The Manufacturing Process
Spinning
1: As mentioned above, some factories spin their own yarn for bath towels. If this is done at the factory, the manufacturer receives huge 500 lb (227 kg) bales of either high or "middling grade" (of medium quality) cotton for conversion into yarn (quality depends on the manufacturer and quality of the towel in production). These bales are broken open by an automated Uni flock machine that nips a bit off the top of each bale, opens it up and then lays it down. The Uni flock opening machine blends the cotton fibres together by repeatedly beating it so impurities fall out or are filtered out (these bales contain many impurities within the raw cotton). The more pure fibres are blown through tubes to a mixing unit where the cotton is blended together before they are spun. Higher quality towels use cotton with fibres that are blended together three times before spinning. In some factories, the cotton is blended with polyester during this blending process.
2: The mixed fibres are then blown through tubes to carding machines where revolving cylinders with wire teeth are used to straighten the fibres and continue to remove impurities before spinning. The cotton fibres while not yet yarn, are shaping up into parallel fibres in preparation for spinning.
3: These parallel fibres are then condensed into a sliver'a twisted rope of cotton fibres. These slivers are sent into another machine in which they are blended again and sent between other rollers for straightening. The ultimate goal is long, straight, parallel fibres because they produce stronger yarns. (Stronger yarns require less twisting which also produces strong yarns but makes them less soft and absorbent.) The fibres are wound on a large roll and sent on a cart and fed into the combing machine.
4: Fibres are combed here, further straightening the fibres with a finer set of wire teeth than used on the carding machine. Combing removes the shorter fibres, which are coarser and woollier, leaving the finer, longer, silkier cotton fibres for spinning into yarn. Once combed, the fibres are formed into a twisted rope sliver again.
5: The slivers travel to roving machines where the fibres are further twisted and straightened and formed into ravings. The roving frame also slightly twists the fibres. The result is a long roving of cotton, which is then wound onto bobbins in the final step before spinning.
6: Now the roving is ready for spinning. The bobbin is spun on a ring-spinning machine, which mechanically draws out or pulls the cotton roving out into a single strand. The fibres essentially catch one another to form one continuous thread and twist the thread slightly as it is pulled or spun. Once the yarn is spun, it is automatically wound on large wheels that resemble rounds of cheese when full of thread.
Warping
7: Warp is longitudinal threads in a piece of woven material that are tightly stretched or warped on a beam. Latitudinal threads called weft or filler are passed under and over the warp to form the fabric. The large spools of just-spun cotton are ready to be warped or wound on a beam that will be inserted into the loom for weaving. If the yarn is purchased, the 7.5 lb (3.4 kg) spools are readied for warping. A warping beam is then warped in which threads are anchored and wrapped to a large beam in hundreds of parallel rows. Different towel widths require different numbers of warp threads.
8: These huge beams, full of wrapped warp threads, are placed into a rack that holds up to 12 beams and sized in preparation for weaving. The threads must be sized or stiffened to make the piece easier to weave. PVA starch, urea, and wax are rolled onto and pressed into the yarn. The threads are then run over drying cans. Teflon-coated cans with steam heat emanating from with-in. This helps to dry the warp threads quickly. (1,000 warp ends are pulled over nine cans to dry.) These beams, with coated threads, are now sent to the looms.
Weaving
9: The beams are lifted by pallet jacks or hydraulic lift trucks and delivered to the looms. These looms vary in width but can be as narrow as 85 inches (216 cm) or 153 inches (389 cm). (Not surprisingly, the wider the loom, the slower the weaving because it takes longer for the warp threads to cross the warp.) The beams are mechanically lifted on the looms with a warp jack, which Can withstand weight and size.
10: The towels are woven on dipped looms, meaning each loom has two sets or warps and thus two warp beams - one warp called the ground warp and forming the body of the towel and the other called the pile warp. And it makes a pile of terry. or loop. Each set of warp threads is carefully fed through and attached to a set of metal eyes. (Harnesses are separate, parallel frames that can shift in their vertical relationship to each other.) These harnesses mechanically raise and lower these warp threads so that the weft or filler can pass between them. A woven fabric is a combination of warp and weft.
The filler yarn is programmed to lay loosely in the woven fabric. When this loose filler is beaten or pressed into the fabric, the slack is pushed into a little loop.
The shuttles carrying the filler yarn are run at really high speeds on these large looms, the firing cylinder in these towel making looms can fire 18 shuttles across the warp. One shuttle runs behind the next. As a shuttle fires at the warp threads, the shuttle drops down and moves back into the firing cylinder and is fired again. A typical towel making machine has 350 shuttles per minute, about six shuttles are run every second. Thus, towels are woven very quickly on these large mechanized dobby looms. A small towel factory can make 250 dozen bath towels per loom in a week and the factory has 50 looms.
Bleaching
11: Once the towel is formed (it is a long roll of terry cloth and has no beginning or end), it is wound onto the off-loom take-up reel. It is then taken to bleaching as a large roll of fabric and placed in a water bath with bleaching chemicals such as hydrogen peroxide, caustic defoamer and other proprietary ingredients. All towels must be dyed pure white before being dyed with any color. The wet towel loaded with chemicals is then subjected to very high temperatures. The heat causes the chemicals to react, bleaching the towel. The roll is then washed in a large washer at least once and at most three times to remove all chemicals from the towel. The towel is dried, and if it is to remain a white towel, it is cut up and down, sewn with a lock, and a label is applied (all done by a machine).
Dyeing
12: If it is to be dyed, large, dried uncut rolls are placed in large vats of chemical dyes, which have been proven over time to provide color-fast towels after extensive residential laundering. After dipping into the vat, the towel is removed and pressed between two heavy rollers that force the dye into the towel. Steaming well sets the color. The towel is again steam-dried, fluffed in the drying process, and then the dyed towels are ready for cutting, hemming, and labeling.
Cutting, Folding, and Packaging
13: Final visual inspection of the cut and hemmed towels occurs and they are handfolded and conveyed to packaging, where automatic packaging equipment forms a bag around the towels and UPC labels are attached to the bags. These packaged towels are sent to the stock room, awaiting transport out of the plant.