How many reflow cycles can FR4 materials withstand?

FAQ about printed circuit boardsMATERIAL

It is hard to give a precise answer, but we have made tests with material with up to 22 reflows, four of these with a peak temperature of 270C°. The stress after 22 reflows is considerable and material can degrade, but all connections remained functional. Our recommendation is to choose a higher grade material where there are more than 6 layers and thicker than 1.6 mm.

FR4 test board following multiple reflows