To give synthetic yarns special properties such as stretch, bulk and the appearance of natural fibers.
The false twist texturing principle
For the texturing process the texturing industry has the choice of a variety of DTY machines produced by various manufactures around the world. False twist texturing machines, regardless who offers them, all work on the same principle. The schematic below shows the most important steps in the manufacturing of DTY.
POY, which stands for Partially Oriented Yarn, is now the standard feed yarn for the texturing process. It is a continuous filament yarn spun at a speed, which is, for example for polyester, around 3200 m/min.
Shaft 1 is the input feeding device for the POY. From here the yarn is fed to Shaft 2. When POY is fed into the machine, the yarn has to be drawn. The speed of shaft 2 is always higher by the factor of the necessary draw ratio for the particular yarn and process. The yarn is simultaneously twisted and drawn. The twisting is done with a friction device, such as a set of rotating friction disks. But there are other twisting devices such as belts. After Shaft 1 there is a yarn heater, which heats the yarn to a temperature where it can be thermo-set. Right after the heater is normally a cooling plate, which must cool the yarn to a substantially lower temperature in order to permanently thermo-set the twist. As the yarn is released from Shaft 2 we observe how each single filament is trying to assume the three dimensional helix formation it was set in. The result is a voluminous bulked stretch yarn.
Shaft 1 is the input feeding device for the POY. From here the yarn is fed to Shaft 2. When POY is fed into the machine, the yarn has to be drawn. The speed of shaft 2 is always higher by the factor of the necessary draw ratio for the particular yarn and process. The yarn is simultaneously twisted and drawn. The twisting is done with a friction device, such as a set of rotating friction disks. But there are other twisting devices such as belts. After Shaft 1 there is a yarn heater, which heats the yarn to a temperature where it can be thermo-set. Right after the heater is normally a cooling plate, which must cool the yarn to a substantially lower temperature in order to permanently thermo-set the twist. As the yarn is released from Shaft 2 we observe how each single filament is trying to assume the three dimensional helix formation it was set in. The result is a voluminous bulked stretch yarn.
Source: http://www.polyspintex.com
1 comment:
I enjoyed seeing my own website on your blog. I wish there would be a bigger participation in your textile science blog.
regards,
Udo Schweizer
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