Grey Fabric Inspection and Grading in Textile Industry
Mustaque Ahammed Mamun
Department of Textile Engineering
Dhaka University of Engineering and Technology (DUET)
Grey Fabric Inspection:
After manufacturing of grey fabric on loom or knitting machine, it is inspected using an grey fabric inspection machine. During this inspection, defects such as knots, broken and loose warp ends, broken weft ends are removed. It is done in batch section in textile industry. In case of holes, either it is mended or the fabric is cut off depending on the position of the hole and its severity. The inspection and grading of fabric quality is one of the important functions of quality control in the grey or finished state, the grading of fabric is a difficult task, taking two primary considerations: as the frequency of effects and the seriousness of defects.
Different types of grey fabric are inspected in batch section:
- Single Jersey
- Single Lacost
- Double Lacost
- Double Jersey or Heavy Jersey
- Plain Interlock
- Needle Top Interlock
- 1×1 Rib
- 2×1 Rib
- 2×2 Rib
- Lycra Rib
- Very Rib
- Loop Back
- Fleece Fabric
- Fleece Terry
- Lycra Fleece
- French Terry
- Plated Fabric
- Lycra Single Jersey
- Polo PK
- Interlock with lycra
- Rib with lycra
- Twill tape
Objects and purposes of grey fabric inspection:
- To check dia and G.S.M of fabric
- To identify the fabric faults
- To ensure about the fabric quantity
- To ensure fabric produced is of required quality.
- To identify the looms or knitting machine producing defects and taking corrective action.
- To prevent losses after cutting the fabric for making a garment because of fabric defects.
- To classify the products according to the different quality based on the demands of the buyer/market or client.
Grey fabric inspection process:
- The fabric rolls are received from loom shed or knitting machine.
- Inspector is given special instruction if any by writing on job card by supervisor as per instruction of in-charge of weaving.
- Checking the details of fabric received and conforming before taking them for checking.
- Cleaning the inspection table and the surrounding before start of the work.
- Checking the fabric weight and comparing with the ‘should be weight’ as per design. If the weight is differing than the norms, rechecking shall be done and the concerned persons shall be given alarm to take decision.
- Setting the length counter after the fabric end reaches the inspection area.
- Switching on lights both below the table and above the table.
- Checking the back and face side of the fabric first and then inspecting the goods for visible defects as per the required standards, for e.g. four points system.
- Marking the defects with sticker at the location of defect or with a marker (sticker, tag etc.) at selvedge edge.
- Informing the supervisor regarding the materials checked and taking Instruction for further checking. If damages are found, the counting of defects is not done and the in-charge is informed to take decision.
- Keeping the inspected fabric roll on the fabric stand and putting the tag.
Quality control in grey fabric inspection:
Some points are needed to maintain for high quality fabric:
- Brought good quality yarn.
- Machines are oiled and greased accordingly.
- S.M, Stitch length, Tensions are controlled accurately.
- Machines are cleaned every shift and servicing is done after a month.
- Grey Fabrics are checked by 4 point grading system.
Four point inspection system:
Grey fabric inspection is performed according to 4-point system.
4 point numbering system is followed for finished fabric inspection. Defects found in the final inspection:
|SL No||Fabric faults||SL No||Fabric faults|
|3||Grease stains||13||Needle line|
|4||Sinker line||14||Thick thin place|
|5||Hole/pin hole||15||Missing yarn|
|8||Wheel mark||18||Broken needle|
|10||Double yarn||20||Foreign materials|
Table: Grey fabric inspection system
|0 to 3’’||1||Up to 40 Points/100Yds = A|
|>3’’ to 6’’||2||21-30 Points/100Yds = B|
|>6’’ to 9’’||3||31-40 Points/100Yds = C|
|>9’’||4||Above 40 Points Reject.|
AS per formulation:
Dia × 36” × GSM ×2 ÷ 1550 ÷ 1000
Roll wt in KG
Roll wt ×39.37× 1000 ÷GSM÷ Dia ×39.37÷ 36 = Yds
………………………TT´L PTS ×36 ×100
……………Roll Length (Yds) ×Actual width
General instructions for the final inspection:
- All pieces will be graded on the base of 40 points per 100 Linear yards Mapping will be done on each piece to insure proper grading. Do not count more than 4 points per one yard.
- All defects must be recorded and marked in final inspection and an accurate account of points made to insure proper grading.
- All fabric must meet specifications.
- At the end of each piece of fabric, the inspector will add up total points and decide whether the piece can be shipped as first quality or not, reworked, placed in lower quality, or cut and upgraded for shipment. Fifteen yards or more can be shipped as first quality.
- The quality control supervisor must approve the grading of all quality levels and check the lower quality.
- Major or unsightly defects in the first and last yard of a roll or piece will be cut. All defects of one-yard length or more will be cut out of the piece. Defects within the first 2 inches or the last 2 inches of a piece will not be cut out or counted in the grading.
- Open defects on the back of fabric such as drops, runs and hanging picks are to be included in the grading of fabric.
- Pieces can be connected together, once each piece must be the same shade.
- All defects such as runs that extend more than a yard in length will be cut out.
- Fabric up to 70 inches will be allowed a bow of not more than 1 inch and a Bias of not more than 2 inches.
- Defects within one inch of the fabric edge will not be counted except on tubular fabrics. All defects will be counted in tubular goods.
Problems occur during grey fabric inspection:
The normal problems in grey inspection are as follows:
- Disagreement between two inspectors regarding allocating penalty points. It is suggested to have periodic round tests, i.e., getting the same fabric inspected by different inspectors and making them to explain why they consider something as a defect and something as not defect. Let them come to one consensus. By this the difference of agreements shall reduce.
- Fatigue of inspection; inspectors cannot see certain defects. When same type of fabric is inspected for a long time, the eyes get fatigued and some of the defects cannot be seen. It is therefore necessary to give rest to the eyes for some time by asking the person to do other works like the entries, moving the fabrics, cleaning the area and so on.
- Demand for inspecting fast, whereas the defective points are more and inspection is getting delayed. When the defects are more, the time taken for inspection increases as each defect need to be marked, flagged and data entered in the system.
Grey Fabric Grading:
The grading has two primary functions:
First, to classify the fabrics according to standard qualities based on the end-use and costumer demands and second, to supply information as to the qualities actually being produced.
The Knitted fabric can be classified into three levels of quality, each one has a number of points for defects as follows.
- The First quality level ……………..40 points per 100 Linear Yards.
- The Second quality level …………(40 – 80) points per 100 Linear Yards.
- The Third quality level …………… 80 points or more per 100 Linear Yards.
- All open defects or major defects counted with 4 points per defect.
- Surface defects over 9-inch length counted with 4 points per defect.
- Surface defects 6 to 9 inches length counted with 3 points per defect.
- Surface defects 3 to 6 inches length counted with 2 points per defect.
- Surface defects up to 3 inches length counted with one point per defect.
- Running defects, such as tucks, needle lines, barre, crack marks, are judgment defects
- Handbook on fabric manufacturing by B. Purushothama
- Handbook of Value Addition Processes for Fabrics by B. Purushothama
- Class lecture of DUET
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.