Abstract: A method and an apparatus for manufacturing rigid computer memory disc substrates is disclosed wherein the apparatus comprises a circular base plate, the base plate being mounted horizontally for rotation about a vertical axis; a plurality of spindles rotatably mounted on motors mounted on the base plate, the spindles extending radially outwardly from the base plate, in equally spaced relationship therearound, the outwardly extending end of each spindle including a fastening means for mounting a rigid disc to be processed thereon; a plurality of work stations spaced around the circular base plate for performing work operations on the discs; and a motor for rotating the base plate so as to convey each of the discs consecutively to each of the work stations.

Abstract: An apparatus for measuring and controlling the force exerted on a disc by a rotating pad. More specifically, the present invention relates to an apparatus for controlling the forces exerted by a plurality of polishing pads used for polishing the surfaces of rigid computer memory discs. The spring mechanism that provides the load force to a free sliding shaft which transmits the force to the polishing member is fitted with a suitable transducer, such as a strain gauge, which senses the axial force transmitted down the sliding shaft to the polishing pads by way of the force/strain relationship of the spring mechanism. The strain sensed by the transducer is converted to an electrial signal which is conducted to the input of a closed loop, feedback control servo system which maintains the desired contact force of the pads on the disc and, at the same time, maintains an equality of forces on each side of the disc.