High-speed bobbins

High-speed bobbins. The critical component in today s commercial lockstitch sewing machine is the rotary hook and bobbin (Fig. 12.11). These parts traditionally have been manufactured out of stainless steel, which requires constant lubrication and stitch tension adjustments. Both can play havoc with operator productivity and stitch consistency, particularly with lighter-weight or delicate fabrics. Hooks and bobbin baskets made... 

Spindle spin-d l [ME spindel, fr. OE spinel akin to OE spinnan to spin] (12c) n. A slender, upright, rotating rod on a spinning frame, roving frame, twister, winder, or similar machine. A bobbin is placed on the spindle to receive the yarn as the spindle is rotated at high speed. 

Finally, the yams are wound up at high speed (up to 6000 m/min) on special equipment (take-up), producing bobbins with a weight of 10-20 kg. Some special technologies (FOY, FDY) require a drawing stage on appropriate rolls before winding the yam. 

The final step is yam stretching or drawing to orient the molecular chains to a high degree in the machine direction. Orientation also reduces the diameter of the fibers. The process is performed at a temperature close to, but less than, the melt temperature by stretching between rolls operating at a speed differential. The orientation process has a critical influence on the properties of the finished fiber. The orientation is set by an annealing step and the continuous filament yam is wound on spools or bobbins for subsequent use in textile operations. 

A guide roU at the bottom of the spinning tube directs the fibers out to a collection device. For staple fiber, the filaments from numerous spinnerets are combined into tow form, crimped, cut to the required length, and packaged in bales. A take-up bobbin is used to insert a small amount of twist. Take-up speeds are typically between 200 and 400 m/min but can be as high as 1000 m/min. For filter tow the filaments are crimped, dried, and packaged in bales. 

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