When the new yarn is creeled onto one of the 80 positions, the mixing of yarn shipment dates begins to take place. For this discussion, we will assume that this new yarn will cause barré when mixed with the old yarn. Once all positions are knitting the new yarn, there will be no barré. How many rolls of fabric will have barré when both these yarns are present in the rolls?
If the knitter is making 50 pound rolls, then each yarn package will supply 1/80th of the 50-pound roll or 0.625 pounds of yarn. Therefore, the new yarn will make 8.0 rolls of fabric with barré (5-pound package divided by 0.625 pounds per package for a 50 pound roll).
It is important to realize that while this new package is knitting, other old yarn positions on the creel are also being replaced by new yarns. By the time the first new package has knitted out, all feeds will be using the new yarn. When the last old package is replaced and all positions have new yarn, the barré will disappear.
Often, many machines will be knitting the same style. If ten machines are knitting this style and are using the old yarn and new yarns are placed on these 80 feed machines, then the total number of rolls knitted with barré will be 80. A total of 4,000 pounds of fabric will be made with barré. If the style in question weighs 5.8 ounces per linear yarn, then a total of 11,035 yards of fabric will be made. Further, if it can be assumed that each yard of fabric can make 1.2 shirts, then a total of 13,240 defective T-shirts will be made. This is 1,103 dozen garments. If the cost per shirt is $2.05 per unit, then a loss of $27,142 plus is realized.
If open-end yarn was used for this case study instead of ring-spun yarns, then 8-pound packages of yarn could be used. This would result in 128 rolls containing 6,400 pounds and 17,655 yards of fabric. From this, 21,186 T-shirts (1766 dozens) would have been made. Based on a cost per shirt of $1.86, the loss would be $39,405. The result is that bigger packages mean bigger losses.
The best methods to reduce the possibility of this catastrophe are listed below:
1. When mixing yarn shipment dates of only one week, try to reduce the number of machines using the old and new yarns.
2. As more machines are expending the old yarn, consolidate the old packages to fewer machines. This means removing the yarns from one creel and using them on other machines that are still knitting the old yarn.
3. Knit dye lots from a single machine if possible.
4. When a roll is known to have mixed yarns, a laboratory dyeing should be done on a swatch from the roll to determine if barré is present. If not, then proceed as normal. If barré is present, then the roll should be processed in shades that are not known to be barré sensitive or prepared with more aggressive chemistry.
CONCLUSIONS It is evident that barré is a problem that results from inconsistencies and is a result of poor management of fiber, yarn, and/or related knitting processes. The spinner, the knitter, and the dyer must communicate and work as a team to reduce the potential for barré to occur. A well planned and executed system of monitoring the spinning, knitting, dyeing, and finishing systems in the mill can provide for defect free fabrics.
