Effect of Conical Spindle Disk Shape on Both Twisting Tension and Ballooning in Two-for-One Twister

The tension in a filament yarn twisted by two-for-one twister was calculated theoretically by the use of the twisting conditions and this calculation was compared with experimental results. 1) As results of analyzing the balloon theory, the yarn tension can be estimated from the nondimensional number Kb/m and h/b. Where K is the proportional constant for air-drag, b is the radius where the yarn leaves the spindle disk, m is the linear density of the yarn and h is the balloon height from the point where the yarn leaves the spindle disk to the snail guide. 2) The region of Kb/m where the yarn leaves from the conical plane decreases with increasing the apex angle of the conical spindle disk. 3) For the larger value of Kb/m, the yarn takes off the upper edge of the spindle disk and the tension is the same as the case where the yarn takes off the cylindrical spindle disk that has the same radius as its upper edge.