AUTOMATIC-DETERMINATION OF SHRINKAGE TEMPERATURE FROM SHRINKAGE DATA OF LEATHER

It is difficult to determine the beginning of the shrinkage-temperatur e distribution of leather (Ts). Earlier it was the practice to do this visually. It is possible to determine Ts automatically by applying a condition for the first derivative of the measured shrinkage data. A l inear-curve fitting method is applied for the length-temperature data below a tested Ts and for from the next five to ten sample-data points resulting in two lines. A condition that the first derivative of the latter line should be four times the first derivative of the former li ne gives satisfactory results.