Spot Welding in the automotive Industry was originally a hard and physical manual job in an unpleasant and unhealthy environment. Pressed steel car components were assembled and jigged prior to the manual manipulation of spring balanced welding heads to apply a given number of spot welds to hold the assembly together. Consistency and quality were required to give the car body structural integrity.

Perfect for automation, the first robots moved into create the spot welding body lines which are producing all over the world.Two techniques were favoured. The pre-assembled bodies could either be processed by robot lines or dedicated transfer lines.

The robot lines consisted of multiple robot stations which were serviced by an indexing conveyor system. Each pair of robots at a workstation, one each side of the body, would be designated a number of spots on the body, and they would only repeat these spots for each new body which entered their station. The length of the line and the number of stations would be determined by production requirements. Bodies/hour would determine how many stations were required.

In the development of a new line, the first requirement would be for a weld study. This would determine where the spots were, how many axes were required to access each location and move/spot weld cycle times. It would also determine whether any special configurations were required to access spots like robots on overhead gantries or underbody locations.

A robot line is based on taught locations and pre-programmed activity, whereas the dedicated transfer line has much less flexibility but a higher line speed.

The dedicated line is based on a single weld gun for each spot so the tranfer line indexes the body into position. A multi head is then moved into position around the body and the spots can be produced simultaneously. There is no programming and no lost move time between spots.

If you would like to make a contribution contact us
Send us your copy, or a web address for any papers that you have published.