Abstract: The invention relates to a method for machining flat workpieces in a double-sided machining tool, which has an upper and a lower work disk, wherein at least one of the work disks is rotatingly driven and the work disks each have an annular work surface, wherein the work surfaces amongst themselves limit an also annular work gap, in which at least one carrier is located, which guides at least one workpiece in the work gap, so that the at least one workpiece is machined in a double-sided manner between the work surfaces. The distance between the work disks is measured at at least two radially spaced measurement locations of the work gap and in that, from the measured distances, a distance between the work disks is determined at a location of the work gap representing the thickness of the at least one workpiece machined in the work gap.

Abstract: A device for determining the position of a working surface of a working disc of a double-sided machine tool, a double sided grinder in particular, wherein the double-sided machine tool has two working discs, which form a working gap for double sided machining of work pieces between working surfaces facing each other, and of which at least one is rotatingly drivable, wherein the device comprises an optical measurement device having a radiation source, an optical detector device, and an analysis device, designed for being disposed outside of the working gap.

Abstract: The invention relates to a method for machining flat workpieces in a double-sided machining tool, which has an upper and a lower work disk, wherein at least one of the work disks is rotatingly driven and the work disks each have an annular work surface, wherein the work surfaces amongst themselves limit an also annular work gap, in which at least one carrier is located, which guides at least one workpiece in the work gap, so that the at least one workpiece is machined in a double-sided manner between the work surfaces. The distance between the work disks is measured at least two radially spaced measurement locations of the work gap and in that, from the measured distances, a distance between the work disks is determined at a location of the work gap representing the thickness of the at least one workpiece machined in the work gap.

Abstract: The invention relates to a method for measuring the thickness of a discoidal workpiece, which serves as a substrate for electronic components, comprising the steps: infrared radiation is directed at the top side of the workpiece, wherein a first radiation portion is reflected on the top side and a second radiation portion penetrates the workpiece thickness, is reflected on the bottom side of the workpiece and emerges again on the top side of the workpiece, the first and the second radiation portion interfere under formation of an interference pattern and the optical workpiece thickness between the top side of the workpiece and the bottom side of the workpiece is determined using the interference pattern. It is provided according to the invention that the mechanical workpiece thickness is determined from a measurement of the intensity of the infrared radiation reflected and/or transmitted from the workpiece.