smt培訓(xùn)資料05-資料下載頁
2025-02-25 06:34本頁面
【正文】 Hot bar and thermode bonding ? Hot bar bonding uses metal bars that contact all the leads on a package simultaneously. ? The choice of bar metal and its shape are critical. ? The bars must resist heavy oxidation. ? The bars should be easily cleaned to assure optimum and uniform heat transfer ? q=kA(TB TA)/e ? q=heat flow through the material being heated ? k=the average thermal conductivity at the heater and material interface , A= the contact area ? TB= temp of the bar at the interface ? TA = temp of the assembly at the interface ? e = thickness of the region to be heated Heating profile hot bar Hotbar thermode heating unit Lasers beams soldering ? Laser heat sources operate on the same principle as infrared radiation soldering except the heated area is only the area exposed to the laser light ? Common lasers used for soldering are neodymindoped yttrium aluminum gar(Nd : YAG) and carbon dioxide ? The potential advantages of laser reflow are precise placement of the reflow heat in very dense areas ? A fiber optic of or mm diameter is sufficient to transmit enough thermal energy to reflow a typical FPT lead joint Temperature Profiling ? To achieve the ideal temperature profile by adjusting : – specific emitters temperature – better speed ? Method of getting feedback from temperature : – thermocouples – reflow temperature profiles 謝謝觀看 /歡迎下載 BY FAITH I MEAN A VISION OF GOOD ONE CHERISHES AND THE ENTHUSIASM THAT PUSHES ONE TO SEEK ITS FULFILLMENT REGARDLESS OF OBSTACLES. BY FAITH I BY FAITH
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