Fellow TechNetters:

IPC DR-572A 9.3.3 has defined that the maximum allowable roughness is recommended to be 25 μm. Is this for all size drilled holes? 
Sometimes I head from PCB fabricator that the drill hole roughness is depends on hole size, ex.: 0.5-0.8mm drill hole roughness <25.4 μm, 0.8-2.6mm drill hole roughness <30 μm.
The hole wall roughness will cause blow hole in solder joint during wave or selective soldering if moisture go in to PCB inside. So we need to control the roughness on hole wall surface.
Is anyone have experience on this?   What roughness is reasonable for PCB hole?

Best regards
Deng