A Method for Determining the Minimum Thickness of the Cut Layer in Precision Milling

The minimum cutting thickness is a key value in machining processes, as below this value the material will only undergo elastic and plastic deformation without chip removal. Existing measurement methods require time-consuming preparation and complicated procedures. This work focuses on the development of a new, simplified method for determining the minimum cutting thickness (h_min) using a contact profilometer that can be used in industry. The use of the contact measurement method has made it possible to directly determine the value of the h_min parameter, to determine the length of the characteristic zones of interaction of the tool with the surface of the specimen, and to measure the angle of inclination of the working plane of the specimen. Measurement using a profilometer allows for the obtainment of results with high resolution, which greatly facilitates the identification of zones of tool interaction with the workpiece material during the cutting test and reduces the value of the measurement error. The proposed method simplifies the specimen preparation process by using rectangular specimens positioned on an inclined plane, which allows the depth of the cut to be varied smoothly. This paper presents experimental results and statistical analysis. Tests were carried out on C45 steel, and an ANOVA analysis was carried out to evaluate the effect of the grinding parameters on the h_min parameter. It was found that the feed rate had the largest effect on h_min (93%), while cutting speed had a smaller effect. A mathematical model was developed to predict values based on selected technological parameters such as cutting speed and feed per tooth.