Development Of Direct Writing Printing Platform And Printing Process For Flexible Circuit

Flexible electronics have a wide application in the fields of information,energy,medicine,and defense,with emerging and fast-growing.Flexible circuits are important components of flexible electronic devices.Ink direct printing technology,as a new free-forming technology,shows great potential in flexible circuit manufacturing due to its advantages of customizability,simple processing method,and wide range of sizes.In this paper,the authors have built an ink direct printing platform with self-developed direct printing pre-processing software to realize the preparation of flexible circuits.On this basis,further aiming at improving the line width uniformity of direct-written printed circuits,the direct-written printing process parameters are optimized by the Taguchi experimental design.Technical support is provided to solve the line width uniformity problem in the direct-write printing process.The result shows that the printing equipment overcomes the existing challenges of an expensive and complex process of flexible circuit manufacturing equipment,and has great significance for reducing printing costs,shortening printing time,and improving printing accuracy.The particulars are as follows:(1)The overall design of the direct printing platform.A peristaltic pump was used as the extrusion mechanism of the direct printing platform,a 0.2mm inner diameter dispensing needle was selected as the direct printing nozzle,the connection structure between the nozzle and the silicone tube and the nozzle mounting device was designed,the motion resolution was calculated to improve the motion accuracy of the printing platform,the temperature control module of the Marlin firmware was compiled,the test platform for direct printing was built,and the overall goal of direct printing at room temperature was achieved.The overall goal of direct writing printing at room temperature was achieved,and the hardware conditions were created for subsequent process research.(2)Software development for direct writing and printing pre-processing.The DXF file was used as the source file of the flexible circuit,and a method was developed to accurately read the graphic element information of the circuit file and read the graphic element information such as straight lines and circular arcs in the DXF file.With the optimization goal of minimizing the empty travel of the printhead,a genetic algorithm was applied to optimize the print path of the test pattern,and the empty travel of the printhead was reduced by 54%after optimization.Finally,we used PyQt5,a graphics-based programming framework,to write a direct printing preprocessing software that integrates pattern reading,path planning and G-code generation functions.(3)Optimization of direct writing printing process parameters.With the printing speed v,extrusion volume E and the ratio of the height of the printhead exit from the substrate to the inner diameter of the printhead H as variables and the minimum deviation of the line width size of the printed pattern as the optimization objective,27 sets of direct writing printing tests were designed according to the Taguchi method,and the line width uniformity was evaluated by signal-to-noise ratio calculation and analysis of variance.The results show that the order of influence on the linewidth uniformity is:E>v>H.The optimal combination of process parameters is selected as v=6mm/s,E=0.003mm,H=0.The average linewidth of complex patterns reaches 270μm,and the dimensional deviation of linewidth is within 50μm.