The Study Of Die Wear Of Rotational Fine Blanking Of Helical Gear

The composite fine blanking is an extension of fine blanking.The combined fine blanking and other forming methods can save processes and improve production efficiency.Rotational fine-blanking,as a new composite fine blanking forming process,can be used to manufacture helical gears and has many advantages,such as high efficiency and high material utilization.At present,the research about this technology is in the early stage in China.The die wear is the difficulty of fine blanking.The die wear can directly affect the quality of fine blanking parts and the life of die.The technology of fine blanking die is the main determinant of the die life,so the study of the wear of rotational fine blanking is of great significance.Based on this,the main contents about the die wear of rotational fine-blanking include:Establishing an accurate wear model is the first step.In this paper,the pin-disc sliding wear test was accomplished on the MM-W1 B vertical universal friction and wear machine to find the friction coefficient and the wear factor between 45 carbon steel and Cr12 MoV steel.A more accurate Archard wear model was established,improving the accuracy of finite element simulation.Based on PRO/E and DEFROM-3D software environment,a reliable three-dimensional rigid-plastic finite element model was developed on the DEFORM-3D platform for rotational fine blanking of helical gear.By the FE model,the metal flow velocity field,the damage,the mean stress field,the product quality and the temperature field were analyzed.The relationship between die wear and the shape of helical gear was studied,and the die wear characteristics of fine blanking of spur gears and helical gears were compared.The research shows that the edge of the die is the worst part of rotational fine blanking die wear.The effect laws of stamping process parameters such as pressure pad force,ejector force,blanking speed,blanking clearance,fillet radius of bottom die and hardness of bottom die on the die wear was analysed based on the three-dimensional finite element simulation model of rotational fine blanking of helical gear.Combining the wear theory and the Archard wear model,the die wear mechanism of the process parameters was investigated and a reasonable value of each process parameters was given.The research shows that increasing the blanking clearance and hardness of bottom die can reduce die wear and increase the service life of die.The quality of cut surface,the maximum punch load and the maximum die wear were improved based on orthogonal experimental of Taguchi method and the concept of Signal Noise Ratio.The optimized maximum die wear of every time is 6.26e-6mm,which is shortened to compare to the initial maximum die wear result 6.87e-6mm.Based on multi-objective optimization design,according to the quality of cut surface,the maximum punch load and the maximum die wear,the effects of process parameters on multi-objective and optimal parameters combination were obtained.