Forces monitoring in shape grinding of complex parts

This article deals with the monitoring of process forces when grinding complex mechanical components, such as screw rotors used for the building of gas compressors, which require high dimensional precision and low surface roughness, in order to ensure their proper functionality. Such components must rotate very close together, but without coming into contact, to ensure an airtight seal and to reach maximum efficiency in terms of gas flow rate and compression ratio. This article describes a load force instrumented workpiece holder, employing commercial piezoelectric load washers, to be used for online monitoring of grinding forces. After laboratory calibration, the equipment is then used in a two-level full factorial experimental design for its validation within an industrial environment. The effects of the main grinding parameters (e.g. wheel peripheral speed, feed rate and depth of cut) on the evolution of grinding forces during the process are investigated. The methodology used here can be extended to the grinding of helical surfaces of any shape, such as in precision manufacturing of helical gears.