GB1370356A - Machine tool and a method for abrading a workpiece - Google Patents

Abstract

1370356 Abrading ZNIITMACH 10 Sept 1971 42423/71 Headings B3D and B3V A method of machining a surface of a workpiece comprises holding particles by an electromagnetic field so that they bear against the surface and two relative motions, one being a reciprocating motion, are produced between the workpiece and the electromagnetic field such that the particles held in the field abrade the surface along non-parallel interocating abrasion paths. A machine for carrying out the method has a rectangular body 1 divided by a crosswall 2 to form a chamber 3 having a top plate 8. A support 7 is reciprocable along guide ways on the support by a lead screw 16 driven by gearing 36, 38 from a motor. The support carries a U- shaped electromagnetic core 12 having one limb shorter than the other, each limb having an electromagnetic coil 9. Packs 17, 18 are mounted on the coils and carry adjustably mounted tools 13, 26. The drive screw 16 is mounted in bearings 31 in bases 32, 33 secured to the support 8, the bases carrying heads 45, 89 having centres 52, 88 for supporting a workpiece so as to be between the tools 13, 26. The centre 52 is mounted in longitudinal ball bearing in a sleeve rotatable in bearings in the head 45 by a belt drive 64 from a motor 65. The centre is axially reciprocated while rotating by a mechanism 55 driven from a motor 67. To accommodate the reciprocating movement, the centre 88 is mounted on longitudinal ball bearings in the head 89 and is urged towards the centre 52 by a spring. Particles of ferromagnetic powder are held by the electromagnetic field against the workpiece, which may be a ball race mounted on a mandrel between the centres, and abrade the workpiece as it is rotated and reciprocated and as the support 7 is reciprocated along the plate 8 by the lead screw 16. The chamber 3 houses a tank 4 having cooling liquid which is delivered by a pump 105 to a nozzle 107 adjacent the workpiece. In another embodiment for abrading the inner and outer surface of a workpiece, the latter is mounted in a chuck (118, Fig. 9, not shown), which replaces the centre 52, and the centre 88 is replaced by another coil (120) mounted in a head reciprocable along the support 8. A bunker-dosing unit may be provided for supplying the ferromagnetic powder to the workpiece. The machine may be provided with transparent covers 84, 85, cover 85 being slidable over cover 84 to provide access to the working area of the machine. High electrical resistances at the points of contact of the particles with the workpiece causes current to melt the tips of the micro-roughness.