Tool Run-Out Measurement in Micro Milling

The interest in micro manufacturing processes is increasing because of the need for components characterized by small dimensions and micro features. As a result, researchers are studying the limitations and advantages of these processes. This paper deals with tool run-out measurement in micro milling. Among the effects of the scale reduction from macro to micro, tool run-out plays an important role, affecting cutting force, tool life, and the surface integrity of the produced part. The aim of this research is to develop an easy and reliable method to measure tool run-out in micro milling. This measuring strategy, from an Industry 4.0 perspective, can be integrated into an adaptive model for controlling cutting force, with the aim of improving the production quality and the process stability, while at the same time reducing tool wear and machining costs. The proposed procedure deduces tool run-out from the actual tool diameter, the channel width, and the cutting edge's phase, which is estimated by analyzing the cutting force signal. In order to automate the cutting edge phase measurement, the suitability of two functions approximating the force signal was evaluated. The developed procedure was tested on data from experimental tests. A Ti6Al4V sample was machined using two coated micro end mill flutes made by SECO setting different run-out values. The results showed that the developed procedure can be used for tool run-out estimation.