| 摘要 |
PROBLEM TO BE SOLVED: To suppress deformation of a molded body due to mold release.SOLUTION: In a manufacturing method of a spark plug insulator, a rear-part molding block is used which consists of a plurality of mold parts including: a first mold part which forms a first-part inner surface that encircles in the circular direction in the inner surface of the rear-part molding block; and a second mold part arranged in a tip side compared with the first mold part in an axis direction and forming a second-part inner surface that encircles in the circular direction in the inner surface of the rear-part molding block. During release of the molds, the rear-part molding block is disassembled into the mold parts by starting a movement of the first mold part to the rear-end side with respect to the rear molding part, and starting a movement of the second mold part to the rear-end side with respect to the rear molding part after the movement of the first mold part is started. Alternatively, the rear-part molding block may consist of a plurality of mold parts which form different parts of the inner surface in the rear-part molding block, respectively.SELECTED DRAWING: Figure 6 |
