Laminate Springback

[Farrell]

Fun facts to know and share. From the WestSystem web site:

When a strip of wood, a ply, is bent to a curve and released, it springs back to its original shape. A stack of loose plies will do the same. When these plies are glued together while clamped to a curve, they tend to stay curved, but will straighten out or spring back a little. When building the mold or form for the laminate its common to make the curve a little tighter to compensate for the springback. The amount of springback depends on the number of plies in the laminate, not in the ply material or the ply thickness. A simple formula can help predict the amount of springback you can expect: y = x/n2.

y = the amount of springback
x = the amount of deflection
n = the number of plies

Thus with four plies, the springback (y) will be 1/16" if the amount of deflection (x) is 1". By using plies half the thickness you double the number of plies for a given thickness of laminate and reduce springback four times-in this case to 1/64".

Terry Farrell