Mechanics of High Speed Texturing

The mechanics of the belt twisting principle are analyzed for slipping mode and positive driving mode. In slipping mode the yarn and the friction surfaces are ev erywhere slipping and the relative speed gives frictional forces to the yam in its direction. In positive driving mode, however, the yam is fully gripped by two belts, the system has no slippage in yarn rotational or forward directions, and the belt motion determines the twist level and tension ratios of the yam. General equations are derived relating the variables of tension, belt angle, twist level, ratio of belt speed to yarn speed, and yarn torque. The solutions to these differential equations give the expressions for the yarn tension ratio and yam torque as a function of twist, yarn parameter, and machine variables. In this paper, the theoretical performance of the system with changes in the configuration of the twister is discussed and limitations considered.