ABSTRACT
The magnitude of the drawing process is huge in terms of quality perspective. A draw frame machine is feeding approximately two speed frame machines, and a speed frame is feeding approximately three ring frames. Thus, the fault generated in the sliver delivered from a draw frame significantly affects the yarns produced in three ring frames from that sliver. The drawing process aims at achieving the following objectives:
• Attenuate the card slivers • Reduce the fiber hooks and improve fiber alignment • Blend and mix fibers • Reduce the irregularity of card slivers by doubling
The draw frame contributes less than 5% to the production costs of the yarn.3 However, its impact on quality, especially evenness, is all the greater for this. The drawing depends on some factors such as the number of doublings, feed sliver hank, and delivery sliver hank. The number of doublings may be kept as 6 or 8 depending upon the process requirements. Since the total draft achieved is limited in a draw frame, two draw frame passages
are adopted to effectively enhance the uniformity of the sliver. The amount of draft to be applied immediately after the card cannot be very high as fiber entanglement is very high and the strand is thick. As such, draft has to be increased gradually. Draw frame is a machine where a very high degree of fiber to fiber friction takes place in the drafting zone; this is ideal for separating dust. Many modern draw frames have appropriate suction removal systems; more than 80% of the incoming dust can be extracted.
