What's the difference between row welder, gantry welder and multipoint welder?

There is no complete and accurate answer to this question. The three can refer to a model in general, or they can be expressed separately.

Generally speaking, row welding machine refers to a welding machine that can weld more than three or four points at a time with a single head mesh; Gantry welding machine is a semi-automatic or automatic welding machine composed of multiple welding heads, which can weld a row of mesh pieces at a time; Multi-spot welding machine is composed of more than two welding heads, which is often used where a workpiece has multiple spot welds.

If the above classification is true, it is all exposed loopholes, and I will give you a reference. Your problem is basically unsolvable.