Measurement of macro-geometric characteristic variables involves the acquisition of features of geometric elements that are defined in design by dimensions and tolerances for dimensional, form, and positional deviations (Figure ). The term ‘dimension’ refers both to the diameter of rotationally symmetrical workpieces and to distances and angles between planes and straight lines and to cone angles. The sensors used for measurement can be classified according to the method used to acquire the measured value into mechanical, electrical, and optoelectronic sensors | Sensors in Manufacturing. Edited by . Tonshoff I. Inasaki 71 Copyright 2001 Wiley-VCH Verlag GmbH ISBNs 3-527-29558-5 Hardcover 3-527-60002-7 Electronic 3 Sensors for Workpieces Macro-geometric Features A. Weckenmann Universität Erlangen-Nürnberg Erlangen Germany Measurement of macro-geometric characteristic variables involves the acquisition of features of geometric elements that are defined in design by dimensions and tolerances for dimensional form and positional deviations Figure . The term dimension refers both to the diameter of rotationally symmetrical workpieces and to distances and angles between planes and straight lines and to cone angles. The sensors used for measurement can be classified according to the method used to acquire the measured value into mechanical electrical and optoelectronic sensors. A small proportion work by other methods eg pneumatic measuring methods. The sensors mainly work with point-by-point usually tactile measured value acquisition. Contactless and wide-area measurements of characteristic variables of the rough shape are possible with optical sensors. Fig. Deviations of the macro shape of workpieces 72 3 Sensors for Workpieces Mechanical Measurement Methods By far the greatest number of measuring systems used in dimensional metrology work with tactile probes and mechanical transmission of the measured value. For acquisition and indication of the measured value a linear scale is usually used or the measured value is transmitted to deflection of a needle say by means of a rack and pinion. Indication is analog. Measuring instruments with a digital display usually use measuring systems with capacitive inductive or optoelectronic Section measured value acquisition. Calipers The various designs of calipers DIN 862 are used for outside inside and depth measurements. The measured length is transmitted mechanically and a scale with millimeter divisions that can be read absolutely is used. Use of a
