| FDM Rapid Prototyping Technology is a new method of additive manufacturing and processing,and FDM rapid prototyping technology is widely used in education,medical,aviation,automobile and other fields because of its simple structure,convenient operation,environmental protection of molding process and wide application range.With the increasing demand for the forming workpiece of FDM technology,it is decided that the feed system must have larger stroke,higher precision,higher resolution,stronger anti-jamming and other working characteristics,and the traditional FDM technology feed method can not meet the above requirements,so it is of great significance to develop a set of precision feed system with good performance.Aiming at the special requirements of FDM technology feed system,the macro micro-drive mode is selected to design the feed system.This paper analyzes the working mode of the traditional single-stage drive system of FDM technology,and finally determines the macro micro-drive mode of the ball screw and piezoelectric microdynamic platform.The maximum axial load and driving torque of the macro feed mechanism are calculated and checked,a micro-displacement amplification mechanism is designed based on the straight circular flexible hinge,and the calculation formula of the micro-displacement amplification mechanism is deduced.Finally,the physical modeling and assembly interference inspection of the macro Micro precision feed system are carried out.In order to improve the magnification and dynamic performance of the Microdynamic platform,a microdynamic platform proxy model of radial basis function is proposed,and the structure of the Microdynamic platform is optimized based on the model.A series of sample points are determined by using the Latin hyper-cubic sampling method,the response value of each sample point is calculated by ANSYS,the nonlinear function model reflecting the performance index and the design variable is established according to the radial basis function theory,and the multi-objective genetic algorithm is used to optimize.Comparing and analyzing the optimization results with the pre-optimization performance index,the natural frequency is increased by 22.83%,the magnification is increased by 40.8%,the maximum stress is less than the yield stress of the material,and the voltage-displacement experiment of the optimized micro-platform is carried out,and theexperimental results show that the optimization method is effective.The centralized mass equivalent model of macro micro feed system is established,the calculation formula of equivalent parameters is given,and the kinetic equation of macro micro feed system is deduced according to Lagrange equation.Using MATLAB to simulate the established dynamic equation,taking the common trapezoidal velocity curve as the input of the motor,the first three-order resonant frequencies of the feed system are 63.69 Hz,125.02 Hz and 166.37 Hz respectively,and the influence of the transmission stiffness on the frequency response characteristics of the feed system is simulated and analyzed.The simulation results show that the first two-order resonant frequency of the system increases gradually with the increase of transmission stiffness,but it has no obvious effect on the third order resonant frequency.The experimental platform of the macro micro feed system is set up,the positioning experiment of the platform is carried out by using the feedback displacement data of the grating ruler,and the modal analysis of the experimental platform is carried out,and the natural frequencies of the first five orders of the feed system in different positions are measured in 69.76 Hz,134.83 Hz,179.40 Hz,249.13 Hz and 332.92 Hz,the correctness of the theoretical calculation of the macro micro feed system is verified by experiments.. |
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