| The heat-pipe based on the principle of gas-liquid phase change is the first choice to solve the heat dissipation problem of electronic equipment.The copper powder sintered heat-pipe is the most widely used type of heat-pipe,and its heat transfer performance mainly depends on the copper powder sintered type wick structure.The powder filling process is a key step in the production process.In this article,the powder filling process of copper powder sintered heat-pipe is studied.Based on theoretical analysis,model establishment and experimental test,a new type of automatic powder filling device is designed.And it is used as an experimental platform to investigate the influence of vibration parameters on the packing density of different types of heat-pipe copper powder.This article introduces the powder filling process of copper powder sintered heat-pipe and the manufacturing process of the wick structure.The wick structure obtained by the existing powder filling process is observed by scanning electron microscope.It is concluded that a large amount of boron nitride is deposited on the surface of the wick structure obtained by powder-sintering with a 310 S core rod sprayed with boron nitride,which affects the liquid working fluid reflux.At the same time,the copper powder particles of the wick structure obtained by the existing powder filling process are unevenly distributed,and the phenomenon that small particles are under and large particles are above affects the capillary force of the wick structure.For the copper powder filled vibration system designed and manufactured by the micro-vibration force method,when the vibration motor is located at the center of four support springs of the same specification,it can be simplified into a two-degree-of-freedom vibration model for corresponding theoretical calculation and analysis,and three-axis acceleration sensor is utilized to test the accuracy of the model.A new two-station automatic filling machine has been developed by used servo system,electric cylinder,PLC and other technologies.The powder cup replacement module and the copper tube middle positioning sleeve replacement module by designed can quickly meet the requirements of round straight pipe,single side pipe,double pipe and composite pipe filling with diameter ?5~?8mm and the pipe length 50~400mm,the efficiency of a single filling powder can reach 1200 pieces/ hour,And it is realized that accurate quantification of copper powder,powder filling while filling,precise positioning of copper tube core rod,automatic insertion and removal of powder cup from copper tube,improve the automation degree of equipment and the quality of copper powder filling,and reduced the dust pollution.The influence of vibration parameters on the copper powder packing density of different types of heat-pipes was investigated and the temperature difference and thermal resistance test were carried out by using the developed device.It is concluded that the round copper tube,the single side tube,the double side tube and the composite tube have the best compactness when the copper powder is filled at the 1000 N exciting force and the 50 Hz vibration frequency,and the performance of the corresponding heat pipe is relatively better.In actual production,The optimal filling time of round straight tube and composite tube is between 25~50s,and the optimal filling time of single side tube and double side tube is between 50~70s. |
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