SE320291B - - Google Patents

Abstract

1,169,044. Lapping. SPEEDFAM CORP. 20 July, 1967 [25 Nov., 1966], No. 33512/67. Heading B3D. The work retaining rings on the horizontal surface of a rotating planar lapping disc are rotatably supported by a carrier ring adjacent the outer periphery of the lapping disc, the carrier ring being selectively rotatable about the disc axis, and having means thereon, to allow the retaining rings to move about the axis of the lapping disc but not to rotate with the disc. A lapping machine comprises a framework with a tubular housing 12 providing support for a horizontal lapping disc 14 having a central well-bore 16 and radial slots 20 for conveying a mixture of abrasive and an oil carrier. The lapping disc is rotated by drive means mounted within the housing 12. Resting on the lapping surface are truing rings 22 confining therein workpieces 24. Weight plates may be placed on the workpieces. The rings are located by a central idler wheel 26 and by roller stops 32 mounted on a carrier ring 28. The latter is rotatably supported by idler rolls 34 mounted on the housing 12, and its outer periphery has a groove across which extend circumferentially spaced axial pins 38 with which meshes a pinion 46 driven through a speed reducer 44 by an electric motor (42) supported by a vertical plate 40 mounted on the housing 12. A micro-switch 48 mounted on the plate 40 co-operates with trip lugs 52 secured to the carrier ring 28 During lapping, the lapping disc 14 is rotated and the motor (42) is energized to rotate slowly the carrier ring 28 in the direction of rotation of the lapping disc 14. When the ring 28 has rotated through 90 degrees one of the trip lugs 52 actuates the microswitch 48 to interrupt rotation of the lapping disc 14 and carrier ring 28; after a short dwell, e.g. controlled by a timer, the lapping ring and carrier ring are again rorotated. The carrier ring is thus indexed through 90 degrees, this being effected in approximately one-quarter or less of the time required to lap the workpieces, so that as each ring 22 progresses 360 degrees around the lapping disc the workpieces therein are completely lapped. During the dwell, an operator at a given position, e.g. adjacent the control box 54, unloads lapped workpieces from a ring 22 which has arrived at that position, and loads fresh workpieces into the ring. Progression of the rings 22 through each 90- degree stage may be continuous or intermittent. The rings 22 may be moved continuously by inactivating the micro-switch 48, unloading and loading being carried out while the lapping disc and carrier ring are rotating. The carrier ring may be rotated in opposite direction to the lapping disc.