DETERMINATION OF ABRASION RESISTANCE OF FABRICS

Plain Abrasion Resistance

Apparatus - Universal Wear Tester

Prior to test, the fabric should be Conditioned to moisture equilibrium from the dry side, in the standard atmosphere of 65+-2% relative humidity and 27+-2 deg C temperature. The test should be carried under standard atmospheric conditions.

Method for determination of plane Abrasion Resistance

1. Cut five circular test specimens of 112 mm in diameter, taking care to take specimens from areas containin the same wales or courses in knitted fabric or the same warp or weft yarn in woven fabric.

2. Set the instrument for inflated diaphram test.

3. Place the specimen over the rubber diaphram in smooth condition and clamp the specimen in place without disturbing it.

4. Place the abrasive paper on the abradent plate under sufficient tension to be held smooth and in such a position that the contact pin, reaching through a hole in the abradent is even with the surface of the abradent. In the absence of any specific material specification , zero emery polishing paper should be used as the abradent.

5. Set the air pressure under the diaphram and load on the abradent plate. In the absence of any specific material specifications, the air pressure should be 0.3kg/sq.cm (4 p.s.i.) and the load on the abradent should be 454 gm. Ensure that the air pressure control and contact between the inflated specimen and loaded abradent is in a state of equilibrium before abrasion is started. To ensure consistent inflation of the diaphragm, inflate to a higher air pressure ( 25 per cent) and then reduce the testing pressure.

6. If the unidirectional abrasion is desired, disengage the rotation mechanism of the specimen clamp and bring the specimen into the direction by turning and setting the clamp after the diaphragm has been inflated.

7. In the event that multi-directional abrasion is required, or if no specific indication as to the abrasion direction is given in the fabric specification, engage rotation mechanism of the specimen clamp.

8. Remove pills of matted fibres interfering with proper contact between specimen and abradent during the test if they cause a marked vibration of the abradent plate.

9. If the specimen slips in the clamp or the air pressure does not remain constant during the test or anomalous wear pattern is obtained, discard such individual measurements and test an additional specimen..

10. One of the following methods is selected for determination of end point as per test specifications:

a. Breakage of Thread: Abrade the specimen until all fibres in the centre of the abraded area are worn off so that the diaphragm and abradent head come into contact and the instrument automatically stops.

b. Removing a predetermined thickness of the material. Abrade the specimen using the electrical depth micrometer to determine the automatic end-point for removing a predetermined thickness of the material from the specimen.

11. Unless the continuous changing abrasion head is used, abradent paper is changed after every 300 cycles.

12. Report shall include the following information :

a. Type of abradent
b. Type of abrasion ( unidirectional or multi directional)
c. No. of cycles to reach the end point as determined by electrical contact.

CLOQUE OR CREPON EFFECT

In such fabrics a waved or cockled surface is produced.

The effect may be due to the weave structure, or the use of yarns with different shrinkage properties or both.

Normally the cockled appearance is achieved due to the use of high twisted yarns in one layer and low twised yarns in the other.

The highly twisted yarns form a net like construction through which the finely set structure composed of the low twist yarns is clearly visible.

The Open structure is achieved by the special arrangement of the threads which may be 3 low twist, 1 high twist in the warp and 4 low twist 1 high twist in the weft.





1. Insert plain weave on low twisted ends and picks
2. Insert plain weave on high twisted ends and picks

IMITATION BACKED CLOTHS

Any ordinary weave can be so modified as to produce a structure which very closly resembles a weft or a warp backed texture.

In this each thread interweaves regularly on both sides of the cloth.

This system has the advantage that a heavy single cloth is produced which has a fine surface appearance and is elastic and soft in handle.

Imitation Weft Backing ( reverse convention)

Basic Weave 2/5 twill



Insert 2/5 twill on alternate horizontal spaces


Imitation Warp Backing ( Normal Convention)



Insert 2/5 twill on alternate vertical spaces.

Thus it will be an imitation warp backing construction.

BACKED CLOTH WITH WADDED THREADS

In this construction the object is to obtain a n increased weight - by introducing a thick and cheap yarn between the face texture and the backing threads.

In wap backed cloths, the wadding threads are introduced in the weft and in weft backed cloth in the warp.

Weft Backed and Warp-Wadded Designs

Face Threads= 4/4
Back Weft= 1/7 down
Arrangement= 1Face1 Back, 1 ground 1 wadded.



1. Insert Face weave on face picks 4/4 on ground ends (X)
2.Insert Back weave 1/7 in between two face floats (\)
3. Raise all Face Picks over wadded ends.

Warp Backed and Weft Wadded Constructions

1. Face threads = 4/4
2. Back Threads = 1/7
3. Arrangement= 1 Face 1 Back, 1 Ground 1 Wadded



1. Insert Face Weave 4/4
2. Insert Back Weave 1/7 in between two face floats
3. Raise all face ends over wadded picks.

INTERCHANGING FIGURED BACKED CLOTHS

These cloths are chiefly used for blankets, dressing gowns and rugs.

The weave is the same in every part of the cloth and a weft surface is produced on both sides.
Interchanging Backed Cloths

The design is due to the manner in which differently coloured wefts are interchanged from one side to the other, a dark figure on light ground on one side corresponds to the light figure on a dark ground on the other side.

Common Fabric Particulars

Warp- Cotton

For a 4-thread weave
60/2 tex cotton warp, 9 ends/cm and 350 tex woollen weft, 19 picks per cm.

Weft Backed Construction ( Reversible)



In A

Dark Surface and Light Back

Face Picks--> Dark (3/1 twill)
Back Picks--> Light (1/3 twill)

In B

Light Surface and Dark Back

Face Picks--> Dark (1/3 twill)
Back Picks--> Light (3/1 twill)

By combining the two weaves, a design of two colors is formed.

Interchanging Warp Backed Cloths

Similarly warp backed cloths can be interchanged.

CENTRE STITCHED DOUBLE CLOTH- CENTRE WARP STITCHING

The purpose of incentre stitching is to bind the two fabrics together with the central thread, which are finer than either the face of backing threads.

The two fabrics are less firmly united than with the self stitching and the cloth has a softer and fuller handle.

It is very useful in cloths in which there is a great difference either in the thickness or the color of back and face yarns.

1. Centre Warp Stitching

Face Weave = 2/2 twill
Back Weave= 2/2 twill
Warp Arrangement 4S4B1S



Steps:

a. Make face weave on face ends and face picks

b. Make Back weave on back ends and back picks

c. Raise all face ends over back picks

d. Raise centre ends over face picks where they are covered by two adjacent floats of the face warp indicated by $.

e. Lower centre ends on back picks where they are covered by two adjacent floats of the back warp (#)

f. Centre ends are raised over back picks.(^)

CENTER STITCHED DOUBLE CLOTH- WEFT STITCHING

1. Insert Face weave on face ends and face picks and back weave on back ends and back picks .

2. Raise all face ends over centre picks (o)

3. Raise all face ends over back picks (X)

4. To achieve a face fabric stitch a face end must be dropped at a place where it is covered by two face wefts ($)

5. Similarly to achieve a back stitch a back end must be raised on centre pick at which it is covered by two back wefts ( shown by #)

INTERCHANGING DOUBLE CLOTHS

Double Cloths can be joined together by interchanging fabric layers.

The interchanging of threads means that the series which actually alternates between the face and back of the cloth can no longer be designated as the face or back yarns because it will occasionally be the one and occasionally be the other.

Thus in a cloth in which the ends and picks are arranged in an alternate 1 black, 1 white order, the black cloth will form the face when all the black ends are raised over white picks and vice versa.

Interchanging Double Twill and Sateen Stripe Design

Twill




To Make Red

1. Make 2/1 twill Red on Red
2. Make 1/2 twill Blue on Blue
3. Raise all red ends over blue picks to make red

To Make Blue

1. Make 2/1 twill Blue on Blue
2. Make 1/2 twill Red on Red
3. Raise all blue ends over red picks

You can combine these two to make stripes and checks.