Patent GB-1377837-A (GB)
Title: Machine for simultaneous grinding of a plurality of semiconduct or blanks
IPC: B28D5/02
Filed: 1972-10-18
Abstract: 1377837 Grinding and severing V M DOLGOV V V SAVELIEV V K KRYLOV V M TOMASHEVSKY and E I ZOLOTAREV 18 Oct 1972 47994/72 Heading B3D A machine for grinding semi-conductor blanks 95 comprises a turntable 2 indexable on a bed 1, grinding heads 5, polishing heads 6 and cutting- off heads on the bed around the periphery of the table, the heads being rotatable about their axes which are radial of the turntable and oscillatable in planes perpendicular to their axes, carriages 64 reciprocatable radially of the table, chucks 72 on the carriages for holding the blanks, and a pusher 93 on each carriage for moving a chuck to present a blank held thereby to the cutting-off head. As described, the machine has two grinding heads 5, four polishing heads 6 and two cutting-off heads 7 disposed around the bed, and the turntable 2 has one carriage 64 for each head. Each of the grinding and polishing heads has a body 11, Fig. 2, carried on one end of a hollow shaft 12 mounted in bearings 15, 16 in the bed, the other end of the shaft being secured to a link 10 driven by reduction gearing and a motor to effect the oscillatory movement of the head which produces even wear of the grinding or polishing element. A shaft 21 extends through the hollow shaft 12 and, at one end, has a pulley 22 driven by a belt 9, and, at the other end, a pulley 23 engaged by a belt 24 which runs over a tension roller 25 and a pulley 26 on a shaft 27. The shaft 27 is axially slidable against a friction mechanism 33 in a bearing 29 rotatable in the body 11 and carries the grinding or polishing wheel 28, the wheel being rotated when the pressure of the blanks there against causes the friction mechanism to drive the shaft. The cutting-off head has a body 36, Fig. 3, which is mounted in a similar manner to the body 11, but its shaft 47 has a pulley 49 for a belt 50 which runs over a jockey pulley 51 and around a hollow spindle 52 rotatable in a bearing 54 in the body. The spindle carries a diamond abrasive disc 53 having an inner cutting edge. Each carriage 64 consists of a housing 71 which is movable along a slideway 70 on a base 68 secured to the table 2. A bevel bush 80 is secured to the carriage and mounted on a screw 79 engaging a threaded sleeve 74 which, in turn, is threaded into a bush 73 on the table 2, the bush being secured to a pinion 75. During rotation of the table, after the carriage has presented the blanks to the grinding and polishing heads, the pinion engages a rack portion 8 on the table to cause the screw 78 to advance the carriage to a position for cutting- off of the blank by oscillating moving of a cutting-off head 7. Each chuck 72 is rotatable in bearings 86, 87 in a respective carriage and has a number of plungers 94 which are urged towards its carriage by springs 92 and quickly-detachable clamps for mounting the blanks 95. The chuck is indexable to present the blanks successively to the cutting-off wheel 53 by a motor 85 controlled by a photoresistor 89 which is mounted on the carriage and is actuated when light from a lamp 90 passes through holes in a sleeve 88 on the chuck. After each indexing movement of the chuck, a plunger of an electromagnet 93 moves a plunger 94 against the pressure of its spring 92 to advance a blank to the cutting-off position. The machine is controlled by an electric circuit having a number of counters controlling the various operations so that the blanks are successively ground and polished by the heads 5, 6 and cut-off by the heads 7, the cut blanks being received in a transporting means 60 disposed within the spindle 52.