Tufting is a process used to create carpets, blankets and upholstery. Tufting is done by inserting additional yarns into a ground fabric (see
fabric formation) of desired weight and yarn content to create a pile fabric. The substrate fabric can range from a thin backing to heavy burlap-type material and may be woven,
knitted or web. In modern tufting machines, a set of hollow needles carries the yarn from a series of spools held in a creel and inserts the yarn through the substrate cloth. As each needle penetrates the cloth, a hook on the underside forms a loop by catching and holding the yarn. The needle is withdrawn and moves forward, much like a sewing machine needle. Patterns may be formed by varying the height of the tuft loops. To make cut-loop pile, a knife is attached to the hook and the loops are cut as the needles are retracted. Well over 90 percent of broadloom carpeting is made by tufting, and modern machines can stitch at rates of
more than 800 stitches per minute, producing some 650 square yards of broadloom per hour.