Question: Multiple curves using do while

Dear sir I want to plot the graph for different values of F=0.1, F=0.2,F=0.5 . My codes are given and i am attaching the sample graph. For F=0.1, Nb=0.1,0.2,0.3 three curves

Similarly For F=0.2,Nb=0.1,0.2,0.3 three curves and for F=0.5, Nb=0.1,0.2,0.3 three curves. Total nine curves 

restart:
h:=z->1-(delta2/2)*(1 + cos(2*(Pi/L1)*(z - d1 - L1))):
K1:=((4/h(z)^4)-(sin(alpha)/F)-h(z)^2+Nb*h(z)^4):
lambda:=Int(K1,z=0..1):

L1:=0.2:
d1:=0.2:
alpha:=Pi/6:
plot( [seq(eval(lambda, Nb=j), j in [0.1,0.2,0.3])], delta2=0.02..0.1);

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