trace wrinkles

Why would the time and number of cycles be of concern? The materials are going to expand so much, then contract right back where they started. If they shrank (maybe due to a cold cycle), I can see some cases with some stretching of the copper that would permanently change the dimensions (and even there - the copper may never be stretched into the plastic area). With a heating cycle, any deformations are going to be pulled right out when the contractions occur due to cooling. And if there is a wrinkle, any additional deformations to the metal from cycling are going to be at that wrinkle, as the copper has been weakened at that point. There will be no "incentive" for the copper to wrinkle elsewhere. And how many deep (as in solder machine temperature) cycles? I hope only one, or all your parts are going to be at the bottom of the chassis. Thermal expansion of materials is generally not a cumulative property. And with some "back of the napkin" calculations, running an inch long copper trace thru a solder machine is going to make it expand less that five thousandths more than the substrate - that's not much. Probably not even enough for a single wrinkle. -- Will