In general Slub is the defect , which is due to un even thickness of the yarn at perticular place. It may be on high thickness or Low thickness . High thickness is known as slub , And low thickness is known as negative slub.
If the same defect is created purposely it is known as efect Because know it is in produced in a controlled manner , which gives a pattern, And pattern is a fashion.
Affect the visual effect of slub yarn: There are four factors are affect the visual effect of slub yarn. They are:-
Number of slubs per kilometer (NSm)
Diameter (dia) of slub
Length of slub
Distance between slub.
Fig: Parameters of slub yarn
All these parameters are selected by computer. Slub vision software is used for this purpose.
Types of slub yarn on the basis of visual effect:
Pattern/regular slub yarn
Non-pattern/irregular slub yarn
Multicount slub yarn
Both are pattern and non-pattern slub yarn.
Suppliers of slub yarn attachment m/c:
Amsler – Germany
Jiangyin CF Tex Tech Co Ltd – China
Caipo – Italy
Pinter – Spain
Slub-O-Generator of Fancytex – Gwalior, India, etc.
Some ring frame machine manufacturer are supplying the ring frame with inbuilt mechanisms for slub and multicount yarns. Some popular machine manufacturers are-
FIBER FINENESS, YARN COUNTS AND CONVERSIONS Micronaire Value (Cotton): The unit is micrograms per inch. The average weight of one inch length of fibre, expressed in micrograms(0.000001 gram).
Denier (Man-Made Fibres): Weight in grams per 9000 meters of fibre.
Micron (Wool): Fineness is expressed as fibre diameter in microns(0.001mm)
Metric system: Metric count(Nm) indicates the number of 1 kilometer(1000 meter) lengths per Kg.
Nm = length in Km / weight in kg (or)
Nm = length meter / weight in grams
DIRECT SYSTEM
Tex count
Denier
CONVERSION TABLE FOR YARN COUNTS
Tex
Den
Nm
Grains/yd
Tex
den/9
1000/Nm
gr.yd x 70.86
Ne
590.54/tex
5314.9/den
Nm x .5905
8.33 / gr/yd
Den
tex x 9
9000/Nm
gr/yd x 637.7
Nm
1000/tex
9000/den
14.1 / gr/yd
Grains/yd
tex / 70.86
den / 637.7
14.1/Nm
CONVERSION TABLE FOR WEIGHTS
Ounce
Grains
Grams
Kilograms
Pounds
Ounce
437.5 grains
28.350 grams
Grains
0.03527 ounces
0.0648 grams
Grams
0.03527 grains
15.432 grains
0.001 kgs
Kilograms
35.274 ounces
15432 grains
1000 grams
2.2046 pounds
Pounds
16.0 ounces
7000 grains
453.59 grams
0.4536 kgs
CONVERSION TABLE FOR LINEAR MEASURES
Yard
Feet
Inches
Centimeter
Meter
Yard
3 feet
36 inches
91.44 cms
0.9144 meter
Feet
0.3333 yards
12 inches
30.48 cms
0.3048 meter
Inches
0.0278 yards
0.0833 feet
2.54 cms
0.254 meter
Centimeter
0.0109 yards
0.0328 feet
0.3937 inches
0.01meter
Meter
1.0936 yards
3.281 feet
39.37 inches
100 cms
CALCULATIONS
Grams per meter = 0.5905 / Ne
Grams per yard = 0.54 / Ne
Tex = den x .11 = 1000/Nm = Mic/25.4
Ne = Nm/1.693
DRAFT = (feed weight in g/m) / (delivery weight in g/m)
DRAFT = Tex (feed) / Tex(delivery)
DRAFT = delivery roll surface speed / feed roll surface speed
No of hanks delivered by m/c = (Length delivered in m/min) / 1.605
WINDING
1. Slub catcher settings :
a. Fixed Blade = Carded – (2.0 to 2.5) x diameter Combed – (1.5 to 2.0) x diameter
b. Electronic yarn clearer = 3 cm x 3 diameter Diameter in inch for Blended yarn = 1/( 28 x √count ) = 10 to 15% more settings
Number of objectionable thick faults removed by slub catcher 2.Yarn clearer efficiency =……………………………………………………………………………………..x 100 Total objectionable thick faults present in yarn before winding
Total breaks during winding (at faults) 3. Knot factor =……………………………………………………………………. No. of breaks due to objectionable yarn faults
Strength of spliced joint x 100 4. Retained splice strength = ………………………………………………….. Strength of parent yarn
5. Winding Tension = 0.1 x Single yarn strength in grams
4500 x Y 6. Expected efficiency E = ……………………………………………… S x N (12 + 98)
7. Winder’s workload (0.17 min/operation on conventional winding m/c) = 2300 operations per shift of 8 hours
Where,
1 creeling or 1 piecing = 1 operation
1 doffing = 2 operations
8. Winder’s workload on autoconer (0.08 min per operation) = 4800 operations/shift of 8 hours
Where,
1 bobbing feeding = 1 operation
1 doffing (manual) = 4.5 operation
Y = Length/Bobbin (metres) B = Breaks per bobbin S = Winding speed (metres/min) C = English count 9. Production in Kgs / 8 Hrs = (0.2836 x L x Effy x Nd) / (Ne)
L – delivery speed in m/min
effy – efficiency
Ne – english count
Nd – No of delvieries
10. P =( L x 1.0936 x 60 x Effy ) / (Hank (Ne) x 36 x 840 x 2.2045)
P – production in kgs / hr
L – delivery speed in m/min
effy- efficiency
Ne – English count ( number of 840 yards in one pound)
840 – constant
2.2045- to convert from lbs to kilograms
WARPING
R x 100 1. Machine Efficiency E =……………………….. R + S
R = Uninterrupted running time for 1,000 meters (in sec)
1000 x 60 = …………………………………………. Machine speed in mtr/min.
S = Total of time in seconds for which the machine is stopped for a production of 1,000 meters
B X N X T1 T2 T3 = R + —————- + —— + ———– + T4 400 L L x C
B = Ends breaks/400 ends/1,000 meters
N = Number of ends
L = Set length in 1,000 meters
C = Beams per creel
Timing of activities in seconds are :
T1 = To mend a break
T2 = To change a beam
T3 = To change a creel
T4 = Miscellaneous Time loss/1,000 mtrs.
2. Production in metres per 8 hrs. (K) = 480 x mtrs/min x E/100 kgs. 3. Production in Kgs. per 8 hrs. = (K x N)/(1693 x English Count) 4. Warping Tension = 0.03 to 0.05 x Single thread strength
SIZING
Length in metre x 1.094 x Total ends 1. Warp weight (in kg.) = ……………………………………………x 100 840 x 2.204 x Warp count
Total-ends x Warp length in yards 5. Sized yarn count = ……………………………………………………… Sized warp weight (lbs) x 840
Wt. of sized yarn – Wt. of oven dried yarn 6. % of Moisture content= ………………………………………………… x 100 Wt. of sized yarn
Deliver counter reading – Feed counter reading 7. % of Stretch =……………………………………………………… x 100 Feed counter reading
840,000 x D x C 8. % Droppings on loom = ……………………………. x 100 454 Y x N x P D = Dropping in gms. C = English Count Y = Length woven (yds.) N = Number of Ends P = % size add on 9. Invisible Loss%
Amount of size material issued – Amount of size added on yarn = ……………………………………………………………………………x 100 Amount of size issued
Steam, Consumption (Sizing M/c) = 2.0 kg/kg of sized yarn (Cooker) = 0.3 kg/kg of liquor (Sow box) = 0.2 kg/kg of yarn
No. of Cylinder x 1,000 x English count 10. Max. Speed of machine = ……………………………………………… (metres/min) Number of ends
Number of ends x 0.6 11. Wt. of warp in gms/mtr = ………………………… English count
WEAVING
1. Reed Count : It is calculated in stock port system.
Ends/repeat x 1 / yarn diameter d. Other design = ……………………………………………………….. No. of intersections / repeat + ends/repeat
1 8. Yarn diameter = …………………… 28 x √Count
Weave Density
1. Warp density = Ends/cm x √Tex x K = < 250
2. Filling density = Picks/cm x √Tex x K = < 350
(Warp density – 100) x F.D.- 100 3. Weave Density = 50 + …………………………………………… (Weft density – 100) x F.D.- 100
4. Effective weave density = W.D. x K of loom width x K of Design = < 72
Count Table
To change the count and number of thread/inch, keeping the same denseness of the fabric : 1. To change the EPI without altering the denseness :
EPI in given cloth x √ Warp count in expected cloth EPI in Exp.Cloth =………………………………………………………………
√ Warp count in given cloth2. To change the count without altering the denseness :
EPI in exp. cloth2 EPI in exp. cloth = …………………………………x Count in given cloth EPI in given cloth
Warp requirement to weave a cloth :
Total ends x 1.0936 x 453.59 x crimp% 1. Warp weight in gms/mtrs. =………………………………………………….x Wasteage% 840 x Count
2. Weft weight in gms/mtrs.
R.S. in inches x 453.59 x PPI =…………………………………x Crimp % x Waste % 840 x Count 3. Cloth length in mtrs.with the given weft weight Weft wt. in kgs. x Weft count x 1848 x 0.9144=………………………………………………………. PPI x R.S. in inches For Silk and Polyester :
1. Warp weight in gms/mtrs.
Total ends x Count (Denier) = ………………………………………..x Crimp% x Waste %age 9000
2. Weft weight in gms/mtrs. RS in inches x PPI x Count (Denier) = ……………………………………….. x Crimp% x Wasteage% 9000
Allowance for count in Bleached and Dyed Fabric :
Count becomes 4%
Finer Dyed counts become max.6% Coarser
FABRIC PRODUCTION
Motor pulley diameter 1. Loom speed = Motor RPM x …………………………………. Loom pulley diameter
Actual production 2. Loom Efficiency % = ——————————- x 100 Calculated production
Total ends x Tape length in metre 5. Warp weight in Kg. = —————————————————— 1693.6 x Warp count
RS in centimetres x Coth length in metres x PPI 6. Weft weight in Kg. = ——————————————————————- 4301.14 x Weft count
EPI PPI 7. Cloth weight in GSM = —————— + ——————– x 25.6 Warp count Weft count
GSM (Grams per sq. metre) 8. Oz (Ounce) per sq.yard = ——————————————– 34
Material measurement : For calculating of length of any rolled fabrics :
0.0655 (D – d) (D + d) L = ——————————— t
Where,L = Length of material (feet) t = Thickness of fabrics (inches) D = Outside diameter (inches) d = Inside diameter (inches) Weight of yarn in a cloth : The weight of cloth manufactured on loom depends upon the weight of yarns in the warp and weft : ends/inch, picks/inch and the weight of size on the warp.
Therefore, Cloth weight = Weight of warp + Weight of weft + Weight of size (All in lbs.)
Total No. of Ends x Tape length in yds. Where as Weight of warp in lbs = —————————————————– 840 x Warp yarn count
Also Weight of weft in lbs.
Length of cloth (yds) x Picks/inch in cloth x Reed width (inch) = ———————————————————————————————– 840 x Weft yarn count
100 Grams per square Meters = 2.949 ounce per square yards
How to calculate GSM
GSM is very common word used in the textile industry , It means linear density of the material .
It may be applicable for anymaterial
To calculate the GSM we have to weigh the material in gramms and take the area of the material in square meters , So the weight of 1 square meter is known as GSM.
If the length and width we can measure in meters then it has to be converted in to meters
If Yarn Count is not suitable as per the knitting machine gauge then the fabric will not behave properly .There may be shrinkage problem crease marks problem. Rope marks problem in the dyeing may happen . .
A easytable is here for every one to understand this relationship
Those engaged in the production, distribution, and consump-
tion of textiles, testing can be a valuable aid provided that the
instruments and techniques are used effectively. When tests are
made the results must be studied carefully so that the right course
of action may be taken. Testing instruments cannot make decisions,
and in the end some person has to interpret the data and issue the
necessary instructions for future action. Testing is, therefore, a
means to an end and not an end in itself. The fact that a material
has been tested, no matter how accurately, does not enhance its
technical quality
1. Yarn Count
The yarn numbering system, used to express a relationship between a unit length and weight of yarns. Thus count defines the fineness of yarn used in fabric.
This system is divided into two main systems.
Direct System
Indirect System
Cotton Count = No. of yarn x length of yarn (cm)
169 X Weight of Yarn (gm)
Conversion of Counts
Denier (D) = 5315 / Cotton Count
Tex (Tex) = 590.5/ Cotton Count = 0.111 x Denier
2. Fabric Construction
It defines the density of fabric weave in terms of yarns per inch in warp and weft direction. Fabric construction has an influence on the weight of fabric. Measured in EPI & PPI
3. Dimensional Stability
It determines the change in dimension in length and width of the fabric as a result of shrinkage or expansion after repeated home laundering or dry-cleaning.
The degree of shrinkage depends on the type of the fiber, fabric construction, and temperature of washing and drying.
4. Appearance
It assesses the visual appearance of textile product and color change after repeated home laundering or dry cleaning. The test uses standard scales or replicas to evaluate the amount the change in the appearance.
5. Spirality / Skewness
Angular deviation in length and width direction of the fabric due to twisting of fabric or garments is known as Spirality / Skewness.
B’ B
X A Y
% Skewness = BB’ C 100
AB
6. Colorfastness to Laundering / dry-cleaning:
It refers to the ability of a colorant on a fabric/Garment to withstand by the effects of Laundering or dry cleaning.
A sample of textile fabric sewn with Multifiber test fabric is mechanically agitated in launder-o-meter under specified conditions of time and temperature in soap solution and steel balls then rinsed & dried. The color change of the sample and staining of the Multifiber is assessed with grey scales under standard viewing environment.
7. Colorfastness to Rubbing / Crocking:
It determines the resistance of the color of textiles to rubbing off and staining on white fabrics. Both dry and wet rubbing tests are conducted. The staining of the rubbing cloth is assessed with grey scales under standard environment.
A standard test device, Crock meter is used for this test.
8. Colorfastness to Perspiration:
It shows the effect of human perspiration on fabric in terms of color change and staining. Perspiration tester and hot air oven are used to simulate the body temperature and prolonged body contacts on fabrics. Textile samples and adjacent fabrics are treated in simulated perspiration liquor. The dried sample and adjacent fabric are assessed by grey scales on color change and color staining.
Sports shirts and underwear are necessary for this test.
9. Colorfastness to Light:
It refers to the ability of colorant on fabric to withstand the effects of sunlight. This test is conducted on Atlas Fadometer, which simulate the sunlight and environment on samples by controlling the irradiance, temperature and relative humidity within the equipments.
Exposure is done for a specific period of time (i.e. 20,40,80 hrs etc.) for AATCC standards. And then the sample is assessed for color change with the grey scales.
Swimwear, Sportswear and garments frequently exposed to sunlight should be specially checked for this test.
10. Colorfastness to Non-chlorine Bleach
This test method is designed to evaluate the colorfastness performance of a textile fabric when subjected to the action of usually market available type detergent containing non-chlorine bleach.
A specimen is introduced with a drop of diluted non-chlorine bleach assessed for color change by grey scales.
11. Tensile Strength
It determines the strength of a fabric when subjected to tension by external force. It is measured by the minimum amount of such a force required to rupture a fabric.
12. Tear Strength
It measures an average force required to propagate a tear after a cut mark in the fabric.
For this test Elmendorf tearing tester is used which indicates the degree of damage on fabric. This is generally applicable to bleached, resin treated or coated woven fabrics.
13. Bursting Strength
It is the radial force needed to rupture a fabric by distending it at right angle to the materials. This is especially desirable to test knits, and non-woven fabrics.
In knit fabric, there is no specific warp & weft as woven fabric, so multidirectional force is applied on it
14. Abrasion Resistance
It determines the durability of fabrics under abrasion in simulated fabric rubs against fabric. Its also called “Wear & Tear test”
The end point of the abrasion is evaluated either by the yarn broken or color change.
15. Pilling Resistance
Pilling is the formation of balls of entangled fibers on the textile surface due to rubbing. This pill formation may affect the appearance of garments. Test is conducted on Random pilling tumbler.
Short and hairy fibers such as wool have high tendency to form pills.
16. Stretch & Recovery
The test is used to evaluate the elastic properties as elongation & recovery. This is a cyclic test and conducted on Universal Testing Machine.
Stretch fabrics can elongate to a greater extent degree than ordinary fabrics.
17. Blend Analysis
This test is to identify the fiber and the actual content of different kind of fibers used in the manufacturing of textile product.
The fiber is identified by studying microscopic longitudinal and cross-sectional view or chemically.
Fibers are identified by using three techniques
Microscopic view
Burning Test
By physical Separation or Dissolving In Chemicals
18. pH
Its one of the critical factor for processed fabric and especially applicable to white colored fabrics.
This test is to define the acidity & alkalinity of textiles.
Assessment of Colorfastness
Grey Scale for Staining on Multifiber
All colorfastness/appearance samples are evaluated against two parameters
Color Change
Staining on Multifiber
This evaluation of tested specimen is done by the Grey scale ranging from 1 to 5.
Interpretation of these grey scale values are given below
Fabric : Strength, colorfastness, performance & chemical properties
Garment: SeamSlippage, Appearance, D.P.Rating etc.
Trims & Accessories
Various Standard used in Textile Testing
ØISO – (International organisation for Standardization)
ØAATCC – American Association of textile colorists & chemists
ØASTM — American Society of Textile & Materials
ØBIS — Bureau of Indian Standard
ØBS — British standard
ØSDC — Society of Dyers & Colorists
ØJIS — Japanese standard
ØCAN — Canadian Standard
Most common standard among above are AATCC & ISO Standard.
Selection of test method depends on the country of destination or approved by the buyers.
General classification of tests & equipment used
While textile testing is broad in scope and encompasses several textile properties, most of the tests performed on textile products can be categorized in five major sections, which are listed below.
These tests are mainly physical or mechanical in nature, conducted with the help of mechanical equipments.
No chemical is required for the testing except water in few tests.
The main requirement for these test are standard conditions, which need to be strictly maintained. Relative Humidity & Temperature are the key parameters as they have an affect on the physical properties of the textiles.
Standard Conditions are:
Relative humidity: 65 ± 2 %
Temperature: 20 ± 2 °C.
Example of tests in this category is as given below
These tests are used to determine the resistance of the color to various textiles under various actions such as washing, rubbing, light, perspiration etc.
Usually dyed or printed textiles are tested under this category. Examples of tests included in this category are as follows:
Color fastness tests for Fabric & Garments
Test Name
Equipments Used
Color fastness to Laundering
Launderometer
Colorfastness to Crocking/Rubbing
Crock meter
Colorfastness to Dry-cleaning
Launderometer
Colorfastness to Perspiration
Perspirometer, Oven
Colorfastness to Light
Fadometer
Dimensional Stability to Washing
Washing Machine & Shrinkage Template
Appearance after Laundering
Washing Machine
c. Performance tests
These tests are conducted to determine the performance of textile products after repeated laundering or dry-cleaning under various conditions.
These tests are critical to quality of textile product for end users. Examples of tests under this category are as follows:
Color assessment is conducted for evaluation of Color Change and Visual appearance after repeated laundering or dry-cleaning. This is the indicator of textile performance when subjected to actual use.
Main objective:To study and increase total cutting room efficiency
Sub-objectives:
a)“Time &
Motion Study” of different operations in spreading & cutting leading to:
1) Determination of efficiency of the worker:
The purpose is to optimize on manpower utilization. Put
the best person to best use and avoid
multitude of workforce wherever not required.
2) Identification of bottleneck operations:
Bottlenecks
increase the throughput time, which is a significant loss on the critical time. Bottlenecks should be identified and taken
care of immediately to save on cost and time.
3) Reduction of idle times whenever possible:
Huge expenditure is incurred on machinery. The interest of that
investment should always be kept in mind. As
such, machine idle time is a disguised expenditure in form of loss of interest
on investment. Continuously running machine is an investment justified.
4) Maximum utilization of automatic spreading & cutting systems: Automation is justified only if it is used to the fullest extent. The
intention is to de-skill and increase production,
and wherever possible economize on cost. All the three purposes should be achieved; otherwise the advantage of automation may
not be one hundred percent.
b) Study of the existing layout with reference
to material flow & explore scope of improvement:
Layout affects production flow. It should be conducive to material
movement, and at the same time technically correct. Haphazard
layout may obstruct movement thus costing on time and fatigue, and in
turn resulting in loss of time and energy.
c) To utilize the variable resources
manpower efficiently in the cutting section:
It will help in target setting and
work monitoring for the activities of cutting room.
Our project, thus attempts to
strike at a balance in the production activity- cutting department. And the balance is of the most critical components – Man, Machine and Material…
SINCE WE KNOW THAT TODAY IN THIS GLOBAL WORLD THE COMPETITION IS EXTREMELY HIGH SO EACH AND EVERY COMPANY IS TRYING TO MINIMISE THE COST OF THE PRODUCT BY INCREASING THE PRODUCTIVITY AND THUS THE PROFITS.
A COMPANY ALWAYS NEED TO ACHIEVE ITS MAXIMUM POSSIBLE PRODUCTIVITY ALONG WITH EXCELLENT QUALITY AND ECONOMICS SO THAT IT CAN SURVIVE IN THE MARKET.THESE CAN ONLY BE ACHIEVED WITH PROPER PLANNING AND USAGE OF AVAILABLE RESOURCES AS MINIMUM AS POSSIBLE TO INCREASE THE PROFITS ETHICALLY.
HERE WE HAVE CARRIED OUT STUDY ON DIFFERENT MACHINES TO KNOW THE CAUSES OF NEEDLE BREAK AND THE EFFECT OF MOISTURE CONTENT OF THE YARN ON KNITABILLITY,NEEDLE PERFORMANCE,PRODUCTIVITY AND EFFICIENY.
The study concerns with the following points on different machines and was carried out for a week.
Parent factors which decides the productivity
Knitting yarns properties
Stoppages encountered
Loss of time due to stoppages
Causes of stoppages
Average humidity through a week
Moisture content of different layers of package
Comparison of various properties of yarn of different samples
Comparison of moisture content in different samples of fabric.
Effect of humidity on fabric weight
Effect of time on fabric weight
Effect of storage time after conditioning on the performance of knitting machine
Inspection of fabric
Performance of New slub catcher introduced in the creel
Changing from NON organic to ORGANIC (Bio-cotton) or a dark shade to a white or pale shade, lightly
spray the stainless rollers, mangles and any other part of the machine which
touches the fabric with “COLIN” (household cleaner) and wipe off with a damp
cloth (white or a pale shade). Observe the cloth for dirt. Clean the filters.
Changing from a white shade to a NON WHITE shade blow off and
wipe all the lint, clean the filters.
Cleaning of the
padder & trough
Clean the padder immediately after use. Hose down those parts
which come into contact with the liquor. The trough can hereby be lowered. It
has a middle position which enables the trough guide roll to be serviced
without having to drain the liquor.
After heat setting 1,500 kilos of
cotton/elastane, drain the trough. Clean the trough and rollers with a
scouring pad. No deposits to remain.
Changing over a
batch & cleaning of the stenter
The stenter is a “bottleneck” machine. This means ALL
DOWNTIME has to be kept to a minimum
To reduce the downtime as many tasks as possible need to be
undertaken at the same time.
Therefore extra staff are required during cleaning.
The finishing supervisor or process owner, should notify the
employees before they are required
Gloves are required to be worn (especially inspectors…will dirty
fabric)
ALLOCATION of EMPLOYEES & TASKS DURING CLEANING/LOT CHANGES
ALLOCATION OF EMPLOYEES
PARTS TO CLEAN
CLEAN WITH
A
1st TENSION
ROLL
Wet fabric
STENTER PROCESS OWNER &
ASSISTANT
SPEADER ROLL
Wet fabric
CENTERING UNIT
Air hose
2 nd TENSION ROLL
Wet fabric
3 rd TENSION ROLL
Wet fabric
SPEADER ROLL
Wet fabric
SOFTNER TANK
Wirewool
& water
MANGLES.
Wet fabric
CHECK
the PIECE of WHITE SINGLE JERSEY on the END of the SOFTENER PIPE.
IF CONTAMINATED, REPLACE FABRIC.
DANCER
ROLL
Wet fabric
B
SPEADER ROLL
Wet fabric
STENTER PROCESS OWNER
MAHLO SCROLL
Wet fabric
MAHLO BOWING ROLL
Wet fabric
CAMERAS
Wet fabric
MAHLO DANCER ROLL
Wet fabric
C
UNDER FEED ROLL
Wet fabric
ANY ONE SPARE AVAILABLE
SPEADER ROLL
Wet fabric
SCROLL TENSION ROLL
Wet fabric
FEEDING ROLL
Wet fabric
OVERFEED ROLL
Wet fabric
STEAM BOX
Wet fabric
D
FIVE FILTERS
Wet fabric
QUALITY CONTROL INSPECTORS
CLEAN
THE MOISTURE METER.
Wet fabric
REMOVE THREAD ON PINS & SPREADING
CHAIN
Brush
& hand
If the impurities
cannot be removed with water, use “COLIN” (household detergent).
This Paper is the result of hard work of Mr. John Hardiker
A
General
1
Before adjusting the machine set up to change the fabric performance; check if the machine is set up as per the machine specifications and there is nothing obvious on the machine which could be having a negative affect.
2
N.B The width cannot be made narrower than the specifications (customer cutting efficiency could be drastically reduced, resulting in a claim). Generally the width is fixed (could be made wider is the gsm and shrinkages are within tolerance).
3
When adjusting a machine to achieve the fabric width, gsm and skewness, consideration has to be given to length/width shrinkage and spirality.
4
If the fabric length and width shrinkages are known before processing, the expected shrinkages after processing can be calculated. This information can be used to adjust the gsm and width (if not specified) to their optimum; eliminate batches being rejected for shrinkage after processing.
B
Formula for calculating shrinkages
1
before processing
Width cm
width % shrinkage
target width after
affect on width shrinkage
customer allowed max %
calculated shrinkage
148
6
151.02
2.00
8
8.00
2
before processing
length % shrinkage
customer allowed max %
min required % reduction in length
11
8
3
C
Check & adjustment for length shrinkage
1
Measure and mark 100 cm before the fabric enters the machines, measure the marked fabric exiting the machine. For every 1cm reduced, equals a reduction of 1% in shrinkage. OR use a measure specifically designed for checking fabric shrinkage after processing.
2
Subtract the reduction in % length shrinkage from the fabric shrinkage (before processing) to give the calculated fabric shrinkage after processing E.g. 12% before processing; length reduced by 5%; calculated fabric shrinkage = 7%. Customer specifies a maximum of 8% length shrinkage.
3
If the fabric length shrinkage is not known before processing; this measure will only indicate the amount of length shrinkage during processing, NOT the actual shrinkage of the fabric.
4
To add ‘safety to the length shrinkage (fabric length increased on “rolling”) the calculate shrinkage after processing could be set at 1% to 2% below the customer targets. E.g. Customer specifies 8% shrinkage, calculated shrinkage = 7%.
5
Stenter – To reduce or increases the length shrinkage by 1%, increase or reduce the overfeed by 5%. Re-check the % length shrinkage.
D
Check & adjustment for width & width shrinkage
1
After processing measure the width of the fabric (could be overall width, useable width), compare to the target width.
2
If the width is narrow/wide, increase/decrease the width of the chain by same number of cm. E.g. if fabric 175cm and target is 178cm, increase the chain width by 3cm.
3
For calculating the width shrinkage (if shrinkage known before processing) Measure the width (cm) before and after processing, calculate the shrinkage.
example – calculate shrinkage
width before 170cm with 5% width shrinkage
width after 175 cm
175 – 170 = 5cm
5/175 x 100 = 2.86%
Total calculated shrinkage = 7.86% (5 + 2.86)
E
Check & adjustment of grams per square meter (g.s.m)
1
Before checking the gsm, the width should be within specification
2
Take a sample and cut the sample with a gsm disc cutter. Weigh the cut sample; compare to the target, minimum and maximum allowed gsm. N.B The target gsm could be conditioned or UN-conditioned.
3
If the gsm is too high; the gsm could be reduced by reducing the overfeed. N.B Reducing the overfeed, increases the length shrinkage. Calculate the affect on length shrinkage before adjusting.
4
If the gsm is too low, the gsm could be increased by increasing the overfeed (refer example below) by 10%, slowing down the compactor by 20%.
4.1
Stenter – To reduce or increase the gsm, increase or reduce the overfeed by 8%. Re-check the gsm.
5
Re-check the gsm after adjusting the overfeed.
F
Check & adjustment of fabric skewness
1
The skew is measured by the deviation of the course line across the width against the width.
2
Measure height of course traversed and the width of the fabric
3
% skewness = height/(fabric width) x 100%
course
height
width
4
Compare the result against the maximum allowed skewness.
5
For every 1% above the maximum allowed skewness, increase the angle of the courses straightner by the same %. Re-check % skewness.
G
Courses and wales
1
Courses and wales can also be used to check if a fabric is within tolerance
H
Adjust of the machine does NOT achieve the width, gsm and shrinkages
Usually means the knitting or the dyehouse has affected the fabric in a negative way
1
Stop processing the fabric; INFORM the finishing manager.
