This paper is focused on change in shrinkage, GSM, Wales per Inch and Course per Inch due to structure and count variation and state variation. This work was carried out with 12 samples of single jersey, single lacoste and weft lock knit fabrics of different counts which were scoured with NaOH. After pretreatment process the samples were tested for widthwise shrinkage, width, GSM, Wales per Inch and Course per Inch and compared between different states like grey state and finished state. The result obtained in this research indicated that physical properties like structures with tuck stitch possess higher value of widthwise shrinkage, width, GSM and Wales per Inch and Course per Inch value lowers prominently in those structures having float or miss stitches. In both cases i.e. grey state and RFD state values of those properties are high in coarser yarn and low in finer yarn. During project knitted fabrics specification along with machine specification and major factors which are necessary to calculate different types of variation and variables on which the whole fabric construction depends were managed to watch carefully. Main efforts were to develop a dependable way so that the resulting fabric specifications with required configuration can be easily visualized and be forecasted. A great emphasization was provided to the adjustable points on which fabric GSM, stitch length, fabric width and shrinkage percentage directly or indirectly depends.
Fabric is manufactured assembly of fibers and yarn that has substantial surface area in relation to its thickness and sufficient cohesion to give the assembly useful mechanical strength. Fabrics are most commonly woven or knitted but the term includes assemblies produced by felting, lace making, net making, non-woven processes and tufting. This project is basically on knitted fabric specification and machine which are related to knitted fabric production.
There was problem in our industries to produce knitted fabric of required GSM. Other specifications like fabric width, fabric thickness, fabric shrinkage % are generally maintained in industries by previous data sheet. For this reason problem arises when any order comes which does not have a historical document.
Target of this project is to find out the easy process to get decision about yarn count selection, loop length selection, machine diameter selection and machine gauge selection.
This paper will be able to provide decision about yarn count, loop length, machine gauge and machine diameter for single jersey, single lacoste, polo pique and weft lock knit fabric.
Manufacturing of knitted fabrics involves intermeshing of yarn loops where one loop is drawn through another loop to form a stitch. Since the last few years knitted fabrics are used in manufacturing of fashion garments and even it has the potential in the formal wear segments also. Shrinkage is one of the most serious problems of the fabric faults. Especially, it is obtained in single jersey knitted fabric. Because of difference of both sides of single jersey knit fabric & side (Face or back) of the single jersey always tends to create curling [
Thus, shrinkage is formed in single jersey mostly, where the other fabric is not so affected greatly as compared with it. Shrinkage on fabric creates, stitching problem which resulting seam pucker problem.
Human feels uncomfortable due to wear of shrined cloth. Apart from this, spirality is another serious problem for single jersey knitted fabrics due to their asymmetrical loop formation [
Flexibility exists at the various stages of wet processing in terms of process machinery and methods followed by calendaring or compacting which is often, the final operation prior to the packaging step. The level of shrinkage control needed, composition of yarn (100% cotton, blends) and type of chemicals applied to the fabric decide the final process, i.e., whether calendaring or compacting [
Variable compactors are used to achieve specific stitch count and wet compacting is also carried out in certain cases [
In this project work, the following materials are used to evaluate the properties of weft knitted fabrics. This work is done in Asha Knit Composite Ltd. Konabari, Gazipur, Bangladesh.
・ Single Jersey Fabric (26 Ne).
・ Single Jersey Fabric (30 Ne).
・ Single Lacoste Fabric (26 Ne).
・ Single Lacoste Fabric (30 Ne).
・ Weft Lock Knit Fabric (26 Ne).
・ Weft Lock Knit Fabric (30 Ne).
As per the experiment the variation of properties of knitted fabric, different count of yarn such as 24/1, 26/1 Ne were used for our experiment to produce three different weft knitted structures like―Single Jersey, Single Lacoste & Weft Lock Knit.
Knitting machine (JIUNN LONG, TAIWAN) with 34” & 30” diameter & 24 gauge have been used. And every experiment stitch length has kept individually 2.75, 2.85, 2.85 mm. After producing grey fabric scouring was performed by FONGS Machine, China. A Washing machine was used for shrinkage test.
All Knitted fabrics were scoured in IR dyeing machine. For scouring, Jinterge Eco KS90 is used as detergent, Jinterge Eco 114 Fe is used as sequestering agent and Jintex 2UD is used as demineralizing agent. The Liquor ratio was 1:50 and the temperature for scouring was 90˚C to 95˚C (
Knit fabric has a special property called shrinkage. After the production knit fabric tends to shrink. For this fabric has to undergo a standard condition for complete relaxation. The fabrics had kept at 27˚C temperature & 65% relative humidity at our knitting lab.
1) Counting Glass.
2) Electronic Balance.
3) GSM Cutter.
After relaxation & conditioning of knit fabric samples, the numbers of wales in a 1” length of fabric were determined at five different places on every sample with a magnifying glass, and the average values were calculated of 26 s and 30 s carded yarn at both grey and scoured state for all three structures―Single Jersey, Single Lacoste & Weft Lock Knit.
After relaxation & conditioning of knit fabric samples, The numbers of courses in a “1” length of fabric were determined at five different places on every sample with a magnifying glass, and the average values were calculated of 26 s and 30 s carded yarn at both grey and scoured state for all three structures―Single Jersey, Single Lacoste & Weft Lock Knit.
After relaxation & conditioning, the width of the fabric was measured by measuring tape, for different samples [
After relaxation & conditioning of knit fabric samples, GSM of samples were tested by taking test samples with the help of GSM cutter & weighting balance (electronic) [
The sample was laid on a flat horizontal surface, removing wrinkles without stretching. Then samples were cut into 45 cm × 45 cm centrally so that the edge
Fabric Weight | X gm |
---|---|
Water | Y ml |
Wetting Agent | 1 g/l |
Sequestering Agent | 1 g/l |
NaOH | 3 g/l |
Na2CO3 | 1 g/l |
Detergent | 1 g/l |
M:L | 1:50 |
Time | 1.5 Hr |
pH | 10.5 - 11 |
Temperature | 90˚C - 95˚C |
follows a wale line. Then 25 cm × 25 cm area was marked in each sample the samples were put in the washing machine and continued washing for 45 minutes. After washing completed, the fabrics are dried at room temperature At last all the measurements were taken and shrinkage% is tabulated;
Shrinkage% = a − b a × 100
where, a = Distance between two ends before wash,
b = Distance between two ends after wash.
This operation was performed according to IS 139 and BS 1051 method [
From
In case of RFD fabrics, due to shrinkage WPI values increase.
From
From
During scouring and bleaching process fabric is circulated along the flow of liquor and some stress implies along the length of fabric. Hence the courses decrease in case of RFD fabric.
Here the CPI value of the fabric made of 30 s Ne (both states) follows the previous sequence (
From
During scouring and bleaching process the fabric is circulated along the flow of liquor and some stress implies on the length of the fabric. Hence the width decreases in case of RFD fabric.
From
According to the above
After scouring and bleaching, the fabric has already shrinked. That is why shrinkage % was lower at RFD state.
From
From the
In case of RFD fabrics, due to shrinkage GSM increases in same manner.
From the
When machine diameter, stitch length and machine gauge are fixed, variation
comes in wales per inch, course per inch, fabric width, shrinkage properties, GSM of Single Jersey, Single Lacoste and Weft Lock knit fabrics. Here, GSM is an important parameter which has a vital impact on knitted fabric production. GSM is generally controlled by stitch length. But here different fabric structure and yarn count also affect GSM. This will be beneficial for further thesis of related knitting field.
Sayed, Z.B., Islam, T., Chawdhury, N.H. and Ahmed, M. (2018) Effect of Knitted Structures and Yarn Count on the Properties of Weft Knitted Fabrics. Journal of Textile Science and Technology, 4, 67-77. https://doi.org/10.4236/jtst.2018.42004