日东回流焊介绍2021.1.13.pdf - 第38页
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性能总结(SER-708A回流焊)
35
热效能均匀度
▇如果均匀度不好,表明横向风险程度高,用测温板测试的profile将不能代表产品上和测试点组件同类的其它组件的真实温
度.如果用导热性强的铝板做均匀性测试,则因为其内部导热快,无法保证测试结果的准确性和真实性.
▇冷却区温度的均匀性如果不好,则会影响产品的焊接总时间,影响降温斜率,影响焊料结晶状况,从而影响产品的可靠性.
热效能均衡度
▇如果热效差异度较大，
⑴不同大小（热容）的组件，如QFP和Socket,在焊接过程中的温度相差会比较大，会造成调试困难甚至无法调试出满足
要求的温度曲线设定，
⑵工艺过程的CPK会较大，
⑶合金结构差异较大。 回流量
▇回流炉使用热气对流传热的方式对产品进行加热，其回流程度的强弱将直接影响到焊接质量。只有合适的全程回流量
才能获得良好的焊接质量。
▇如果回流量过大，会造成偏位，竖件、飞件、短路、不熔锡等不良
▇如果回流量过小，会造成对流不足、回流炉稳定性差、热负载能力差、工艺过程的CPK差。 热效能稳定性
▇检测结果可以帮助对回流炉性能问题进行快速定位，提升检测分析及维护效率，如果稳定度较低，则产品在焊接过程
中的实际温度将有较大差异，测温板测试的profile等不具备代表性，可能导致各种相关的严重质量问题。
空满载热补偿能力分析
▇空满载热补偿能力较强的回流炉能够适应不同大小产品的生产，以及不同的产出率。如果空满载能力不足，则回流炉
的负载能力将较低，容易造成冷焊等严重不良质量状况。
各项性能指标
热均匀能力CI
热均衡能力Φ
回流量性能ψ
热效能稳定度Sd
链速稳定率V
空满载能力Ld
重复精度CPK
标准值(处于性能等
Ⅰ<3℃
Ⅰ<22℃
Ⅰ:4.5-6.5
Ⅰ<25%
Ⅰ<1%
Ⅰ<50%
Ⅰ:﹥1.67
级Group)
Ⅱ<6℃
Ⅱ<28℃
Ⅱ:3.0-7.5
Ⅱ<50%
Ⅱ<2%
Ⅱ<75%
Ⅱ:1.33~1.67
Ⅲ<9℃
Ⅲ﹥28℃
Ⅲ:2.0-8.5
Ⅲ<100%
Ⅲ<4%
Ⅲ<100%
Ⅲ:1.0~1.33
SER-708A
1.2℃
25.3℃
4.2KL
13.83%
0.81%
17.66%
1.948
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Performance Summery(SER-708A Reflow Oven)
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Heat Efficiency Uniformity
▇If the uniformity is not good that means the crosswise risk is high, the profile which is tested by temperature test board can not reflect the real temperature of the same
components on the product and the test points components. If doing the uniformity test on aluminum board which have strong thermal conductivity, it can not prove the
precision and factuality of the test result, because its high inner heat conduction.
▇If the uniformity of the cooling zone temperature is not good, it will influence the total welding time of the product, the temperature dropping slope, solder crystallization
effect, and the reliability of the product.
Heat Efficiency Balance
▇Larger differences in the degree of heat efficiency
⑴For different heat capacity components, like QFP and Socket, the temperature difference will be bigger during welding, and will make the debugging difficult and is even
impossible to meet the temperature profiles requirements setting.
⑵The CPK will be bigger during processing.
⑶The alloy structure difference will be bigger. Reflow volume
▇Reflow ovens use hot air convection method to heat products, the strength of the reflow degree will directly affect the welding quality. Only the right fully reflow volume
can obtain good welding quality.
▇If the reflow volume is too big, it will result in defect, like position deviation, upright parts, missing parts, short-circuit, non-wetting etc.
▇If the reflow volume is too small, it will lead to lack of convection, the reflow oven bad instability, poor thermal load capacity, poor CPK during processing.
Heat efficiency stability
▇The test results can help to quickly locate the reflow oven performance problems, enhance the detection analysis and maintenance efficiency, if the stability is low, then the
actual temperature of the product during the welding process will be quite different, and the temperature profile was not representative, may lead to a variety of related
serious quality problems.
Empty full-loading Heat compensation Ability Analysis
▇The reflow oven with strong empty full-loading heat compensation ability can adapt to the production with different sizes products, and various productivity. If the empty
full loading capacity is insufficient, then the reflow oven loading capacity will be lower, and easy to cause serious harmful quality status, like cold welding etc.
Each performance
index
Heat uniformity
ability CI
Heat balance
ability Φ
Reflow
volume
preformance
ψ
Heat efficiency
stability Sd
Chain speed
stability
V
Empty full
loading ability
Ld
Repeatability
accuracy CPK
Standard value (at
Ⅰ<3℃
Ⅰ<22℃
Ⅰ:4.5-6.5
Ⅰ<25%
Ⅰ<1%
Ⅰ<50%
Ⅰ:﹥1.67
performance level
Ⅱ<6℃
Ⅱ<28℃
Ⅱ:3.0-7.5
Ⅱ<50%
Ⅱ<2%
Ⅱ<75%
Ⅱ:1.33~1.67
Group)
Ⅲ<9℃
Ⅲ﹥28℃
Ⅲ:2.0-8.5
Ⅲ<100%
Ⅲ<4%
Ⅲ<100%
Ⅲ:1.0~1.33
SER-708A
1.2℃
25.3℃
4.2KL
13.83%
0.81%
17.66%
1.948
suneast.com.cn
Thank you !
37