Structure Sample

Single Jersey Plain

Needle set out

1 1

Cam arrangement

F

K

Single Lacoste

Needle set out

1 2

Cam arrangement

F1 F2 F3 F4

K T K K

K K K T

Double Lacoste

Needle set out

1 2

Cam arrangement

F1 F2 F3 F4 F5 F6

K T T K K K

K K K K T T

Polo Pique

Needle set out

1 2

Cam arrangement

F1 F2 F3 F4

K K T T

T T K K

Terry

Needle set out

1 2 3 2

Cam arrangement

F1 F2 F3 F4

K T K M

K M K M

K M K T

1X1 Rib

Needle set out

D 1 1

C 1 1

Cam arrangement

D K

F

C K

Single Jersey Plain With Full Feeder

Spandex

Needle set out

1 1

Cam arrangement

F

K

Single Jersey Plain( Feeder Stripe)

With Full Feeder Spandex

Needle set out

1 1

Cam arrangement

F

K

.

Single Jersey Plain (Engineering

Stripe)

Needle set out

1 1

Cam arrangement

F

K

Plain Interlock

Needle set out

D 1 2

C 1 2

Cam arrangement

K M

D M K

F1 F2

C K M

M K

Quality Management System:

Knitted Fabric Faults:

Many types of fault may be found in knitted fabric due to many reasons. These faults occurred

sometimes due to defective parts of machine, or sometimes due to use of defective raw materials.

Some faults occur very frequently and some faults occur rarely. Here some frequently occurring

faults in knitted fabric are given below;

Faults Sample

Hole

Sample 1

Causes:

The main cause is yarn breakage which

happens due to;

Too tight take down tension

Yarn with weak spot.

Clogged surface of yarn guide or

feeder.

Defective or damaged needles.

Remedies:

Main remedy is avoiding yarn breakage and

using defect free needles. Other than these

the followings may help;

Use of fault free yarn.

Using smooth surface of yarn passage

to needle.

Properly adjusting take down tension.

Sample 2

Causes:

It happened because, the needle is broken. It

can also happen due to;

Worn or old needle.

High take down tension.

Dirty or faulty tricks.

Remedies:

It can be avoided by using faultless

needle.

Proper take down tension will help.

Clean needle tricks will also reduce

risk.

Sample 3

Causes:

It is another type of hole of very small size. It

is called loop in the factory. It is created due

to yarn breakage or faulty needle.

Too tight take down tension

Yarn with weak spot.

Clogged surface of yarn guide or

feeder.

Too high yarn tension.

Remedies:

Main remedy is avoiding yarn breakage and

using defect free needles. Other than these

the followings may help;

Use of fault free yarn.

Using smooth surface of yarn passage

to needle.

Properly adjusting take down and

yarn tension.

Fly

Causes:

If dyed yarn, melange yarn and grey yarn are

used in knitting at the same floor, colored fly

may be found in the fabric. It happens

because of;

Improper covering of the machine.

Careless air blowing.

Insufficient cleaning.

Remedies:

To avoid this;

The knitting machines should be

covered or divided by some covering

which would help reducing fly

contamination.

Cleaning has to be done carefully.

Thick Place

Causes:

It happens due to faulty yarn or slub yarn

which creates thick horizontal line in the

fabric of small length.

Remedies:

By using fault free yarn, this fault can be

avoided.

Needle Line

Causes:

It happens due to one and only reason, that is

needle breakage. Needle breakage can

happen due to;

Too high take up tension.

High yarn tension

Old needle.

Large knots or slub in the yarn.

Remedies:

It can be avoided by using needles which are

not defected. To do so;

Old needles should be replaced.

Fault free yarn should be used

Take down tension should be adjusted

correctly.

Oil Spot

Sample 1

Causes:

It happened due to too much oiling of the

machine parts.

Remedies:

Proper amount of oiling may help avoiding

this fault.

Sample 2

Causes:

It happens due to;

Too much lubrication.

Dirty tricks and sinker.

Use of improper needle oil.

Remedies:

It can be avoided by;

Avoiding excessive oiling of machine

parts.

Proper cleaning of needles, sinkers,

tricks etc.

Use of proper needle oil.

Press Off

Causes:

It happens when;

The yarns are not properly laid in

needle hooks.

Too loose take down tension is

applied.

Defective needles are used.

Needle timing is wrong.

Improper yarn tension is set.

Remedies:

It can be avoided by;

Using defect free needles.

Using correct needle timing.

Applying correct take down and yarn

tension.

Fault Detection System:

Fabric faults are detected in fault detection machine. The faults are marked and cut off from the

fabric. Fabric fault is detected by mainly two ways; 4 point system and 10 point system. But for

knitted fabric, 4 point system is mainly used.

4 point system:

Theoretical definition:

The 4-Point System is a standardized test method for fabric visually inspecting and grading.

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. Fabric defects are assigned points based on the

following:

Size of defect Penalty

3 inches or less 1 points

Over 3 but not over 6 2 points

Over 6 but nor over 9 3 points

Over 9 inches 4 points

Total defect points per 100 square yards of fabric are calculated and the acceptance criterion is

not more than 40 points.

Individual rolls exceeding the specified point count level shall be graded as second quality. A

shipment shall be failed the inspection if the shipment penalty count points exceed the specified

point count level.

Any roll having a running or repeating defect through more than ten continuous yards shall be

rejected regardless of point count.

No roll that contains more than four full width defects per one hundred linear yards shall be

accepted as first quality.

Any roll found to contain defects, in any increment of one hundred yards, with an average of

more than one major defect per ten linear yards will be rejected.

No roll shall be accepted that contains a major defect in the first or last three yards of the rolls. A

major defect is considered to be any three or four point defect.

Inspection:

For different knitting faults, the following table is followed for assigning points.

Procedure In this system fabric quality is evaluated by penalty points per 100 square yards.

Formula:

Points / 100 sq. yd. = (Total points in roll X 36 X 100)/ (Total length in yards X width in inches)

So, to evaluate fabric quality you need to know fabric width and length of the inspected roll. In

knits; fabrics are sourced in weight and supplier does not mention length. That's why when it

comes to use 4 point system in knits fabric, inspector finds it difficult to use given formula for

calculating penalty points. To use the 4 point system for fabric inspection it is needed to

calculate length of the fabric in a roll.

Evaluation of fabric quality of Knitted fabric in 4 point system

Step#1: Measuring fabric length in a roll.

Generally the following specification in knitted fabric roll found

Weight of the roll (in Kgs)

Fabric weight Grams per square meter (GSM) and

Fabric width (inches)

For example, fabric weight of a roll is 50 kgs, fabric GSM 250 and fabric width (W) 46 inches.

The following formula is used to know approx. length of the roll with above information.

Fabric length (in meters) = Fabric weight X 1000 / (Fabric GSM X Fabric Width X 0.0254)

Using data from above example

Fabric length (L) = (50 X1000)/ (250 X 46 X0.0254) = 171.17 Meters

Step#2: Converting fabric length into yards.

Multiplying factor is 1.09361

Fabric length in yards = 171.17 X 1.09361 = 187.2

Step#3: Calculating total penalty points.

Suppose total 34 penalty points are given to the above roll. Once the length is found of each

fabric roll, the above formula can be used to calculate points per 100 square yards.

Point /100 square yards = (Total penalty points X 36 X 100)/ (Roll length X Width in inches)

= (34X36 X 100)/(187.2 X 46)

= 14.21

Check sheet or inspection format:

To record or to collects defects during inspection simple check sheet is used. A check sheet

includes general details, details of fabric lot, fabric defects according their sizes, summary of

fabric defects, quantity inspected and total penalty points and result of the fabric lot after

inspection. Tally marking can be used for recording of number of defects. A sample 4 point

system fabric inspection format has been attached at the bottom.

Image: Sample format for 4-Point system for fabric inspection.

Practically Used Procedure in the Factory

Practically the fabric roll of 20kg is taken and inspected in the fabric inspection machine where

the fabric is passed over a lighten surface as lights are placed under the inclined surface. The

fabric is passed at a uniform speed. The inspector looks for any types of faults and when he finds

any, he stops the machine and marks the faulty area with yellow color or cuts off the faulty area.

The faults are detected in 4 point system which is already mentioned. But in factory, the process

differs from the theoretical process. Here the faults are detected in the following way;

If a fault is found, for example; a fly, then it is marked and given 1 point. If another fly is found

within 3-6 inches, another point is increased for it, so 2 points in total. If another fly is found in

the next 3 inches, then again 1 more point is increased and 3 points in total is given. If any fly is

found after 9 inches, another point is increased and 4 points in total is given. If more than one fly

is found in the 0-3 inches area, it is given 1 more point. But if any fly is found in same line in

any position of the fabric, no point is given. But a fly can be found at any position along the full

width of the fabric, for that reason, the full width is considered in case of taking the range of 0-3

inches or 3- 6 inches and point is given to any faults according to the range given above.

If any fly is found after 9 inches, it is given 4 points in total. But it is not applicable for full

length of the fabric. If a fly is found after 3-4 meter of the previous one, the whole procedure is

restarted from there as the 1st one is given 1 point and the followings are done as described

before.

Some very commonly found knitting faults and the points are given below;

Knitting faults Points

Hole

Fly

Press off

Slub

Star mark

Needle line/ Sinker line/ Vertical line

Barre mark/ Horizontal line

4

1

4

1

4

4

4

Total points are calculated from the following formula;

Points= 𝑇𝑜𝑡𝑎𝑙 𝑝𝑜𝑖𝑛𝑡𝑠𝑋 36𝑋 100

𝑅𝑜𝑙𝑙 𝑙𝑒𝑛𝑔𝑡ℎ𝑋 𝐴𝑐𝑡𝑢𝑎𝑙 𝑤𝑖𝑑𝑡ℎ 𝑖𝑛 𝑖𝑛𝑐ℎ𝑒𝑠

Acceptance criteria

Up to 20 points

20-30 points

Above 30 points

A grade

B grade

Rejected

But actually this formula is not used always. All points are summed and then the acceptance

criterion is considered. This summation is done for total points found in 100 meter of fabric. If

the sum goes beyond 30 points, then the fabric is rejected. The whole rejection is done depending

on this calculation. For example, if the fabric roll is shorter than 100 meter, say, 50 meter, and

total points found sums 20, then the fabric is not cleared, instead it is taken as on hold.

Maintenance:

Maintenance is defined as a process which is used to retain a product or restoring a product to a

satisfactory operational condition. It is very essential in every part of textile factory as the

machines need better care for smooth and continuous running. The main objectives of

maintenance programme are;

Retaining equipment at maximum operating speed and productivity.

Ensuring best possible level of quality of product.

Minimizing idle time.

Cleaning the equipment.

Maintenance mainly of two types;

1. Planned maintenance

2. Breakdown maintenance

Planned Maintenance:

It is a more technical approach as maintenance is done to avoid any possible breakdown. It

requires a planning, scheduling section for maintenance. A routine is made for this type of

maintenance and it is done on daily or weekly or monthly basis. It is a type of routine

maintenance where the maintenance is done according a routine or schedule and steps are taken

to ensure any avoidance of breakdown. The procedure of routine maintenance is described

below;

Routine Maintenance:

Routine maintenance usually denotes those activities of maintenance which are bare minimum to

ensure efficient working of machines. These activities have to be performed according to

predetermined frequencies which are based on technical and quality considerations.

Routine Maintenance Tasks Followed In The Factory:

Daily work

Positive feeder checking.

Oil line checking.

Take up roller checking.

Needle, cam box, sinker cleaning.

The yarn guides, tensioners, feeders cleaning.

Cleaning the floors in every 30 minutes.

In every 15 days

Gear box checking.

All bearing greasing.

All needles, cam, sinker cleaning by oil.

Full machine checking.

Breakdown Maintenance:

This system is used only when the machine breaks down. It is unplanned system, but since there

is no planning, scheduling etc, not much concern has to be given on maintenance department

when only this system is used.

Examples of breakdown maintenance done in the factory are given below;

For any breakage of needles, it is replaced immediately.

In case of any mechanical or electrical problem, technician is called.

Other than these, the machine parts are cleaned every time before setting up the machine for a

new product.

Setting the Machine:

The needle set out and cam arrangements are set as planned before for different fabric

structures. The machine used in this factory contain latch needle. For single jersey

machine, latch needles are a bit longer while the latch needle of double jersey machine is

a bit shorter. The single jersey machines contain sinker along with every needle which is

the second primary knitting element of a knitting machine. It holds down the old loop

during the needle making the new loop. In double jersey machine, here is no sinker,

instead the needles of alternate beds help holding down the old loop.

To set up the knitting elements and the whole machine, some tools are required. Some of

them are shown below;

Equipment Uses

Pulley Key or Allen Key

It is used to adjust VDQ

pulley diameter of the

machine.

Handle

It is used to adjust yarn

tension and to rotate the

cylinder for one or a couple

of times if required when the

machine is stopped.

1 no T-L key

It is used to put Lycra

package at its creel.

2.5 no L-L key

It is used for feeder spring

adjustments.

3 no L-L key

It is used for yarn tension

adjustments.

4 no L-L key

It is used for feeder ring.

5 no T-L key

It is used for cam box.

6 no T-L key

It is used in auto striper

machine to adjust striper

fingers.

10 no L-L key

It is used for adjusting the

dial.

15 no L-L key

It is used as the motor key.

There are some other tools used for various purposes. Some of those tools are given below;

Use:

To set different type of nuts

and bolts

Tightening & loosening of

nuts & bolts.

Adjustable Wrench

Use:

To set nuts and bolts.

Tightening & loosening of

nuts & bolts.

Double Head Spanner

Use:

To set nuts and bolts.

Tightening & loosening of

nuts & bolts.

Single Head Spanner

Use:

To fitting varies type screw.

Tightening & loosening of

nuts & bolts.

Flat Screw Driver

Use:

To beat metal parts.

Hammer

Use:

To hold m/c parts,

Cut metal wire,

Set nuts and bolts.

Multi-Pliers

Use:

To cut metal wire.

Cutting-Pliers

Use:

To hold and set m/c parts

in thin or narrow space.

Long Nose-Pliers