Heat-setting using tenter frame

Stenters are widely used for stretching, drying, heat-setting and finishing of fabrics (Fig. 8-3). Woven and knitted fabrics of polyester and nylon fibres and 

The shrinkage in length and width may be as much as 10% and this must be taken into consideration in determining the overfeed and the adjustment of the width. Most of the stenters make provision for overfeeds - 5% to + 40%. If the entry rollers feed the cloth at a slower speed, the cloth will be actually pulled by the 

---

Figure 7-44. Use of a tender frame to biorient film or sheet. In a), the feeder-roll speed to puller-roll speed ratio can be set, such as 1 4, and simultaneously the ratio of width can be set, as 1 4. However, the machined direction ratio is usually accomplished prior to the plastic s entering the temperature-controlled oven that contains the tenter frame, by having it move around heat-controlled rolls where the rotational speed of the rolls increases from one roll to the next. Part b) is a schematic of the drawdown phenomenon with swell to produce orientation in the machined (longitudinal) direction.

---