A projection welder uses the heat generated by electricity to join the sheets. The protruding electrode can carry more current than the spot welding electrode, so it can weld thicker materials. In projection welding, two flat electrodes cover the surface of the connector. The projection welder itself absorbs and radiates heat, so you can get a strong joint with unusual aesthetics.
The consistent contact and pressure between the fastener projection and the base material help to avoid excessive electrode pressure. The projection welding process is very suitable for joining metal parts with relief. It is often used in electrical, automotive, and construction applications, in part because of the strength of the weld it produces.
By definition, the projection welding technique produces various roughnesses. The metal element to be joined is held between two electrodes of the projection welder. More pressure is exerted on the electrode. As current flows through the system, heat is generated due to the internal resistance of the metal workpiece. It should be noted here that the cause of the heat generation is the internal resistance of the metal workpiece rather than the arc. These protrusions concentrate heat. As the pressure applied to the electrode increases, the protrusion collapses and a weld nugget appears. Therefore, a high-quality projection weld is created.
Projection welding is a type of resistance welding in which the shape or design of a part is used to create precise contacts to concentrate the current during the welding process. Generally speaking, in almost all projection welder applications with a variety of small protrusions, they must be formed on the surface of a single part to be welded. The two main advantages of projection welding machines are their excellent thermal balance compared to other resistance welding methods and they are ideal when joining thick sheets. The protrusion may be a circular recess, around a slender ridge, or a long corner of a weld nut. The two-round wires are placed together at a 90-degree angle to form a point of contact. This is projection welding.
After gathering the mating parts, the performances will focus on the current. Heat is generated in these places. When the heat is extreme, the lump of the solder joint collapses. When the heat drops, you can see lumps holding the parts together. However, with cross projection welding, you will see a single weld at each intersection. Yet, multiple wires or sheets are often welded at the same time the fence is welded.
Projection welders are mainly used for mass production. It has many applications, for example in the automotive industry, for the production of fan guards and hollow metal doors, compressor parts, and semiconductors.
Traditionally projection welding is performed using AC control and a power supply. The welder is often a traditional pressure welder and more recently a fixed station welding gun. Both provide good alignment and can be designed for fast, low inertia refilling systems. Rocker machines are not a good choice because they exert force on the arc and cannot maintain good alignment.
In all cases, the cylinder or servo system should be inspected to ensure high quality. With the advent of intermediate frequencies, also called MFDC control and their accuracy, the projection welders have become the logical participants of welding applications. To make them suitable for the applications, a fast time rise technology was developed due to the slower rise of the MFDC standard current. Another system that has shown some application in the welding of nuts and studs is a capacitor welder. This technology has been around for many years. In more recent history, the CD has evolved into a high-energy projection welder for welding nuts and studs.
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