Study On New Method And Tool Structure For Efficient Cutting Of Difficult-to-cut Materials

Difficult-to-cut materials have been widely used in many industrial areas. These materials always satisfy actual application requirements because of their excellent properties. Previous studies have examined methods for decreasing cutting forces and cutting heat as well as for increasing tool life and machining efficiency by the new method and the tool structure for efficient cutting of difficult-to-cut materials. In this thesis, the new method and the tool structure for efficient cutting of difficult-to-cut materials was researched. The main of this paper is as follows:1. The proposed method, i.e., the milling-milling machining method, is based on the concepts of composite machining, wear ideological homogenization, orderly multi-edge machining,and multi degree of freedom cutting method. It adopts a composite machining process. The milling-milling machining method combines the advantages of face milling and helical end-milling cutters and uses the synthesis motion of these two cutters to complete surface processing. The principle of milling-milling machining method is analyzed, and the milling-milling machining method is carried on the classification. According to the advantage of combination of the milling-milling machining method, up–down millingmilling machining method is proposed.2. Through theoretical and experimental methods the advantage of the milling-milling machining method is obtained: The cutting force of the milling-milling machining method is smaller than that of the common face milling method. The milling-milling machining method successfully solve the problem of chip breaking. The actual cutting speed of the millingmilling machining method is the synthesis speed of end-milling cutter and cutter body. Therefore, when the end-milling cutter speed has a large value, the cutter body speed has a smaller value, which can realize high-speed cutting. The milling-milling machining method improve the tool life. The milling-milling machining method has high processing efficiency and high material-removal rate. The milling-milling machining method provides the advantages of a large milling area for a large-diameter face milling cutter as well as a light, stable, and highly efficient cutting of a helical end-milling cutter. The outstanding achievements of face milling and helical end-milling cutters can be applied directly to the milling-milling machining method. Meanwhile, the milling-milling machining method also has its unique characteristics. In particular, the up–down milling-milling machining method can offset a portion of the cutting forces.3. Through theoretical and experimental methods we found that the milling force in the milling-milling machining method increases with the speed rate ratio increasing. With the increase of the speed rate ratio the thickness of chip will decrease and the equivalent thickness of chip will also decrease. With the increase of the speed rate ratio the surface roughness Ra decrease and the surface morphology is getting better and better. From the perspective of theory and practice, the speed rate ratio of the multi degree of freedom cutting method is analysised deeply.4. According to the principle and mechanism of the milling-milling machining method, a variety of hardware realization form of the milling-milling machining method is proposed, which has carried on the innovation from the structure. Based on its characteristic, the milling-milling machining method can be achieved by integrating mechanical and electrical aspects. The milling-milling machining method can be realized by using epicyclic gear trains. The planetary cutter, the electromechanical milling-milling driving head, the mechanical milling-milling driving head have been designed. According to the characteristics of the milling-milling machining method itself, nonlinear helical end-milling cutters is designed.5. With the same idea of the milling-milling machining method, the driving rotary milling processes, another form of multi degrees of freedom milling method, is analyzed, including the relationship between the speed rate ratio and the surface morphology, the tool flank wear, cutting force, and hardware realization form, etc.