Integrated autonomous monitoring of ball screw drives

In ball screw drives wear occurs which results in decreasing dynamic performance and accuracy and can finally lead to machine breakdown. In order to avoid unacceptable machining results and failures, ball screws are changed based on previously calculated motion cycles and loads. State dependent maintenance requires monitoring of the wear progress. Here, an integrated sensory ball screw double nut system is presented. It measures the pre-stress as a wear indicator by strain gauges or sensory thin layers. Sensor information is processed by integrated electronics and communicated wirelessly. Energy harvesting and hybrid energy supply strategies are introduced. Measurement results are discussed. (c) 2012 CIRP.