Abstract: An on line high precision system with laser and optical fiber sensors for measuring the surface roughness in precision machining is reported. The operation principle of the system is based on the theory of surface scattering. To ensure high precision of the measurement, a series of technology such as the intensity compensating and modulating, signal processing in a single channel and complementary sampling and others, are synthetically adopted. In this system, a single chip microcomputer is used, and the whole process of measuring, including signal switching, complementary sampling, calculating or processing, displaying or printing and so on,is controlled by the single chip microcomputer.

Key words: surface finishing, roughness, optical fiber, measurement, system