| 摘要 |
PURPOSE:To mold a sound hole net for acoustic devices, having a completely matched net shape without burr even when knitted net is somewhat crooked by machining a cavity in one surface of a screen electrode and also a core in the remaining surface. CONSTITUTION:A metal net 13 of the same shape as a sound hole net is knitted by using copper wire, etc., and the metal net is pressed by press molds 14 and 15 having the same shape as that of the molded net of a molded cabinet to form a copper screen 24 which is in turn adhered to both internal and external supporting parts 16 and 18. A cavity 25 is fastened to a machining base 26 and the screen 24 is attached to the electrode-fitting shank 27 of a discharge machining device to subject it to discharge machining, whereby the shape of one side of the screen electrode 24 is transferred to the surface of the cavity 25 to form a groove 35. Then, by exchanging the inside supporting part 18 with a core 30 made of the same shape of a molding material, the core 30 is subjected to discharge machining on the surface of the screen 24 to which the internal supporting part 18 is adhered. Thus, the shape of the screen is completely matched with the cavity and the core 30 and, therefore, no burr occurs by distortion. |
