1. After reflow some boards start producing bumps/bubbles which damage the internal layers causeing PCBs failed in Electrical-testing. How can I eradicate this problem from my assembling process?
2. If SMT components are mounted on non-rigid FLEX PCBs, how it can be soldered?
3.Reflow oven Spec. says that to put PCBs in these temperatures for preheat, activation and reflow zone but these temperatures are not in the range (doesn't mingle) of my solder paste temperatures so when I put my temperatures according to oven then soldering is good but if I put temperature according to solder paste specification it is not. Is that effect on my soldering process?