Resistance Seam Welding

In resistance roller seam welding, the sheets run between two roller electrodes that transmit the current and seal the seam at the same time. The thing is, you have to match the current and the electrode force properly, otherwise the seam either won't be welded through properly or you'll burn the material. Make sure the rollers are clean and run true, otherwise you'll get irregular weld spots that overlap. When welding thin sheets, you have to be careful not to put in too much heat, or you'll distort the part. Generally speaking, the seam has to be tight and look clean, then it's fine.