A cut-and-sew T-shirt moves through six stages: yarn is knitted into fabric, the fabric is finished and dyed, panels are cut from a marker, the panels are sewn into a garment, decoration and finishing are applied, and quality checks run through the whole line. Each stage leaves measurable evidence of quality, from fabric GSM and shrinkage data to seam measurements and print adhesion tests. Understanding the process lets a buyer ask the right questions at the right stage instead of judging the product only from a finished sample. The seamless alternative follows a different route, but the cut-and-sew process described here covers the majority of T-shirt production. Sino Finetex, the Shenzhen OEM and ODM manufacturer referenced here, runs both cut-and-sew T-shirt lines and seamless production, so its factory operations reflect both routes.

The Material Journey of a T-Shirt

Every T-shirt starts with yarn, and the fabric quality is decided before the garment exists.

Knitting. Cotton, polyester, blends, or other fibers are knitted into fabric on circular knitting machines. The machine settings control the stitch density and the fabric’s hand feel, and the resulting fabric is measured by GSM, the weight in grams per square meter.

Dyeing and finishing. The grey fabric is dyed and finished to stabilize shrinkage, set the color, and achieve the desired softness. Finishing chemicals and processes vary widely, which is why two “identical” fabrics can feel completely different. Test reports for colorfastness and shrinkage belong at this stage.

Quality gates on the fabric. Before cutting, the fabric should be checked for GSM, width consistency, shade variation, and defects. A defect that reaches the cutting table multiplies through every garment cut from that section of fabric.

Composition testing is worth a mention here: the label states a fiber blend, and the fabric should actually match it. Independent fiber-content testing is routine for serious brands, and the test report belongs in the pre-production documentation alongside shrinkage and colorfastness data.

The material journey is where most T-shirt quality problems begin, which is why serious factories inspect fabric before they cut it.

Cutting: Marking, Spreading, and Saving Fabric

Cutting turns fabric into panels, and the way it is planned determines both cost and consistency.

Marker making. The pattern pieces are arranged on the fabric to minimize waste. Marker efficiency, the percentage of fabric actually used, directly affects the fabric cost per garment. A good marker can save several percent of fabric compared with a careless layout.

Spreading. Layers of fabric are spread on the cutting table, carefully aligned so every layer matches. Tension during spreading must be controlled, because stretched fabric produces distorted panels.

Cutting. Panels are cut with manual knives or automated cutting machines. Automated cutting improves precision and consistency across hundreds of identical garments, which is why factories that run large T-shirt orders invest in it.

Bundling. Cut panels are counted and bundled by size and color so the sewing line receives exactly what it needs. Counting errors here create missing pieces that surface as delayed orders.

Fabric utilization is a hidden cost lever. A marker that saves three percent of fabric saves money on every garment in the order, which is why factories with automated cutting and good marker software can quote better prices at the same quality. Asking about marker efficiency is a legitimate technical question, not a negotiation trick.

Sewing the Tee: Seams and Necklines

Sewing assembles the garment, and the neckline is the most demanding part.

Shoulder and side seams. The body panels are joined with the seam type specified in the tech pack. Side seams should match at the hem, and seam allowances should be consistent so the garment lies flat.

Sleeves. Sleeves are set into the armholes, and the sleeve cap must align with the shoulder seam. A poorly set sleeve twists during wear, which is a common quality complaint in cheap T-shirts.

Neckline. The neck ribbing or binding is cut and attached with even tension. This is the hardest step to execute well, because uneven tension creates a wavy or puckered neckline that never improves with washing.

Hems. The bottom hem and sleeve hems are folded and stitched. Hem width should be consistent, and the stitching should stretch with the fabric so it does not pop.

The finished garment is then checked for loose threads, seam integrity, and measurement consistency before it moves to decoration.

Stitch density is a measurable quality signal. A seam with too few stitches per inch is weaker and more prone to popping under stretch; too many can pucker the fabric. The tech pack should state the stitch type and density for the seams that matter, and the sample should be checked against it rather than judged by eye alone.

Printing and Finishing

Most custom T-shirts carry decoration, and the decoration method should be matched to the fabric and the order size.

Screen printing works for large quantities with bold designs. DTG handles detailed, full-color designs on smaller orders. Heat transfer offers flexibility for short runs, and embroidery adds durability for logos. Each method has different durability characteristics, which is why wash-testing a decorated sample matters.

After decoration, finishing can include garment washing for softness or a vintage feel, pressing, and folding. Finishing affects how the T-shirt looks on a hanger and in a photo, and it should be specified in the tech pack rather than left to the factory’s default.

Finishing choices also affect the fit story. A garment wash softens the fabric and adds a lived-in look but can change dimensions, so the measurement table for a washed garment differs from a non-washed one. Decide the finish before the sample, then measure against the correct standard.

Quality Checks Along the Line

Quality control in a T-shirt factory is a series of gates, not a single final inspection.

Fabric inspection checks GSM, shade, and defects before cutting.

In-line checks during sewing catch seam issues, needle damage, and thread problems while they are still cheap to fix.

Measurement checks verify that garments match the approved size spec, because grading errors create a size range where one size fits and the rest do not.

Final inspection reviews the finished garment for appearance, print quality, labels, and packaging, often with a random sampling plan.

The inspection results should be recorded so a brand can review them. A factory that cannot show inspection records for its own production is asking the buyer to trust without evidence.

Random inspection follows a sampling plan, which means the number of pieces checked depends on the order size and the agreed quality level. The important habit is to record what was inspected and what was found: a factory that logs defects by stage can show where problems come from and what changed between orders. That record is more useful than a one-line “passed inspection” note.

Specifying Your T-Shirt for Production

A complete T-shirt specification prevents most sampling surprises. Include:

1. Fabric composition and GSM, plus shrinkage and colorfastness requirements.
2. Fit profile (regular, slim, oversized) and the full measurement table with tolerances.
3. Neckline type and ribbing specification.
4. Seam types and stitch density for the seams that matter.
5. Decoration method, placement, and artwork files.
6. Finishing requirements, including any garment wash.
7. Labels, tags, and packaging.

For the seamless route, the specification changes completely: the garment is programmed and knitted rather than cut and sewn, and the difference between the two construction families is explained in the seamless versus cut-and-sew guide. Whichever route you choose, a detailed spec plus a wear-tested sample is the minimum preparation for a successful T-shirt order.

Tolerances matter as much as targets: a spec without tolerances is a wish, and a factory will interpret it its own way. State the acceptable range for the critical measurements, especially chest, length, and sleeve, and verify the sample inside those ranges.

The production steps set the QC points; the t-shirt quality control guide lists what to check before approving bulk.

A a production engineer’s view

A production engineer would trace a t-shirt from the fabric to the finished tee through the gates that control its quality: the fabric inspection, the cutting, the sewing, the neckline construction, and the finishing and pack-out. The tee looks simple, but the collar and the hem carry the construction detail that separates a premium tee from a commodity one, and the sample approval has to verify those details on the production fabric. Before the first conversation, use the Sino Finetex’s t-shirt manufacturing page to verify fabric, cutting, and sewing against the brand’s own requirements, because each one changes what the factory can promise.

Frequently Asked Questions

What fabric is used to make T-shirts?

Most T-shirts use cotton, cotton-polyester blends, or performance fabrics. Cotton offers breathability and softness; blends add durability and wrinkle resistance; performance knits add moisture management for activewear.

How is a T-shirt cut and sewn?

Fabric is knitted, dyed, and finished, then cut into panels from a marker, sewn into a garment, decorated, finished, and inspected. The neckline and seams are the most quality-sensitive steps.

How long does T-shirt production take?

The factory’s published program details state sampling at roughly 5-7 days and bulk production at 15-45 days after deposit, depending on style and quantity, plus shipping time.

What is the difference between cut-and-sew and seamless T-shirts?

Cut-and-sew T-shirts are made from flat fabric panels joined with seams. Seamless T-shirts are knitted closer to the final shape with fewer seams, which changes fit, comfort, and production economics.

How do factories control T-shirt quality?

Through fabric inspection, in-line sewing checks, measurement checks, and final random inspection. Inspection records should be available for review rather than kept internal.

What information do I need to order custom T-shirts?

Fabric composition and weight, fit and measurements, neckline and seams, decoration method and placement, finishing, and labels and packaging. A complete spec produces a testable sample.

Sources

• Sino Finetex — T-Shirt Manufacturing
• Sino Finetex — Capabilities
• Sino Finetex — Seamless T-Shirts & Polo Shirts Manufacturing
• Sino Finetex — FAQs
• OEKO-TEX — Textile Testing and Certification
• ASTM International — Textile Standards
• Textile Exchange — Preferred Fiber & Materials