Tuesday, 21 July 2009

Loom Temples



Temples

The warp sheet normally contracts from 2 to 15 percent in width from reed to the cloth. This contraction is due to interlacement of warp and weft.

This contraction need to be avoided temporarily because otherwise:

1. There is a possiblity of damage to the warp ends near the selvedge due to abrasion with reed dents.

2. There is a possibility of reed dents getting themselves distorted.

3. There will always be a tension in the beat-up zone.

The temples are used to hold fast the width of the woven cloth as equal to as possible to the width of the warp.

Types of Temples

1. Ring Temples


In ring temples the rings are usually at an angle of 12 deg to 21 deg and the angle reduces in steps of 3 deg towards the centre of the cloth.

As a thumb rule the lenght of the pints should be about one and a half times to two times the cloth thickness. The pins exert their pull on the warp.


Also the greater the tube diameter the greater the wrap of the cloth on the temple tube.

The length of the temple tube depends upon the cloth width. A rule of thumb is one ring for 10 cm fabric.

For delicate cloth, pinned rings are used only in the cloth selvedge zone. The inner rings are substituted by textured surface rubber, plastic or bras rings.


2. Roller Temples


The roller temples usually have two rollers supported at both ends which guide the fabric in the warp directions by means of raised points. The rollers are usually of steel and are covered with rubber or plastics.


Ring and roller temples hold the fabric in the selvedge zones only and stretches the fabric outwards.

These temples have the disadvantage that the pressure of the beat-up of the reed against the fabric is transmitted to the next guiding point of the fabric, which is the breast beam. This point is several inches from the fell of the cloth and therefore extensive tension is required for the beat-up. The tension causes breakages of the warp yarns.

Another disadvantage of this group of temples is the presence of different lengths of the fabric from the fell of the cloth to the breast beam, caused by the looping of the fabric around the temple cylinders. This causes a deformation of the straightness of the weft and therefore of the design. In extreme cases it creates waviness of the selvedges.

3. Full Width Temples

The other group consists of full-width temples.


The full width temples hold the fabric across its full width under uniform tension. The advantages of using full width temples are that weaving can be done at lower warp tension. One more advantage is less stress for the ends, resulting in less ends breakage.There are no temple ring marks. A higher weft density is possible. There is a straight weft insertion over the whole width. Also less maintenance is required.

However the full-width temples cannot avoid a contraction of the fabrics weft wise. By reason of this contraction, the warp ends in the selvedges do not pass at straight angle through the weaving reed. This causes extensive friction between yarn and reed and can lead yarn breakages.

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