Draw Frames

A recent development is the integration of a draw frame into the card. This supposedly improves process efficiency and reduces throughput time combined with lower costs for can transport and so on. 

After carding, the processing usually continues with one or more drawing (Fig. 3.8). The draw frame has the following tasks  

Draw frames consist of a can creel, a frame that holds the drive and control devices, the drawing field, and a can coder with automated changer (Fig. 3.8). 

The drafting unit consists of three consecutive pairs of rollers (Fig. 3.9). The continuous sliver is drafted between the nip lines, as the surface speeds of the roller pairs increase in the machine direction. The appropriate setting for the nip line distances as well as the roller geometry and the roller surfaces significantly determine the result of the drafting process. 

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Using as many as six drawings (frames) for each, depict... 

Can n. (1) A cylindrical container, about 3 feet high and 10-12 in. in diameter, that is used to collect sliver delivered by a card, drawing frame, etc. (2) See drying cylinders. 

Draw frame blends n. Blends of fibers made at the draw frame by feeding in ends of appropriate card sliver. This method is used when blend uniformity is not a critical factor. 

Frame n. (1) A general term for many machines used in yarn manufacturing such as the drawing frame, roving frame, and spinning frame. (2) See tenter frame. 

Sliver 1 is usually sli-vsr, 2 is usually slI- [ME slivere, fr. sliven to slice off, fr. OE -sUfan akin to OE -sUfan to cut] (14c) n. A continuous strand of loosely assembled fibers without twist. Sliver is delivered by the card, the comber, or the drawing frame. The production of sliver is the first step in the textile operation that brings staple fiber into a form that can be drawn (or reduced in bulk) and eventually twisted into a spun yarn. 

With the combing itself, the fiber web rolled off the lap is pinched between tongs and mechanically combed out with combs. The removed short fibers and dirt particles are called noil or comber waste. The combed cotton is deposited as sliver into cans. The last stage in the combing room is an autoleveller draw frame that homogenizes the combed slivers. 

The carded sliver is drafted, similar to other spinning principles, on draw frames and then fed into the machine. The draft in the air-jet spinning machine is around 40- to 200-fold. Due to the high spinning speed of up to 450 m/min, the drafting... 

The conventional woolen card incorporates a web sheer at the end that divides the fiber mat into multiple parallel strips depending on the required fineness. These strips are directly fed to a rubber spinning frame that compacts them into rovings and winds them onto bobbins. As with the rubber draw frame used in worsted yarn spinning, the sliver cohesion is caused by false-twisting the fiber strips. 

Web divider and rubber draw frames run at relatively low speeds and limit the card in its production capacity. This is of particular importance with fine yarns, as the roving accordingly has to be fine as well. To achieve a low web weight, the throughput of the card has to be reduced. 

The next processing steps are carding and drawing. The doubled and attenuated sliver is processed into a combed top at the combing machine. The combing principle is the same as for cotton fibers explained in Section 3.1.2. The combing machines are substantially different because of the very different raw materials (crimp). To even out the soldering joints, the combed top is drawn with an autoleveller draw frame. 

Figure 3.34 Rubber draw frame position (Hormes, 1991, Notzold, 1953)...

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