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Unlike Spot and Projection welding, which are static welding processes, seam welding is accomplished through motion. A seam welding machine has one or two motor-driven wheels that rotate to create a series of overlapping spot welds on sheet components to achieve air and/or liquid-proof sealing on the welded part. The current passes through these rollers, and the components to be welded are pressed in between them. The electrical resistance within the electrode rollers generates heat that joins the weld materials continuously.

Projection welding is characterized by joining a predetermined weld point with the parent material. These points are also referred to as projections or embossments. Projection welding machines apply the current and weld forces on these predetermined weld points, unlike spot welding where the weld is determined by the size or shape of the electrode. These Projections can be produced by embossing on sheet metal, machining or cold forging on a solid piece and press punch on the edge of a piece. Projection welding has a wider range of applications than spot welding; from welding nuts and bolts to sheet components to huge bearings and crossbars that form grating panels. Projection welding machines are usually larger than spot welders and offer more weld power and weld force.

Flash butt welding is a type of electrical resistance welding used to join components in which the energy is transferred by the resistance heat created by the parts themselves. The components are positioned end to end throughout the whole joint region. A range of section sizes and sophisticated shapes can be combined ( examples are bicycle wheel rims and railway rails, see below). While a flashing voltage is applied, the connecting components are held and gently pushed together. Although the procedure can be performed by hand, the majority of welding machines are mechanical or semi-automatic. Dahching has a wide range of butt welding and flash butt welding machines for its customers. Read on to find out more about these two types of welding machines.

Spot Welding machines use a method called resistance spot welding to join overlapping metals between two electrodes using electrical resistance. Squeezing the workpieces between the electrodes applies pressure, and the passage of welding current through the resistive metals generates heat. This allows the materials to bind together and form a welding joint. Spot welding has its name as the current is applied precisely over a small area on the metal's surface. The resistance spot welding equipment can be in the form of stationary or bench-type welding machines, portable spot or robotic welding guns, and multi-head spot welding machines designed for different applications. Here at Dahching we have a wide range of spot welding machines and resistance welding equipment to choose from.