Welding machine, in particular grid-welding machine, having at least two movable welding apparatuses, - wherein each welding apparatus has at least one first electrode, - wherein each first electrode can be used together with one of a plurality of second electrodes for welding together two components, in particular two bars, to form a product, in particular to form a grid, - wherein the welding machine has at least one first crossmember, - wherein each welding apparatus has a clamping mechanism, and the welding apparatuses can be clamped firmly onto the at least one first crossmember in selectable positions, and fastened thereto, by means of the clamping mechanisms, - wherein the welding machine has at least one positioning apparatus, - wherein the welding machine has at least one first linear guide with a guiding part and at least one guided part, wherein the at least one guided part is part of the at least one positioning apparatus and can be displaced along the guiding part, - wherein the at least one positioning apparatus has at least one first coupling means and each of the welding apparatuses has at least one second coupling means, and the at least one first coupling means and one of the at least one second coupling means can be coupled to one another, - wherein the at least one positioning apparatus has a disengaging means, in order to disengage the clamping mechanism of a coupled-on welding apparatus from the crossmember, - wherein a weight of a welding apparatus coupled onto the at least one positioning apparatus is borne, at least predominantly, merely by the at least one positioning apparatus, characterized in that the disengaging means and the first coupling means comprise a single common linear drive. - wherein each welding apparatus has at least one first electrode, - wherein each first electrode can be used together with one of a plurality of second electrodes for welding together two components, in particular two bars, to form a product, in particular to form a grid, - wherein the welding machine has at least one first crossmember, - wherein each welding apparatus has a clamping mechanism, and the welding apparatuses can be clamped firmly onto the at least one first crossmember in selectable positions, and fastened thereto, by means of the clamping mechanisms, - wherein the welding machine has at least one positioning apparatus, - wherein the welding machine has at least one first linear guide with a guiding part and at least one guided part, wherein the at least one guided part is part of the at least one positioning apparatus and can be displaced along the guiding part, - wherein the at least one positioning apparatus has at least one first coupling means and each of the welding apparatuses has at least one second coupling means, and the at least one first coupling means and one of the at least one second coupling means can be coupled to one another, - wherein the at least one positioning apparatus has a disengaging means, in order to disengage the clamping mechanism of a coupled-on welding apparatus from the crossmember, - wherein a weight of a welding apparatus coupled onto the at least one positioning apparatus is borne, at least predominantly, merely by the at least one positioning apparatus,