Limiting structure for precision casting welding

The limiting structure comprises a supporting frame, the supporting frame is in a three-fork shape, horizontal sliding strips are installed at the triangular positions of the supporting frame in a sliding mode, a positioning sleeve is fixedly installed at the tail end of each horizontal sliding strip, and vertically-distributed positioning guide rods are installed at the tail ends of the horizontal sliding strips in a sliding mode. A mounting plate is arranged at the center of the lower surface of the supporting frame, a threaded ejector rod is in threaded connection with the center of the supporting frame, the tail end of the threaded ejector rod is rotationally connected with the mounting plate, and an angle scale is fixedly mounted on the lower surface of the mounting plate. An arc-shaped support is rotationally connected to the angle scale, and vertically-distributed supporting rods are fixedly installed on the lower surface of the arc-shaped support. By means of the structure, the placing position of the