BTU Pmax 125N 设备介绍 中文-0511 - 第35页
不同静压下对器件的影响 0. 5 I W C 0. 8 I W C 1. 2 I W C 1. 5 I W C Ta n t a l u m C a p 209. 1 212. 1 213. 6 215. 7 L ar ge QFP 199. 2 203. 5 206. 7 209 Ch i p Re s i s t or 209. 9 213. 6 215. 2 216. 8 SO I C 209. 7 212. 6 214. 8 2…
Peak Temperature versus Static Pressure
Conveyor Speed = 45 IPM - Temperature Constant
180
190
200
210
220
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57
Time in Seconds
Temperature Deg. C
S. P. = 1.5 IWC
S. P. = 1.1 IWC
S.P. = 0.8 IWC
LOW <0.8 IWC
数字静压对峰温与熔锡时间的影响
不同静压下对器件的影响
0.5 IWC 0.8 IWC 1.2 IWC 1.5 IWC
Tantalum Cap 209.1 212.1 213.6 215.7
Large QFP 199.2 203.5 206.7 209
Chip Resistor 209.9 213.6 215.2 216.8
SOIC 209.7 212.6 214.8 216.2
TC Mean 207 210.5 212.6 214.4
TC SD 5.2 4.7 4 3.6
Delta T 10.7 10.1 8.4 7.8
Convection Rate Measured in In/H2O
Low High
Effects of Low Convection Rate
qLower Peak Temp
qLarger Peak Delta T
qThermal Uniformity Deteriorates
Effects of Increasing Convection Rate
qGreater Peak Temp
qSmaller Peak Delta T
qThermal Uniformity Improves
40 HZ 50 HZ 60HZ 70HZ
Peak Temp
数字静压 – 结论
• As temperatures increase static pressures
decrease 数字静压随温度升高而降低
• Low static pressure 数字静压低
– Decreases peak temperature and dwell times
降低峰温和熔锡时间
– Increases peak delta T across products
增加产品上的温度偏差
• High static pressure 数字静压高
– Increases peak temperature and dwell times
增加峰温和熔锡时间 – 低的设定温度
– Improves heat transfer and thermal uniformity
改进热传输和热均衡性 – 无铅工艺窗口小
– Improves potential for one universal profile
改善工艺曲线