Patent GB-1381021-A (GB)
Title: Shaping method and apparatus
IPC: B23Q35/34
Filed: 1972-02-17
Abstract: 1381021 Making dies and electrodes; beds and frames; copy-milling INOUE-JAPAX RESEARCH Inc 17 Feb 1972 [19 Feb 1971 22 Feb 1971 (2) 26 March 1971 21 May 1971 28 May 1971] 7301/72 Headings B3A B3B and B3K [Also in Divisions G1 G3 and C7] A computer-controlled process for the automatic production of dies (see Divisions G2-G3) comprises producing an electrode, or electrodes, by copy-milling and subsequently producing a die in an electrical-discharge machining apparatus. Optionally, an intermediate rough-shaping stage can employ an electro-chemical machining apparatus (see Division C7). Copy-milling.-A milling-machine for producing the electrode comprises a sensing head 301, Fig. 2, horizontally movable on a slide 310 so that it can be located at any point on a pattern S carried by a superposed table 311a, 311b which together with the slide provides for X, Y and Z movements. These movements are controlled by a programme 320 which coordinates the pattern position with that of workpiece W. The output signals from head 301 pass through an analyser 321 and control the position of a rotary tool T so that the latter is always placed at right-angles to the workpiece. The tool head is pivotable about an axis Ha by an arcuate rack-and-pinion 322a, 322b and the head is basically movable. Workpiece W is movable in the X, Y directions and may also be rotatable. In a modification, the workpiece and pattern W, S, Figs. 10-12, are mounted on a slide 831 and the sensor 801 comprises a plurality of sensing fingers 801a, 801b, &c. The slides are moved by lead-screws and the tool is preferably given at least five degrees of freedom. In the arrangement of Figs. 13, 14, a tool carriage 933 is vertically movable by a worm-and-wheel 933b, 933b<SP>1</SP> and a lead-screw 933a is pivotable by an arcuate rack 938 actuated by a servomotor 938d and a pinion 938c is rotatable about an horizontal axis Hc by a servomotor 935a and the worktable is movable in two horizontal planes. The tool and workpiece can be replaced by a sensor head and a pattern. In a further modification, both the pattern S and the workpiece W, Figs. 15, 15A, are mounted on a slide 1031 and the tool T and sensor 1001 are carried by a carriage 1033. A plurality of tools are carried in turrets 1040, 1041 which are indexed by stepping motors. The sensor may be electronically coupled to the tool head or mechanically by a link 1042. A similar mechanical coupling is used in the embodiment of Figs. 16A, 16B (not shown). The sensor head (1201), Figs. 17, 17A (not shown), is mounted on an arm (1232) rotatably mounted on a bar (1246) and is connected by a link (1243) to machining heads (1208). A number of variations for mounting the tool head are described in relation to Figs. 18-18E (not shown). A still further arrangement of tool and electrode support is described in relation to Fig. 19 (not shown) and a system of two degree angular rotation for a tool head (1708) is described in relation to Figs. 20, 20A (not shown). Electrical discharge machining.-Following inspection of a machined electrode by the automatic computer controlled system it is machined roughly by an EDM machine and finished in a further EDM machine. It is stated that the two machines can be combined, that the workpiece may be hardened prior to electrical machining, and that an automatic electrode changer may be employed for automatically controlled rough, medium and fine machining. In an example, the workpiece was of carbon steel and machined by a graphite electrode using kerosine as the machining liquid.