A solid-analytical-based method for extracting cutter-workpiece engagement in sculptured surface milling

Abstract

Five-axis milling is used extensively to machine the complex parts with sculptured surfaces in die and mold, automotive, aerospace industries, and so on. Cutting force, a key input in simulating the vibration of cutting tools prior to implementing the real machining process, is mainly determined by the feed rate, spindle speed, cutting depth, and cutter-workpiece engagements (CWE). However, identifying the CWE efficiently and accurately is one of the most challenging problems in milling workpiece with complex geometry. This paper presents a novel and integrated solid-analytical-based approach to extract the CWE data in five-axis milling complex parts with sculptured surfaces. In this method, cutting tool and workpiece are modeled exactly. By performing “Boolean Subtraction” operations between cutting tool and workpiece at any cutting location (CL), the possible CWE is obtained firstly. For first cut and slotting cases, the exact CWE can be extracted easily according to the relationship between feed direction and surface normal direction of cutting tool. For following cut cases, the extra steps are needed because the CWE in these cases is associated with the previous cut. The critical line swept surface is constructed analytically at three continuous cutting locations in a previous cut. After trimming the possible CWE using the critical line swept surface, the exact CWE can be identified finally. The advantages of the proposed method are its robustness and flexibility to cancel the complex steps for constructing tool swept volume and updating in-process workpiece. Validation tests show that the developed method has higher efficiency and accuracy.