Accuracy Analysis And Design Of Lever Type High Speed Precision CNC Punching Mechanism

As technology is being innovation,the development of modern stamping towards to high speed and high precision.In this paper,a new type of high speed press mechanism is proposed,which is based on the innovative design of the mechanism principle.Focusing on the accuracy research of the mechanism,the paper mainly completed the following aspects of the study.At present,the mechanism design of crank slider high-speed press is deficient,so the lever mechanism was proposed.The biggest feature of the mechanism is to avoid horizontal forces due to the high-speed movement of main and deputy slider,rather than balancing inertia forces.Thus,it not only can effectively reduce the vibration of the press body,but greatly reduce the friction heat between the slider and the body.In addition,the lever mechanism is uncomplicated.it does not need to carry on the optimization of the kinematics parameters,so greatly simplify the design process.The kinematic model of the mechanism is established at first,and the kinematic parameter equations are obtained.According to the same type of punch to design each component’ section and length dimension parameter.By using the Darren Bell principle to calculate the dynamic balance of the mechanism,and get the force parameters of the component.Then the dynamic balance of machine tool is analyzed and designed,the model of physical prototype is also established.The elastic deformation of each components is calculated when the mechanism is being at the bottom dead center(BDC)according to the dimension parameters and load status.And then get bottom dead center offset by through the transmission chain.Respectively,the model and equation are established of the kinematic pair to solve contact stiffness,which based on the classical Hertz theory and Persson theory.And an example is chosen to calculate the contact deformation amount,contact stiffness that including under different rotating speed.At the same time,by ANSYS finite element analysis to calculate the stiffness of the contact pair,and the results are compared with the theoretical results.High speed rotary friction of motion pair generates a large amount of heat,which leads to the deformation of the parts and seriously affects the precision of the mechanism.On the basis of heat transfer principle,the forced cooling heat transfer coefficient between cooling system of machine tool and motion mechanism is being calculated.And by using Energy balance method,the finite difference equation is established to solve the temperature field of kinematic pair.So the thermal deformation of the moving pair is obtained by the temperature field and thus gets the gap dimension changes.Meanwhile,the influence of the BDC by the main drive mechanism and the body temperature of the beam is studied,so with the accuracy compensation to the bottom dead center of upright post temperature in the end.The research on the vibration response of the body is based on the known model of the physical prototype and the load.The prototype model is imported into ANSYS software,and the force curve of the body is loaded by Fourier transform.The node vibration response on the bearing hole is reflected the vibration of the body,and on behalf of the vibration of bottom dead center.Finally.the vibration response under different speed and different loads is analyzed.