Design And Analysis Of Cross Wedge Rolling Mill For Forming Micro Shaft Parts

With the rapid development of micro electromechanical equipment and micro system technology,micro shaft parts have been used more and more widely.At present,there were many methods of forming micro shaft parts,but its efficiency and precision could not meet the market demand.Therefore,a new method for the production of micro shaft parts by cross wedge rolling was put forward,which combines the advantages of micro forming and cross wedge rolling technology.On the basis of optimizing the forming process of micro shaft,considering the forming precision of equipment and workpiece,a micro wedge rolling mill has been designed and developed.The research lays a theoretical and experimental basis for the roll forming of micro shaft parts.In this paper,according to the structural characteristics of the micro shaft parts,considering the rotation,friction conditions and other factors,the forming die has been designed.Based on the analysis of the Influence of different combination forms of forming angle and broadening angle on the equivalent stress of micro shaft,the optimum selection of the technological parameters of the wedge die is carried out.According to the Selection of parameter combination,the micro shaft forming analysis under different cross-sectional shrinkage was carried out,and the influence rule of the section shrinkage on the equivalent stress,axial stress and tangential direction stress of the micro shaft was obtained.Comparing the forming precision of the workpiece with different rolling speed,it is found that the lower speed 0.5mm/s was the best quality.The quality of the workpiece is decided by the precision of the equipment,such as press down,rotation,displacement and phase.The design of the equipment was based on the designed wedge mould.In order to realize the precise adjustment of the roll gap of the upper and lower rollers,the stepping motor and ball screw were used as the power of the system.In order to ensure the accuracy of the axial position of the wedge shape of the upper and lower rollers,the upper roller system was connected with the rolling guide rail to limit the freedom of the upper roller system.After the design of the equipment,the stiffness of the machine frame was analyzed,so as to ensure that the structural parameters of the machine frame to meet the requirements.The accuracy of the Roll gap adjustment system has great influence on the quality of final rolled forming,through the closed-loop control of the system,to achieve the precise adjustment on the roll gap,in order to ensure forming quality of micro shaft.