Textile Raw Material Inspection 1 Fabric www Assignment

Textile Raw Material Inspection. 1 Fabric www. Assignment. Point. com

Inspection in reference to the apparel industry can be defined as the visual examination or review of raw materials (like fabric, sewing threads, buttons, trims, etc), partially finished components of the garments and completely finished garments in relation to some standards. The main objective of inspection is the detection of the defects as early as possible in the manufacturing process so that time and money are not wasted later on in either correcting the defect or writing off defective garments. The quality of a final garment depends on the quality of a fabric when it is received as a roll. Even the most outstanding manufacturing methods cannot compensate for defective materials. www. Assignment. Point. com

Purpose of fabric inspection: Fabric Inspection is an important aspect followed prior to garment manufacturing to avoid rejects due to fabric quality and facing with unexpected loss in manufacturing. Fabric inspection is done for fault/defect rate, fabric construction, end to end or edge to edge shading, colour, hand or feel, length/width, print defect and appearance. Fabric inspection ensures to minimise the rejection of cut panels or rejected garments due to fabric faults. Cutting inspected and approved fabric ensures not only finished garment quality but also reduces rejects, improves efficiency and timely deliveries. www. Assignment. Point. com

The purpose of fabric inspection is to determine the quality and acceptability for garments. As fabric is received, it should be inspected to determine acceptability from a quality viewpoint. Some garment manufacturers rely on their fabric suppliers to perform fabric inspection and fabric defects. In many small companies, spreading and cutting is done by the same personnel and fabric is inspected as it is being spread on a table for cutting. Fabric inspection, mapping or marking defects is important prior to spreading and cutting because: • Spreading can be done more quickly because the spreader is not also inspecting the fabric. • A cutter's productivity will increase because the defects are already marked. • The patterns are cut around the defects so as not to include them in the finished garment. www. Assignment. Point. com

How much to inspect? When a sewing factory receives fabric from the mill, it is difficult to conduct a full 100% inspection of the fabric. A minimum 10% inspection of all piece goods prior to spreading the fabric is recommended. Fabric Inspection Systems There are various fabric inspection systems: 10 -Point System. Graniteville "78" system. Dallas system. 4 - Point system. www. Assignment. Point. com

Ten Point System It was developed in the 1950's. This system assigns penalty points to each defect, depending on the length of the defect. Penalty points are assigned as per the following: www. Assignment. Point. com

Under the Ten-Point System, a piece is graded a "first" if the total penalty points do not exceed the total yardage of the piece. A piece is graded a "second" if the total penalty points exceed the total yardage of the piece. Limitations: This system is bit complicated because points per length are different for warp and weft defects. It is difficult in practical use. www. Assignment. Point. com

Graniteville "78" system This system was introduced in 1975 for the field of fabric grading. The system divides defects into major and minor types. The major defect is one, which is very obvious and leads the goods to second quality. The minor defect is one, which may or may not have caused garment to second, depending on its location in the end use item. Penalty Points are assigned as per the following: www. Assignment. Point. com

The following points are noteworthy in this system) Features/ Limitations): The principle was established in garment cutting piece, in which, the short length defects (less than 9") will normally be removed. The system tries to balance the importance of longer defects (over 9") and put less weight on 1 -10" defects such as slubs. The system also suggests the viewing distance of 9 foot instead of normal 3 foot viewing distance. The system tends to eliminate very small defects from the total penalty score. This is mostly recommended for use, where larger garments are to be cut with fabrics of wider widths. www. Assignment. Point. com

Dallas System This system was developed in 1970 s specifically for knits. It was approved by Dallas Manufacturers Association. According to this system, if any defect was found on a finished garment, the garment would then be termed as a "second". For fabrics, this system defines a second as "more than one defect per ten linear yards, calculated to the nearest ten yards". For example, one piece 60 yards long would be allowed to have six defects. www. Assignment. Point. com

4 -Point System The 4 -Point System, also called the American Apparel Manufacturers (AAMA) point-grading system for determining fabric quality, is widely used by producers of apparel fabrics and is endorsed by the AAMA as well as the ASQC (American Society or Quality Control). The 4 -Point System assigns 1, 2, 3 and 4 penalty points according to the size and significance of the defect. No more than 4 penalty points can be assigned for any single defect. Defect can be in either length or width direction, the system remains the same. Only major defects are considered. No penalty points are assigned to minor defects. In this system, one should inspect at least 10 per cent of the total rolls in the shipment and make sure to select at least one roll of each colour way. www. Assignment. Point. com

Fabric defects are assigned points based on the following: Total defect points per 100 square yards of fabric are calculated and the acceptance criteria is generally not more than 40 penalty points. Fabric rolls containing more than 40 points are considered "seconds. " www. Assignment. Point. com

The formula to calculate penalty points per 100 square yards is given by: The following are noteworthy points for this system) Features): No more than 4 penalty points can be assigned for any single defect. The fabric is graded regardless of the end-product. Any continuous defect (i. e. , roll to roll shading, narrow or irregular width, creasing, uneven finish, barre’, skew, etc. ) should be assigned a maximum of 4 points for every yard or meter within a shipment. This system makes no provision for the probability of minor defects. 4 point system is most widely used system in apparel industry as it is easy to teach and learn. www. Assignment. Point. com

Fabric defects by name: • Askewed or Bias : condition where courses are not square with wale lines on knits. • Barre : occurs in circular knit. Caused by mixing yarn on feed into machine. Fabric will appear to have horizontal streaks. • Birdseye: Caused by unintentional tucking from malfunctioning needle. Usually two small distorted stitches, side by side • Bowing : Usually caused by finishing. In knits the course lines lie in an arc across width of goods. Critical on stripes or patterns and not as critical on solid color fabrics. • Broken Color Pattern : Usually caused by color yarn out of place on frame. www. Assignment. Point. com

• Crease Streak : Occurs in tubular knits. Results from creased fabric passing through squeeze rollers in the dyeing process. • Drop Stitches Results from malfunctioning needle or jack. Will appear as holes, or missing stitches. • End Out : Occurs in Warp knit. Results from knitting machine continuing to run with missing end. • Hole : caused by broken needle. • Missing Yarn : Occurs in warp knit. Results from wrong fibre yarn (or wrong size yarn) placed on warp. Fabric could appear as thick end or different colour if fibers have different affinity for dye. • Mixed Yarn Occurs in Warp knit. Results from wrong fiber yarn ( or wrong size yarn) placed on warp. Fabric could appear as thick end or different color if fibers have different affinity for dye. www. Assignment. Point. com

• Needle Line: Caused by bent needle forming distorted stitches. Usually vertical line. • Pin Holes : Holes along selvage caused by pins holding fabric while it processes through tenter frame. Major if pin holes extend into body of fabric far enough to be visible in the finished product. • Press-Off : results when all or some of the needles on circular knitting fail to function and fabric either falls off the machine or design is completely disrupted or destroyed. Many knitting needles are broken and have to be replaced when bad press-off occurs. Bad press-offs usually start a new roll of fabric. • Runner : Usually caused by broken needle. Will appear as vertical line. (most machines have a stopping device to stop machine when a needle breaks). www. Assignment. Point. com

• Sanforize Pucker : Results from uneven wetting out on sanforize; usually caused by defective spray heads. Fabric will appear wavy or puckering when spread on cutting table. Difficult to detect during inspection on inspection machine with fabric under roller tension. • Slub (Knit fabric) : Usually caused by a thick or heavy place in yarn, or by ling getting onto yarn feeds • Straying End : Warp Knit. Caused when an end of yarn breaks and the loose end strays and is knit irregularly into another area. www. Assignment. Point. com

www. Assignment. Point. com Some knitting defects :

Measurement of Bias. . www. Assignment. Point. com Skew or Bias - Measure the skew in three places spaced as widely as possible along the length of the fabric or along a minimum of 1 linear yard. If possible, make no measurement closer to the ends of the roll or piece of fabric than 1 yard. Draw a line perpendicular to the selvage across the fabric from a point C where the marked yarn or course meets one selvage, meeting the other selvage at point B. Measure the distance between points A and B or D and B, and B and C, as shown in Fig. 2. Record the three or more skew or bias measurements. Calculate the maximum skew or bias as a percentage of the fabric width using the equation: "% Skew = Distance AB or DB x 100 / width BC"

Measurement of Bowing. . Bow – A straightedge is placed across the fabric between the points at which a marked filling yarn or knitting course meets the two selvages or edges. The greatest distance between the straightedge and the marked filling yarn or course is measured parallel to the selvages (Fig. 1 Distance "D"). www. Assignment. Point. com

Different Causes of Fabric Barre. . Raw material, Knitting and Yarn consideration www. Assignment. Point. com

Some other Fabric Defects. . www. Assignment. Point. com Small bits of contaminants spun into the yarn White specs Synthetic fibre contaminant

www. Assignment. Point. com Pointers focussing on the Defected area. .

Shade Variation and some Defect examples . . Weak spots (over bleaching) Shade variation in knitted fabrics is an issue of concern. It could be during dyeing and finishing. Mixing could be a suspect. The problem can be machine related or material related. Filling streaks and slubs of varying lengths www. Assignment. Point. com

www. Assignment. Point. com Another Fabric Defect. .

Another Fabric Defect. . www. Assignment. Point. com

There can be certain defects which arise during the knit-in process thus are shown here. www. Assignment. Point. com Knit-in Contaminants. .

SEVERITY Ø Barre Usually major Ø Askewd or bias Could be major or minor Ø Birdseye Major Ø Bowing Major or minor Ø Broken colour pattern Major Ø Crease streak Major or Minor Ø Drop stitches Major Ø End Out Usually Major Ø Hole Major Ø Missing Yarn Major Ø Mixed Yarn Major Ø Needle Line Major or Minor Ø Pin Holes Major Ø Runner Major Ø Slub Major or Minor www. Assignment. Point. com DEFECTS

www. Assignment. Point. com

Acceptable Quality Level (AQL( www. Assignment. Point. com

Definition : The AQL is the maximum per cent defective that for the purpose of sampling inspection can be considered satisfactory as a process average. When a buyer specifies a particular AQL for sampling inspection, it is an indication that as long as the percentage of defective garments in the shipments (lots) supplied by a manufacturer is lower than the AQL, most of the shipments will be accepted. Defects are broken into 3 categories: Minor, Major and Critical. While these can vary from client to client, the typical definitions are as follow: A Minor defect is a discrepancy from the standards, but one that is not likely to affect the usability of an object. A Major defect is one that is likely to create failure of the unit for its intended purpose. A Critical defect is one that is deemed to be hazardous or unsafe. www. Assignment. Point. com

OC (Operating Characteristic) Curve: The Operating Characteristic (OC) curve describes the probability of accepting a lot as a function of the lot’s quality. The first thing to notice about the OC curve is the shape; the curve is not a straight line. Notice the roughly “S” shape. As the lot percent nonconforming increases, the probability of acceptance decreases. To help determine the quality of a process (or lot) the producer or consumer can take a sample instead of inspecting the full lot. Sampling reduces costs, because one needs to inspect or test fewer items than looking at the whole lot. www. Assignment. Point. com

Ideal OC Curve: Sampling is based on the idea that the lots come from a process that has a certain nonconformance rate. The concept is that the consumer will accept all the producer’s lots as long as the process percent nonconforming is below a prescribed level. This produces the, so called, ideal OC curve. When the process percent nonconforming is below the prescribed level, 4. 0% in this example, the probability of acceptance is 100%. For quality worse than this level, higher than 4%, the probability of acceptance immediately drops to 0%. The dividing line between 100% and 0% acceptance is called the Acceptable Quality Level (AQL). www. Assignment. Point. com

Specific Points on OC Curve: The first risk is that the consumer will reject a lot that satisfies the established conditions, i. e. , the process quality is acceptable, but, by the luck of the draw, there are too many nonconforming items in the sample. This is called the producer’s risk, and is denoted by the Greek letter α. When we locate these values on the OC curve, expressed in terms of probability of acceptance, we actually locate 1 – α. The second risk is that the consumer will accept a lot that doesn’t meet the conditions, i. e. , by the luck of the draw there are not many nonconforming items in the sample, so the lot is accepted. This is the consumer’s risk and is denoted by the Greek letter β. he point associated with β is often called, in contrast, the Rejectable Quality Limit or RQL. consider the process quality where the lots have a 50% probability of acceptance. This is called the Indifference Quality Limit or IQL. www. Assignment. Point. com The acceptance decisions based on AQL based inspections contain two kinds of risks as detailed below:

Sewing Thread: Necessity of good quality sewing thread: • In high speed lock stitch machine, the thread is subjected to complex kinematic And dynamic conditions. The speed of thread passing through the needle eye can Reach 140 -165 km/hr. • While moving at such speed, the thread got friction from a number of guides, needle eye, the fabric being sewen, from the bobbin case assembly and from the bottom thread. • A certain length of thread before being incorporated in a stitch, may pass more than 30 times through a fabric, the needle eye, and the bobbin-case mechanism. • Such severe working condition with the heat generated in the needle can reduce the initial strength of thread by as much as 60%. www. Assignment. Point. com

Sewing thread should be checked and tested for following characteristics: Construction: Yarn count, yarn ply, number of twist, twist balance, yarn strength, yarn elongation. Sewability: Three sweing thread package from a specific lot should be used for 100 yds of sewing and then evaluate the following properties: Imperfection: Sewing thread should be free from slubs, knots, or any such defects. These make machine stoppage and reduce efficiency. Finish: To pass easily and smoothly through the eye of needle and through various thread handling parts, a lubricant is applied as per the weight of 3 % to 15% of thread. Color: Should match the standard sample and should not very too much with in the lot of sewing thread. The color should not bleed in washing and or dry cleaning and fade in sunlight. Package density: If package density veries too much within and between lot to lot, operators will have to adjust hte tension frequently, results in lower productivity. Winding: Winding should be uniform otherwise results in excessive thread breakage. Yardage: Lenght should be accurate as specified to package. 2% of lebeled length is tolerable limit. www. Assignment. Point. com

Zipper Problem due to handling of zipper: Ratcheting: This is the act of forcing the slider down the chain by pulling the two open halves apart. Some sliders are designed to ratchet. Others are positive locking sliders. Shear: This is the act of attempting to shift one half of the chain with respect to the other half after the slider is mounted. It occurs when a operator tries to adjust the waisband alignment with out first removing the slider. Slider distortion: A slider is called clam shelled when teh top and bottom have been spread apart, as in opening a clam. A crushed slider usually occurs in the pressing buck of the garment factory or industrial laundry. www. Assignment. Point. com

Problem of zipper due to sewing: The major casue of zipper failure is poor sewing. A garment panel attached too close to the teeth will interfere with the slider and get caught inside. Attempting to free the slider can cause garment and chain damage, or clam shelled sliders. A sew line that is not parallel to the chain or wanders, causes localized high stresses and curvature which can eventually lead to erratic slider action. Low stitch count can lead to tape sleaziness, and using blunt, large diameter needles will cause heating and melting during sewing because of the high density tight weave inherent in zipper tape. Improper thread trimming will cause interference with slider action when the loose ends become caught. www. Assignment. Point. com

Other problems of zipper: Fly Serging: The outer edge of zipper tape can be accediently cut during right fly serging by the serging knives, causing disastrous zipper failure. The best policy is to remove the knives entirely, or use the positive edge guide. Hump: it is the roller coaster effect of either the zipper chain or garment at the sew line. A humpy zipper is usually caused by the operator over tensioning the garment panel during sewing or feeding the assembly with the chain down in engagement with the feed dog. Hump after wasing or dry cleaning is the result of excessive differential shrinkage between the garment and zipper. Popping: A zipper that open in one spot has been popped. This can be caused by a very high localized force, but is usually the result of folding the zipper back upon itself tightly while under cross-wise load. www. Assignment. Point. com http: //grainlinestudio. com/2012/09/19/sewingtutorial-inserting-a-fly-front-zipper/

Waistband hook/eye closures: The hook and bar, snap, hook and eye, and button closures used at the top of the zipper opening are intended to absorb all of the crosswise stress when closed. Mislocated or poorly attached closures will subjcet the zipper teeth to very high stresses at the top. Chemical degradation: The largest casue of the longterm zipper failure is teh repeated laundering in overly harsh agents. The faded jean craze is probably the number one problem. Soaking the garment in a high concentration bleach solution and subjecting in repeatedly to harsh low phosphate detergents will corrode brass chain and sliders and harden the teeth of plastic zippers. Missing bar tack: Bar tacks serve the function of protecting the bottom stop from excessive load in fly applications. A missing bar tack, or one set too low, could result in a bottom stop failure. www. Assignment. Point. com

Buttons : Following should be checked to determine button quality: • Button should have large clean sew holes that are free from flash and will not cut the thread. • Hole must be located properly in relation to the edge of buttons • Buttons should be of uniform thickness. • The color or shed of the buttons should be within a certain visual tolerance. • Buttons should be able to withstand laundering, dry cleaning and pressing without any changes such as cracks, melting of surface (scorch) and change in color or shed. Impact test of Buttons: It is to test the durablity of buttons. Individual buttons are placed on a surface centered under a tube through which a preselected mans falls from a preselected height. After the mans impact the button, the button is removed from testing device and visually examined using 5 X magnifying glass for breakage, cracking or chipping. The buttons are classified as class A, B 1 -B 3 depending upon the impact resistance, the class A button being the most durable. www. Assignment. Point. com

Snap fasterners: • The attaching machinery should locate the snap fasteners accurately and at proper pressure. • Component parts should be checked to close tolerances and free from dirt and other foreign substances so the assembly would be touble free. • Hardness and workability of metal are important factors. • if the metal is too hard the parts will be formed poorly and may crack; if it is too soft the clouser will be weak. Plastic snap fastener is free from such problem. • The snap fastener should attach firmly and withstand the maximum pull that they can be expected to endure on the garment. Testing of snap fasteners: The quality of snap fasteners is generally judged by how easily they can be fastened or unfastened and their holding power. The resistance of unsnapping the snap fastener can be determined by testing snap fasteners mounted on a strip of enduse material near the end are tested on standard tensile testing machineries equipped for testing the strenght of textile fabrics and having sensivity for accurate low force levels. Test are made on snap fasterners before laundering and after a pre-determined number of laundering or dry-cleaning. www. Assignment. Point. com

Interlining The purpose of fusible interlinings is to give shape or form and imporve the aestheitics of a garment. There is no better way to test fusible interlining other than to actually fuse the interlining with the end item fabric and evaluate such samples before starting mass production. Threfore, at least 12 inx 12 in piece of end item fabric are cut and fused to 9 inx 9 in pieces of fusible interlining at the recommended time, temperature and pressure. Then this specimen are checked for compatibility, shrinkage and bond strength. Compatibility means that the fusible interlining material should provide good drapability, bulk and support without altering the natural hand of the end itemfabric. Shrinkage can be measured by placing gauge marks on the interlining and shell fabric before fusing and measuring the distance between these gauge marks after fusing. Any significant shrinkage of the interlining fabric would result in a noticeable bubbled appearance on the right side o the shell fabric. Specimen may also be used for laundering and dry cleaning according to the intended care instructions of the end itemto evaluate fusing performance for defects such as bubbling, cracking, delamination etc. www. Assignment. Point. com