| 摘要 |
PURPOSE:To obtain a stem with an outer diameter of 40mm. or more, eccellent in precision of the shape and flatness (thickness), and with a high yield by making the length of metal wires protruded from the lower mold shorter than a predetermined value. CONSTITUTION:A pair of molds 5, 6 molding a desired stem shape are arranged above and below, metal wires 3 are inserted respectively into multiple metal wire inserting vertical holes 4 provided at predetermined positions of the lower mold 6, a short tube with predetermined weight is placed on the lower mold 6, the short tube 2 is melted around the metal wires 3 by means of burner heating while the mold 6 is rotated, then it is press-molded with the upper and lower molds 5, 6. In such a production method of a stem, the outer diameter of the stem is made 40mm. or more, and the length of the metal wires protruded from the surface of the lower mold 6 is made 20mm. or less. |
