Robotics Case Studies
Robotic Submerged Arc Welding
by Wolf Robotics
Wolf Robotics, A Lincoln Electric Company Posted 07/02/2009
Cast Iron Pipe
Ductile Iron Pipe
Automates the subarc welding process
Adapts weld program to part variations
Controls all aspects of the production cycle
Improves product quality and consistency
Tracks service and maintenance requirements
The welding cell consists of two individual IRB 4400 robots mounted on risers and equipped with a Wolf Cell Control, Lincoln PowerWave power sources, submerged arc welding torches with flux hopper and a linear transducer head, flux recycling conveyor and collection area, large capacity welding wire drums, Tactile Sensing and protective fencing.
The cast iron pipes are brought into position with a conveyor system and loaded on turning rolls. The robots are equipped with Tactile Sensing to determine pipe location and the weld program starting point. The robots then position the linear transducer head on the ductile pipes. Fluctuations in the pipe surface curvature are compensated for with the transducer head as it maintains a consistent wire-to-surface distance and clock and weld angles.
Flux is dispensed onto the welding surface and the arc is struck. The pipe begins rotating at the prescribed rate for the desired weld bead. The flux dispenser is fed by a pressurized flux hopper located outside the robotic working area. As the pipe rotates, the used flux and resulting slag falls onto a conveyor system that transports them to a collection area where the slag is separated from the flux and discarded. A needle scaler located at the bottom of the pipe assists in the slag removal. The flux is then separated from the slag and then returned to the flux hopper for reuse.
The subarc welding wire is supplied by a large capacity welding wire drum and distributed to the welding torch using a wire feeding mechanism. An automated wire cutting device is also used to maintain the proper wire stickout.
Robot automation is accomplished through the initial location sensing, weld equipment and program control, process monitoring, information documentation and maintaining the production operation with minimal operator involvement.