The effect of coefficient in swift’s law, F and n values in Fig. 7, and
intensity of residual stress on the optimum pressure Po is shown in
Table 3. The intensity of residual stress was evaluated by the maximum
valuersmax, the definition of which was shown inFig. 6. Some
correlation between F value and Po seem to exist. The results was
rearranged in terms of the relationship between the proof stress
and the optimum press pressure as shown in Fig. 13 taking the
maximum tensile stress generated by the laser rsmax as a parameter.
The optimum contact pressure Po and the proof stress and
1% proof stress 1% show a strong correlation. It is revealed that
the optimum press pressure Po is roughly proportional to 1% proof
stress 1%, and the proportion ratio Po/1% was 110–120% regardless
of the mechanical properties of F value and n. If large strain is
given to the sheet metal as in normal processes such as bending
and rolling, the effect of F value and n value on the deformation
resistance would be large. However, as small strain is given on the
edge of sheet metal in the light press, the effect of F value and n
value is small.
Fig