Twinlap achieves results of 2-pass operation (weld, and anneal/planish) with only 1 pass when welding dual phase 600/800, HSLA, silicon, stainless steel, and specialty alloys. Unlike laser welding, seam welder offers forgiving parameters, extending range of materials that can be joined. Machine processes full hard materials up to 84 in. wide and 3.5 mm thick; soft materials to 4 mm thick. It is offered with pneumatics or hydraulics, and single-phase ac, or single-/3-phase dc weld control.