The majority of T-shirts are made of 100% cotton, polyester, or a cotton/polyester blend. Environmentally conscious manufacturers may use organically grown cotton and natural dyes. Stretchable T-shirts are made of knit fabrics, especially jerseys, rib knits, and interlock rib knits, which consist of two ribbed fabrics that are joined together.
- 1 The T-shirt style is designed and the dimensions are transferred to patterns. Adjustments are made for size differences and stylistic preferences.
- 2 The T-shirt sections are cut to the dimensions of the patterns. The pieces consist of a tubed body, or separate front and back sections, sleeves, perhaps pockets, and trim.
Assembling the front and back
- 3 For fabric that is not tubed, the separate pieces for the front and back sections must be stitched together at the sides. They are joined at the seam lines to form a simple, narrow, superimposed seam and stitched together using an overedge stitch. Care must be taken to avoid a needle cutting the yarn of the fabric, which can lead to tears in the garment.
Assembling the sleeves
- 4 The hems of sleeves are generally finished before they are fitted into the garment, since it is easier to hem the fabric while it is flat. An automated system moves the sleeves to the sewing head by conveyor. The edge may be finished by folding it over, forming the hem and stitching, or by applying a band. The band may be attached as a superimposed seam or folded over the edge as binding.
- 5 If the T-shirt body is tubular, the sleeve material is first sewn together, and then set into the garment. Alternatively, if the T-shirt is “cut and sewn,” the unseamed sleeve is set into place. Later during the final stage of sewing the shirt, the sleeve and side seams are sewn in one action.
Stitching the hem
- 6 The garment hem is commonly sewn with an overedge stitch, resulting in a flexible hem. The tension of the stitch should be loose enough to allow stretching the garment without tearing the fabric. Alternative hem styles include a combination of edge finishing stitches.
- 7 Pockets may be sewn onto T-shirts intended for casual wear. Higher quality T-shirts will insert an interlining into the pocket so that it maintains its shape. The interlining is inserted into the pocket as it is sewn onto the T-shirt front. Pockets may be attached to the garment with automated setters, so the operator only has to arrange the fabric pieces, and the mechanical setter positions the pocket and stitches the seam.
Stitching the shoulder seams
- 8 Generally, shoulder seams require a simple superimposed seam. Higher quality T-shirt manufacturers may reinforce seams with tape or elastic. Depending on the style of the T-shirt, the seams at the shoulder may be completed before or after the neckband is attached. For instance, if a tubular neckband is to be applied, the shoulder seams must first be closed.
Attaching the neckband
- 9 For crew neck shirts, the neck edge should be slightly shorter in circumference than the outer edge where it is attached to the garment. Thus, the neckband must be stretched just the right amount to prevent bulging. Tubular neckbands are applied manually. The bands are folded, wrong sides together, stretched slightly, and aligned with the neckline. The superimposed seam is stitched with an overedge stitch.
for a V-neck look is to attach the band to the neckline and then sew a tuck to form a V.
Finishing the neckline
- 10 Necklines with superimposed seams may be taped, so that the shirt is stronger and more comfortable. Tape may be extended across the back and over the shoulder seams to reinforce this area as well and to flatten the seam. The seam is then cover stitched or top stitched.
- 11 One or more labels are usually attached at the back of the neckline. Labels provide information about the manufacturer, size, fabric content, and washing instructions.
- 12 Some T-shirts will have trim or screen prints added for decorative purposes. Special T-shirts for infants have larger openings at the head. The shoulder seams are left open near the neck, and buttons or other fasteners are attached.
- 13 T-shirts are inspected for flaws in the fabric, stitching, and thread.
- 14 High-quality T-shirts may be pressed through steam tunnels before they are packaged. Packaging depends on the type of T-shirt and the intended distribution outlet. For underwear, the shirts are folded and packaged in pre-printed bags, usually of clear plastic, that list information about the product. Shirts may be boarded, or folded around a piece of cardboard, so that they maintain their shape during shipping and on the shelf. Finally, they are placed into boxes by the dozen or half-dozen.
There are standards that apply specifically to the T-shirt industry, which include proper sizing and fit, appropriate needles and seams, types of stitches, and the number of stitches per inch. Stitches must be loose enough to allow the garment to stretch without breaking the seam. Hems must be flat and wide enough to prevent curling. T-shirts must also be inspected for proper application of neck-lines, which should rest flat against the body. The neckline should also recover properly after being slightly stretched.