Tension monitoring in a belt-driven automated material handling system

The extension of the useful life of manufacturing equipment is one of the keys to sustainable manufacturing. The high uptime requirements of the semiconductor industry result in the need for conservative preventive maintenance schemes, which leads to replacement of key components before the end of their useful life. This paper presents the results of research toward a more intelligent condition based maintenance scheme for belt monitoring in a belt driven automated material handling system. An experimental study of belt dynamics showed that transverse belt vibrations were sensitive to changes in belt length, belt tension, belt misalignment, and excitation location. Based on these findings, a novel, contact based device was designed to consistently excite belt vibrations in the material handling system with greatly reduced variations in belt length and initial condition location. On average, standard deviations of tension estimates using the device were 65% lower than that of a trained technician performing the current standard technique on three different robots. This design was then further adapted to facilitate a non-contact belt excitation and monitoring approach that did not require bringing the material handling system offline in order to obtain sensor readings. Such a procedure greatly eased and accelerated the monitoring process.