Due to the printed leaf is easy to break . After testing Several types of leafs I tried to use flex material such like Tpu and flex pla ，but it's too soft , so I decide to add bones for it . Print it with flex material , no Supports is needed. cut 1mm steel Wire and bending it as you like , I use a printed leaf for reference . Insert the steel Wire into the tunnel , apply a drop super glue at both end . Maybe 1mm steel wire is too stiff , you may flatten the wrie with hammer just like what I did.