I am trying to implement a quality check for our PCBs. We have a pick and place machine and a vapour solder machine. But, unfortunately, even after optical inspection and such, we end up with a lot of tombstones. The worst are the 0201 package passives. They are so small that even after manual inspection, many are assumed to be ok as they are a tiny speck. Is there any documentation that can guide me for a thorough quality check of inhouse PCBs please. I am sure that PCB houses have their own quality checks and protocols. Can anyone share a document that details out the process please. What are the testing and quality control standards implemented by PCB assembly houses ?