Technology Center

Quality testing, thread sizing, a selection guide, and technical documents on request.

Quality testing

Yarn is tested in the laboratory before it moves on to twisting, dyeing, and winding.

Yarn fault classification

A yarn fault classifier counts thick places, thin places, and foreign fibers in the yarn, cutting thread breaks at the source.

Evenness

Measures variation in yarn thickness. More even yarn gives finished thread steadier strength and a cleaner look.

Hairiness

Measures the amount and length of fiber ends on the yarn surface. Lower hairiness means cleaner thread, more even dyeing, and smoother passage through the needle.

Twist

Checks twist level and direction in single and plied yarn. Correct twist keeps sewing thread from untwisting or kinking.

How thread sizes work

The same thread can be sized in several systems. These four are the most common.

Tex: Weight in grams of 1,000 meters of thread. A higher number means a thicker thread. Used for every thread type.
Denier (D): Weight in grams of 9,000 meters, mostly used for filament thread. Tex = denier ÷ 9. Example: 210D/3 totals 630 denier, about Tex 70.
Cotton count (Ne, written S): How many 840-yard hanks weigh one pound. A higher number means a finer yarn. Used for spun and cotton thread. Tex ≈ 590.5 × plies ÷ count. Example: 20S/2 is about Tex 60.
Ticket number (Tkt): The metric ticket used for synthetic sewing thread. Tkt ≈ 3000 ÷ Tex, so a higher number means a finer thread. Example: Tex 60 is about Tkt 50.

Nominal values differ slightly between makers. When you ask for a quote, tell us the count or denier, the ply, and the brand and ticket you use now, and we will match it.

Thread selection guide

General practice for matching thread and needle to fabric weight.

Fabric and product	Recommended thread	Typical size	Typical needle
Light fabrics: shirts, dresses, underwear	Poly-poly core-spun or spun polyester	Tex 18–27	Nm 60–75 (#8–#11)
Medium fabrics: T-shirts, sweatshirts, uniforms, bedding	Spun polyester; polyester overlock thread for overlocking	Tex 27–40	Nm 75–90 (#11–#14)
Medium-heavy fabrics: trousers, workwear, light denim	Poly-poly or cotton-poly core-spun	Tex 40–60	Nm 90–100 (#14–#16)
Heavy fabrics: denim, canvas, bags, sofas	Core-spun, polyester filament, or bonded nylon	Tex 60–105	Nm 100–130 (#16–#21)
Leather, footwear, outdoor goods	Polyester filament or bonded nylon	Tex 70–135	Nm 110–140 (#18–#22)
All-cotton and garment-dyed apparel	100% cotton or cotton-poly core-spun	As for fabric of the same weight	As for fabric of the same weight
Flame-retardant protective wear, high-temperature filter bags	Flame-retardant thread (meta-aramid or para-aramid)	By fabric and the standard required	Matched to the thread size
Blind hems, quilting, edge rolling	Nylon monofilament	By filament diameter	Matched to the diameter

These are general guidelines. Confirm the final choice by test sewing on your fabric, stitch type, and machines.

Common sewing problems

Thread breakage

Likely causes: Thread too fine or too weak; needle-thread tension too high; needle too small, or burrs in the needle eye or thread path; needle overheating on heavy material at high speed.
What to do: Lower the tension first and check the needle and thread path. On heavy or high-speed operations, switch to core-spun or filament thread and go up one needle size.

Skipped stitches

Likely causes: Needle bent, set the wrong way, or the wrong point for the fabric; thread too thick or too stiff to form a stable loop; stretch fabric moving up and down with the needle.
What to do: Fit a new needle and check the point type, using ball-point needles on knits. Match thread size to the needle and adjust presser-foot pressure.

Seam puckering

Likely causes: Thread tension too high; thread stretches and then relaxes after sewing; needle and thread too thick for the fabric; top and bottom plies feeding unevenly.
What to do: Run the lowest tension that still gives a balanced stitch. On light fabrics use a finer thread and needle, and choose thread with low stretch and low shrinkage.

Thread melting from needle heat

Likely causes: Needle temperature rises on heavy or multi-layer seams at high speed, and polyester or nylon thread softens and breaks at the needle eye.
What to do: Switch to poly-poly or cotton-poly core-spun thread, use machines with needle cooling or silicone lubrication, and reduce sewing speed.