Experimental And Simulation Study On Ultra-high Speed Drilling Of Printed Circuit Boards

To meet the Integrated and portable requirements of modern society for electronic products,micro-hole processing on PCB board is the necessary process for electronic components to achieve electrical interconnection.In this paper,a series of experiments are carried out on the influence of PCB board's own structure and its material ratio on the mechanical drilling performance of PCB board under the condition of high speed.The mass ratio of each kind of material in the PCB is defined as four levels,Then based on the experimental results,and refers to mass grades of the five typical PCB boards,a PCB optimization scheme point to drilling temperature,axial force and micro-hole quality was proposed utilizing comparative analysis method.On the other hand,the PCB micro-hole drilling is simplified as the drilling of copper foil and multi-layer glass fiber composite(GFRP),and the copper foil and multilayer GFRP finite element model are successfully established in ABAQUS,and the drilling simulation is carried out under the condition of ultra-high speed,the simulation is effective.In the experimental study,the drilling temperature,axial force and hole quality were investigated.The influence of the material content and the sheet structure on the drilling temperature,drilling force and hole quality were analyzed by comparative analysis method.And the structure and material optimization scheme of PCBs point to drilling temperature,drilling force and hole quality are summarized: For PCB drilling with better axial force characteristics,double sided PCBs with 16%-30% fillers and 31%-50% resins should be used;to achieve lower drilling temperature or better hole quality during PCB drilling,multilayer board should be used with 31%-50% filler and 16%-30% resin,and the smaller filler size and the even distribution would make it better.In the aspect of simulation research,the multi-layer GFRP finite element model based on Hasin damage criterion and the finite element model of copper foil based on Johnson-cook shear criterion are established,and the drilling simulation is carried out respectively.The copper foil drilling simulation results show that under the condition of ultra-high speed drilling,the temperature distribution of the main cutting edge of the drill bit is obviously uneven,and the higher the spindle speed,the more obvious the phenomenon,the temperature difference increases with the drilling depth.The results of GFRP drilling simulation show that the stress of drilling multilayered GFRP can be regarded as the superposition of the stress of drilling single layer composite material,and the more layers are superimposed,the greater the degree of mutual interference between layers.The resin matrix is always broken before the glass fiber,and the degree of damage is higher than the fiber;the glass fiber is mainly subjected to the stretching effect;the multilayer GFRP pores have more obvious tear,fluff and delamination than the copper foil pores,and the phenomenon is aggravated with the decrease of the spindle speed.