Laser Sintering Mechanism Of Nano-silver Ink Sprayed By Microdroplet

The droplet spray forming technology is a key method for the integrated forming of heterogeneous and heterogeneous functional parts.Among them,the most important step is to conduct sintering to the jet material,so that the jet forming pattern has the conductive property.Laser sintering has the characteristics of fast heating speed,high sintering efficiency and small damage to substrate.In this paper,a nanoparticle silver ink was used as a jet material to analyze the laser sintering process of the material.Firstly,molecular dynamics model and porous medium model were established to analyze the thermal properties of silver nanoparticle layer with temperature variation,which laid a foundation for the simulation of laser temperature field.The first step is to calculate the variation of the thermophysical parameters of a single silver nanoparticle with temperature.The second step is to calculate the change of porosity of the silver nanoparticle layer during the temperature rise.The third step is to calculate the macroscopic thermal properties of the silver nanoparticle layer with the change of temperature by using the equivalent medium theory.Secondly,a finite element analysis model was established to analyze the temperature field distribution of laser sintered silver nanoparticles,which provided a theoretical basis for the selection of laser sintering parameters.A simulation model was established based on the thermodynamic parameters obtained by molecular dynamics simulation.On the basis of this model,the influence of different laser sintering parameters on the temperature field of the substrate and the silver nanoparticle layer was simulated,and the influence law of different sintering parameters on the temperature field was obtained,which provided parameter guidance for the subsequent experiments.Thirdly,a laser sintering system is developed,which can realize the integration of injection and sintering of conductive patterns.Finally,combining with the results of temperature field simulation,the orthogonal experiment,single factor experiment and response surface experiment of laser sintering were carried out by using the developed equipment,and the conductivity prediction model was established,and the optimal value of conductivity and the corresponding sintering parameters were obtained.Compared with the average value of orthogonal experiment,the electrical conductivity is increased by 21%to 1.819×10~7S/m.The optimized parameters were used to manufacture the microstrip patch antenna.The test results show that the peak return loss of the antenna is 18.73d B,the center frequency is 5.98GHz,and the bandwidth is 200MHz.Compared with the simulation results,the center frequency difference is80MHz,and the performance meets the requirements.In this paper,through the research on the laser sintering process of nanoparticle silver ink,the electrical properties of conductive patterns were improved,which laid a foundation for the related research on the integrated forming of electronic equipment.