When the graphite electrode is connected, the electrode hole, the electrode end face and the joint are blown off with compressed air. There should be no dust accumulation and foreign matter embedding, and the joint should be kept clean and flat. When the two electrodes are screwed to a certain extent (the gap is about 10mm), then use compressed air to blow once, then tighten the electrode with torque clamp. The torque applied when tightening should be appropriate. If there is a gap at the joint after tightening, it must be re-joined until there is no gap.