Yarn dyeing and finishing are different from woven fabric finishing because there is no desizing operation.
This category is typically characterized by operational units such as cleaning, scouring, bleaching, mercerizing, dyeing and special finishing. This category includes plants which clean, dye and finish fibre stock or yarn. Sewing thread, textile and carpet yarn are typical products in this category. Several techniques are available for processing raw yarn into the finished product. The most common process is probably package dyeing, in which yarn wound on perforated tubes is placed in a large vessel, which is sealed. The dye solution, at an appropriate temperature, is circulated through the yarn. The dyed yarn is washed, rinsed and dried. The fabric is then unraveled and the yarn is wound on cones for subsequent use by other mills. Figure 7 represents typical operation of a stock and yarn dyeing and finishing mill .