What causes pilling ?
Pilling is caused by the abrasion of short fibers into small balls on the surface of the fabric. As a guideline, some pilling usually occurs in new sweaters, especially if you ware them under other garments. But the problem will not persist in a sweater after the initial cleaning. Continuous pilling can be result of a high percentage of short fibers combined with a loosely knit fabric. Low quality manufacturers use shorter fiber because it is cheaper. They also knit loosely reducing the amount of used cashmere to a minimum. To make these low quality garments feel better, they are produced with a significant amount of surface fiber which leads to pilling troubles in long term.
Pilling is caused by a slight migration of fibers breaking away from the yarns. These loose ends create fuzz balls that cling to the surface of the fabric. This migration is a result of repeated abrasion, in other words, general wear and tear. These annoying little cling-ons anchor themselves with tiny hooks much like a burr does.
