<title>Fundamentals of the advanced Fresnel tracer used for two-dimensional in-process micromeasurements</title>

Abstract

The authors would like to dedicate this paper to Prof Em. Dr. -Ing. Klaus Horn. We are all looking forward to celebrate his 70th anniversary at the 23rd! ofoctober, 1998. We would like thank himfor all ofhis support and construtive critics." ABSTRACT The drive to short development times and closed-loop process control has created a demand for new tools to collect the needed dimensional data. Optical technologies in fields such as sensors, signal processing, metrology, and instrumentation offer unique solutions to many areas of monitoring, diagnostics and control. The Advanced Fresnel Tracer (AFT), an innovative instrumentation for in-process micromeasurement consisting of a smart optical sensor and an automatic follow-up system, based on a temperature controlled grated glass scale or interferometer will be presented. This device may readily be integrated into a turning or grinding machine, e.g. for the ends of quality assurance and to enable an on-line automatic compensation of diameter deviations /1/2.The device contains an optical Fresnel diffraction sensor allowing a fast measurement of the workpieces actual diameter with an error less than 2im at scanning rates of more than 1 kHz. This paper presents the basic elements of the measurement of the surface topography, achieving three goals: 1) improvement of the instantaneous diameter measurement, 2) surface quality inspection, and 3) determination of the edge gradient or the waviness of the workpiece. The new compact, smart, and precise optical multiparameter sensor, the AFT has been developed and tested.