Textile Testing & Quality Control-1

Quality is an attribute property special factures or the nature, kind or character of something. Quality consists of those product features which meet the need of customers and thereby provide product satisfaction.

The European Organization for Quality control Glossary (1941) has given the following definition for quality “The totality of factures and characteristics of a product or service that bear on its ability to satisfy a given need”.

Quality Control:

Control means to check or verify and hence to regulate. Quality control is the checking, verification and regulation of the degree of excellence of an attribute or property of something.

Objects of Quality Control:

• To produce required quality product.
• To fulfill the customer's demand.
• To reduce the production cost.
• To reduce wastage.
• To earn maximum profit at minimum cost.

Factors affect the quality system:

·         Enquire &orders.

·         Services.

·         Inspection &testing.

·         Calibration of test equipment.

·         Organizational structure.

·         Quality audit.

·         Training.

Types of quality control:

1.     Online quality control.

2.     Offline quality control.

Online quality control:

This type of Q.C is performed in process stage i.e., without stopping the production process. During the production running time, the m/c automatically tests the variation and takes immediate step to rectify the variation. Sensor is used to measure and rectify the variation.

Checking and rectification of variation of variation fault in processing stage is known as online quality control.

Example of online QC:   

i.                   Sliver hank control by auto leveler in carding in & D/F.

ii.                 Lap wt. variation control in L/F.

iii.              Yarn faults remove by EYC in auto winding m/c.

iv.              Roving tension control by tension compensating device in S/F.

Offline Quality Control:

These types of QC consist of laboratory test which are done by stopping the production process. Here necessary steps are taken according to test result.

Example of offline QC:

         I.    Evenness testing

         Ii. Checking of count &TPI variation

        Iii. Irregularity (thick thin naps) check

        Iv. Strength testing.

Q. Give typical quality control equipment for a modern cotton spinning mill:

Proper quality of products can be maintained by checking the materials at the different stags and take proper action or decision. To check the materials quality, the following equipments are required in QC department of a cotton spinning mill:

Fibre testing equipment:

1.     HVI- for fineness, color, trash, length& strength measurement.

2.     AFIS- for neps, seed coat naps, sage of neps, fibre length, short fibre con dia/fineness, and immature fiber content no. & size of trash, no. & size of dust.

3.     Shirley analyzer- for trash content measurement.

4.     Counter- for fibre length neps, short fibre% measurement.

5.     Fibre bundle strength tester(pressley/stelometer)- psi.90000

6.     Moisture regain tester.

7.     Rapid conditioning unit strictness tester – for testing honey dew.

What is sampling? What terms we used in sampling?

The process of taking representative sample from a bulk is called sampling. The amount of material that is actually tested can represent a very small proportion of the total output. It is therefore important that this sample should be truly representative of the whole of the material.

Ø Consignment:

Ø Test lot or batch

Ø  Laboratory sample

Ø Test specimen

Ø Package

Ø Container or case

·        Consignment: this is the quantity of material delivered at the same time. Each consignment may consist of one or several lots.

·        Test lot or batch: this consist of all the container of textile material of one defined type & quality delivered to one customer according to one dispatch note. The material is presumed to be uniform so that this is the whole of the material whose properties are to be characterized by one set of test. It can be considered equivalent to the statistical population.

·        Laboratory sample: This is the material that will be used as a basis for carrying out the measurement in the laboratory. This is derived by appropriate random sampling methods from the test lots.

·        Test specimen: This is one that is actually used for individual measurement & derived from laboratory sample. Normally measurements are made from several test specimens.

·        Package: Elementary units within each container in the consignment. They might be bump top, hanks, skeins bobbins, cones or other support on to which have been wound tow, top, sliver, roving or yarn.

·        Container or case: A shipping unit identified on the dispatch note, usually a carton, box, bale or other container which may or may not contain packages.

Relative humidity: It is the ratio of the actual vapor pressure to the saturated vapor pressure at the same temperature and pressure.

Standard atmosphere: Standard atmosphere may be defined as an atmosphere at prevailing barometric pressure with a relative humidity of 65% and temperature of 20’C.

Moisture Regain (MR %): It is the ratio of water in a material to the oven dry weight of that material.

Let,

Weight of water in a material=W

Oven dry weight of a material=D

MR %=( W/D)*100

Moisture Content: Moisture Content is defined as the ratio of the weight of water in a material to the total weight of the material.

MC %=( W/D+W)*100

Moisture regain and moisture content of different fibres:

Fibre	Moisture regain (MR %)	Moisture content (MC %)
Cotton	8.5	7.834
Jute	13.75	12.1
Viscose	11	9.91
Silk	11	9.91
Nylon	4	3.1
Polyester	0.4	-
Acetate	6	-
Acrylic	1.5	-
Flax and hemp	12	10.4

IMPORTANCE OF RELATIVE HUMIDITY AND TEMPERATURE:

The atmospheric conditions with respect to temperature and humidity play very important part in the manufacturing process of textile yarns and fabrics. The properties like dimensions, weight, tensile strength, elastic recovery, electrical resistance, rigidity etc. of all textile fibre whether natural or synthetic are influenced by Moisture Regain.

Moisture regain is the ratio of the moisture to the bone-dry weight of the material expressed as a percentage. Many properties of textile materials vary considerably with moisture regain, which in turn is affected by the ambient Relative Humidity (RH) and Temperature. If a dry textile material is placed in a room with a particular set of ambient conditions, it absorbs moisture and in course of time, attains equilibrium. Some physical properties of textile materials which is affected by RH is given below:

·        Strength of COTTON goes up when R.H.% goes up

·        Strength of VISCOSE goes down when R.H.% goes up

·        Elongation %ge goes up with increased R.H.% for most textile fibres

·        the tendency for generation of static electricity due to friction decreases as RH goes up

·        At higher levels of RH , there is also a tendency of the fibres to stick together

Temperature alone does not have a great effect on the fibres. However the temperature dictates the amount of moisture the air will hold in suspension and, therefore, temperature and humidity must be considered together.

PSYCHROMETRY:

Psychometrics is the study of the thermodynamic properties of air and water vapor mixture or simply the study of solubility of moisture in air at different temperatures, the associated heat contents and the method of controlling the thermal properties of air. There are various properties of moist air, they are:

·        Dry bulb temperature

·        wet bulb temperature

·        dew point temperature

·        relative humidity

·        specific volume

·        Enthalpy etc.

DRY BULB TEMPERATURE:

This is the temperature of air-moisture mixture as registered by an ordinary thermometer.

WET BULB TEMPERATURE:

It is the temperature of air-moisture mixture as registered by a thermometer where the Bulb is covered with the wetted wick.

DEW POINT TEMPERATURE:

This is the temperature of air at which moisture starts condensing when air is cooled.

SPECIFIC HUMIDITY:

This is the weight of water vapor present in unit weight of dry air.

RELATIVE HUMIDITY:

This is the ratio of the mass of water vapor to the mass of dry air with which the water vapor is associated to form the moist air. Relative humidity is a measure of how thirsty the air is at a given temperature. At 100%, the air is completely saturated. At 50%, the air holds one-half of what it could hold if saturated at the same temperature. The thirstier the air, the lower the percentage and the more it can rob fibres of moisture.

SPECIFIC VOLUME:

It is the volume per unit weight of air.

ENTHALPY:

It is the total heat contained in unit weight of air, taking the heat content of dry air at 0 degree

centigrade. Enthalpy includes both the sensible heat and latent heat contained in the air.

SENSIBLE HEAT AND LATENT HEAT:

Sensible Heat is any heat that raises the temperature but not the moisture content of the substance. This is our regular and familiar every day heat. Because it raises the temperature it can be detected by the senses, and this in fact, is why it is called Sensible Heat.

Latent Heat is the tricky one. When we talk of Latent Heat we mean 'Latent Heat of Vaporization'. It is that heat required transforming a liquid to vapor. Take water for example. Water can be heated to its boiling point of 100oC. If more heat is added at this point the temperature of the water does not increase. The water continues to boil and becomes steam. So where does all the heat go? Well, the heat goes into changing the water into steam. The latent heat of vaporization in this instance is the heat required to change water from liquid at 100oC to vapor at the same temperature.

TYPICAL AIR-CONDITIONING PROCESSES:

SENSIBLE COOLING / HEATING:

Involving a sensible change in the temperature of air with the specific temperature of air with the specific humidity or moisture content of air remaining the same. This process is shown as a horizontal line in Psychometric chart as no moisture has been added or removed from the air and the humidity ratio remains the same. The heat required to bring this change is shown below

H = G(h2-h1)

H = (Q/V)(h2-h1)

Where,

H is the rate of heat flow, kcal/h

G is the mass rate of flow of air, kg/h

Q is the volume rate of flow of air, meter cube / h

h1,h2 are the enthalpy before and after heating, kcal/kg

V is specific volume of air, meter cube/ kg

COOLING AND DEHUMIDIFICATION:

This is a process involving reduction in both the dry bulb temperature and the specific humidity.

If air is cooled to temperature below its dew point, condensation of moisture occurs.

This condensation continues as long as the air is being further cooled. By noting the enthalpy of air before and after cooling, we can determine the heat to be extracted or the tonnage of refrigeration required for cooling air continuously.

COOLING AND HUMDIFICATION:

This is a process involving reduction in DRY BULB Temperature and increase in specific humidity.

HEATING AND DEHUMIDIFICATION:

This is a process where there is an increase in DRY BULB temperature and reduction in specific humidity.

LATENT HEATING:

This is a process where there is only an increase in specific humidity. This is a process of steam injection.

HEATING AND HUMIDIFICATION:

This is the process where there is an increase in both DRY BULB temperature and specific humidity.

EVAPORATIVE COOLING:

This is a process of cooling and humidification but with no change in the enthalpy of air during the process. This is the process through an air-washer using recalculated water for spraying. This is the most commonly used humidification system in a textile mill.

ADIABATIC SATURATION OR EVAPORATIVE COOLING:

In this process air comes in direct contact with water in the air washer. There is heat and mass transfer between air and water. The humidity ratio of air increases. If the time of contact is sufficient, the air gets saturated. Latent heat of evaporation required for conversion of water into water vapor is taken from the remaining water. When equilibrium conditions are reached, water cools down to the wet bulb temperature of the air. In general it is assumed that, the wet bulb temperature and before and after the process is the same. If the air washer is ideal, the dry bulb temperature and wet bulb temperature of the air would be equal. If a process is adiabatic, heat is neither added or removed from the system Dry bulb temperature of the air goes down in the process and the effect of cooling is due to the evaporation of some part of the water. That is why it is called EVAPORATIVE COOLING. The sensible heat is decreased as the temperature goes down but the latent heat goes up as water vapor is added to the air. The latent heat required by the water which is evaporated in the air is drawn from the sensible heat of the same air. Thus it is transformation of sensible heat to latent heat. During this process the enthalpy of air remains the same. If humidity ratios of saturated air and of the air before saturation is known, then the difference between the two would be the amount of water vapor absorbed by unit weight of dry air. The amount of water sprayed in the air-washer to maintain misty condition can be as much as 200 times the quantity of water absorbed by the air during summer time.

AIR CONDITIONING PROCESS FOR THE TEXTILE INDUSTRY:

Air is drawn in and is passed through the air washer, it gets saturated adiabatically. Since it is not

saturated 100%, the dry bulb temperature of the saturated air will be 1 degree greater than WBT.

When this air is admitted into the conditioned space, it gets heated due to the heat load of the room. During this heating process the air does not lose or gain any moisture as latent heat load is absent. The air displaces an equal amount of air in the room which is pushed outside the room.

If we know the heat load of the room, we can easily calculate the rate of flow of air, G, which is the air circulation rate necessary to give the required relative humidity, from the following formula?

G = H(h2-h2)

Where,

G-mass flow rate of dry air, KG/h

H-total heat of air,Kcal/h

H1-enthalpy of supply air, Kcal/kg

H2-enthalpy of outgoing air,Kcal/kg

The air circulation rate is generally expressed in cubic meters per hour and not in terms of mass

flow rate. (h2-h1) can be calculated from the initial and final temperatures. Therefore

H = (Q/V)* Cp * (DB2-DB1)

Where,

Q-rate of air flow,metercube/h

Cp- specific heat of air

V-specific volume of air,metercube/kg

DB1- supply air DBT,degree centigrade

DB2- leaving air DBT,degree centigrade

However in practice, the air washer does not continuously supply air of 100% RH. The efficiency of air washer falls. It is considered satisfactory, if the difference between DBT and WBT of air after the air washer is 1 degree centigrade. The following equation can be used for practical purposes. (DB2-DB1) = ((3.39 H)/Q)+0.52

Once the relative humidity to be maintained is decided, the quantity (DB2-DB1) is fixed. In other words, once the inside relative humidity is fixed; the minimum dry bulb temperature in the condition space is determined by the wet bulb temp. Of the outside air. It is not possible to go below this DBT unless refrigeration is used.

Why refrigeration is required?

Let us assume that WBT of outside temp is 35 degrees. If the RH% to be maintained in the department is 60%, then DBT of the conditioned space should be 43.5 degrees. Whatever we do, we cannot reduce this temperature as long as we are maintaining a RH OF 60%. Under this circumstance, refrigeration plant is required to bring down the WBT of the air inside, so that 60% RH can be maintained at lower DBT depending on the refrigeration capacity.

What do you mean by “3M”? Explain.

Quality control is governed by 3M i.e. Men, Machines & Materials.

Men: 

·         One of the main functions of top management is the coordination of complete labor force, administration, supervision & operations.

·        The quality controller should be well learned of vast technical knowledge so as to operate the testing lab.

·        80% responsibility goes to the top management.

·        The selection & training of operators is of great importance for quality control.

·        The operators must possess the enthusiasm & self discipline required for maintenance of standards.

·        For testing laboratory great care should be taken to choose the right type of operators in recording tests & carrying out the tests.

Machines:

·         Machines are to be selected on the basis of skillness of operators.

·        A first class, well refined, complex machine for high skill operators.

·        A simple maintainable machine for poor skilled operators.

·        Machine should be selected on the basis of technical view point.

·        Machines should be selected on the basis of economical view point.

·        Machines should be suited for high production.

·         Machines should be suited for the production of high quality goods.

·        A first class maintenance system of the machines is essential for quality control.

Materials:

·        The selections of raw materials are the key factors that determine the profit & loss in production.

·        When raw materials are selected, fibres for spinner; yarn for knitter/weaver; fabrics for finisher.

·        Knowledge of the properties of alternative materials is very useful when the preferred type is either not available or too expensive.

·        Substitution with alternative material has to be made without impairing “Degree of excellence”. Of the product.

·        Raw material should be selected on the basis of test results.

What is the difference between process control & product control?

S/L	Process Control	Product Control
1	Manufacture oriented.	Consumer oriented.
2	Independent in nature.	Dependent in nature.
3	Proper utilization of raw materials is occurred.	Not proper utilization.
4	Proper utilization of auxiliaries.	Not proper utilization.
5	From process control we can have information on process study, time study, costing & way of minimization.	We can not recover any defects after the production of end product.
6	During process controlling we can correct any defects of products.	We can not recover any defects after production of end product.
7	Motto is processing the raw material for subsequent process.	The motto is to prepare an end product that meets the buyer’s desired qualities.
8	To develop process control we have to prevent unnecessary wastage of time, change the settings of machines or even change the process.	To develop product control we have to develop a sample product first to the desired qualities.

What is the importance/objective of textile testing?

·        Selection of raw materials.

·        Process control.

·        Product control.

·        Process development.

·        Product development.

·        Specification test.

·        Research.

Selection of raw materials:

It’s relative. The raw materials for:

1.     Spinning: Textile fibre.

2.     Weaving: Yarn.

3.     Dyeing: Grey fabrics & dyes.

These raw materials always vary in their properties likewise:

1.     Fibre: Color, strength, length.

2.     Yarn: Strength, count, TPI.

3.     Grey fabrics: GSM, EPI, PPI.

4.     Dyed fabrics: Color, fastness, shrinkage.

5.     Finished fabrics: Color, softness, handle, feeling, drape luster

6.     Dyes: Adjustment, fastness.

So we see that selection of raw material is of great importance.

Process control:

·        The motto of process control is to process the raw materials for subsequent process:

·        Process in textile: Fibre-Yarn-Grey fabrics-Finished fabrics.

Process	Output	Controlling of process by factors
Spinning	Yarn	Weight per lap length, roving length etc.
Weaving	Grey fabrics	Excessive breakage of warp & weft yarn.
Dyeing	Dyed fabrics	M: L pH, pressure.
finishing	Finished fabrics	GSM

 Product control:

The motto is to prepare an end product of desired qualities.

Process	Output	Controlling of process by factors
Spinning	Yarn	Count, strength, twist (TPI)
Weaving	Grey fabrics	GSM, EPI, TPI
Dyeing	Dyed fabrics	Color fastness, shrinkage
finishing	Finished fabrics	Color fastness, softness, size, luster, drape, handle.

Process development:

To develop a process we have to prevent unnecessary wastage of time change the machine setting or if necessary process can be changed.

Ring spinning	Rotor spinning	Air jet spinning
1.     Cotton bale 2.     Lap 3.     Sliver 4.     Roving 5.     Yarn	1.     Cotton bale 2.     Lap 3.     Sliver 4.     Yarn	1.     Cotton bale 2.     Lap 3.     Sliver 4.     yarn

Product development:

·        To develop a product we should develop a sample product first to the desired qualities.

1.     For yarn: Count, strength, twists (TPI).

2.      For grey fabric: GSM, EPI, TPI.

3.     For dyed fabric: Color fastness, shrinkage.

4.     For finished fabric: Color fastness, handle, drape, size, and luster.

Specification test:

To reproduce the product first we should deal with the specification test like:

1.     For yarn: Count, strength, twists (TPI).

2.      For grey fabric: GSM, EPI, TPI.

3.     For dyed fabric: Color fastness, shrinkage.

4.     For finished fabric: Color fastness, handle, drape, size, and luster.

Research:

The research results, shows the scientist which route to take for process & production.

1. Write down the name of tensile properties & describe them.

The name of tensile properties is:

·        Tensile strength

·        Tenacity

·        Breaking extension

·        Work of rupture

·        Initial modulus

·        Yield stress

·        Yield strain

·        Elastic recovery

·        Tensile strength: force applied to break the fibre to the cross sectional area is known as tensile strength.

Tensile strength= Force applied to break/Cross sectional area.

Unit: dyne/cm², ib/ft², M/m²

·        Tenacity: Tenacity is the maximum strength to break a fibre.

Tenacity= Force required to break / Linear density or mass per unit length.

Unit: gm/tex, N/tex, CN/tex, gm/denier.

·        Breaking extension: The extension to break materials to the initial length of that material is known as breaking extension.

Breaking extension= (Elongation at break/Initial length) X 100%

·        Work of rupture: if the fibre obeyed Hook’s Law, from the load elongation we should be a straight line & the work of rupture would be given by-

Work of rupture= ½(Breaking load X Breaking elongation)

·        Initial modulus: The value of initial modulus is equal to the value of the stress that would be necessary to double length of the specimen

·        Yield stress & Yield strain: The point (A) up to which a material shows elastic properties after which the fibre shown the plastic properties is called yield point. The point is then characterized by its stress strain- yield stress & yield strain. Here AA’= yield stress & OA”= yield strain

 

·        Elastic recovery.

Elastic recovery= Elastic extension/Total extension.

2. What is crimp? Write down the effect of crimp.

Crimp: when warp & weft yarn interface the fabric, they follow a wavy path. The waviness of yarn is called crimp.

Effect of crimp:

·        Resistance to abrasion: the more crimp percentage in yarn, the more will be the resistive power to abrasion of fabric.

·        Shrinkage: When the fabric is wet, yarn swelling is occurring. So more the crimp, less the shrinkage.

·        Tensile properties: The more the crimp, more the tensile properties.

·        Fabric design: Control the crimp% is necessary, when the fabric is designed to give a desired degree of extensibility.

·        Fabric costing: Crimp is related to the length of yarn. So more yarn will be required to made fabric if the yarn is more crimped.

·        Absorbency: Crimp is high, absorbency is high.

·        Fabric handling: if crimp% is higher fabric will be soft handle.

·        Stiffness: crimp high stiffness high.

·        Dimensional stability: crimp high dimensional stability high.

·        Production calculation: For proper process control crimp% is controlled.

·        Process control for dyeing & finishing: If crimp% is higher pick up% will be higher, dyeing will be uneven.

3. What is the method of measuring threads per inch? (EPI, PPI)?

·        One inch counting glass- a simple microscope

·        Traveling thread counter – a traveling microscope fitted with a pointer to aid counting.

·        Fabric dissection- a known width is unraveled & the threads counted by a useful method where the threads are difficult to distinguish

·        Parallel line gratings- a rapid optical method.

·        Taper line gratings- a development of Parallel line gratings.

·        One inch counting glass method: The one inch counting glass is not recommended the no of threads per inch is less than 25. In such a case 3 inch sample could be unraveled the threads are counted. In the specification it will be noted that specimen should be conditioned foe at least 24 hours before testing. The reason near the selvedge should be avoided because the spacing of threads is often little different than the body of the fabrics.

4. Write down the important factors for measuring fabric thickness.

·        Shape & size of the pressure foot: A circular is usually used. A common diameter being 3/8 inch, but this may differ if desired. The ratio of the foot diameter to the cloth thickness should not less than 5:1

·        Shape & size of the anvil: When a circular anvil is used it should be at least 2 inch greater in diameter than the pressure foot.

·        Applied pressure: Preferred applied pressure is recommended.

·        Velocity of pressure foot: The pressure foot should be lowered on to the sample.

·        Time: The thickness is read from the dial of the instruments when the visible movement of the pointer has stopped.

·        Indication of thickness: A clock type dial gauge is usually built into a thickness tester.

Causes of count variation:

Count Variation is one kind of fault in ring frame. Generally 3% count variation is acceptable. The variation is two types:

1.     Variation within bobbin

2.     Variation between bobbin

Variation may also be:

·        Shift to shift variation

·        Day to day variation

·        m/c to m/c variation

·        doff to doff variation

Causes of within bobbin count variation:

1.     Defective draw frame drafting.

2.     Irregular drafting & stretching of roving.

3.     Stretching between creel & back roller.

4.     Irregular movement of self weight back top roller.

Causes of between count variations:

1.     Variation in the average hank of roving

2.     Difference in the effective draft between ring frame

3.     Draft & waste difference between groups of card & comb

4.     Difference in blow room lap weight over long period.

Causes of strength variation: Causes of within bobbin yarn lea strength variation

·        High within bobbin count variation

·        Inherent testing errors

·        Spindle speed variation causes TPI variation

Causes of between bobbin yarn lea strength variations:

·        Level of twist variation

·        Between bobbin count variation

·        The differences in two condition of drafting system between the spindles

Causes of yarn imperfection:

Thick place, thin place & neps are known as Causes of yarn imperfection.

Causes of thick place & thin place:

1.     Excessive short fibre present in cotton mixing

2.     Type of drafting system

3.     Quality of carding & combing

4.     Drafting variation of faulty drafting in cotton mixing

5.     Excessive twist of roving

Causes of Neps:

1.     Excessive immature & fine fibres have greater tendency to form crimp.

2.     Saw ginning cotton have more neps than roller ginning

3.     Incorrect beater speed & setting of blow room

4.     Incorrect carding speed, fault card setting & unsuitable wire fail to remove sufficient neps.

5.     Excessive drafting speed also create nep

6.     Poor mechanical condition of combing removes less neps

Causes of end breakage:

Technical causes:

·        Excessive yarn tension

·        Incorrect traveler selection

·        Excessive spindle speed

·        Wrong TPI selection

·        Bobbin variation

·        Ring traveler fly out

·        Improper break draft

·        Bent spindle

·        Large ballon formation

·        Unsuitable atmospheric condition

·        R/r lapping

·        Static electricity formation

·        Lack of lubrication in the bobbin cage

Mechanical cause:

·        Defective ring

·        Improper setting of drafting R/r

·        Faulty apron

·        Faulty cot R/r

·        Improper R/r pressure

Factor affecting yarn strength:

Quality of mixing:

·        Fibre properties: Better length, strength & fineness of fibre gives better yarn strength.

·        Mixing ratio: Proper mixing leads to higher yarn strength.

Quality of carding:

·        Mechanical condition of all carding surface

·        Proper maintenance & grinding particle

·        Waste control in carding action

Quality of combing:

·        Level of comber waste

·        Mechanical condition of comber

Quality of drafting of ring frame:

·        Types of drafting system

·        Total draft

·        Break draft

·        Mechanical condition of the drafting system

Quality of twisting of ring frame:

·        Amount of appropriate twist

·        Uniformity of twist

Other factors:

·        Direction of feeding of fibre hook

·        Atmospheric condition or static electricity

Yarn fault:

1.     Count variation

2.     Unevenness or irregularity

3.     Frequently occurring faults

4.     Seldom occurring faults

5.     Hairiness

6.     Lot mixing

·        Count variation: Count is the numerical expression which indicates the fineness or coarseness of yarn. Generally 3% count variation is allowed. Count can be measured by wrap reel & balance or using count measuring software (CMS).

·        Unevenness or irregularity: It is the mass variation per unit length. Cut length is taken generally 1 cm. This fault is expressed as CV%. Evenness tester is used to measure unevenness.

·        Frequently occurring faults: These faults occurring in yarn 10-5000 times of yarn. Yarn spun from staple fabrics contains imperfection which can divide into three groups. Thick place, thin place & neps. These types of faults are determined during evenness testing.

·        Seldom occurring faults: These faults are referred as tarn fault & characterized in the form of thick & thin place in the yarn which is so seldom occurring that for their determination at least 1000000 meter of yarn must be tested.

·        Hairiness: hairiness means the projectile fibre on yarn surface. Hairiness = Total length of hair in any unit / Length of observed yarn in same unit. The acceptable range of yarn hairiness is 3-5%. Evenness tester is used to measure hairiness.

·        Lot mixing: Sometimes two lots can be mixed at the stage of sliver, or bobbin, or cone in spinning mill. These types of mixing cause several problems in subsequence process.

Waste control in spinning mills

In a spinning mill generally 12-13% raw materials are wasted for card process & 22-30% raw materials are wasted in comb process. So waste control is important for achieving good profit.

 There are two types of waste in spinning mill such as usual waste & unusual waste. Hard waste, sweeping, noils, dropping etc. be used for rotor yarn processing. So if rotor spinning machine present in industry we can use them to produce rotor yarn. Again when there are no rotor spinning machine in industry, these waste can be sold comparatively price of rotor yarn processing to increase maximum profit of a spinning waste control is obviously a great factor.

Yarn realization: It is a term used to denote the % of yarn produced for given weight of cotton bale. It depends on waste extraction, mainly to yarn realization.

Yarn realization = (92-Z); for card yarn.

                               = (95-Z) (1-C/100); for comb yarn

Here, Z= trash percentage in raw cotton

C= noil extraction percentage

Waste of a spinning mill depends on:

1.     Characteristics of raw cotton used.

2.     Condition of machinery & processing parameter used.

3.     Atmospheric condition control.

4.     Carrying & storage facilities of material.

5.     Overall working environment.

Name of waste in different stages of cotton spinning:

Stage	Name of waste	Amount (%)
Blow room	Dropings-2	3%
Carding	Dropings-1	4%
Draw frame	Sliver	0.5%
Lap frame	Lap & sliver wastage	0.5%
Comber	Lap & sliver wastage, noil	12-18%
Sliver	Sliver & roving wastage	0.5%
Roving	Pneumafil, hard waste, lapping, sweeping, vacuum cleaner	2.5%
Winding	Hard waste	1%

QA MANAGER

■ Career Profile

• QA leader with a proven track record of strategic QA vision, quick delivery, and demonstrated ability to inspire/mentor quality assurance teams to implement latest QA programs for maintaining industrial quality standards.
• Ensures that the organization’s standards meet legal compliance and clients’ expectations.

Core Competencies:

• Close familiarity with the tools, concepts and methodologies of quality management.
• Eye for detail – Plans and organizes tactics for improvements at work.
• Good team-handling abilities – Possess the ability to interest and convince others when changes are required.
• Presentation and technology leading skills, results-oriented person.

■ Professional History

QA Manager

• Acted as a focal point and leader to all quality related programs – Directed QA activities to ensure maximum quality and effectiveness.
• Supervised and guided quality managers and departments to establish quality standards as per industry and market requirement.
• Directed employees to ensure highest standard of quality so that the organization meets both internal and external requirements – Ensured that all quality standards are met by all departments, by explaining the importance of maintaining quality standards.

Selected Activities

• Worked in coordination with other departments in implementing the quality standards and benchmarks – Developed new matrices and benchmarks of quality standards, directed towards improving performance of departments.

• Evaluated and compared performance of different departments to establish quality standards – Worked closely with human resources departments to develop performance improvement programs and appraisals.
• Procured QA software tools, developed QA procedures and established quality assurance methodologies/standards in order to clarify the quality objectives of the organization.

■ Educational Qualifications

• Bachelor’s in Science/ Commerce/ Business Administration
• BSQA, Bachelor’s degree in quality assurance or quality control, and/or computer sciences
• QCI certification, Quality Management | Quality Training | Quality Assurance training program.

Quality management

In recent times the development of quality systems and quality assurance models has been facilitated by increasingly reliable and almost fault-free production methods, including robotics and as a consequence reduced reliance on manpower. Nonetheless the textile and apparel industry is still searching for a commonly accepted universal approach to quality management.

Quality Assurance involves the application of an integrated approach to quality management that focuses on the issues arising from the design of the process in order to create a continuous self-improving system which will eventually guarantee that quality is “built in” and not just something “inspected into” products.

Werner has accumulated a unique set of experiences and competences in supporting textile and apparel companies in the development of their quality management approach.

We have special capabilities in all levels of quality management. The first level is defect tracking back to the production process of origin, along with elimination of the problem perhaps with re-setting equipment, re-training of operators or even through purchase of new machines.

The second level, often called “total quality control” involves sustained quality performance, within the organization and extended also to include suppliers.
The third level requires commitment to quality by all individuals in the organization and applied to all aspects of operation, and not just to the production areas. This often focuses on such techniques as quality circles.

Charged with the increasing weight of intangibles, the definition of quality largely depends on the specific strategic positioning of a product proposition or brand. No matter what techniques are used for assessing quality, it is vital that the company sets goals and is measuring itself against them.

These goals must be seen as interim steps in the process of continuous improvement, knowing that such a process cannot be successful without participative management and an environment which promotes employee empowerment and a “quality culture”.