Scaling of the milling process of tungsten-copper-composites: Experimental and numerical research

This article deals with the experimental and numerical research of scaling effects occurring in the milling process of tungsten-copper-composites (WCu). The experimental tests served to quantify single scaling effects like e.g. milling cutter diameter and the feed per tooth. To enhance the understanding of the process the effects were emulated numerically with finite element simulations. In all experiments an intense impact of the specific WCu material properties on the machining process and the quality of the process output was detectable. The tests concerning the tool displacement showed that an enlargement of the feed per tooth causes a significant increase of the tool displacement and also that a smaller mass fraction of tungsten promotes a smaller tool displacement, however at the cost of higher data scattering. A high tungsten mass fraction impedes the chip formation and leads to intense tool deformations due to the hardness of tungsten. The preliminary quasistatic chipping tests validated that a lower tungsten mass fraction leads to decreasing cutting forces. The increasing cutting forces coming along with smaller tungsten particle size correlated with milling experiment executed previously but were only detected with WCu 60/40 so far. The SEM pictures show clear differences between the WCu specifications and support the high impact of the WCu material characteristics. A thermographic test setup was developed to obtain knowledge about the temperatures at the tip of the cutting edge of a milling tool. The tests pointed out that the temperature rises during the engagement time whereas most of the cooling happens in the first quarter of the idle time. Since the previous 3D model used for FEM simulations did not provide a constant element size in the model for different WCu specifications a new fully parameterized geometry preprocessor was programmed. First simulations confirmed the strong influence of the WCu specifications on the process outcome. Entnommen aus TEMA