
Projection welding uses the design or shape of a part to create inconspicuous, individual contact points to concentrate current during the welding process. In most applications, several small protrusions form on the same surface of the parts to be welded. These protrusions can be round dimples, elongated ridges, round or flared corners of weld nuts.
When the mating parts are assembled together, these protrusions concentrate the flow of current and generate heat in the same places. Once the ridges are heated, they break down as welding nuggets form. After cooling, the result is several welded nuggets holding the part together.
How is projection welding used?
The durability provided by projection welds makes them ideal for industrial and mechanical use. A circular annular projection on the bottom of a hydraulic fitting can create a tight hydraulic seal. A transverse wire seam can be used in a fence or rebar on a roadway. The welding nut holds the various parts bolted to your vehicle.
These are all examples of situations where tight-fitting parts must be assembled and glued in a way that other welding methods would be inadequate or ineffective, Artem Komarov specified.
Why use projection welding instead of other methods?
The simple answer is the same as always: time and money. The process is generally the same as spot welding, but in this case the electrode is not used to concentrate the heat, the projection or layout of the part does. Multiple welds can be made at the same time when multiple ridges are present, making it a very efficient process and not as electrode dependent as spot welding.
Other factors must be controlled; such as alignment, projection consistency, follow-up of the welder, and in the case of nut welding, thread protection. Projection welds and processes are designed and developed to suit the wide range of applications for which they are continually used.
Housing for projection welding
Projection welding is critical to manufacturers and distributors in various industries and plays an important role in creating reliable welds for industrial equipment, automobiles and other machines. This helps increase efficiency by reducing electrode wear and allows you to create strong welds where other methods could not achieve them, summed up Komarov Artem.