Fully Drawn Yarn (FDY) is produced by a process similiar to POY manufacturing except that the yarn is produced at higher spinning speeds coupled with intermediate drawing integrated in the process itself. This allows stabilisation through orientation and crystallization. Yarns are produced by a continuous polymerisation process. All critical yarn properties such as tenacity, elongation, Uster variation and boiling water shrinkage are closely monitored and controlled. Controlled interlace enables the yarns to be twisted or sized in subsequent operations.