Uniform Shirt Order: Shrinkage, Colour Bleed and the Cutting Deadline
A tailoring unit in Guwahati has won a contract for 50 school uniform shirts from a 65/35 polyester–cotton fabric, 112 cm wide. The client has supplied 90 m and insists the shirts must not shrink after repeated home washing at 60°C. A cutter has already prepared a marker at 1.30 m per shirt, with no shrinkage allowance, and cutting is due tomorrow. A one-metre sample washed at 40°C showed 5% warp shrinkage and 2% weft shrinkage, and the colour bled slightly. The unit has no shrink-testing equipment beyond a domestic washing machine and a steam iron. The delivery date is 10 days away, and the client has not specified a care label. The production supervisor wants to start cutting immediately to save time and ‘adjust later’.
1. What tests should be done before cutting, and why is the existing 40°C test insufficient?
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The existing test is insufficient because the client will wash at 60°C, not 40°C. Shrinkage and colour bleed usually increase with temperature, so the 5% warp and 2% weft figures are only a lower bound. Before cutting, the unit should: (1) wash a full-width sample at 60°C with the detergent the client is likely to use; (2) measure length and width shrinkage after line drying and after tumble drying if that is allowed; (3) test colour fastness by rubbing the washed sample with a white cotton cloth; (4) check for skew or bowing after washing. The sample should be large enough to show whether the marker will still fit across the shrunken width. Cutting should not begin until these results are recorded and the client accepts the care conditions.
2. Calculate the revised fabric requirement if the fabric is cut before pre-shrinking, and decide whether 90 m is sufficient. State your assumptions.
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Without shrinkage allowance, 50 shirts × 1.30 m = 65 m. If the fabric is cut before washing, length shrinkage of 5% requires 1.30 × 1.05 = 1.365 m per shirt, or 68.25 m. Width shrinkage of 2% reduces usable width from 112 cm to 109.76 cm. If the marker used nearly the full 112 cm, it may no longer fit, so consumption could rise by about 1/0.98, giving roughly 69.6 m. If the whole roll is pre-shrunk first, 90 m becomes about 85.5 m in length, which is still more than the 65 m needed. On length alone, 90 m is sufficient either way, but only if there are no major defects and the marker fits the reduced width. A 5–10% buffer and a width check are essential before confirming to the client.
3. Recommend a production change and a care label that match the client’s 60°C washing demand.
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The safest change is to pre-shrink the entire roll at 60°C before cutting, rather than cutting first and ‘adjusting later’. Pre-shrinking converts the unknown risk into a known fabric state. The unit should then re-measure width and length, redraw or adjust the marker, and cut with the correct grainline. Because the colour bled at 40°C, the unit should also test a 60°C wash and, if bleed continues, inform the client that 60°C is unsafe for this dye lot. A suitable care label would say: machine wash at 60°C only after pre-shrinking, do not bleach, tumble dry low, warm iron. If the fabric cannot meet 60°C colour fastness, the honest recommendation is a 40°C label and written client approval, not a hidden compromise.