Abstract. Several convert processes, e.g. Scouring, Bleaching, Heat setting, High temperature & high pressure dyeing (HTHPD), which might damage the breaking strength of PU filaments were examined in this research. The influence of temperature, time and elongation percentage in heat setting was discussed in particular. The experimental results show that the dominant processes which damage the PU filaments are heat setting and HTHPD. The breaking strength retention of PU filaments range between 51.74%-84.03%, 67.64%-74.67%, respectively after heat setting & HTHPD. The higher the elongation percentage, the lower the heat setting efficiency.