| 摘要 |
<p>983,738. Making dies; electro erosion. BUDD CO. Dec. 4, 1963 [Dec. 7, 19621, No. 47887/63. Headings B3A and B3V. A blanking die set is made by using a steel rule die 22b, Fig. 3, as an electrode in the electrical discharge machining of a plate 30, 32 to form two separate pieces at least one of which is used subsequently with the rule die as a shear member, Fig. 1. The steel rule stock in its annealed state is bent to the required profile and then hardened. It is mounted between retaining plates 18, 20 of resin or plastic impregnated with filler, against a backing plate 16 supported through an insulation pad 14 on a platen 12; the pad 14 may be omitted. Alternatively, the inner plate 20 may be of metal to which the rule die 22 is connected by resistance welding. The rule die may also be flash or resistance welded or brazed to its backing plate 16. During machining, Fig. 3, the tool steel workpiece 30, 32 is immersed in a dielectric 44 circulated by a pump 46 through filter 48. High frequency pulses at over 50,000 c.p.s. are supplied by an adjustable power source 38. After the machining is completed the working edge of the rule die is bevelled by grinding to co-operate with the inner shear plate 30 and outer stripper plate 32 supported on a resilient pad 34. Alternatively, the inner plate 30 may be supported on a resilient pad whilst the outer plate is rigid.</p> |
