• Journal of Institute of Convergence Technology
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• v.7 no.1
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• pp.7-10
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• 2017

In general, the shoe stretcher is utilized to stretching the leather of shoe upper in the longitudinal direction. In the capstone design class, we tried to make a shoe leather stretcher for the ball of foot. Since a natural cow leather was recovered in length according to relaxation time after stretched, it was difficult to predict the initial amount of set up of stretching. In this paper, tensile and relaxation experiments were conducted in order to predict the amount of initial stretching for appropriate tensile length. Apparatus of leather stretching was designed and strains of leather were measured according to relaxation times of 12, 18, 24 hours after stretching of 24 hours. It was revealed that the ratio of the final relaxed strain and the initial applied strain was about 0.404 with R-square of 0.990 for a shoe cow leather.