Sun Yuwen

An Approach to Modeling Cutting Forces in Five-Axis Ball-End Milling of Curved Geometries Based on Tool Motion Analysis

The prediction of five-axis ball-end milling forces is quite a challenge due to difficulties of determining the underformed chip thickness and engaged cutting edge. To solve these concerns, this paper presents a new mechanistic model of cutting forces based on tool motion analysis. In the model, for undeformed chip thickness determination, an analytical model is first established to describe the sweep surface of cutting edge during the five-axis ball-end milling process of curved geometries. The undeformed chip thickness is then calculated according to the real kinematic trajectory of cutting edges under continuous change of the cutter axis orientation. A Z-map method is used to verify the engaged cutting edge and cutting coefficients are subsequently calibrated. The mechanistic method is applied to predict the cutting force. Validation tests are conducted under different cutter postures and cutting conditions. The comparison between predicted and measured values demonstrates the applicability of the proposed prediction model of cutting forces.

Determination of the scheme of precision grinding compensation on the radome

The radome, which is often used to house airborne scanning radar antennas, causes a large boresight error and boresight error slope of the radar antenna. One way to decrease the boresight error induced by the radome is to modify its geometric thickness. Determining the grinding scheme from the boresight error performance is the most important problem to be solved. A typical inverse problem about electromagnetic fields is solving the precise grinding compensation area and allowance according to the antenna aperture distribution and the radome’s boresight error performance, which could hardly be solved by a purely mathematical method. An effective approach combining theoretical analysis and mathematical calculations with experimental measurement is presented in this paper to determine the grinding area and allowance for compensating the boresight error performance of the radome. By comparing the calculated and measured data of the boresight error and the boresight error slope before and after grinding, it is shown that this method is simple and practical and can be used for many kinds of radomes.