Thickness

N

ΔL

Δa

Δb

0.5 mm

20

0.83 ± 0.01a

0.30 ± 0.03a

0.25 ± 0.03a

1 mm

20

0.82 ± 0.02b

0.21 ± 0.02b

0.15 ± 0.02b

1.5 mm

20

0.81 ± 0.01c

0.18 ± 0.02c

0.13 ± 0.02c

2 mm

20

0.80 ± 0.01d

0.16 ± 0.02d

0.12 ± 0.02d