Ukey P; Kadole PV

Research Article

Adv Res Text Eng. 2016; 1(2): 1011.

Effect of Seam Formation on Draping Quality of the Stitched Fabric

Ukey P* and Kadole PV

Department of Textiles, DKTE’s Textile & Engineering Institute, India

*Corresponding author: Pravin Ukey, Department of Textiles, DKTE’s Textile & Engineering Institute, India

Received: September 08, 2016; Accepted: December 21, 2016; Published: December 28, 2016

Abstract

The drape is the important aesthetic property of the fabric which allows a fabric to bend in multi-directions. Since last so many years, the researcher has studied the fabric drapability in order to improve the drape and appearance of the garment over the body. However, fabric panels must be stitched together to form the garment. A seam and stitch are believed to affect a garment appearance significantly.

Thus, the study of the fabric drape can be more realistic with stitches and seams. In this paper, the study was made to check the effect of stitches and seams on the different GSM of the fabric.

Keywords: Drape; Sewn; Seam, Garment, Stitches, GSM and fabric

Introduction

The stitched fabric or the apparel is assembled by cutting and sewing the fabric panels together. The seam is the joint where the sequence of stitches unites two or more layer of the fabrics together, and this seam affects the fabric stiffness greatly [1]. It is unrealistic to realise the appearance of the apparels without the consideration of the seams and the methods of assembling of fabric into the garments [2]. Therefore, there is a necessity to optimise the seam parameters in order to decrease the stiffness of the fabric of the garment [3]. The beauty of the garment seems to affect the seam formation. Bending of the fabrics are evaluated by 2 dimensional whereas drape is evaluated for 3-dimensional properties of the garment [4].

To overcome the limitations of estimating fabric drape via twodimensional measurement of stiffness, researchers in Fabric Research Laboratories developed the F.R.L. Drapemeter by the Chu, Cummings, and Teixeira [5].Later Cusick [6] developed a drapemeter based on a similar principle. By developing drapemeter, Chu et al., and Cusick made a significant contribution to the practical determination of this fabric property by measuring drape in three-dimensions.

Dhingra and Postle investigated bending properties of fabrics with a seam. Two plain seams, one vertical (perpendicular) and one parallel (horizontal) to the bending axis, were tested. With the introduction of the vertical seam, bending properties were greatly increased and they were further increased when the seam allowance was increased to 10 mm. [7]. Suda and Nagasaka investigated the effect of the seam on fabric bending rigidity tested in the Kawabata Evaluation System (KES) by varying seam allowances, the number of seams on the same specimen, the type of stitches, seam and sewing thread. They concluded that a seam has distinctive effects on the bending property of the fabric [8,9]. Although thread balance during sewing, thread crimps, width, layers and thickness of the seamed piles [10-13] are important factors affecting the drape of fabrics.

Materials and Methods

Materials

The upper garment i.e. the shirt under study was made with 100% cotton fabrics for the premium shirts. The specification of the material used is given in Table 1.

Table 1: Fabric specification.




  
    Sr. No. 
    Parameter 
    Light Weight Fabric 
    Medium Weight Fabric 
    Heavyweight Fabric 
  
  
    1
    Ends/inch
    168
    160
    152
  
  
    2
    Picks/inch
    102
    58
    62
  
  
    3
    Warp Yarn Count (Ne)
    65.62
    49.21
    32.81
  
  
    4
    Weft Yarn Count (Ne)
    49.21
    21.87
    13.12
  
  
    5
    Warp  crimp %
    3%
    2%
    6%
  
  
    6
    Weft  crimp %
    6 %
    8%
    10%
  
  
    7
    Warp  cover factor
    20.73
    22.80
    26.53
  
  
    8
    Weft  cover factor
    14.54
    12.40
    17.11
  
  
    9
    Cloth cover factor
    24.50
    25.10
    27.42
  
  
    10
    GSM in (gms/Sq. meter)
    116
    127
    222



Table 1:  Fabric specification.

Methods

The stitch samples are prepared on the single needle lock stitch machine of make Silversun of model SMX 8700. The Needle number used is DB X 1 of 14 Nos. for light and medium weight whereas DB X 1 of 16 No. is used for the heavyweight material. The sewing thread used was 3 ply polyester having ticket number 80. The same thread is used to avoid any variation for seam formation. Apart from this overlock, multithread chain stitch and flat lock machines were used for the stitching of the sample preparation of shirts. All specimens were ironed at standard temperature and conditioned at 27° C and 65 RH for 24 hours before testing.

For manufacturing, the shirt various seams are used. In the research study, the shirt is assembled with a superimposed seam, lapped seam and flat seam. The experimentation was carried out with a combination of the superimposed seam with lock stitch in 3 different GSM of a fabric. Likewise, the lapped seam with chain stitch and flat lock with covering chain stitches was used for the preparation of 9 samples with lightweight, medium weight, and heavy weight GSM of fabrics. Following seam and stitch combination is used for Shirt sample preparation under study.

Superimposed seam and lock stitch
Lapped seam with chain stitches
Flat lock seam and covering chain stitch

Seam and stitch sample preparation

The samples are prepared on the single needle lock stitch sewing machine for the stiffness and drape coefficient with a seam. Hence, the seam is formed on the samples according to the seam standards. Actually, in the garment when the seams are used these are basically formed with the same allowance rather than varying seam allowance. But different types of seams are mostly used in a wide variety of garments. So here the study was made particularly with the seams used for the bottom wear and upper wear garments.

The Figure 1, shows the representative sample preparation for the DC% and stiffness calculation with seams.

Figure 1: Sample preparation for drape coefficient and stiffness.

    
    
    Figure 1:  Sample preparation for drape coefficient and stiffness.

The samples for the upper wear garments particularly for shirts were prepared from varying GSM viz. lightweight, medium weight and heavyweight, by forming the basic seams like a superimposed, lapped, and flat seam. It is very important here to discuss the properties of the seams though explained earlier in the literature review.

Superimposed seam: The superimposed seam is the most commonly used seam in the garment. The panels of the garment are just exactly kept over each other and then the stitch is formed on that garment panels to be joined together. So the limited edge of the panels is overlapped over each other Figure 2.

Figure 2: Superimposed seam.

    
    
    Figure 2:  Superimposed seam.

As shown in the diagram the two layers of the fabrics were exactly kept over each other and the dotted line shows form the stitches over it for joining purpose.

Lapped seam: The lapped seam is formed when the limited edge of the panels of the fabrics are overlapped for the limited width. This type of lapped seam formation is basically seen in the shirts. As shown in the below Figure 3, the one edge of the fabric is folded inside to the other edge of the fabric, so that the firm locking is formed between the edges of the fabric and over which the stitches are formed for joining purpose.

Figure 3: Lapped seam.

    
    
    Figure 3:  Lapped seam.

Flat seam: The flat seam as the name itself explains aims to reduce the thickness of the seams. Because when any seams will be formed the thickness at the overlapping area will be doubled or in the multiplication of original sample. So in this seam, the samples are just butted together. This is mostly suitable for the joining the panels of the undergarments so to avoid any discomfort to the body Figure 4.

Figure 4: Flat seam.

    
    
    Figure 4:  Flat seam.

Stitch formation

Lock stitch: It is the most common stitch made by the single needle lockstitch sewing machine. The lock stitch uses two threads upper thread which passes through the needle and bottom thread i.e. bobbin thread. Lock stitches are the secured stitches because they formed the locking with each successive needle penetration and hence it’s unravelling are quite difficult Figure 5.

Figure 5: Lock stitch.

    
    
    Figure 5:  Lock stitch.

Chain stitch: Chain stitch is made by using one or more group of sewing threads. The stitch which is formed by using two or more groups of sewing thread is called multi-thread chain stitch. Here, the loop of one group sewing threads is bounded by interloping with the loop of another group of sewing threads. Stitch type-401 is called multi-thread chain stitch Figure 6.

Figure 6: Chain stitch.

    
    
    Figure 6:  Chain stitch.

Covering chain stitches: Class-600 named as covering chain stitch which is produced with three groups of threads. Threads of two groups can be seen from either side, the first group of the thread is called needle thread, the second group is called top cover thread and the third group is called bottom cover thread. This stitch is very complex and uses up to 9 threads in producing these types of stitch. These types of stitch are used for knits, lingerie, binding elastics, decoration, etc Figure 7.

Figure 7: Covering chain stitches.

    
    
    Figure 7:  Covering chain stitches.

Results and Discussion

Stiffness testing

Bending length known as drape Stiffness is very important property which decides the two-dimensional drape of the fabric. As studied by the pierce [4] this property is one of the major for the study of the drape. The rectangular strip of fabric is mounted on the horizontal platform and slides until the fabric overhang like a cantilever. Flexural rigidity was also calculated by multiplying the thickness of the samples and expressed in the table below.

Shirley stiffness tester was used for stiffness calculation. The testing was done according to IS 6490-1971 based on the BS 3356: 1961 and ASTM Designation: D 1388-64. The average of the five samples each taken for the warp and weft way. Prior to the test, the fabric samples were conditioned at moisture equilibrium and tested in standard atmospheric conditions of 65 % RH and 27°C temperature

The Figure 8 and the Table 2 shows the flexural rigidity of the light, medium and heavyweight fabric. The lapped seam is formed with chain stitch combination. As lapped seam is formed by binding the hem together of the fabrics and hence it shows more resistance towards the bending of the fabrics. Whereas the flat seam forms almost the same type of combination as that of original fabrics although the fabric shows more resistance to bending than the original without seam fabrics. This is because of the formation of the flat seam as very less thickness is used for the joining of the edges of the fabrics.

Figure 8: Flexural rigidity of the different GSM fabrics.

    
    
    Figure 8:  Flexural rigidity of the different GSM fabrics.

Table 2: Flexural rigidity (mg-cm).




  
    Sr. No. 
    Shirt Samples 
    Lightweight 
    Medium weight 
    Heavyweight 
  
  
    1 
    Original    (without seam)
    266.43
    382.63
    537.82
  
  
    2 
    Superimpose    Seam & lockstitch
    844.87
    1301.33
    1660.13
  
  
    3 
    Flat    Seam & Covering chain stitch
    494.35
    1392.49
    1443.71
  
  
    4 
    Lapped    Seam & chain stitch
    4358.82
    7266.1
    6793.98



Table 2:  Flexural rigidity (mg-cm).

Overall it can see that if the thickness and the weight are the influencing factors for flexural rigidity. So the increase in thickness will increase the stiffness and found to be more in heavyweight fabric and lapped seam.

Seam strength

Seam strength refers to the load required to break a seam. This measures the strength and tenacity of a seam. Two pieces of woven fabric are joined by a seam and if tangential force is applied the seam line, rupture ultimately occurs at or near the seam line. It is a function of the strength of thread used for the seam, type of seam assembly in a garment and type of fabric used. Tensile tests on the sample fabrics were performed to determine seam efficiency using the ASTM D 5034-95 (grab) methods. Or a large number of tests are done with ASTM 1683-04 standard which expresses the value of seam strength in terms of maximum force to cause the seam specimen to rupture (Table 3).

Table 3: Seam strength of warp and weft way samples.




  
    Sr. No. 
    Seams    & Stitches 
    Fabric    Sample 
    Load in    kgf for warp 
    Load in Kgf for weft 
  
  
    1 
    Superimposed seam &    lockstitch
    Light    Weight 
    48.8
    15.2
  
  
    2 
     
    Medium    Weight 
    22.4
    42.2
  
  
    3 
     
    Heavyweight 
    66.6
    26.4
  
  
    4 
    Lapped seam & Chain    Stitch
    Light    Weight 
    37.2 
    15 
  
  
    5 
     
    Medium    Weight 
    38.6 
    10 
  
  
    6 
     
    Heavyweight 
    38 
    7.06 
  
  
    7 
    Flat seam &Covering    Chain stitch
    Light    Weight 
    19 
    14 
  
  
    8 
     
    Medium    Weight 
    16 
    12.8 
  
  
    9 
     
    Heavyweight 
    35 
    17



Table 3:  Seam strength of warp and weft way samples.

As observed Figure 9, the seam strength for warp way is higher for superimposed seam and lock stitch combination. Where as it shows less for the lapped and chain stitch combination. The strength of seam is the combined effect of fabric strip strength and seam strength. For the warp, the lockstitch is having more strength than other chain stitches. Whereas for the weft, the trend shows that the superimposed seam shows highest seam strength because of its locking for each successive needle penetration.

Figure 9: Seam strength in warp and weft way.

    
    
    Figure 9:  Seam strength in warp and weft way.

Seam efficiency

Seam efficiency measures the durability along the seam line. Durability is identified as necessary to satisfactory seam’s functional performance and efficient seams are assumed to be more durable than weak ones. Seam efficiency is measured by the strength tester, based on the pendulum lever principle according to the ASTM 1683-04 standard method. In this method, seam efficiency was measured by using the following formula (Table 4).

$S e a m e f f i c i e n f y (%) = \frac{(F a b r i c w i t h s e a m t e n s i l e s t r e n g h t)}{f a b r i c t e n s i l e s t r e n g t h} * 100$

Table 4: Seam Efficiency in warp and weft way.




  
    Seams    & Stitches 
    Fabric    Sample 
    Warp    efficiency % 
    Weft efficiency % 
  
  
    Superimposed &lockstitch 
    Light    Weight
    17.82
    16.48
  
  
     
    Medium    Weight
    63.27
    54.35
  
  
     
    Heavyweight 
    4.32
    2.22
  
  
    Lapped &Chain Stitch 
    Light    Weight
    54.10
    23.07
  
  
     
    Medium    Weight
    73.77
    45.29
  
  
     
    Heavyweight 
    49.56
    37.03
  
  
    Flat seam &Covering Chain 
    Light    Weight
    10.14
    17.58
  
  
     
    Medium    Weight
    36.27
    57.26
  
  
     
    Heavyweight 
    42.24 
    73.85



Table 4:  Seam Efficiency in warp and weft way.

Seam strength is inversely proportional to the fabric strength. The same trend is seen in the warp direction for the superimposed seam but observed different with other seam and stitch combination. For the weft way, the same trend is observed. As the superimposed is most commonly used seam for shirting whereas another seam formation is quite different for the lapped and flat seam. And hence the trend for the superimposed seam is same for warp way and weft way direction Figure 10.

Figure 10: Seam efficiency in warp and weft direction.

    
    
    Figure 10:  Seam efficiency in warp and weft direction.

Seam shrinkage

This test is carried out for dimensional stability of the seams after different washing. Shrinkage can be expressed in percentage (Table 5).

Table 5: Average seam Shrinkage in percentage.




  
    Seams    & Stitches 
    Fabric    Sample 
    Warp Shrinkage % 
    Weft shrinkage % 
  
  
    Superimposed &lockstitch 
    Light Weight 
    0.3 
    0.1 
  
  
     
    Medium Weight 
    0.3 
    0.1 
  
  
     
    Heavyweight 
    0.4 
    1.2 
  
  
    Lapped &Chain Stitch 
    Light Weight 
    0.3 
    0.2 
  
  
     
    Medium Weight 
    0.25 
    0.2 
  
  
     
    Heavyweight 
    0.5 
    1.1 
  
  
    Flat seam &Covering Chain 
    Light Weight 
    0.27 
    0.3
  
  
     
    Medium Weight 
    0.35 
    0.1
  
  
     
    Heavyweight 
    0.4 
    1.1



Table 5:  Average seam Shrinkage in percentage.

It is observed from the Figure 11, that the heavy weight fabric shows more shrinkage than the light and medium weight fabrics under study.

Figure 11: Seam shrinkage in warp and weft way direction.

    
    
    Figure 11:  Seam shrinkage in warp and weft way direction.

Figure 12: Drape coefficient of different seamed fabric with stitches.

    
    
    Figure 12:  Drape coefficient of different seamed fabric with stitches.

Drape coefficient of seamed fabric

The drape ability of seamed fabric or garment affected by both the flexibility of the materials and by the construction of the seam. The drape is calculated as the area covered by the shadow of the draped specimen expressed as a percentage of the annual ring of fabric (Table 6).

Table 6: Average of Drape Coefficient.




  
    Samples 
    Lightweight % 
    Medium    weight % 
    Heavyweight % 
  
  
    Superimposed&    Lock stitch 
    63.67 
    74.05 
    78.04 
  
  
    Lapped    seam & chain stitch 
    60.87 
    66.06 
    87.35 
  
  
    Flat    seam& covering chain stitch 
    53.69 
    64.25 
    70.56



Table 6:  Average of Drape Coefficient.

The graph shows the drape coefficient of the varying GSM of the fabrics under study. Superimposed-lock stitch combination and Flat seam-covering chain stitch combination shows an almost same trend for the drape coefficient of the fabrics. Whereas the Lapped seamchain stitch combination shows the higher drape coefficient for all the varying GSM of the fabrics. This is because of the structure formation with a lapped seam.

Subjective Analysis of the shirts

There are several dimensions for evaluation of the graceful appearance of the fabrics. In order to simplify the analysis of appearance, it is essential to choose only most important evaluating dimensions, which can well represent the overall graceful appearance of the garment. This study tried to identify the most important dimensions for the graceful appearance or fall of the garment through the subjective analysis of the samples.

Selection of the judges: The selection of judges is an important element for the subjective ranking in order to achieve greater reliability and consistency. The judges were selected from the Industry and academics of the apparels. It was found that researchers had industrial experiences in the garment field. They had experiences in areas such as apparel quality control, apparel design and apparel manufacturing. Based on this the results of the subjective ranking were calculated and interpreted in the table.

Subjective ranking: In order to evaluate the most important dimensions for the appearance of the garment i.e. shirts. The researchers were asked to give the ranking based on the appearance in the following category with the numbers.

Poor
Satisfactory
Moderate
Good
Excellent

The shirts were evaluated with three categories for functionality, serviceability and appearance of the garment Table 7.

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Citation: Ukey P and Kadole PV. Effect of Seam Formation on Draping Quality of the Stitched Fabric. Adv Res Text Eng. 2016; 1(2): 1011. ISSN:2572-9373

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