Abstract: An apparatus for the heat treatment of synthetic yarn is provided where synthetic yarn is provided by a synthetic yarn source and is fed via rollers to a first heating surface and then via a heating pin to a second heating surface and from there via rollers to a warping beam. A speed control of the yarn and a breakage control of the yarn can be provided. Depending on the resulting control signals the heating pin and concurrently therewith a cam wheel can be rotated, where the cam wheel and the heating pin are joined by an endless cable. The cam wheel is connected to the two heating surfaces via bars which allow to move and remove the heating surfaces from the path of the yarn. Heat transfer can be provided from the output rollers to the input rollers.