Responsibility of QA

8/6/2019 Responsibility of QA

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Responsibilities:

The Project Manager reviews all deliverables to ensure that they are within scope

and to ensure that they are meeting the objectives of the contract.

Each Analyst reviews his own work and the work of the other Analysts to ensure

that there is a consistency among all the components of the system.

The Systems Assurance Officer (if one exists for the project, or the Project

Manager) reviews all deliverables to ensure that they are consistent with the

project standards and of suitable quality to be released to the Acceptor.

Methods of QA for Textile material:

An analyst acting as the Data Analyst verifies the contents of the Functional

Specifications modules and ensures that the data has been integrated across

functional boundaries.

The Systems Assurance Officer verifies that the level of detail in the FunctionalSpecifications is consistent among the modules, and that the Module

Documentation File contains the minimum set of documents. Also ensure that the

formats of the Functional Specifications and the External (Human) Interlace

adhere to documentation standards.

The Team Leader or Project Manager reviews and verifies the Functional

Specifications and the External (Human) Interface to ensure that they fit in with

other specifications under development, and that the contents are consistent with

the overall project objectives specified in the Initiation Report and the

Architecture Definition.

Such as-

Textile testing & quality control-1Page 2


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Yarn twist Testing

Washing Fastness Testing

Arc Testing

Dial/Analogue Compression Testing

Tearing strength Testing

Transference of color testing

Button And Snap Pull Testing

Lea Strength Testing

Fibre Fineness Testing

Colour Matching testing

Bursting Strength Testing

Light Fastness Testing

Snap Button Pullout Testing

Spray Testing

Flammability Testing

Maturity yarn Testing

Thermal Stress Testing etc .

In this perspective, now I am going to discuss about Yarn twisting method in detail-

Yarn twist testing is a system by which we can count the twist in the yarn. Different

methods are available. In one system consists of a set of clamps, one of which rotating

and the other fixed. The rotating clamp is driven by hand through a speed increasing

http://www.ets-testingmachines.com/dial-analogue-compression-testing-machine.htmlhttp://www.ets-testingmachines.com/dial-analogue-compression-testing-machine.html


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arrangement (by motor in motor operated model) and a five digit reset able revolution

counter (digital counter in motor operated) to count the number of twists.

Why twist a yarn?

Why don't you take a thicker yarn instead of twisting two yarns together?This would not cost as much!

A two-fold twisted yarn has, depending on construction, not onlyapproximately 20 per cent more tensile strength and more extension thanthe two single yarns together, but even more than the equivalent thicker single yarn.

The twisted yarn and the fabrics which have been produced out of it, aremore even.

The twisted yarn, which is made by a normal twist, is more voluminous,

that means, the produced fabrics are better covered. With a twisted yarn a softer and pleasant fabric feel will be obtained. Fabrics made of twisted yarns are more durable and resistant to chaffing. With a twisted yarn a higher dimensional stability of the end-product will be

achieved. With special twisted yarns a specific effect and character can be achieved. The twisted yarn has better running characteristics in the subsequent

processing and allows a higher efficiency rate. A normal twisted yarn produces less curl than a single yarn (reduction of

the inner torque).

Objectives of Twist:

For Higher twist-

To increase yarn tenacity and yarn elonga tion;

To produce lean yarns with low hairiness;

To improve spinning stability;

To obtain a clean-cut fabric appearance; and

To improve the shifting resistance of the yarns.

For lower twist -

To achieve a soft hand in Textile testing & quality control-1

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A tear-resistant thread with a round transverse section will thus be created.

The voile is produced from a spun fibre which is twisted in Z direction. The special thingis, that the twisted yarn is also twisted in the same direction, as the spun fibre (zdirection). A hard twisted yarn is the result, with a tendency to curl. The fabric madefrom it, will be transparent, robust in grip. Curtains were often produced from it yearsago. To get a higher transparency and also to produce luminous colours the finishedtwisted yarn has to be gassed. This means that the fibres which stick out are burnt off.

Very highly twisted yarns are called crepe twists.

Fancy twists or nub yarn:

Fancy twists or nub yarns are twisted yarns which are made from differentkinds of components such as nub, loop and other effects and are produced onspecial machines.

Special constructions are multiple and multi stage twisted yarns, which arein praxis of little consequence due to the price factor.



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Manufacture:

The twisting and post treatment takes place in several stages. First two (or more)threads on a doubling bobbin come together.

Doubling

This operation can also be made on the twisting machine, where the twisted yarn is verycoarse. After that the actual twisting process follows by twisting two (or more) threadstogether.

Twisting

To produce more gloss and to avoid pilling, the fibres, which protrude after the twistingprocess, can be burnt off.



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Gassing

Finally you can wind the package to remove the dust, to apply wax or just to get therequired package format.

A specialty of the company RUOSS-KISTLER AG is the combination of the doublingand gassing processes. With this combination it is possible to get an almost dustfree twisted yarn.

Process:

In the area of cotton yarns there are three main types of twisting processes.

1. Two-for-one twisting2. Terrace twisting / Tritec) 3. Ring twisting

Two-for-one twisting is the most common twisting process in our field. In this processthe twisted yarn gets two ply twists with just one spindle turn.

http://www.ruoss-kistler.ch/english/Twisting_Mill/encyclopedia.htm#Doppeldrahtzwirnenhttp://www.ruoss-kistler.ch/english/Twisting_Mill/encyclopedia.htm#Stufenzwirn-%20und%20Tritexverfahrenhttp://www.ruoss-kistler.ch/english/Twisting_Mill/encyclopedia.htm#Stufenzwirn-%20und%20Tritexverfahrenhttp://www.ruoss-kistler.ch/english/Twisting_Mill/encyclopedia.htm#Ringzwirnverfahrenhttp://www.ruoss-kistler.ch/english/Twisting_Mill/encyclopedia.htm#Doppeldrahtzwirnenhttp://www.ruoss-kistler.ch/english/Twisting_Mill/encyclopedia.htm#Stufenzwirn-%20und%20Tritexverfahrenhttp://www.ruoss-kistler.ch/english/Twisting_Mill/encyclopedia.htm#Ringzwirnverfahren


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Fig: Two-for-one spindle Fig: Two-for-one twisting machine

back to process

The process of terrace twisting or tritec is mostly employed in the coarse counts and isused in special areas.

Tritec-Spindle

http://www.ruoss-kistler.ch/english/Twisting_Mill/encyclopedia.htm#Zwirnverfahrenhttp://www.ruoss-kistler.ch/english/Twisting_Mill/encyclopedia.htm#Zwirnverfahren


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The ring twisting process is still only meaningful for nub yarn production. It would bevery profitable, but for quality reasons (too many knots in the twisted yarn) hardly usedany more.

Had a way been found to replace the knots with a perfect twisting connection (splice), a

renaissance of the ring twisting machine would not be impossible.

Preparation of yarn samples :

Combed cotton yarn samples of 14.8 tex and 9.8 tex were spun using a Lakshmi G 5/1Ring frame from rovings of 369.1 tex and 246 tex respectively. The yarn samples wereproduced with different levels of twist (a normal twist level and 10 to 50% higher than anormal twist level). Then each of these yarn samples was ply-twisted in the oppositedirection to single-yarn twist at three different ply-twist levels (1/3, 1/2 and 3/4 thesingle-yarn twist).

Figure 1 . Mechanism of surface fibre trapping between

Y arn twists Tester:

Yarn twist is tested by the tester which is in bellow -

Hand drive twist tester

Power drive twist tester

Hand Drive Twist Tester:


Fig: Hand Drive Twist Testing

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The use of hand drive twist tester is much. This tester is driven by hand. This is a slow

process and sometimes it is fail to give accurate result.

Feature of Hand Drive Twist Tester:

Hand driven twist tester is suitable to test single yarn In "Z" twist at 10 inch

specimen length with variable tension arrangement.

It works in the principle of untwist and retwist.

Test results are obtained by the help of precise

mechanical counter.

Power drive twists tester:

The types of power drive twist tester is given bellow

Double Yarn Twist Testing

Electronic Twist Testing

Torsion Twist Testing

Microprocessor Twist Testing

Double Yarn Twist Tester:

Double Yarn Twist Tester is used to check the twist in yarn. It is used to determine the

twist per inch/cm in double or plied yarns.

Our Double Yarn Twist Tester widely finds its applications in various textile industrial

sectors. These double yarn twist tester are widely available in various specifications and

dimensions.



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Feature of Double Yarn Twist Tester:

Ergonomically latest design with modern aesthetics.

Smooth precision-engineered mechanism.

With analogy re-settable twist counter.

Complete with all accessories along with proper tension

device.

Supplied with calibration & inspection certificates.

Specification of Double Yarn Twist Tester:

Working Procedure:

Double Twist Tester for yarns consists of a set of clamps; one of which is rotating

and the other fixed. The rotating clamp is driven by hand through a speed

increasing arrangement and a five-digit re-settable revolution counter to count

the number of twists. The fixed clamp has a knob by which yarn is clamp. Applied

the require Tension to the yarn.

The fixed clamp assembly can be moved over a guide bar for setting the required

test length of yarn. The Test Length is indicated on a strip scale fixed to the base

against a pointer attached to the moving assembly.


Fig: Double Yarn Twist Testing m/c

Test length : 50 mm, 100 mm, 150 mm & 200mm

Counter : Five digit revolution counters to give twist directly and Z twist

by subtracting from 100,000

Overall Dimension of

the units: 350mm (L), 100mm (W), 100mm (H).

Weight of Machine : 1.260 Kg


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The various components are fixed on a rigid cast iron base. The unit is nicely

finished and all parts are bright chrome plated to give a corrosion resistant finish.

Electronic Twist Tester:

Determining optimum twist can have a critical effect on the physical characteristics of

yarns. Yarns with a low twist count are capable or producing a yarn with increased

softness for knitting and warmth. Increasing twist count can provide additional tensile

strength. However, maximum tensile strength can decrease if the twist angle is greater

than the desired amount.

The model Electronic Twist Tester meets applicable International Standards for

measuring both the untwist/retwist method and yarn twist method by direct rotational

counting. In addition the software reports sample statistics including average, standard

deviation, maximum and minimum. Result data can also be printed or sent to a PC.

Electronic Twist Tester is a motorized unit consisting of two clamps. One clamp is

adjustable for varying sample length before and during a test and a second clamp is

rotated in either direction to measure counts.

Feature of Electronic Twist Tester:

Clamp distance is variable from 1 to 50 centimeters.

Elongation indicator up to 100 mm with accuracy of 1 mm.

Electronic counter with 4 displays.

Pre-determined shutoff setting at end of test.

Specification of Electronic Twist Tester:

Depth: 10 in. (25cm)


Fig: Electronic Twist Testing m/c


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Height: 8 in. (20cm)

Width: 42 in. (106cm)

Weight: 42bs (19kg)

Working Procedure:

The Electronic Twist Tester meets applicable International Standards for measuring

both the untwist/retwist method and yarn twist method by direct rotational counting.

Instrument software allows the selection of both twist methods, in addition the software

reports sample statistics including average, standard deviation, maximum and

minimum. Result data can also be printed or sent to a PC.The Electronic Twist Tester is

a motorized unit consisting of two clamps. One clamp is adjustable for varying sample

length before and during a test and a second clamp is rotated in either direction to

measure counts.

Torsion Twist Tester:

The Torsion Twist Tester rotates a wire sample about its owncenter to test the wire for brittleness, inclusions, hidden sea ms

and other flaws. This offers three different types for wire diameters

ranging from .010" to .750"(0,2mm to 19mm).

Feature of Torsion Twist Tester:

Programmable counter with automatic forward and/or reverse capability

12 possible twisting programs with memory of the

complete cycle

Includes a digital display and positive holding chucks with replaceable jaws

Interlocked guard to ensure operator safety


Fig: Torsion Twist Testing


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Working Procedure:

The system consists of a set of clamps, one of which rotating and the other fixed and

weight. The rotating clamp is driven by hand through a speed increasing arrangement

and a five digit reset able revolution counter to count the number of twists. The fixed

clamp is pivoted on jewel bearings and carries of a pendulum arm having a sliding weight

to give the desired tension to the yarn. The fixed clamp assembly can be moved over a

guide bar for setting the required test length of yarn which is indicated on a strip scale

fixed to base against a pointer attached to the moving assembly. A viewing plate and a

magnifying glass are provided for accurate determination of the end point. A dissecting

needle for ascertaining complete removal of twist is supplied as standard accessory with

the equipment. The various components are fixed on a rigid base strength and durability.All parts of the instruments are either painted or bright chrome plated to give a corrosion

resistant finish and highly aesthetic appearance.

Benefits:

Safe, automatic operation

Provides consistent output test results

Meets ASTM Test Specifications E558 and A930

Application:

The Torsion Twist Tester is used whenever wire needs to be tested for brittleness,

inclusions, hidden seams and other flaws.

High carbon steel wire

Copper and aluminum rod

Microprocessor Twist Tester:

Microprocessor twist tester is used to test single yarn,

double yarn and open-end yarn. Built in auto program


Fig: Microprocessor Twist Testing


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Fig to control the test automatically. A special auto multiple

Untwist and twist program for open end yarns. Auto

Selection to test S and Z twist of yarn with specimen

length adjustable from 0 to 20 inch or 0 to 50 cm.

Feature of Microprocessor Twist Tester:

Test results contains Individual readings in TPI or TPM, Mean, Standard Deviation and

CV%

It has the provision to interface printer

Results available in display and printout

Calculation of Twist:

Ply twist table (of a twisted yarn)

NmWeaving Knitting

NeWeaving Knitting

T/m T/m tex T/i T/m T/i T/m tex

30/2 470 440 33.3 x2 20/2 12.7 500 11.7 461 29.5x2

40/2 540 510 25.0x2 30/2 15.6 614 14.4 567 19.7x250/2 610 570 20.0x2 40/2 18.0 709 16.6 654 14.8x2

60/2 670 620 16.7x2 50/2 20.1 791 18.6 732 11.8x2

70/2 720 670 14.3x2 60/2 22.0 866 20.3 799 9.8x2

80/2 770 720 12.5x2 70/2 23.8 937 21.9 862 8.4x2

90/2 820 760 11.1x2 80/2 25.4 1000 23.5 925 7.4x2

100/2 860 800 10.0x2 90/2 27.0 1063 24.9 980 6.6x2

110/2 900 840 9.1x2 100/2 28.4 1118 26.2 1031 5.9x2

120/2 940 880 8.3x2 110/2 29.8 1173 27.5 1083 5.4x2130/2 980 910 7.7x2 120/2 31.1 1224 28.7 1130 4.9x2

140/2 1'020 950 7.1x2 130/2 32.4 1276 29.9 1177 4.5x2

150/2 1'050 980 6.7x2 140/2 33.6 1323 31.0 1220 4.2x2

160/2 1'090 1'010 6.3x2 150/2 34.8 1370 32.1 1264 3.9x2

170/2 1'120 1'040 5.9x2 160/2 36.0 1417 33.2 1307 3.7x2



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180/2 1'150 1'070 5.6x2 170/2 37.1 1461 34.2 1346 3.5x2

190/2 1'190 1'100 5.3x2 180/2 38.1 1500 35.2 1386 3.3x2

200/2 1'220 1'130 5.0x2

210/2 1'250 1'160 4.8x2

220/2 1'280 1'190 4.5x2

230/2 1'300 1'210 4.3x2

240/2 1'330 1'240 4.2x2

250/2 1'360 1'260 4.0x2

260/2 1'390 1'290 3.8x2

270/2 1'410 1'310 3.7x2

280/2 1'440 1'340 3.6x2

290/2 1'460 1'360 3.4x2

300/2 1'490 1'390 3.3x2

Rotation coefficient (alfa):

The twist of a doubled yarn depends on the twist number. The rotation coefficient (alfa)determines the hardness of a twisted yarn.

The formula for the corresponding numbering-system:

Examples of rotation coefficient:

Numbering system (fineness):


tex-system

Nm Ne

alfa tex = T * tex

alfa m = T / Nm alfa e = T / Ne

T = twist rotation per mtex = Number in tex

T = twist rotation per mNm = metrics twist number

T = twist rotation per inchNe = English twist number

soft medium hard

alfa tex 3100 3800 5700

alfa m 100 125 180

alfa e 3.25 4 6

Conversion:

alfa tex = alfa m * 31.6

alfa tex = alfa e * 957


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* Conversion factor dtex/Macronaire

The number of turns inserted in a yarn depends on how long a given length of yarnspends in the rotor. If a yarn is withdrawn from the rotor more rapidly at a given rotor speed, fewer turns can be inserted (by the rotating rotor) in the yarn per unit of timethan at a lower take-off speed when the yarn therefore spends more time in the rotor groove:

The specified number of turns for a given yarn is thus inserted, at a given rotor speed,by adjusting the delivery speed. The feed rollers are driven by infinitely adjustableinverters.

Conclusion:

As soon as the buyer gives the order to the company, which the product is madeaccording to the above process, the buyer will specially test the product. According to



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the product testing result, the buyer will investigate either the product has adjusted or rejected. From the discussion, ultimately we can say that this process is called QualityAssurance (QA).

Reference:

1. http://pixel.quantserve.com

2. http://www.rieter.com

3. http://it.toolbox.com

4. http://www.wisegeek.com

5. http://www.bravenet.com

6. http://www.ruoss-kistler.ch

7. http://www.statcan.gc.ca

8. http://dmtracking2.alibaba.com

9. From Our teacher Sheet

10. http://www.hjsstudio.com

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Responsibility of QA