GB1533456A - Sawing - Google Patents

Abstract

1533456 Severing SIEMENS AG 16 Aug 1976 [20 Aug 1975 18 March 1976] 34085/76 Heading B3D Apparatus for sawing, for example, brittle material 30 such as semiconductor material, stone or quartz, comprises at least one elongate saw cutter 2 and a device for holding the material, the cutter being supported by leaf springs disposed transverse to the length of the cutter, first drive means for moving the cutter in the direction of the length of the cutter at a relarelatively high frequency small amplitude movement and second drive means for moving the holding device at a relatively low frequency large amplitude movement. The high frequency movement is between 50 and 2000 Hz with an amplitude of 0À01 to 0À3 mm., and the low frequency movement at about “Hz with an amplitude of between 50 and 100 mm. As described, a plurality of saw blades 2 having cutting edges provided with a diamond layer 4 or 6 are secured at one end to a tentering frame 8 and at the other end by a clamping block 10 fixed to the frame by screws 12, 14. An iron core 16 at one end of the frame 8 cooperates with a magnetic coil 18 and supply 22 mounted on a base 26 to effect the high frequency, small amplitude movement, the tentering frame being supported by leaf springs (60, ... 63, Fig. 2, not shown) in the base 26. The material 30 to be sawn is secured by adhesive 34 to an arm 36 mounted by a pivot 42 on a nut 54 engaging a screw 52 connected by gears 50 to a motor 48 for effecting the low frequency large amplitude movement. The arm 36 is movable about the pivot 42 by a lever 36 actuated by an hydraulic cylinder 44 to lower and raise the material 30 out of and into engagement with the blades 2. The blades are provided with apertures 82 so that the cross-section F1 at their edges is greater than the cross-section F2 at their centres so that the tensile stress is smaller at the edges of the blades than at their centres. In another embodiment, the high frequency small amplitude movement is effected magnetostrictively. The spacing between the saw blades may be maintained by a device 84 connected to the holding device 32 for the material to be cut and consisting of a comb, the back of which is below the teeth 88, ... 91 which extend upwardly between the blades and move downwardly as the depth of cut increases. In a further arrangement, the spacing device consists of two combs which are spaced apart a distance such as to be located one each side of the material to be cut and are connected to the drive for the arm 36 so as to move therewith.