Projection Welding Machine Guide

The Basics

The projection welding machine is one type of welding machine that is very popular in the industry. Traditionally this type of processing equipment was controlled by an AC unit and power supplies and operated as a press welder and later also with fixed station weld guns. The projection welding machine provides good alignment for precise welding results.

Some consider the projection welding machine a modification of the spot welding mechanism. However, projection welders are usually more powerful in terms of weld force and welding capacity. During the process, the weld is localized utilizing projections on one or both of the workpieces to be joined. The heat is concentrated at the projections, which permits the welding of heavier sections of welds. The projections can also serve as a means of positioning the workpieces. Welders are of many different types.

Working Principle

A projection welder is used to weld studs, nuts, and other threaded machine parts to metal plates and are very effective tools for these machining procedures. It is considered a subset of electric resistance welding. During the projection welding process, workpieces are clamped together under pressure exerted by the electrodes. The sheets used are usually ranging from 0.5 to 3 mm in thickness.

By definition, a resistance welding machine produces various roughnesses. Here, 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. 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.

The process is very similar to spot welding. However, here it is not the electrode that concentrates the heat, but the part projection itself. Projection welding allows for processing multiple welds simultaneously and therefore is very efficient and offers a lot of flexibility.


A projection welding machine uses 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, but usually, multiple wires or sheets are welded at the same time the fence is welded.

Projection Welding Machine Applications

Projection welders are mainly used for mass production. Thanks to their relatively low energy consumption and reliable weld quality projection welding machines are used in a wide range of industries, such as:

  • Automobile industry for connectors like screws, nuts, and bolts to flat sheets
  • Consumer industry for fasteners in consumer goods such as fans and fan covers, furniture, and household appliances
  • Construction industry for components such as hollow metal doors, heavy plates, and metal panels
  • Mechanical industries for fasteners fixation and covers in mechanical equipment especially where high-pressure resistance is needed
  • Semiconductor industry for hermetically sealed semiconductor equipment to prevent gas intrusion

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