Experimental Study On The Optimal Parameters Of Hardened Mould Cavity In High-Speed Milling

Along with the development of the die & mould industry, the manufacturing level is raised,and the high-speed milling to the hardened mould is popularized.However, because of the hardness of hardened steel, and the operators lack of corresponding knowledge in machining, the tools are worn or even damaged easily in the milling process in early days, which directly affects the quality of surface in the mould.Firstly, in order to lay the foundation for the follow-up measure of surface quantity, and optimization of maching parameter, the characteristics of high-speed milling, the process parameters, the characteristics of surface profiles and the evaluation standard(especially surface roughness) of surface quantity are detailedly explained in this paper.Secondly, as a science and technology subject of the government,and supported by the company, the study for the milling process in hardened steel mould cavity (HRC55) using coated-carbide end-mill of 6mm diameter is proceeded,and a lot of milling experiment is carried out using high-speed milling machine(maximum rotating speed up to 30000rpm). With the approach of "the Single Factor", the infuences of materials of harden steel die & mould (4Cr5MoSiV1) made in China in different cutting parameters on the surface quality of the cavity are studied,and the cutting parameters in high-speed milling are optimized.The experiment indicates that the cutting speed, feed speed and cutting depth influence surface quality of the mould differently. In experiment on cutting speed,if the feed rate per tooth and axial cutting depth are settled, the result indicates that if the tool rotateing is higher, the surface quantity grows better; however, after the speed increases to a certain value, the relation between the surface roughness and variety in cutting speed is not so close. In experiment on feed rate, if the cutting speed and axial cutting depth is settled, the result indicates that the value of surface roughness increases along with the increasing value of Vs, but the relation between them is more than linearity.In experiment on axial cutting depth, if the cutting speed and feed rate is settled, the result indicates that the value of the surface roughness of workpiece varies from 0.4μm to 0.65μm along with the axial cutting depth varying from 0.05mm to 0.3mm, which is unconspicuous. Taking various factors into account, the optimal cutting parameters are: v(?) =240m/min, v(?)= 1750mm/min, a_d=0.15mm.Finally, taking the high-speed maching process of the mould cavity of a typical mobile telephone shell for example, this paper elaborates the high-speed machining process of modern mould.Through measuring the surface quality of the mould before and after the parameters are optimized, the correctness of the optimal parameters is proved.