Patent ID: 8901449

Claim:
A spot welding system comprising: a welding gun provided with an electrode pair capable of opening and closing; and a dressing determination device configured to determine a quality of a shaping process applied to an electrode of said electrode pair, wherein said dressing determination device comprises: a visual sensor configured to obtain an image of said electrode, said visual sensor configured to identify a base and a tip of said electrode on said image and measuring a distance between said base and said tip on said image, by image processing; a visual sensor control section configured to allow said visual sensor to measure said distance immediately before and after said shaping process is performed; a cut amount calculation section configured to calculate a difference between said distance measured by said visual sensor immediately before said shaping process is performed and said distance measured by said visual sensor immediately after said shaping process is performed, as a cut amount of said electrode; and a cut amount judgment section configured to judge whether said cut amount calculated by said cut amount calculation section is within a predetermined acceptable range or not, wherein said visual sensor is configured to obtain a position and an orientation of said base, based on said image of said electrode and an image of a shaft part on which said electrode is disposed, and identify said tip based on said position and said orientation.