Fabric Defects And Point Grading System 35

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ACKNOWLEDGEMENT We are thankful to the L.D. institute of engineering to provide the greatest opportunity to work on the topics like fabric defects, inspection system & point grading system. This project helps us to understand the importance in textile field and the credit goes to our respected HOD G. C. BHRAMBHATT to allow us to work on this project. So we also like to thank to him. As per the older says nothing is possible without guidance and it also affect our project. It will not be possible without the guidance of Professor A. I. THAKKAR. So at last we want to thank to him.

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1.

INTRODUCTION ___4

2.

TYPES OF DEFECTS ___6 2.1.

WOVEN DEFECTS ___6

2.2.

KNITTED DEFECTS ___7

2.3.

GARMENT DEFECTS ___8

2.4.

OTHERS DEFECTS ___9

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1.

INTRODUCTION 1.1.

What is a Fabric Defect? A Fabric Defect is any abnormality in the Fabric that hinders its acceptability by the consumer.

1.2.

Major defects are classified as follows: Woven defects include slubs, hole, missing yarn, conspicuous yarn variation, end out, soiled yarn, wrong yarn. Knitted defects include barre, thick yarn, thin yarn, and holes, and broken needle, fly. Dye or printing defects include dye spots, machine stop, colour out, and shading. Garment defects include faulty zippers, irregular hemming, loose buttons, and raw edges.

1.3.

What is a Defect-Free Fabric? A Fabric that exhibits a consistent Performance Within the boundaries of human use & human view. A Fabric that exhibits a consistent Appearance Within the human sight boundaries

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1.4. What are the Factors that could lead to Fabric Defects? There are two types’ factors MATERIAL-RELATED FACTORS: • • • • • • • • •

Fiber contaminants Excessive neps and seed coat fragments Excessive short fiber content Excessive trash content High variability between and within-mix Clusters of unfavorable fiber characteristics Weight variation Twist variation Excessive Hairiness

MACHINE-RELATED FACTORS: •

• • • • • • •

Failure of spinning preparation to eliminate or minimize short and long-term variation Failure of opening and cleaning machines to completely eliminate contaminants and trash particles Failure of the mixing machinery to provide a homogenous blend Excessive machine stops particularly during spinning Excessive ends piecing during spinning preparation Poor maintenance and housekeeping Weaving-related defects Knitting-related defects

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2.

TYPES OF DEFECTS 2.1. 2.2. 2.3. 2.4.

Woven defect Knitted defect Garment defect Other defect

2.1.

WOVEN DEFECT:

According to [4] the woven fabric defects can be organized into three basic categories. The weft direction defects, the warp direction defects and defects with no directional dependence. Some of them in the weft direction are irregular weft density, double pick, broken pick, weft yarn defect, and float; defects in the warp direction are broken end, double end and warp yarn defect. Defects with no directional dependence involve defects: stain, hole and foreign body.

Structure without defect

Float

Double end

Hole

Stain

Irregular end density Irregular pick density

Double pick

High tenacity 6

2.2. KNITTED DEFECT :

Broken thread

Broken niddle (hole)

Thick yarn

Stain

Barre

Thin yarn

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2.3. GARMENT DEFECT :

UNRAVELING SEAMS

UNRAVELING SEAMS WITH Broken Stitch

RESTITCHED SEAMS

SAGGING OR ROLLING POCKET

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2.4. OTHER DEFECTS :

Small Bits of contaminants Spun into the Yarn

Filling Streaks & Slubs of Varying Lengths

Weak Spots (Over-bleaching)

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1.

INTRODUCTION ___11

2.

CLASSIFICATION ___11

3.

EVS ___12

4.

I-TEX ___13

5.

BARCO (CYCLOPS) ___20

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USTER ___26

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1.

INTRODUCTION 1.1. What is it? Inspection in reference to quality control in apparel industry can be defined as the visual examination or the review of raw material partially finished component of garment in relation to some standard, specification or requirement, as well as measuring the garment to check if they meet required measurement.

1.2. Why is it required? • To trace the source of defect, so that appropriate measures can be taken to make use of the faulty fabrics. • To minimize the future reoccurunce of the defect. • To determine quality and hence the price of the fabric. • To supply information to proper levels of management as to the qualities being produced

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CLASSIFICATION OF INSPECTION SYSTEMS 2.1. MANUAL INSPECTION: The manual inspection is usually carried out by running the fabric in an open width form over a wide table under appropriate illumination. Defect in a fabric can be seen readily with these machines as the inspector has a very good view & the fabric does not need to be reversed to detect the defects at the back. The defects are located, marked and recorded according to their type.

2.2. AUTOMATIC INSPECTION: The field of fabric inspection has adopted automation to detect faults after inspecting the fabric thoroughly. Today’s automated fabric inspection systems are based on adaptive, neural networks. They can learn. The s are able 11

to simply scan a short length of good quality fabric to show the inspection system what to expect. They are designed to find and catalog defects in a wide variety of fabrics including greige fabrics, sheeting, apparel fabrics, upholstery fabrics, industrial fabrics, tire cord, finished fabrics, piecedyed fabrics and denim

3. E V S ELBIT VISION SYSTEMS Elbit Vision Systems is an innovative company that develops, markets and supplies solutions, products and services worldwide for the modernization and improvement of production processes by computerized vision technology to the textile market in its various applications - woven and non-woven, natural and synthetic fabrics, denim, technical fabrics, as well as to other web inspection applications. EVS systems automatically detect and categorize spinning, weaving, finishing and other fabric defects, analyze the shade consistency of fabrics or monitor printing processes with consistency, reliability and at very high speeds. EVS offers its consumers a wide range of inspection, monitoring and software solutions, which can be integrated with their quality standards, existing work methods and production lines. EVS also presents utilization of the inspection data for improved process control and upgraded quality control which result in operational cost savings. EVS maintains a global sales and service coverage with over 300 inspection systems installed in 25 countries.

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4.

I – TEX

Manual operation such as second inspection, mending or roll cutting will be achieved more efficiently, faster and its lower cost using I-TEX process. • It offers : o New dimension of accuracy. o Reliability. o Cost effectiveness in fabric inspection. • Types of I-TEX Machines: o I-TEX 1000 o I-TEX 2000 o I-TEX 2000D o Loom tax o Printex

4.1. I-TEX1000 : • Greige & Industrial Fabric Automatic Inspection System The I-TEX1000 is a computerized vision inspection system that automatically detects, memorizes, locates and further grades weaving defects on greige fabrics and process defects on several industrial fabrics. The system is based on a state-of-the-art technology of unique image understanding algorithms and structure that imitate the human visual mechanism.

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• Benefits : o Continued fabric quality improvement o Substantial savings on inspection and operational expenses o Consistent and reliable quality standards o Accurate and accessible quality data o Reduced customer claims I-TEX1000 is EVS’ new generation of Greige & Industrial fabric automatic inspection systems. The system replaces EVS’ I-TEX100 system which has been utilized by hundreds of satisfied customers during the last decade. • The new I-TEX1000 features: o New and modern human interface for easy operator training and friendly system operation. o New frame for a “dust free” environment, which enables maximum flexibility in cameras and illumination design. o Upgraded detection algorithms for higher inspection level. o Easy fabric styles and parameter setting. Full integration with EVS’ advanced process tools for a tailormade quality process. I-TEX1000 Inspects 100% of the fabric, at fabric speed up to 150 meters per minute. The system can detect defects as small as 0.5 mm, such as the following multiple Greige defect types: • • • • • •

Yarn and weaving faults Holes Oil stains Missing threads Starting marks Broken yarns

Virtually every visible defect is detectable by the system.

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I-TEX1000 can be configured and designed to fit your specific application and needs. The system's modularity enables configuration that matches your demands in the following categories: • • • •

Fabric width Fabric speed Desired resolution (minimum defect size) Grading standards

External optional connecting devices: Length meter, Seam detector, Visual alarm, UV/IR Ink marker, Metal label marker, Modem, Data interface by Ether link III communication and a printer.

4.2. I-TEX2000 : •

Finished Fabric Automatic Inspection System

The I-TEX2000 is a computerized vision inspection system that automatically detects, memorizes, displays and further grades - weaving, dyeing, finishing, coating and yarn defects on fabrics. The system is based on a state-of-the-art technology of unique image understanding algorithms and structure that imitate the human visual mechanism. • Benefits o Continued fabric quality improvement o Substantial savings on inspection and operational expenses o Consistent and reliable quality standards o Accurate and accessible quality data 15

o Reduced customer claims I-TEX2000 is the only proven industrial solution for automatic fabric inspection in textile dying and finishing processes. The ability to automate the quality inspection process resulting in high inspection performances convinced leading textile manufacturers to adapt the ITEX2000 solution and to continuously increase the number of I-TEX 2000 installations. I-TEX2000 new model presents new features for better performance and easier operation: • New and modern human interface for easy operator training and friendly system operation. • Full integration with shade variation analyzer (EVS' SVA Lite) for the purpose of combining the fabric and shade defects into one output. • Up to 4 different lines of site and illuminations, for optimal detection performances. • Upgraded detection algorithms for higher inspection level. • Easy fabric styles and parameter setting. • Full integration with EVS' advanced process tools for a tailor made quality process. I-TEX 2000 Inspects 100% of the fabric at fabric speed up to 150 meters per minute. The system can detect defects as small as 0.5 mm, such as the following multiple Finishing defect types: • • • • • • • • •

Yarn and weaving faults Holes Oil stains Missing threads Starting marks Broken yarns Water and dyestuff stains Dyeing and Finishing irregularities Virtually any visible defect is detectable by the system.

I-TEX2000 can be integrated in-line with existing production processes, or used as an off-line unit with fabric winding machines. The system is compatible with EVS' Shade Variation Analyzer - SVA Lite. The system's modularity enables configuration that matches your demands in the following categories: 16

• • • •

Fabric width Fabric speed Desired resolution (minimum defect size) Grading standards • External optional connecting devices: Length meter, Seam detector, Visual alarm, UV/IR Ink marker, Metal labels marker, Modem, • Data interface by Ether link III communication and a printer.

4.3. I-TEX2000D Denim Fabric Automatic Inspection System

The I-TEX2000D is a dual surface computerized vision inspection system that automatically detects, memorizes, displays and further grades weaving and finishing defects on Denim fabrics. The system is based on a state-of-the-art technology of unique image understanding algorithms and structure that imitate the human visual mechanism. The worldwide denim industry is continuously growing, as is the demand for denim quality. As a leader of Finished Fabric Automated Inspection, EVS has set as its goal the design of a denim-compatible inspection solution that meets manufactures requirements, including denim new fashioned styles. The I-TEX 2000D inspection is specially designed to optimize the Denim fabric inspection:

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• Combines inspection results of front and back sides of Denim fabric • Optimal detection performances u to 4 different lines of site and illuminations • Special detection algorithms designed to detect typical fashion Denim fabric defects • Easy fabric styles and parameter setting New and modern human interface for easy operator training and friendly system operation. Full integration with EVS’ advanced process tools for a tailormade quality process. Full integration with shade variation analyzer (EVS’ SVA Lite) for the purpose of combining the fabric and shade defects into one output I-TEX 2000D inspects 100% of the fabric, at fabric speed up to 100 meters per minute. The system is also capable of inspecting the modern Denim styles such as: Multi color, Cross Denim and Bicolor and more. The system can detect defects as small as 0.5 mm, such as the following multiple Denim defect types: • • • • • • •

Yarn and weaving faults Holes Oil stains Missing threads Starting marks Broken yarns Virtually any visible defect is detectable by the system.

I-TEX2000D can be integrated in-line with existing production processes, or used as off-line unit with fabric winding machines. The system is compatible with EVS' Shade Variation Analyzer (SVA Lite), and its modularity enables configuration to match your demands in the following categories: • • • •

Fabric width Fabric speed Desired resolution (minimum defect size) Grading standards

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•

External optional connecting devices: Length meter, Seam detector, Visual alarm, UV/IR Ink marker, Metal label marker, Modem, Data interface by Ether link III communication and a printer.

4.4. LOOM-TEX On – Loom Automatic Fabric Inspection System Real-time detection of spinning and weaving defects within a short distance of the reed, during the weaving process Inspects 100% of the fabric Increases the yield of 1st choice fabrics Eliminates Manuel inspection reduces the need to cut out running defects enables exact fabric length weaving, while considering the actual Defect rate Optimizes loom’s assignment Real-time alarm informs of major defects Stops the loom when warp and running defects are detected • LOOM-TEX modules: o Full width fixed line video scanner o Integrated dual illumination module o Dedicated image processing computer for each loom o Central computer for monitoring management •

LOOM-TEX utilizes proprietary image acquisition and processing technologies, designed to fit with rough weaving conditions: o No moving parts o Configured for on loom/off loom take up o Wide loom configuration up to 390 cm o Sealed electronic module o Remote diagnostics

LOOM-TEX inspects 100% of the fabric and selvage, suitable for a wide range of applications such as: Technical fabrics, Apparel, Home Furnishing, Silk, Shirting and more. Each loom performance can be viewed in real time, displaying defect images, roll defect’s map and statistical data. • Detectable weaving defect types : o Broken pick 19

Double pick Stop marks Double end Broken end Missing end Wrong draw Kinky filling Reed mark o Density change and more, o o o o o o o o

• Central Monitoring and Management A communication network interfaces several LOOM-TEX systems in the weaving hall with the Central Computer which can be located at the control room and which receives from each loom its status and data. The Central Computer main screen displays the weaving hall looms status and allows detailed viewing of each loom. The systems software is also linked to EVS Video Album software designed to store and review Inspection data.

5. BARCO Barco’s automatic on-loom inspection system detects warp and filling defects by means of a moving camera system installed on the offloom take up or integrated in the weaving machine. In case of a warp defect or a concentration of filling defects, the system stops the loom, lights a warning lamp in the loom’s light tree and informs the defect nature and location on the loom’s micro-processor display. The system holds the loom in the stopped position till the weaver has made the “defect corrected” declaration. Connected to Barco’s QualiMaster system, all defect information, pick stamped, is sent to a fabric quality data base. This allows producing defect maps and various types of quality reports.

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5.1. QUALIMASTER • Fabric Inspection and Optimized Cutting

Barco is proud to introduce “QualiMaster”; a Windows ® based system for on-loom, grey and finished fabric inspection. Installed as a stand alone system or as an extension to Barco’s WeaveMaster production management system, QualiMaster offers a powerful fabric inspection module that allows full quality analysis and fabric classification in first, second, third,… quality. Weaving plants equipped with the WeaveMaster production monitoring system can integrate QualiMaster’s powerful “onloom” inspection package, thus minimizing the risk for off-quality fabric in the weaving plant and reducing the workload in the grey fabric inspection department. For finished fabric inspection, special software for optimized mapping and cutting allows to maximize the first quality yield with a minimum of cut operations.

5.2. CYCLOPS PRINCIPLE OF OPERATION The Cyclops on-loom inspection unit uses a moving image acquisition head, consisting of a camera and illumination unit, installed on the off-loom take up or above the cloth roll. At a number of pre-defined positions, an image of the fabric is taken and transferred to the image processing unit. Here, proprietary algorithms are applied to analyze the texture of the fabric and to detect deviations from standard. Any detected defect is signaled to the loom.

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Setting up the Cyclops system is very simple. The scanning range is self-adjusted to the fabric position and width by automatic detection of the fabric boundaries. Illumination and camera settings are optimized by the calibration software module in relation to the optical characteristics of the fabric. Also, the structure of the fabric is automatically identified in order to calculate the algorithm parameters for optimal defect detection.

5.3. CYCLOPS APPLICATIONS • CYCLOPS installed on the batching motion

• CYCLOPS installed in the loom

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• CYCLOPS installed for glass fibre fabric

5.4. AUTOMATIC ON-LOOM INSPECTION BARCO’s automatic on-loom inspection system detects warp and filling defects by means of a moving camera system installed on the off-loom take up. An automatic fabric inspection system for each loom. In case of a warp defect or a concentration of filling defects, the system stops the loom, lights a warning lamp in the loom’s light tree and informs the defect nature and location on the loom’s micro-processor display. The system holds the loom in the stopped position till the weaver has made the "defect corrected" declaration. Cyclops avoids off quality fabric, in fact it stops your looms if the quality is not perfect. No need anymore for expensive and complicated automatic inspection systems or a manual inspection for greige fabrics. So, on top of a better fabric quality the logistics of your weaving mill gets simplified. Fabric can be sent directly to processing, no more inventory between weaving and inspection. Automated fabric inspection also avoids problems finishing the fabric. The fabric is simply of a better quality. Close collaboration with weaving machine builders allowed Barco to install the Cyclops in the loom, right under the sand roller. This shortens the distance between fell and defect detection considerably, allowing to stop the weaving machine much earlier in case of a running defect. Connected to BARCO’s QualiMaster system, all defect information, pick stamped, is sent to a fabric quality data base. This allows producing defect maps and various types of quality reports.

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CYCLOPS INTERACTION WITH WEAVING MACHINE

 The on-loom inspection system communicates with the microprocessor of the weaving machine. In case a running defect is detected, the on-loom inspection system stops and holds the loom, preventing to continue the production of defective fabric. Before the loom can be put back in production, the weaver has to make a declaration, confirming that the defect cause has been eliminated.  The weaver’s declaration also allows to further specify the nature of the defect for which the loom has been stopped by the Cyclops onloom inspection system.  The loom will be stopped for any detected running warp defect as well as for a too high concentration of weft or filling defects in a set length of fabric.

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5.5. CYCLOPS CONNECTION QUALIMASTER SYSTEM

TO

THE

All detected defects are transmitted to the QualiMaster system. In order to complete the information, each defect is marked with time, date and pick stamp. This allows locating the defect in the cloth roll, to generate quality reports by weaver, per shift, per style and many more. A typical application of QualiMaster is the “by ” software. At cloth roll doffing, the system formulates a fabric quality advice. In case the fabric is judged to be first grade, based on the number and concentration of the detected defects, the system will indicate on the loom’s display that the cloth roll can the greige cloth inspection and can be sent on directly for further processing.

5.6. CYCLOPS INTERACTION WITH THE WEAVING MACHINE The on-loom inspection system communicates with the micro-processor of the weaving machine. In case a running defect is detected, the on-loom inspection system stops and holds the loom, preventing to continue the production of defective fabric. Before the loom can be put back in production, the weaver has to make a declaration, confirming that the defect cause has been eliminated. The weaver’s declaration also allows to further specifying the nature of the defect for which the loom has been stopped by the Cyclops on-loom inspection system. In order to help the weaver, a lamp in the loom’s light tree is activated indicating the stop and a message on the loom’s display informs the weaver that the loom is stopped because of a fabric defect. The loom will be stopped for any detected running warp defect as well as for a too high concentration of weft or filling defects in a set length of fabric.

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5.7. CYCLOPS SPECIFICATIONS Camera: CMOS technology - 10 pixel/mm Single looms (max 280 cm) - single camera Double looms (max 500 cm) - dual camera Illumination: infra red LED - option: blue LED allowing the detection of stains Scanning speed - standard version: 18 cm/sec, high speed version: 54 cm/sec Window: 60 x 45 mm Automatic calibration Communication with the loom: VDI, Ethernet, T/IP Integration with the QualiMaster system CTerminal for single machine evaluation

6. USTER

It classifies defects in a matrix called Uster Fabric lass, which is similar to the well-known Uster Classimat system for yarns. Fabric lass have two axes. On the y-axis is the contrast of the defect and on the xaxis is the length of the defect. This allows the system to tell the difference between disturbing defects versus non-disturbing defects. Data on defects can also be stored in a relational database, allowing s to generate any type of report that they need.

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6.1. THE FUTURE: EXPECT AUTOMATED INSPECTION TO GROW EVS has been working for years to brand fabrics inspected with its system using “I-Tex Inspected” stickers. The ability of a mill to certify that its fabrics have undergone automated fabric inspection could very well become a requirement for certain applications or markets.

6.2. INSPECTION AND MEASURING MACHINES EASILY EXAMINE YOUR FABRICS FOR PRODUCTION DEFECTS • • • • • • •

Easy to operate Automatic Edge Alignment System Simple Tension Adjustment Cradle feed and rewind system Programmable counter for yards or meters Top and Bottom Illumination Models available to handle rolls up to 490 lbs (200 kg) and 83" (210 cm) in width • Motor reversing switch to handle fabric which is rolled side in or side out • Optional Cut-Off Device

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1. INTRODUCTION ___29 2. 10 POINT SYSTEM __29 3. 4 POINT SYSTEM ___29 4. 6 POINT SYSTEM ___30 5. GRANITEVILLE ___30

SYSTEM

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INTRODUCTION

1.

Fabric inspection and QC is one of the major areas in textile and garment sector. To establish a workable system for inspecting and evaluating piece goods shipments is vital. No single accepted system for measuring the quality of fabrics, but some of the more commonly used systems are described in this section. We recommend a minimum of 10% inspection of fabrics prior to spreading. Some are intending to inspect the goods while spreading. However this is unrealistic and the spreaders are not the QC. • TYPES OF GRADING SYSTEMS:

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10 POINT SYSTEM In 1955, the Ten-Point System for piece goods evaluation was approved and adopted by the Textile Distributor's Institute and National Federation of Textiles. This system assigns penalty points to each defect, depending on its length. The Ten-Point System is somewhat complicated because points-per-length vary for warp and filling defects. Table blow shows a breakdown of the points: warp defect up to 1” 1” to 5” 5” to 10” 10” to 36”

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weft defect up to 1” 1” to 5” 5” to half width > half width

Point 1 3 5 10

4 POINT SYSTEM The Four-Point System has received the widest acceptance in both the textile and needle trades because it is the most lenient. It is simple and easy to understand. Since it is the most widely used?

• Amount to Inspect - Inspect at least 10% of the total rolls in the shipment.

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Selection of Rolls Select at least one rolls of each color. If more than one roll per color must be inspected, then select the number of additional rolls in proportion to the total rolls per color received.

•

Points/100sq yd =

Total pts scored in a roll*3600 Fabric width (“)*Total yds inspected

LENGTH OF DEFECT Upto 3” 3”-6” Above 6” Above 9” HOLES 1”or less Over 1”

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POINTS ALLOTED 1 2 3 4 2 4

6-POINT GRADING SYSTEM UP TO 25 CM 25 TO 50 CM 50 TO 74 CM 75 TO 99 CM 100 TO 124 CM 125 TO 150 CM

1 points 2 points 3 points 4 points 5 points 6 points

The average of all pieces must not exceed the range of 2426points per 100 sqrm for it being considered as a fresh quality. However for individual pieces a range of 30 -32 points per 100 sqrm may be permissible

5.

GRANITEVILLE SYSTEM LENGTH OF DEFECT UPTO 9” 9” TO 18” 18” TO 27”

POINT ALLOTED 1 2 3

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BIBLIOGRAPHY • • • •

www.google.com www.ststus.com www.i-tex.com www.barco.com

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