CHECKING-UP OF OPTICAL GRADUATED RULES BY LASER INTERFEROMETRY

The main aspects related to the operating principle, design, and imple mentation of high-productivity equipment for checking-up the graduatio n accuracy of optical graduated rules used as a length reference in op tical measuring instruments for precision machine tools are presented. The graduation error checking-up is done with a Michelson interferome ter as a length transducer. The instrument operation is managed by a c omputer, which controls the equipment, data acquisition, and processin g. The evaluation is performed for rule lengths from 100 to 3000 mm, w ith a checking-up error <2 mu m/m. The checking-up time is about 15 mi n for a 1000-mm rule, with averaging over four measurements. (C) 1996 Society of Photo-Optical Instrumentation Engineers.