Study On Multi-axis CNC Milling Process For Deep Cavities Of Molds

With the widespread use of CNC machine tools and the development of die manufacturing technology and the market competition domestically and abroad, five-axis CNC machining as the representative of the advanced technology is becoming an important performance of the country’s manufacturing strength. The developments of new die machining technology improve processing accuracy, surface quality and efficiency. Multi-axis machining can reduce the number of clamping and EDM machining, greatly improving efficiency. The study of CNC multi-axis machining technology on deep cavity molds can rapidly improve the processing level of dies. However, there are some problems in multi-axis machining, such as uneven tool deflection error and uneven surface roughness, limiting its application. Aimed at the existing problems, this paper makes in-depth research on the five-axis machining processing of deep cavity molds.Firstly, the force model of the climb and conventional climb milling, flat cutter and ball cutter are analyzed and established. The angles of the cut in and the cut out and the instantaneous chip thickness model are established. The difference of deformation and machining accuracy affected by the climb milling and conventional milling are studied. Also the relationship of the tool tilt angle and the precision of machining are studied.According to the geometrical analysis, the motion mathematical model of climb and conventional milling point has been established. The maximum residue height can be calculated. The relationship of the tool tilt angle and the surface roughness are studied. The adjustment of the climb and conventional milling method, the tool tilt angle and the feed-rate can improve the surface roughness. The theory has been verified by experiments in this paper.Based on analysis of its structure and kinemics, the post processing algorithms of two five-axis machine tools (XKH800 and HSM400u) were deduced in detail, including calculation of the table rotary angle and the motion coordinates of the spindle. The post-processors of the two five-axis machine tools are established by UG. The processors are verified by experiments in this paper.The five-axis machine HSM400u simulation environment is built on VERICUT software. The five-axis NC machining simulation of the die cavity is made on this system. Processing problems reduce, such as over-cut and less cut and the collisions and interference of the tool and the work-piece, the tool and the fixture, the tool and the machine parts. The processes reduce production costs and improve efficiency.The multi-axis CNC milling processing for deep cavity molds was optimized. The cutting parameters based on multi-target objective function,design variables, constraints and the optimization algorithm (genetic iteration)are optimized. The tool paths are optimized by determining the milling method mode and the tool angle. Through the experiments, the optimization parameters can improve efficiency under the quality assurance. Finally,the feed-rate is optimized based on the constant surface roughness.