The Sweaters Passed Inspection. Three Weeks Into Sales, They Started Pilling
Fabric Pilling and Abrasion Test Guide - Why Fabric That Passed Inspection Pills and Wears Through After Sale, ICI Box, Martindale, Random Tumble and Circular Locus Pilling Tests and Martindale and Wyzenbeek Abrasion Tests Compared, Reading Pilling Grades and Abrasion End Points, Approximate Criteria by End Use, Gaps in Fabric Mill Reports, Supplier Yarn and Fabric Substitution, Spec Sheet Items, Stage-by-Stage Checks and a Checklist

Hello, this is StartMade.

A Korean knitwear brand produced 3,000 wool-acrylic blend crewneck sweaters at a knitting factory in Tongxiang, Zhejiang. The approval sample felt soft and had a clean surface, and the pre-shipment inspection found no problems with appearance, measurements or sewing. The sweaters also passed the inspector's check of rubbing the surface by hand.

Reviews started coming in during the third week of sales. After two or three wears, customers said, the underarms, inner sleeves and shoulders where a bag strap rests were covered in pills. The return rate climbed to 12%. When remaining stock was sent to a lab for a Martindale pilling test, it rated grade 2, two full grades below the approval sample (grade 4). Checking the yarn showed that the factory had switched to a cheaper acrylic yarn with shorter fibers and reduced the twist to hit its cost target. The color, weight and fiber content label were the same, so inspection could not catch it.

Pilling and abrasion defects are tricky because they barely show on a new garment. A freshly made sweater has a smooth surface even if it was knitted from weak yarn. How much it pills after a few wears and washes, and how many rubs it takes to wear a hole, only show up after repeated friction. This post starts with why pilling and abrasion happen, then covers test types and how to read grades, criteria by end use, common supplier tricks, and how to build pilling and abrasion tests into your spec sheet and inspection checklist.

A reply of "We'll use fabric that doesn't pill" or an inspector rubbing the surface by hand is not enough. To prevent pilling and abrasion claims after sale, set yarn specs, fabric mill and weight in the spec sheet along with numeric pilling grades and abrasion cycles, including the test method, and test production fabric before and after washing.

1. Why Fabric That Passed Inspection Pills After Sale

Pilling happens when fibers on the fabric surface work loose through friction and tangle into small balls. Abrasion is what happens when friction continues until yarns break and a hole eventually forms. Neither can be predicted from the fabric's appearance; the outcome is already decided at the yarn, knitting or weaving, and finishing stages. The main causes of pilling and abrasion after sale are:

• Short fibers and low twist: Yarn with short fibers or little twist lets fibers escape to the surface easily. This is the first thing to change when costs are cut.
• Strong synthetic blends: Strong fibers such as polyester and acrylic hold on to pills, so they stay on the surface instead of falling off.
• Loose construction: Low-gauge or low-density fabric gives fibers room to move, making it weak against pilling and abrasion.
• Brushing and finishing problems: Over-brushing, or skipping singeing (毛烧) and anti-pilling finishes, leaves loose surface fibers in place.
• Surfaces masked with softener: Pressing down the surface with softener or resin makes a new product feel smooth, but the effect washes out after a few washes.
• Fabric not suited to the use: Using apparel fabric on a sofa people sit on every day, or where a bag strap rubs, wears it through quickly.

Pilling and abrasion should be considered separately from shrinkage and color bleeding. Shrinkage after washing and colorfastness are covered in Episode 132, and importing textiles and apparel in general in Episode 67. This post focuses on how much friction the fabric surface can take.

2. Test Types - Pilling Tests and Abrasion Tests Compared

If you only say "Please run a pilling test," the factory will likely send an old report from the fabric mill or choose whatever method it likes. The same fabric can score a grade or two differently depending on the method, so settle the method and conditions first.

How to Read Pilling Grades

Pilling grades are assigned by placing the tested specimen next to standard photographs or reference samples and comparing by eye. Grade 5 means no change, 4 slight, 3 moderate, 2 distinct and 1 severe. Because people judge by eye, results can differ by about half a grade between labs. When comparing a factory report with a third-party lab result, first check that both used the same method and the same number of cycles.

Define the End Point Before the Cycle Count

The "number of cycles" in an abrasion test depends on what was treated as the end point. For wovens it is usually two broken threads and for knits a hole, but some tests use a change in appearance or color instead. Do not write only a cycle count in the spec sheet; include the end point, load (9kPa or 12kPa) and abradant type as well.

3. What Criteria to Set

The approximate ranges commonly referenced in the industry are below. Requirements differ by buyer and brand, so treat these as a starting point only and set actual criteria with your sales channel and a testing lab.

Martindale cycles and Wyzenbeek double rubs work differently and cannot be converted into each other. Furniture sold in the US commonly uses Wyzenbeek, while Martindale is more common for Europe and Korea, so get reports using the method your buyer asks for.

4. Why You Should Not Take the Fabric Mill's Report at Face Value

Sewing and furniture factories do not knit or weave their own fabric; they buy it from fabric mills. When you ask for testing, they often hand over a report "from the fabric mill," and that document has several gaps.

5. Common Supplier Tricks

Pilling and abrasion performance is hard to tell apart by appearance, which makes fabric substitution easy. These are types we have actually encountered in consultations.

The most common case, as in the opening example, is swapping only the yarn while leaving the fiber content label unchanged. The care label only shows fiber content, so a change in fiber length or twist still looks like the same fabric. Simply keeping a piece of the approval sample fabric and testing it alongside production fabric under the same conditions filters out many cases. For managing changes in trim and fabric suppliers, see Episode 115.

6. What Happens When Fabric Pills or Wears Through

Pilling and abrasion defects barely show at shipment and appear a few weeks to a few months after sale.

• Low ratings and reviews: Pilling shows clearly in photos, so one or two reviews are enough to drag down product page conversion.
• Returns and exchanges: Customers often see pilling as a "defect" and ask for returns even after wearing the item.
• Holes in furniture fabric: Sofa armrests and the front edge of seat cushions wear first, and replacing the fabric can cost nearly as much as the product.
• Defects across all stock: All stock made from the same fabric lot has the same problem, making it hard to sort out only some units.

For furniture fabric, check flammability requirements as well as abrasion. See Episode 72 for furniture and interior imports and Episode 55 for after-sales returns management.

7. Items to Include in the Spec Sheet

With just one line like "fabric that doesn't pill," every factory uses its own standard. Put the items below into a table and attach it to your spec sheet. For how to write a spec sheet, see Episode 59.

Asking for fabric mill delivery records may seem excessive, but they do more. Testing only checks a few specimens, while delivery records show whether the specified fabric actually arrived in production quantities. For process change management, see Episode 119.

8. How to Add Pilling and Abrasion Testing to Your QC Checklist

Sample Stage

When you receive the approval sample, cut and keep a piece of fabric at least 30cm long, and send specimens to a third-party lab for pilling and abrasion testing separately from the factory's report. These results become the baseline for comparing production fabric.

Production Stage

When fabric arrives at the factory, check that the mill name, article number and dye lot on the roll labels match the spec sheet. Cut fabric from each dye lot, weigh it, and send it to the lab together with the retained approval sample fabric. Get test records for every lot, but if the grade is the same every time and there are no photos, first question whether the tests were actually done. For production schedule management, see Episode 102.

Pre-Shipment Inspection Stage

The inspector picks packed products directly, weighs the fabric, and looks for signs that surface fuzz was shaved off. If you need tests that require cutting products, set the specimen quantity in advance. For pre-shipment inspection, see Episode 100.

9. Example Request Wording to Send the Factory

Putting the wording below in your purchase order or spec sheet takes fabric selection out of the factory's discretion and makes it easier to assign responsibility if a pilling claim arises.

"本产品面料须与确认样为同一面料厂、同一面料编号、同一纱线规格，克重允许偏差±5%。起球按ISO 12945-2（马丁代尔法，2,000次）测试，洗涤前不低于3-4级，3次洗涤后不低于3级。未经我方书面同意不得更换面料厂、纱线或降低克重，如需更换须事先书面通知并重新测试。每个缸号须从大货面料中取样测试，并提交注明面料编号、颜色、缸号、测试方法、等级及照片的测试记录和面料厂出货凭证。测试样品由我方验货员随机抽取。如有不合格，须加抽复测；复测仍不合格的缸号暂停裁剪。"
(The fabric for this product must come from the same fabric mill, with the same fabric article number and the same yarn specifications as the approval sample, with a weight tolerance of ±5%. Pilling must be tested to ISO 12945-2 (Martindale method, 2,000 cycles) and rate grade 3-4 or higher before washing and grade 3 or higher after 3 washes. The fabric mill or yarn may not be changed, nor the weight reduced, without our written consent; any change requires advance written notice and retesting. Specimens must be taken from production fabric and tested for every dye lot, with test records showing fabric article number, color, dye lot, test method, grade and photos, plus fabric mill delivery records. Test specimens are selected at random by our inspector. If any result fails, additional specimens must be retested; dye lots that fail again will have cutting put on hold.)

10. Three Real Cases

These are anonymized versions of types we often encounter in consultations. Amounts and figures are examples.

Case 1 - Wool-Acrylic Blend Sweater

This is the case from the opening. The brand sent the test results to the factory and pressed for responsibility, but the spec sheet only listed fiber content and weight, with no yarn specs or pilling grade, so the factory held out, saying "We kept the fiber content exactly." In the end the factory admitted it had not reported the yarn change and refunded part of the cost, but returns handling and discounted sales still left a loss of about 27 million won. From the next order, the brand added the yarn supplier, yarn count and pilling grades before and after washing to the spec sheet, and decided to check yarn labels directly when yarn arrives.

Case 2 - Fabric Sofa

A company importing three-seat fabric sofas from a furniture factory in Foshan, Guangdong, received several complaints eight months into sales about holes in the armrest fabric. The report from the factory stated 50,000 Martindale rubs, but fabric from a returned sofa had threads breaking at 12,000. It turned out the report had been issued to the fabric mill for a different article number, and the factory had used similar-looking fabric from another mill in production. The company now only accepts reports that show the fabric article number and dye lot, and checks photos of fabric roll labels.

Case 3 - Children's Brushed Tracksuit

A company sourcing polyester-cotton brushed tracksuits from an apparel factory in Zhejiang got reviews saying "covered in pills after two washes." The factory's report showed pilling grade 4, but that value came from unwashed fabric; retested after 3 washes, it rated 2-3. The company then added the pilling grade after washing to the spec sheet and had the factory match the brushing intensity to the approval sample. If you do not specify washing conditions, the factory will test under the most favorable ones.

11. Common Mistakes

• Not setting grades and test methods in numbers, as in "fabric that doesn't pill"
• Listing only fiber content and weight, not yarn specs or the fabric mill
• Judging only by an inspector rubbing the fabric by hand
• Accepting a fabric mill's report from a different lot as is
• Looking only at results before washing and not checking grades after washing
• Comparing Martindale and Wyzenbeek numbers as if they were the same

12. Pilling and Abrasion Control Checklist

Specification Stage

• Set the fabric mill, article number, yarn specs and weight
• Wrote the pilling test method, cycles and grade for before and after washing
• Wrote the abrasion test method, load, end point and cycles
• Set specimen sampling per dye lot and how failures are handled

Sample and Production Stage

• Kept a piece of the approval sample fabric
• Had the approval sample tested separately at a third-party lab
• Checked labels, article numbers and dye lots on incoming fabric rolls
• Received test records with photos for each lot

Pre-Shipment Inspection Stage

• Weighed fabric from production units
• Checked for signs of fuzz removal
• Tested specimens cut from finished products where needed

Wrapping Up - Check With Grades and Cycles, Not a Rub of the Hand

At shipment, every fabric looks smooth. Quality differences only show up as pills and holes after a few wears and washes or a few months of sitting. Writing yarn specs, the fabric mill, pilling grades and abrasion cycles into the spec sheet and checking test results for every dye lot does not cost much. Put a few hundred thousand won in testing fees next to a 12% return rate, and it is clear which is cheaper.

There is something you can do right now. Ask the factory currently producing for you to send the mill name and article number of the fabric in use, along with pilling test records for the latest dye lot. If the answer is a single line saying "It's fabric that doesn't pill," make a fabric control terms sheet and send it before your next order.

StartMade supports you on the ground with spec sheets covering fabric specs and pilling and abrasion criteria, third-party testing of approval samples, checks on incoming production fabric, and pre-shipment inspection. If you have already received pilling claims, we start with testing remaining stock and finding the cause; if you are preparing a new product, we start with fabric selection and setting criteria.