Automatic welding machine and method for thermal joining of material sheets

An automatic welding machine for thermally joining sheets of material, in particular for edge side joining of an overlapping upper material sheet to a lower of material sheet, to be connected to one another in a materially bonded manner under the application of heat and subsequent application of pressure, is provided comprising: a heating device for at least partially heating the material sheets to be joined in a connection region; a support frame with a housing; a pressure roller; at least two traveling rollers; wherein the pressure roller and the traveling rollers are arranged on the support frame and together with the support frame form a chassis, wherein the chassis comprises a longitudinal axis and a transverse axis perpendicular thereto, which span a chassis plane; wherein at least a first travelling roller of the two travelling rollers and/or the heating device is arranged to be movable by a telescopic pull-out relative to the support frame in directions parallel to the transverse axis; wherein the first travelling roller and the heating device are with respect to a longitudinal center of the chassis arranged on opposite sides of the chassis. Further a corresponding method is provided.