What is pilling?#
Pilling is the formation of small balls of tangled fiber (pills) on the fabric surface during wear and washing. Rubbing pulls fiber ends out of the yarn; these tangle into small balls; the balls either break off or stay attached, depending on fiber strength.
Pilling makes garments look old quickly. It is one of the most common consumer complaints for knitwear, fleece and blended fabrics. See pilling testing for test methods and grades.
What it looks like#
- Small balls of fiber on the surface, from pinhead size upwards.
- A fuzzy, worn appearance before distinct pills form.
- Pills concentrated at friction points: underarms, sides, thighs, cuffs and where bags rub.
- On blends, pills that stay attached and collect lint.
Where it occurs#
- Fleece and brushed fabrics, especially on the brushed side.
- Polyester-cotton blends and acrylic knitwear.
- Single jersey and interlock made from short-staple or open-end yarns.
- Loose knits with long stitch length.
Likely causes#
Pilling depends on how easily fibers escape from the yarn (fiber length, yarn twist, hairiness, fabric tightness) and how strongly the pills are held once formed (fiber strength). Finishing can reduce pilling by removing surface fibers or by stabilising the surface.
Machine-related causes#
- Brushing and raising that pull many fibers to the surface.
- Harsh mechanical action in dyeing or garment washing.
Material-related causes#
- Short fibers and hairy yarns (such as some open-end or carded yarns).
- Low twist yarns.
- Strong synthetic fibers (polyester, nylon, acrylic) in blends, which anchor pills.
Operator and process-related causes#
- Finishing steps skipped or run at reduced settings: singeing, biopolishing, shearing, anti-pill finish.
- Process changes without re-testing.
Method-related causes#
- Loose construction: long stitch length in knits, low density in wovens.
- Yarn selection based on cost without considering pilling.
- No bulk pilling test before cutting.
How to confirm the cause#
- Run the buyer's pilling test on finished bulk fabric. Compare with the requirement and with the approved fabric.
- Compare yarn type and twist with the approved quality.
- Check finishing records for the steps and settings used.
- Test before and after finishing to see how much finishing helps.
- Examine returned garments to see where pilling occurs.
Immediate containment#
- Hold fabric lots that fail the pilling test.
- Test garments from lots already produced.
- Discuss options with the buyer: re-finishing, use for other products, or rejection.
Corrective action#
| Cause | Corrective action |
|---|---|
| Hairy or short-fiber yarn | Change to combed, compact or higher-twist yarn |
| Loose construction | Tighten stitch length or density |
| Blends anchoring pills | Low-pill fiber variants; change blend |
| Missing finishing | Add singeing, biopolishing, shearing or anti-pill finish |
| Aggressive brushing | Adjust brushing and shear afterwards |
Preventive action#
- Pilling requirements and method in the fabric specification.
- Pilling test on every bulk lot before cutting.
- Yarn and construction approval for pilling-sensitive products.
- Finishing route documented and checked for each lot.
Inspection notes#
- Pilling is a performance property; it is found by testing, not by visual inspection of new garments.
- Test both sides of fabrics where the back is exposed, such as fleece.
- Severity depends on the buyer's requirement and product; a failed test grade is normally a reason to reject the lot.
Example investigation#
A polyester-cotton fleece hoodie receives complaints of pilling inside the body after a few washes. The fabric lot passed the face-side pilling test but the back was never tested. Testing the brushed back gives a low grade. The supplier had reduced shearing after brushing to save time. Shearing was restored, the back side was added to the test program, and the fabric specification was updated.
Pilling and product type#
Pilling risk and expectations differ by product:
| Product | Typical concern |
|---|---|
| Fleece hoodies and sweatshirts | Brushed back and face both at risk |
| Knitwear (sweaters) | Acrylic and blends hold pills |
| T-shirts in blends | Underarm and side pilling |
| Trousers | Inner thigh pilling |
| Uniforms and workwear | Durability over many washes |
Set the test method and number of cycles to suit the product and its use, following the buyer's requirements.
Factory checklist#
- Pilling requirement and method in the specification
- Bulk fabric tested before cutting (both sides if needed)
- Yarn type and twist approved
- Finishing route recorded for each lot
- Returned garments examined for pilling pattern
Related guides: pilling test, nep.