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: The method of finishing the surface of a disc, such as a disc whereon information is magnetically recorded for use in computers and the like. It involves urging against one side of a rotating disc, a polishing pad having a polishing compound or medium thereon, and simultaneously urging a non-polishing pad against the opposite side of such disc in alignment with the polishing pad. To simultaneously polish the opposite side surfaces of the disc, a second pair of pads (one polishing and one non-polishing) is equiangularly spaced on the disc in relation to the first pair of pads, but the pads of the second pair of pads are reversed so as to cause the finishing process to occur on the disc side not being polished by the first pair of pads. Any desired even numbered pairs of pads may be employed.The polishing and non-polishing pads are caused to rotate relative to and against the respective side of the disc as the disc itself is caused to rotate about its axis.

Abstract: A method and apparatus for disc position centering is disclosed. The invention is adapted to precisely position the center of a disc at a predetermined position, in relation to the disc's outer diameter, when the allowable variation of the absolute value of the outer diameter is larger than the degree of centering precision required. The apparatus is adapted to determine the outer diameter of the disc using a displacement measuring device, and data provided to the system computer. The apparatus then positions the disc to the desired center position using devices which grip the disc by its outer periphery and whose relationship to the desired center position is known.

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.

Abstract: A method of manufacturing a rigid computer memory disc where manufacturing operations may be simultaneously performed on both surfaces of the disc. The method that accomplishes the above is to initially provide a disc with a false inner diameter which is smaller than the desired inner diameter thereof. The space between the false inner diameter and the final inner diameter is used for clamping the disc. Thus, the whole final face is exposed for performing the various manufacturing steps.