| 摘要 |
PURPOSE:To improve the sound quality of a diaphragm without increasing the manufacture cost by cold-pressing two metallic foils coated with a press contact preventing agent at a part other than parts corresponding to a projected pattern of a core member and then swelling out the foils according to the projected pattern. CONSTITUTION:The press contact preventing agent 7 such as carbon is printed and coated to the part than the parts corresponding to the required projected pattern 5 of the aluminum foils 4 at first. Then the aluminum foil 4' is overlapped on the aluminum foil 4 and they are cold-pressed through rollers 8 and 8'. After arranging the two aluminum foils 4, 4' in a metallic die 9, high pressure gas is delivered from a pipe 10 to form the part not coated with the press contact preventing agent 7 as a recessed pattern on the metallic die 9 and a core member 11 is obtained by using the metallic die 9. A diaphragm is obtained by adhering a skin member to the core member 11 thus obtained. |
