Consumption formula
Sewing thread per garment from each seam length and the measured thread-to-seam ratio of its stitch type, plus wastage.
Thread per garment (m) = Σ(seam length (cm) × ratio) / 100 × (1 + wastage / 100)
| Symbol | Meaning | Unit |
|---|---|---|
| S_i | Seam length for stitch type i | cm |
| r_i | Thread used per cm of seam for that stitch type | cm/cm |
| w | Wastage allowance | % |
Use it to order thread by color and ticket for an order, and to cost thread accurately in the BOM.
Side seams and shoulders, 150 cm of four-thread overlock at a measured ratio of 18; hems, 190 cm of coverstitch at 16; label, 10 cm of lockstitch at 2.5. Wastage 12%.
Sew 10 cm of seam on the production fabric at the production SPI, unpick all threads of that stitch, measure them straightened and divide by 10.
How to calculate sewing thread consumption per garment using seam lengths and measured thread-to-seam ratios for each stitch type, then convert it into cones per order by color and ticket.