Research On Theory And Simulation Of Short-Pulse Laser Polishing On Mold Surface

Polishing is a very important process in the mold manufacturing process.Nowadays,the demand for the surface precision of the products is increasing day by day,so the demand for the surface polishing precision of the mold is also increasing.However,at present,it is mainly carried out by manpower,the polishing precision is poor,the efficiency is low and it is difficult to polish the microstructure.As a new surface polishing technology,laser polishing is widely used in the polishing of various materials with its advantages of high precision,high efficiency and high flexibility.In this paper,the short pulse laser polishing process of metal and ceramic mold surface will be studied theoretically and simulated.In this paper,the photothermal process of short pulse laser is analyzed theoretically.In this paper,the interaction process of laser and matter is briefly analyzed,the theoretical model of laser absorption rate of materials is described,and the laser heat source model,heat transfer model and the physical change process of material surface and interior are analyzed.In this paper,the short pulse laser polishing process of metal and ceramic mold surface is also simulated.Based on the theoretical analysis of the process of laser photothermal interaction,the numerical model of laser polishing of die surface is established.Based on the theory of one-dimensional Gaussian rough surface,the geometric model of the original die surface morphology is established.The numerical model of laser polishing of metal and ceramic die surface is established by setting the material properties,laser parameters,boundary conditions,mesh division,etc.The coupling simulation of two-dimensional transient temperature field and flow field of S136 die steel under the action of single pulse and laser scanning is carried out respectively by COMSOL.The coupling simulation of two-dimensional transient temperature field and flow field under the action of single pulse and thermal stress simulation of Si C ceramic are carried out respectively by COMSOL.The simulation results show the temperature change,material melt flow and vaporization removal in the laser polishing process.The influence of single pulse energy,pulse width,scanning speed,scanning times and root mean square roughness of the original surface on the laser polishing effect is analyzed through the simulation results.In addition,the mechanism of short pulse laser polishing of metal and ceramic materials is analyzed.