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1、迴焊爐溫度設定 廠務處 劉年桂2013/Nov/071技术知识Contents爐膛設計Profile 四個區間說明融錫狀態PWI高溫影響CTE測溫線埋設爐溫升溫圖型說明速度與爐膛加熱計算模擬2技术知识Inside of Oven (加熱爐膛內部加熱爐膛內部)HeatingIn the ovenUse Vitronics XPM21030 3技术知识Reflow profile4技术知识Angle-chip for Capacitor5技术知识tc1 small SMDT: the smaller the mass, the hotter it gets! tc1 medium SMDtc3 l
2、arge SMD6技术知识TimeTemp.230C250Ctc1 small SMDtc1 medium SMDtc3 large SMD20C20CSmall SnAgCu Process WindowToo Hot!Too Cold!Peak: 230 250C tc1 255Ctc2 235Ctc3 225C7技术知识High Temperature Profiles for lead free reflow soldering High temp. reflow profiles are often recommended to solder lead free assemblies
3、. Peak temperatures up to 260 C are written in the literature. This extreme high temperatures may damage components, PCB laminate and influence solder joint reliability and shape.SnPbSnAgCuSnAgCu Tmax 215CTmax 235CTmax 260CComponent: Chip C 1206 AgPdBoard: NiAu Pictures: Zollner, Zandt Lead Free Ref
4、low Process Concerns8技术知识Lead Free Reflow Process Concerns: Component Damage225 C250 CVapor pressure in ELCOPictures: PhilipsLF Peak: 230C 250C ?9技术知识Lead Free Reflow Process Concerns : Component Damage225 C255 CPictures: PhilipsLF Peak: 230C 250C ?10技术知识240 C270 CDeformation of thermo-plastic compo
5、nent bodiesLead Free Reflow Process Concerns: Component DamagePictures: JabilLF Peak: 230C 250C ?11技术知识Lead Free Reflow Process Concerns: Open or Near Open JointsResult of board warpage and component bulging due to high temperaturePicture: Philips12技术知识The risk of micro cracks increase with the dist
6、ance to the center. As higher the temperature, as higher the expansion thermal expansion (CTE)13技术知识Higher temperature increases mechanical stress on solder joints14技术知识Failure to properly mount TCs will result in an unwanted T!Reflow Machine Profiling The Most Important Step!XX?Surface measurementB
7、GA ball measurement15技术知识Classical Temperature Profile of a Hotflow 2/24Gradientsdelta TPCB PBGASpeed: 1m/min T = 5,8C !Thermal Management: Flexible Profiling Classical Soak (1)High Plateau Temperature may damagePCB laminate16技术知识Thermal Management: Flexible Profiling Classical Soak (2)Classical Tem
8、perature Profile of a Hotflow 2/24Gradientsdelta TPCB PBGASpeed: 1m/min T = 4,5C !Raising Preheat tempcan reduce T 17技术知识Linear Temperature Profile of a Hotflow 2/24Gradientsdelta TPCB PBGARunning just a linear profile on such ahigh sofisticated machine makes no sense !Delta T can be reduced by diff
9、erent setup. T = 9,3C !Speed: 1m/minThermal Management: Flexible Profiling Straight Line (1)18技术知识Linear Temperature Profile of a Hotflow 2/24 with flat peakGradientsdelta TPCB PBGASetting up a flat peak will reduce the delta T tremendously. T = 6,0C !Speed: 1m/minThermal Management: Flexible Profil
10、ing Straight Line (2)Flat peakcan reduce T 19技术知识Linear Temp. Profile of a Hotflow 2/24 with flat peak/slow speedGradientsdelta TPCB PBGASlightly Increasing the process time willreduce the delta T additionaly. T = 4,8C !Speed: 0,85m/minThermal Management: Flexible Profiling Straight Line (4)Flat peak &slower speedcan reduce T 20技术知识爐膛長度與溫度設定21技术知识
