Design of End of Arm Tool, Guide Plate and Support Plate for Robotic Spot Welding Application

ABSTRACT Ventilation lamination sheets are required for cooling the stator core of the steam turbine generator and are manufactured by welding ventilation spacer bars on a lamination sheets using resistance welding (spot welding) process. The existing process in the industry to weld spacer bars on a lamination sheet is performed manually. It takes approximately 60 minutes to weld ventilation spacer bars onto one lamination sheet manually. Automating this process can reduce this time to as low as 15 minutes thereby increasing the production rate by at least 400%. Also, for mass production, the running cost of an automated process is much lower than a manual process. The automated process employs a robot to move the lamination sheet through a precise path which corresponds to the location of the weld-spots. As the lamination sheet needs to be suspended off the robot's flange for the entire duration of the process, it becomes necessary to provide a rigid support to the lamination sheet. Also, the spacer bars need to be held in their defined position before they are welded. The lamination sheet is very thin and undergoes considerable deflection under its own weight. While supporting the lamination sheet, the welding operation must not be hindered in any way. This paper aims to design guide and support which sandwiches the lamination sheet between them. The guide plate is used to hold the spacer bars in their defined positions accurately and the support plate is used to support the weight of the lamination sheet with the spacer bars and the guide plate with minimum deflection. Both of the plates are required not to obstruct the movement of the robot and the welding operation in any way.