Manufacturing method of crucible protecting frame

A manufacturing method of a crucible protecting frame comprises that (a) each protecting plate is divided along the length direction of each protecting plate to form a first plate body and a second plate body, each first plate body is respectively provided with a first end face and a second end face, and a first surface and a second surface along the length direction and the thickness direction, and the first end face and the second end face are opposite to the first surface and the second surface; (b) a first groove and a second groove are formed in each first plate body, each first groove is concaved inwards from the first end face of the first plate body of each first groove, each second groove concaves from the first surface of the first plate body of each second groove to the second surface and is adjacent to the second end face, and the first groove and the second groove of each first plate body extend from top surface to the bottom surface along the height direction; (c) each second plate body is segme