A ply can be planned well and the laminate can still be weak, because defects in plies with the same orientation line up through the thickness. Staggering those plies (shifting the start point by a fraction of a tow) moves the defects apart. How far to shift depends on two things: the shift has to clear the defect plus the placement error, and the positions repeat every course width.

Up next · 6.1 · 2:56Why you can't just look at carbon