An optical tomographic method to characterize the mist distribution in MQL Tools

摘要

Proper mist flow is important to Minimum Quantity Lubrication (MQL) machining as only a small amount of lubricant-air mixture is applied to the cutting zone. This paper presents an optical-tomography-based method to visualize the lubricant distribution of MQL mist flow in through-tool channels, particularly for drilling. Highspeed images of the flow are acquired from multiple view angles to capture the 2D projections of 3D flow. The Filter Back Projection (FBP) algorithm is used to perform tomography and produce tomographic reconstruction image of the lubricant distribution in the through-tool channels. The method is validated with a known annular flow created using a vertical pipe flow. The method is also applied to two 3D printed drill bits, one with two straight channels and another with two helical channels to emulate actual through-tool channel geometries of drills. The tomographic reconstructions obtained using FBP match with the literature and show a clear influence of the channel geometry on the lubricant distribution. Physical, imaging, and lighting requirements to achieve proper results using this technique are also detailed in the paper.