Tuesday, February 14, 2017

Quality Control in Apparel Industry

What is quality:
Quality may define as the level of acceptance of goods or services. It is a relative term. It completely depends on customer satisfaction. Actually product quality is based on product attribute. In textile and apparel industry, quality is calculated in terms of quality and standard of fibers, yarns, fabric construction, color fastness, designs and the final finished garments. Quality is very important in apparel business. Customers demand and expect is the supreme importance in garment business because of clothing trends become change with short time period. There are various factors on which quality fitness of apparel industry is based such as - performance, reliability, durability, visual and perceived quality of the garment.
Quality control in apparel industry
Fig: Checking quality in apparel industry
Quality control in garment manufacturing technology:
In the apparel industry quality control is practiced right from the initial stage of sourcing raw materials to the stage of final finished garment. Quality control in garment industry is very complex and lengthy task. There are several stages to control quality in garment manufacturing. They are given below:
  1. Pre-production quality control
  2. Quality control during production
  3. Final inspection
  4. Quality control to developing a sampling plan
  5. Post-production quality evaluation
1. Pre-production quality control
In pre-production quality control, each component of a garment is tested prior to assembling. Closures, interlinings, sewing threads, and other design elements are tested for their quality and durability. Fabric with too many defects or closures that do not work properly can be detected prior to construction, which saves time and money in the long run. Fabric, accessories, closures, interlinings, sewing threads, and other design elements are all tested prior to the garment manufacturing in the pre production quality control phase.

Fabric quality:
Fabric quality is of utmost importance to the overall quality of apparel and textile products. Regardless of how well a product is designed or constructed, if the fabric is of poor quality, the product will most likely to fail with the consumer. Most fabric is comprised of fibers that are spun into yarns and then woven or knitted into fabric. Support materials like interlinings usually go from the fiber to the fabric stage. Since fibres are the building blocks of all apparel and textile products, it is important to start with quality fibers regardless if they are natural, manufactured, regenerated, or synthetic. Fabric should keep the following properties.
  • Comfort: Comfort is very important fabric property. It Comfort is studied by looking at fabric in terms of elongation and elasticity, heat retention and conduction, moisture absorbency, water repellency, waterproofing, hand and skin contact, drape, and air permeability
  • Colorfastness: Colorfastness relates to appearance retention and can be described as “how consumers use textile products and includes factors that may cause colorants to change color or migrate from one material to another”. Colorfastness is studied by exposing the fabric to different conditions including acids and alkalis, crocking, environmental conditions, frosting, heat, light, perspiration, or water. 
  • Durability: Durability evaluates “how various materials used in a product perform when subjected to different conditions”. Durability of a fabric is tested until it fails, and both warp and weft yarns are tested. There are many ways to assess fabric durability, including strength (tensile, tear, and bursting), abrasion, pilling, snagging, and dimensional stability.
Quality inspection of other accessories:
Garment accessories are inspected in the same manner as other textile and apparel products. Accessories are checked during preproduction, production, and post production with a final inspection. Various fashion accessories include closures, interlinings, sewing threads, elastic waistband, and other design elements. These accessories should be able to withstand the care and maintenance procedures devised for the clothing.

A brief inspection procedure for the accessories is described below:
  • Closures: Closure strength and durability is extremely important to garment construction and consumer satisfaction. Closures for apparel and textiles products include zippers, buttons, hooks, snap fasteners, drawstrings, hook-and-loop fasteners, and others. 
  • Interlinings: Interlinings, also called interfacing, are generally nonwoven fabrics that add more structure and body to garment components like collars, button plackets, waistbands, and cuffs. Interlinings may be fusible or sew-on. Interlining durability is important for garment construction.
  • Sewing threads: Sewing thread is the yarn used to combine two or more fabric pieces together in garments, accessories, and other textile products. Thread encompasses the majority of the stress and strain from movement and needs to be strong and durable. It must resist breaking and be compatible with the rest of the garment in terms of color, care instructions, and construction. Sewing thread should be free from imperfections such as knots, slubs, thick and thin places. 
  • Elastic waistband: Elastic waistbands are tested for fit (as per size) and durability (loss of elasticity). The fit is measured by the force needed to stretch the waistband about 200 more than the hip size (as per the size label) and bringing back to the waist size. The durability can be measured by stretching the waistband by 50% and measuring the force needed to stretch it. The loss of force in the two cases should be less than 10% for the waistband to be acceptable.
Other design elements include beads, sequins, braids, and fringes. They are tested for quality in similar ways as closures. Beads are similar to buttons and are tested for their impact resistance against creaking, chipping, or breaking during sudden external force. Sequins are assessed for their strength and resistance to breaking or tearing. Braids and fringes are checked for their quality in terms of durability from fraying, unraveling, tearing, and ripping.

2. Quality control during production
Each step in the garment production process is vital to the overall quality of apparel products. The production of apparel products includes cutting, assembling, pressing and other finishing procedures, and final inspection. Pattern pieces need to be cut with precision and on grain. Cut pattern pieces should be assembled with accuracy and care. Assembled garments are finished and pressed. Poor attention to detail, or carelessness when sewing, could have the domino effect on other components or future assembling. For example, skewed fabric pieces will not fit together easily and sewing is difficult. Poorly sewn garments have popped stitches and loose seams. Poorly pressed garments will not lie on the body correctly and could have permanent wrinkles. The following section describes the quality control of apparels during various production processes.

a. Spreading and cutting defects
Proper care should be taken to avoid any mistakes during spreading, otherwise, it will result in improperly cut components. The major parameters such as ply alignment, ply tension, bowing, and splicing should be done with a great care. Not enough plies to cover the quantity of garment components required should also be taken care. Misaligned plies will result in garment parts getting cut with bits missing in some plies at the edge of the spread. Narrow fabric causes garment parts at the edge of the lay getting cut with bits missing. Incorrect tension of plies, i.e., fabric spread too tight or too loose, will result in parts not fitting in sewing, and finished garments not meeting size tolerances. Not all plies facing in correct direction (whether “one way” as with nap, or “either way” as with some check designs), may create in pattern misalignment or mismatch. This happens when the fabric is not spread face down, face up, or face to face as required. The patterns should be aligned with respect to the fabric grain, or else may not fit or drape properly. Spread may be distorted by the attraction or repulsion of plies caused by excessive static electricity.

Cutting is an important stage of the garment production process. Precision is needed to cut accurate pieces that will fit together during the assembly process. Cutting defects include frayed edges; fuzzy, ragged, or serrated edges; ply-to-ply fusion; single-edge fusion; pattern imprecision; inappropriate notches; and inappropriate drilling. Garment defects are occured by careless use of knife, perhaps overrunning cutting previous piece. Garment parts have bits missing at edge of lay. If too tight or too loose then garment parts are distorted. Slits opened inaccurately or omitted.

b. Defects in assembling

After the pattern pieces have been cut, they are assembled. Many issues and defects can arise during the sewing process. Defects in assembling include defects with both stitches and seams. Possible stitching defects include needle damage, feed damage, skipped stitches, broken stitches, wrong or uneven stitch density, balloon stitches, broken threads, clogged stitches, hangnail, and improperly formed stitches. Seam defects include seam grin, seam pucker, incorrect or uneven width, irregular or incorrect shape, insecure back-stitching, twisted seam, mismatched seam, extra material caught in seam, reversed garment part, wrong seam type used, slipping seam, and wrong thread used.

c. Defects during pressing and finishing
After garments are constructed, final preparations are completed. These final preparations include pressing garments to help set seams and finish garment shaping. Defects during pressing and finishing include burned garments, water spots, change in original color, flattened surface or nap, creases not correctly formed, fabric of finished garment not smooth, edges stretched or rippled, pockets not smooth, garment not correctly shaped, and shrinkage from moisture and heat.

3. Final inspection
After materials have been tested for quality and the products have been manufactured, products are tested for their performance requirements, overall appearance, and sizing and fit. Proper sizing and fit can be measured as per the size of the garment or they can be tested by putting the garments in manikins or even live models. They are also checked visually for any faults during the production process. Hence, the quality of stitching, joining of garment components and accessories are inspected.

Although each component of a garment is tested individually, in pre production quality control, products are tested for a final time to assess the compatibility of materials used together and any noticeable fault. Garments are inspected for off-grain fabric, poor or uneven stitching, mismatched plaids or stripes along seams, puckered or extra material caught in seams, and uneven seams along hems, among many other problems that can occur in the apparel industry.

During inspection, some parts of a product are more important than others in terms of allowable defects. Every garment manufacturer defines its own product zones and includes these in their specifications as there is no industry standard. They will also define what they deem as critical, major, and minor defects. A critical defect results in a flaw that produces an unsafe or hazardous situation like a hole in a latex glove that would compromise the safety of the wearer. A major defect is a flaw that often contributes to product failure or lack of usability for a product. Examples of a major defect could be a broken zipper, broken stitches, or tears in the fabric. A minor defect is a flaw that does not reduce the usability of a product, but still deviates from standards and specifications. Examples of minor defects could be an unclipped thread, untrimmed seam allowance, or slubbed yarns in the fabric.

4. Quality control to developing a sampling plan
Although quality has been incorporated into each product up to this point, products are selected for audits and sorted into acceptable or unacceptable categories prior to shipment to their final destination. There are many types of samples including random, representative, convenience, stratified, constant percentage, and systematic samples. A random sample is where every item has an equal chance of being selected.

A representative sample includes a planned variation of items in a ratio that is appropriate. A convenience sample is made up of items that are easier to inspect over others and not random. A stratified sample is selecting a sample when a large lot of similar items exist. A constant percentage sample is sampling with a known constant percentage regardless of lot size to determine the sampling size. A systematic sample consists of items from equal intervals of time or the same location.

Types of sampling plans include lot-by-lot sampling, lot-by-lot sampling by attribute, skip-lot sampling, continuous production sampling, and arbitrary sampling.

5. Post-production quality evaluation
Post-production quality evaluation in the apparel industry includes wear testing for realistic reactions to everyday scenarios and testing with a simulation study when a consumer’s reliability is in question. In wear testing, which is sometimes called product testing, companies provide a small group of consumers with products. Consumers are contracted to wear garments under certain stated guidelines and requirements in order to determine whether they meet the company’s intended performance criteria. Consumers report back to the company and identify issues with the product before an entire production lot of garments are produced. Testing with a simulation study is similar to wear testing, but a consumer’s safety might be in question. Companies would test items like helmets with a simulation prior to producing an entire production lot, or would test the effectiveness of nonskid shoes on wet surfaces. Appearance retention and care are other aspects of post-production quality evaluation.

Conclusion:
From the above discussion we can say that controlling quality in apparel industry is really tough task. If quality properly controlled then costs remain at an acceptable level and customers be satisfied. Because quality is ultimately a question of customer satisfaction. We can say that quality control in terms of apparel manufacturing, pre-sales and posts sales service, delivery, pricing, etc are essential for any garment manufacturer, trader or exporter. For getting quality garments have to use latest technology and well trained worker to give best output and complete planning before the production.

References:

  1. http://www.fibre2fashion.com/industry-article/3092/defects-in-garments
  2. http://textilelearner.blogspot.com/2011/08/quality-control-system-in-garments_2589.html
  3. http://www.fibre2fashion.com/industry-article/3055/quality-systems-for-garment-manufacture
  4. http://textilelearner.blogspot.com/2012/09/quality-control-in-garment-manfacturing.html
  5. http://www.slideshare.net/sheshir/quality-control-of-garment
  6. Garment Manufacturing Technology by Rajkishore Nayak & Rajiv Padhye