| 摘要 |
1364245 Making dies; abrading E G FELDCAMP 9 Nov 1971 [11 Nov 1970] 53551/70 Headings B3A and B3D An extrusion die or other apertured component is made by making a spark erosion electrode from. a blank by a cutting tool moving in a plane at right angles to the desired electrode axis, forming an aperture in a die blank using the electrode and thereafter forcing an abrasive compound through the aperture. A copper plate is soldered to a steel plate which is mounted on a milling machine table by an electromagnetic chuck, whereupon the copper plate is machined in a single pass to the desired shape by a vertical side milling cutter. The copper plate is removed from the steel plate and the profile finished by hand. The spark-erosion electrode formed is used to make an aperture in a die blank, after which the die is mounted in a holder at one end of a cylinder and a billet of 150 grit silicon carbide particles contained in a plasticised petroleum wax having a penetration hardness not greater than 45, is extruded through the die aperture by a ram. The extruded wax shape is examined to check the shape of the die aperture. An abrasive of liquid or pastelike form may alternatively be used. The die aperture is subsequently polished by hand using an emery cloth, the abrading and polishing steps being repeated using abrasion particles up to 1000 grit size. The die may be heat treated at various stages during the process. |
