Preheating arrangement for a welding device, a respective welding device as well as a preheating method and a welding method

A preheating arrangement for a welding device having an upper tool mounted to an upper support and a lower tool mounted to a lower support, wherein the upper and the lower support are movable relative to each other between an initial position and a welding position, and the preheating arrangement comprises:

• a. a preheating device defining a first plane by a first centerline extending along a first axis X and a second centerline extending along a second axis Y being perpendicular to the first axis X, and
• b. the preheating device has a first side with a first preheating structure and an opposite second side with a second preheating structure, wherein
• c. the first preheating structure is asymmetric with respect to the first and/or the second centerline so that a respective axis is an axis of asymmetry, and
• d. the second preheating structure is oriented like the first preheating structure such that, when viewed along a third axis Z perpendicular to the first plane, the first and the second preheating structure are arranged one above the other, wherein
• e. the preheating arrangement comprises further a first actuator arranged to rotate the preheating device between a first position and a second position such that the preheating structures in the first position have a first orientation and in the second position a second orientation
• e1. in which the preheating structures are rotated around the axis of asymmetry by 180° compared to the first orientation or
• e2. in which the preheating structures are rotated by an angle α in the range of 0°<α<360° around the third axis Z compared to the first orientation.