EEVblog #782 - The Dangers Of Reflow Soldering

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I don't agree with the "cool it down as quick as possible after reaching the peak temperature". Temperature differentials can cause stresses in components, leading to component failure. Controlled cooling is the best approach. Hence one of the reasons for the preheating. Using toasters that are unmodified can create hot spots and cold spots. Having a more controlled oven environment reduced the chance of hotspots. Check this out...http://www.whizoo.com/. He installs plenty of insulation and reflective material the oven to avoid hotspots. He also uses a controlled door opener for cooling using a servo motor. From what I heard, the ControLeo's work very well.

Whoever laid out those boards in the video scores 9/10. A great job. Component designators clear, and the smart engineer used triangles for pin 1 designators rather than those fly vomit round dots that are unfortunately so common. He has also labelled things like the i2c bus signal labels. Consistency is important - he did use a few round dots. Another issue is the large QFICs are better oriented 45 degrees to the direction of applying paste so there is no shadowing... statistically you generally get higher yields. Still, the boards are well laid out.

Good video!