Monday, March 30, 2020

TESTING OF CREASE RECOVERY ANGLE OR CREASE RESISTANCE OF THE FABRIC



TESTING OF CREASE RECOVERY OF A FABRIC OR CREASE RESISTANCE OF THE FABRIC:

Crease resistance or crease recovery of fabric: 

“The ability of the fabric to prevent the formation of wrinkles or creases on the surface of the fabric during various uses or process is called crease resistance of the fabric”. The crease resistance of the fabric is expressed in the term of crease recovery angle.

APPARATUS USED:

1 - specimen loading device

2 - Crease recovery tester

3 - loading plates

5 - Stop watch

6 - Scissor

7 - Marking pen

8 - Fabric swatch

9 - measuring scale.

PREPARATION OF SPECIMENS:

The test specimens are prepared in both directions ( warp way and weft way) separately. 10 specimens from each direction are prepared. The specimens are measured with the help of measuring scale and then cut by scissor. The warp and weft directions are identified carefully with the help of magnifying glass before preparing the specimens. The specimen size is kept 15 mm.  X 40 mm. A technician can also use marking template to prepare the test specimens. You can see below picture also:



TESTING PROCEDURE:

1 - The warp way and weft way specimens are placed separately. First of all, 5 warp way specimens are folded in the middle of the length. These 5 specimens are folded face to face of the fabric. Now other 5 remaining warp way specimens are folded back to back. These specimens are also folded in the middle of the length of the specimens.

2 - Above process is repeated for weft way specimens also.

3  -Now start the testing of specimens of warp way specimens one by one.

4 - The folded specimen is placed between base plate and pressing plate.



5 - A loading plate of 2 kgs is placed over pressing plate. Now the technician brings the pressing plate downward by revolving the eccentric disc in releasing position. This is the time when, the stop wach us started at the same time. The load from the specimen is released after 5 minutes by revolving the eccentric at pressure releasing position. The specimen is taken out of the plates.

6 - Now this pressed specimen is placed between the clamping specimen as shown in the diagram. The specimen has been shown in red colour.



7 -  Asthe technician place the one leaf of specimen between clamp, he releases the specimen from his hand. At the same time, he start the stop watch again. The recovery of the creasing angle takes place during relaxation period. The technician keeps his eye continuously over the relaxation process. The hanging leaf of specimen should always be in vertical position. As the position of hanging leaf of specimen goes out of vertical position, the technician requires to adjust it's position by rotating graduated disc manually.The reading of crease recovery angle is recorded after five minutes from releasing of the specimen from hand. This process is repeated for all remaining warp way specimens. The result of the test is expressed in angle degree.

8 - The recovery angle is measured by graduated disc fitted in the instrument.

9 - The same process gets repeated for weft way specimens.

10 - Five nearest reading of warp way specimens are selected among all warp way specimen and mean of these selected readings is calculated.

11 - The above method is repeated in the calculation of weft way crease recovery angle too..

PRECAUTIONS:

1 - The below precautions must be followed during this test:

2 - The warp and weft directions should be identified precisely.

3 - The dimensions of the each specimen should be accurate.

4 - The fabric should be conditioned for 4 hours under standard atmospheric conditions.

5 -  Two - three inches of the fabric should be removed from both the selvedge before specimen's preparation.

6 - The loading time should be recorded precisely.

7 - The vertical position of the hanging leaf should be adjusted continuously during angle recovery period.

Please note that the dimensions of specimen, pressing load and time, recovery time during hanging of specimen may be varied according to  standard system followed during testing.

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