Tentering is an essential final routine finish especially for wet finished fabrics. The purpose of tentering is twofold:
Straightening the fabric as per the desired dimensions
Drying the fabric
Fabrics after wet finishing loose their shape due to shrinkage. To produce a good quality fabric, the grain should be perfect. The warp and weft yarns should be right angled to each other, so that subsequent processing like printing will also be perfect.
On tentering, the fabric is pulled to desired dimensions and taken into a chamber with sufficient temperature to dry the fabric.
Two types of tentering frames are present to pick the fabric along the selvage.
Pin Tentering: The frame consists of two chains with series of pins that hold the fabric along selvage. The holes of the pins are evident after finishing also.
Clip Tentering: The frame consists of two chains with clips that hold the fabric along the selvage. The two chains on the tenter frame are distanced as per the final width of the fabric. Fabrics should be picked up in a proper way positioning warp and weft yarns at right angles to each other. Otherwise, finishing defects arise after tentering. Fabric defects such as off grain, bow and skew result if tentering is not done properly. There are various devices that help in this regard such as variable chain drive that enables the operator to deal with even one chain, electronic eyes that detect the defect etc.
