Seam Strength Vs. Seam Slippage

Difference Between Seam Strength and Seam Slippage

Both the parameters measure the performance of seam. Seam strength referes to the strength when seam finally ruptures or when the fabric breaks.

However before rupturing there is an unacceptable opening in the seam which makes the seam 'failed' commercially even when there is no visible rupture. Seam slippage measures that.

Seam strength depends upon stitch type, thread strength, stitches per inch, thread tension, seam type and seam efficiency of the material.

Seam slippage depends upon the stitch rate, the weave structure of the fabric and the width of the seam allowance.  

There is another term called 'yarn slippage' which measures the shifting of warp yarn over weft yarn to render the garment unusuable. 

Yarn slippage depends upon a low number of warp or filling yarn, two shallow seam allowance, too tight a fit and improper seam construction.  

Find Pictures of Seam Quality Defects here.

Fabric Parameters

Woven fabric parameters

There are four basic parameters that are essential for every woven fabric.

1. Ends per Inch and Picks per inch (EPI and PPI).
2. Yarn count
3. Crimp

4. Weave or Fabric Structure or Design

1. Ends per Inch or Picks per Inch

It is a measure of thread density. The normal method used to determine thread density is to use a pick glass.

2. Yarn count

EPI and PPI affects the compactness of the fabric. It is also known as thread count or cloth count. Thread counts range from as low as 20 threads per inch as used in tobacco cloth to as high as 350 threads per inch, found in type writer ribbon fabrics. Normally EPI and PPI of a fabric are described as EPI×PPI. Thus a fabric of 74×66 means 74 EPI×66 PPI.

Balanced constriction

A fabric is said to be well balanced if the number of warp yarns and weft yarns per inch are almost equal.

3.Crimp

Crimp refers to the amount of bending that is done by thread as it interlaces with the threads that are lying in the opposite direction of the fabric. Crimp is defined as the ratio of difference of length of yarn (Ly) taken from length of fabric (Lf) to the length of fabric (Lf).

Crimp = (Ly-Lf)/Lf

Often it is more convenient and preferable to use percentage values. Thus we can define crimp percentage as:

Crimp% = (Ly-Lf)/Lf

A crimp will normally give values ranging from 0.01 to 0.14 ie. (1% to 14%).

Crimp is related to many aspects of the fabric. It affects the cover, thickness, softness and hand of the fabric. When it is not balanced it also affects the wear behaviour and balance of the fabric, because the exposed portions tend to wear at a more rapid rate than the fabric. The crimp balance is affected by the tensions in the fabric during and after weaving. If the weft is kept at low tension while the tension in warp directions is high, then there will be considerable crimp in the weft and very little in the warp.

4. Weave

It refers to the arrangement of warp and weft in the fabric.

OTHER FABRIC PROPERTIES

1. Fabric weight (W)

It is the weight of the yarn per square meter in the woven fabric, which is the sum of the weight of the warp (W1) and weight of the weft (W2).

Weight of the warp is calculated as (per square m):

W1= [n1 x 100 (1+c1%)/100] x [N1/1000] g

Where
n1 = Ends per cm
N1 = Warp count in Tex

C1% = Warp crimp percentage.

Similarly weight of the weft is calculated as (per square m)

W2= [n2 x 100 (1+c2%)/100] x [N2/1000] g

Total weight per square meter = W1+W2

weight/piece = (W1+W2) × piece length × piece width in gram.

Example

A fabric 120m long, 1.3 m wide and having 30 ends per cm of 12 tex warp and 24 picks per cm of 15 tex weft. The warp and weft crimp percentages are five percent and eight percent respectively. We describe these fabric particulars as
30×24; 12 tex × 15 tex; 5%×8%

Warp weight per square m = [30 x 100 x (1+5)/100] x [12/1000] = 37.8 gms

Weft weight/square m = [24 x 100 x (1+8)/100] x [15/1000] = 38.8 gms

Piece weight

= total weight per m × piece length × piece width
= 76.68 × 120× 1.3
= 11962.08 gm or 11.96 kg.

2. Cover factor

(K) it is defined as the area covered by the yarn when compared with the total area covered by the fabric.
The warp cover factor can be found by using the formula.
k1= n1 x sqrt(N1)/10
Where
n1 = Ends/cm
N1 = Count of warp in tex

Similarly the weft cover factor can be found by the formula

k2 = n2 x sqrt(N2) /10

So the total cover factor is
K = K1 + K2

Thus with fabric (30×24; 12 tex×15 tex) the values are

k1= (30 x sqrt12)/10 = 10.39

k2 = (24 x sqrt15)/10 = 9.30

K = K1+K2 = 10.39+9.30 = 19.69

3. Fabric Thickness

For a wide range of fabric, this parameter is not important, but it becomes critical for fabrics that are to be used as belts and felts.

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Care of Linen Fabrics

Care of Linen Garments

1. Washing

Washing is recommended. One can use hand or machine washing but take care of the following points

- Use a gentle wash cycle and use a gentle soap.
- Use cool to warm, not hot water.
- Wash colored linens in cool water.
- Use soft water
- Use oxygen bleaches ( hydrogen peroxide) for white linen. Chlorine bleaches can cause yellowing.
- Never wash darker-colored pieces together with the lighter colored articles.
 

2. Drying

Can use any of the drying methods, but bring linen in while it is still damp. If linen dries thoroughly, it may become brittle. Damp Linen also helps in ironing. If a linen has become thoroughly dried, put them in a plastic bag in the refrigerator before ironing.

3. Ironing

Iron with lot of steam at a medium to hot setting. Iron Linen until smooth but not dry. Once wrinkles are gone, hang the linen items until it is bone dry.

4.Storing

Clean linen items before storing .

-Avoid folding linen garments. Linen clothing should be hung on a padded clothes hanger in a cool dry environment.

- If you decide to warp the linen, use bags of linen, cotton or muslin, never plastic bags.  

Tags: Care, Linen, Fabrics

Career in Journalism

Career in Journalism

Being a specialist helps. It helps more if you can deliver that specialised knowledge to the general audience in a way that is interesting and that they can understand. A career in Journalism is one of the options that a Textile Technologist or a Textile specialist can pursue. This is all the more relevant because entertainment and media are one of the hottest careers in the days to come.

An effort to this direction has been made by 9.9 School of Convergence by introducing a course called Diploma in Applied Journalism .The admissions are open with the session starting from September 20th. The aim of this course is to inculcate in a person some high quality editing, writing and reporting skills. The classes are scheduled on Sundays so that the professionals don't have to leave their regular jobs. One can contact them and find more about the details.

As their website suggests, their placement services or "career services" do more than just getting a student a full time job. The career is shaped from the beginning of the course looking at a person's abilities and aspirations. The 9.9 School of Convergence has 100% placement with clients like NDTV, STAR, CNN-IBN to boast of . The leadership team has Dr. Pramath Raj Sinha, Dr. Eric D Saranovitz, Pooja Kothari and Gunjan Aggarwal who have links deep into the media industry.

It can be understood that with a specialisation and a career in journalism, the jobs will be much more enriching and satisfying ( and more lucrative) than with a specialisation alone.