As the reduced indigo dyeing machine has very little affinity for cotton in spite of the deep shades while dyeing with concentrated vat dye, the result is sufficient fastness. For this reason the cotton warps for Blue Jeans are dyed in 4-6 passages in sheet form. By a passage it means the run of goods through an immersion, vat following by squeezing and an air passage for oxidation of dye stuff . A major part already oxidized dye stuff remains fixed to the material while being processed in the following immersion vat. Only the chemical solution is almost completely replaced by fresh indigo vat. Thus with every subsequent passage the depth of dye penetration increases. After the last air passage the stuff ringed by 2 or 3 ringed trough.
Details in Dyeing & Sizing machine:
Machine Name : Slasher Indigo Dyeing Machine.
Country of origin : West Point, USA.
Model No. : 654
No. of Machine : 01
Creel capacity : 21
Speed of the Machine : 16 meters / minute for Dark Indigo,
: 20 meters / minute for S. Black.
: 23 meters / minute for Normal Indigo.
Production capacity per day : (21x1320x.95) = 26334 Mts (Considering the product mix 65% Indigo 20% Dark Indigo,15% Sulphur Black.)
Dyes and Chemicals wastage : 1 – 2 %
Szing material wastage : 2.5%
Pls note : This yarn wastage is already taken in fabric process loss.
Down Time :
If dyeing route is similar then down time 45 minutes/Dyeing Lot. (Two and Half lot per day)
If dyeing route is different then down time 3 hours (Two time per 7 days)
If dyeing route is same but need to colour change then down time 2 hours (Two time per 15 days).
Indigo Denim Manufacturing Process
Yarn Peperation
↓
Continuous Dyeing
↓
Beaming
↓
Slashing
↓
Weaving
↓
Finishing
Dyeing Machine Process
Continuous dyeing of cotton yarn with Indigo Dyeing Machine
Indigo denim dyeing:
The “Mult-dip” process is by far the only continuous method adopted for indigo yarn dyeing.
The dyeing machineries used for yarn dyeing are divided into two categories namely the rope dyeing range and the slasher dyeing range.
The main difference between rope dyeing and slasher dyeing is that for rope dyeing and sizeing have to be done separately while in slasher dyeing, the dyeing and sizing can be done simultaneously.
Rope dyeing technique is more popular in the America region. It is suitable for mass production. And because of its possible non stop dyeing advantage, rope dyeing gives better shade consistency.
Indigo Dyeing Machine wetting
In absence of strong demands for deep (dark) dyeing of yarns, they are only pre-wetted by caustic and wetting agent the degree of dyeing depth is influenced in the second trough rinsing is done more or less by strong overflow of cold
Pretreatment process with sulphur black
In general with continuous dyeing no deep (dark) dyeing of yarn is achieved, they are often pre-dyed to a light medium grey-shade with sulphur Black.
The pre-dyeing is done is done at 80ºC/90ºC in the first wetting trough of the continuous processing plant. The second trough is used for rinsing of dye stuff
The yarn is squeezed to 70% to 80% and the rest humidity is immediately passed through the first vat.
The Dyeing Process
The sequence of dyeing for both rope & slaser are very similar, which include the following stages:
Mercerization (Optional)
↓
Pre-Scouring
↓
Dyeing
↓
Squeezing
↓
Airing
↓
Rinsing
↓
Finished fabric.
Pre-Scouring:
Pre-Scouring has the following functions: wetting out yarn, removing air from yarn and scouring to give cleaner yarn so that a better dyeing can be achieved.
The pre-scouring bath consists of wetting agent, caustic soda and chelating agents. Normally, a minimum of two boxes are required to give satisfactory pretreatment. The first box is the pretreatment with temperature at 85ºC to wet out the yarn. The second
Box is a cold rinsing to coon down and to decrease the yarn.
It also a common practice where at this stage optional Sulphur bottoming application is done.
Dyeing
The desired depth of Indigo on the yarn is mainly achieved by the number of dip. In general, the lower the dye bath concentration (2-4 g/l) as more dips are required, the better the fastness, and the vice versa. For a full Navy shade of about 2% pick up (based on Indigo grain), an initial dye bath will balance itself until it is able to pick up 2% dye.
The reduce Indigo Dyeing Machine solution cannot be prepared directly in the dye baths. Its because it will take much higher quantity in caustic and hydrosulphite, and much longer tome to reduce the Indigo when the concentration of Indigo dyeing is a continuous exhaust dyeing process, a replenishing of dye and chemicals are necessary during dyeing. As a result, preparation of concentrated stock vat is necessarsy for the initial dye bath and the replenishment.
Indigo dyeing is generally carried out at room temperature, although dyeing at higher temperature has a better leveling effect. High temperature will deteriorate the reduction condition of the dye bath at much faster rate. As a result, a higher consumption of caustic and hydro.
In order to produce a consistent dyeing, control over the dye concentration, redox potential and the alkalinity of the dye bath is absolutely necessary.
Indigo Dyeing Machine
Control during dyeing
Hydrosulphite or ORP value
The content can either be checked by a vatometer, range from 1.5-2.5 g/l, or by direct titration method. The control can further be confirmed by measurement of the redox potential of the dye means of an ORP meter range from 730mv-860mv is common.
Caustic soda or pH value
The content can be checked either by titration with HCl or by pH meter, generally pH ranges from 11.5-12.5.
Dye concentration in dye bath
It can be checked by means of leuco solution is oxidized and the transmittance at λ max is measured. The reading can be converted into concentration in g/l by comparing with a calibration curve plot from known dye concentration.
The control figure varies from range to range, so one must establish their own set of control data.
Normal running speed is 20-25 yds/min (18-22 m/mim).
The longer the dipping time, the better will be the penetration and the lesser will be the ring dyeing effect. Dipping time varies from 6-30seconds. The common is 20-30 sec. However, the dipping time should not exceed 60 sec. It is because there is an adverse effect where the Indigo Dyeing Machine fixed on the yarn may be redused back into the dye bath.
However, for super dark shade, beside mercerization of yarns at the pretreatment stage, bottom or topping with Sulphur Black is also a common practice further; there is a newer practice by controlling the pH with the additional of buffer to give significant ring effect which enhances darker shade.
Squeezing
The wet pick up affects the dyeing fastness to a very great extent. Higher squeeze pressure gives lower wet pick up and results in lesser surface colour and better penetration.
Rope dyeing and Looptex units have squeeze pressure from 5-10 Newtons, which can give a wet pick up as low as 60% while for slasher dyeing range have inferior fastness property than the rope dyeing range.
Hardness of the squeezing rollers should be approximately 70-75ºShore. If the squeezing rollers are too hard, slippage will occur and results in uneven yarn tension. If they are too soft, they will groove easily and results in shading.
Maintaining in a smooth surface of the squeezing roller is important. Normally the surface should be ground twice per year. When applying pressure to the squeezing mangle, make sure the mangle is not bended. Otherwise, shading will result.
Oxidation
In between dipping, airing is necessary to oxidize the dyed yarn. Usually, airing time varies from 60-120 sec, and 90 sec is common. Try to avoid long airing time, as this will create unnecessary high tension on the yarn and make the subsequent processes difficult.
Rinsing
Most dye ranges are equipped with2-3 rinse boxes. Cold rinsing is generally sufficient. For rope dyeing, the last box is used for applying re-beaming aid.
Drying
Sufficient drying capacity should be provided, otherwise high range speed cannot be achieved. Insufficient drying or unevenly dried yarn will result in weak size pick up in the case of slasher and poor re-beaming in case of rope dyeing.
Preparation of stock vat, chemicals, dye bath
Preparation of stock vat
Since the dyeing is a wet on wet process, to limit the excess amount of liquid feeding into the dyeing system, it is always advisable to make up the stock vat as concentrated as possible.
During the preparation of the stock vat, there are certain points which need to be observed. First, the vatting temperature should be about 40-45ºC. Second, stirring is to be kept to the minimum, as unnecessary stirring will introduce oxygen into the stock vat and affect the stability of the reduced vat. Third, volume and concentration of the stock vat must be kept constant for every stock vat batch, for the constant volume and concentration will ensure a consistent replenishing amount.
A typical vatting procedure is as follows:
a) Make a mark on stock vat tank so that the volume is easily maintained by watching the level.
b) Add require amount of dye.
c) Add requires amount of NaOH, 50% liquid is preferred, as it generates lesser heat.
d) Add require amount of auxiliaries, chelating agent, wetting and dispersing agent. This is optional as both our paste and grain already have a certain amount of auxiliaries built in.
e) Add water to half the volume of stock vat. Stir for 5 min until the mass in the smooth slurry.
Dyes and Chemical:
Vat dyes (indigo)
Sulpher dyes (Black, Yellow, Green)
Caustic
Primasol
Triplex
Setamol
Hydeose
Sodium stone
Common salt
Sobitol
Rucowet
ASD
Peroxide
Acetic Acid
Starch
Size-ca
PVA
Wax
Etc
Dyeing Recipe:
2% shade for indigo (blue) dyeing
Scouring
Caustic soda : 5 g/l
Wetting agent : 5 g/l
Squesting agent : 2 g/l
Dyeing
Vat (indigo) : 2%
Reducing agent (Hydro) : 4%
Caustic : 90 g/l
wetting : .25%
Sizing: (for 650 Lts)
Starch : 75 kg
PVA : 20 kg
Size CA : 20 kg
Wax : 5 kg
water : 470 lts
Dyeing Recipe:
2% shade for Blue Black dyeing
Hard Bottoming
Sulphur Black : 45 g/l
Sodium Sulphide : 67.75 g/l
Caustic soda : 10 g/l
Wetting agent : 5 g/l
Squesting agent : 2 g/l
Dispersing agent : 3g/l
Dyeing
Vat (indigo) : 2%
Reducing agent (Hydro) : 4%
Caustic : 90 g/l
Wetting : .25%
Sizing: (for 650 Lts)
Starch : 75 kg
PVA : 20 kg
Size CA : 20 kg
Wax : 5 kg
Water : 470 lts
Dyeing Recipe:
Sulphur Black dyeing
Hard Bottoming
Caustic soda : 40 g/l
Wetting agent : 5 g/l
Squesting agent : 2 g/l
Dyeing
Sulphur Black : 7%
Sodium Sulphide : 10.5%
Caustic soda : 20 g/l
Wetting agent : 5 g/l
Squesting agent : 3 g/l
Dispersing agent : 2g/l
Sizing: (for 650 Lts)
Starch : 75 kg
PVA : 20 kg
Size CA : 20 kg
Wax : 5 kg
Water : 470 lts
Sizing
Natural Indigo Dyeing Machine -Sizing is a process where sizing is done to prepare the warp to with stand the weaving operation by binding together the fabric in the yarn to increase its strength by covering yarn with a thin film of size when binds the protruding fibre obtain smooth surface
To improve abrasion resistance of the yarn
To reduce hairiness of yarn to obtain smooth surface
To reduce generation of static charge for polyester blend yarn.
To improve breaking strength of cellulose yarn from Indigo Dyeing Machine
Written By – Farid Ahmed, General Manager, Knit Dyeing Textile Ltd. Epz, Savar, Dhaka
Rope Dyeing Machine forms an essential process in the denim plant. It works on the principle of the form of rope (from the ball warping m/c). In MIL, generally 32ropes are simultaneously fed to the rope dyeing machine through various guides and tensioning arrangement at the creel zone to introduce firstly into the scouring box. The level of this bath is controlled by a leveller which on lowering up to a certain level (manually present) along with liquid level opens a value for addition of the caustic liquor from the main tank. Then come the two wash boxes, hot wash box followed by the cold one.
The ropes now ready to dye enters the first dye bath. There are eight dye baths and number of them employed depends according to the type of dye to be done .The addition of dye liquor and other aux are carried out through different metering pumps like DYSTAR .The liquors circulated between the employed dyes baths to another circulated pumps, as they are inter connected .Formula use for estimating the feeding rate:
After coming out of the each dye box yarns are padded, the pressure being highest at the first and last dye box, which is 55psi and the intermediate 40-50psi.The ropes pass after padding around a no. of sky roller to provide adequate time of oxidation. After this the ropes passes through the five wash box, where hot wash, cold wash and neutralization is carried out.
Sometime softener treatment is also given in one of the wash box .The temperature of the entire wash box is controlled through the control panel by means of thermostat.
Capacity of the scouring /mercerization and wash box=1300 litres
Capacity of the dye box =2500 litres
There are three columns of the vertical drying cylinders range each having twelve cylinder following washing. Each column is providing with the steam trap .The temperature is control from the electronic control panel .The ropes are guided out of the m/c the respective guides ,delivery rollers and the guide pipes which coils the ropes in the large can .
The dimension of the can :height =64in &diameter =68in
The capacity of the can is about 22000 m rope
Colours Processed In Plant
Pure 100% indigo dyed
Midnight indigo
Deep blue
Light blue
Sulphur black
Material Flow In Rope Dyeing Machine
Ball/logs
↓
Creel
↓
Draw nip
↓
Scouring
↓
Washing -1
↓
Washing-2
↓
Dye boox-1
↓
Dye box-2
↓
Dye box-2
↓
Dye box-3
↓
Dye box-4
↓
Dye box-5
↓
Dye box-6
↓
Dye box-7
↓
Dye box -8
↓
Washing-1
↓
Washing -2
↓
Washing-3
↓
Softening
↓
Drying
↓
Coiler
↓
Can
Balls, Creel, Draw Nip:-There are 32 numbers of balls which are feeded continuously in the rope dyeing machine with the help of tensioner and draw nip.
Scouring Box:Scouring is done in scouring box with 4nip 4 dip passages .Then the yarn is passed through 2 wash boxes in which 1st is hot wash and 2nd is cold wash
Recipe For Scouring:-Caustic =1.5gpl
Dekol (wetting agent) =0.5gpl
Sandogen EH (mercerising agent) =0.5gpl
Temperature=90 c
Speed=23mpm
Capacity=1500lts
Washing Boxes:There are 2 washing boxes 1st is hot wash and 2nd is cold wash .The yarn is passed through 4-dip 4-nip sequence .capacity of first wash box is 1300 litres and of second wash box is 1400 litres.
Dye Boxes:There are 5 dye boxes used in which indigo dyeing is done .The dipping time is 24 sec. and oxidation time is 105 sec. Dye pickup is 70% and nip pressure is 0.5kgs per mt.
Drying:
There are 36 drying cylinders used for drying .drying is done with the help of dry steam which is fed in the steel cylinders .the temperature is maintained between 100-110.c
Long Chain Beaming
The dyed ropes in the cans coming from the rope dyeing machines are converted into pre beams. The no. of ends (around 360) in a rope is the same as set in ball warping machine.
The rope are withdrawn from the can by means of a pair of drawing rollers as it passes over a guide and through a trumpet guide to enter the nip of drawing rollers .After this it enters the tension stand, where it warps (usually 3) around the falling rollers on then passes with in a number of guides and around roller to enter the accumulator. The tension at the tension stand is kept between 20-40psi,depending on the count of the yarn .At the accumulator the tension is generally set 60-80psi and it is used to accumulate the length of rope that is reversed drying detection of any broken end .it works on the principle of gate type tensioning .one set tension .The path of yarn is somewhat different in the mill made machine .There is no accumulator & thus an extra person is employed to pull the rope ,while the beam is being reversed to maintain the desired tension .After coming out of the accumulator of the rope passes around the beater bar on the tension stand. The pressure roll presses of 7-15psi on the package i.e. the pre beam.
The denting is made easier with the help of lease threads, which separates the adjacent end in two levels .These lease threads are taken out of the shed before the end crosses the dent.
The yarn produced by mixing Polyester fibre and Cotton fibre with each other during yarn preparation process is known as polyester-cotton blended yarn. Generally, two types of polyester-cotton blended yarn are produced. These are :
65% Polyester + 35% Cotton = PC or TC
40% Polyester + 60% Cotton = CVC (Cheap Value Cotton)
1.2 Pre-treatment Process for Blended Fabric
Pre-treatment process for Polyester-Cotton blended fabric is similar to the 100% Cotton pre-treatment process. Refer to Specification No. 51-301 for detailed pre-treatment process.
1.3 Dyeing Process for Blended Fabric
Two types of dyeing methods are used to dye blended fabric. These are :
One-bath Dyeing Method
Two-bath Dyeing Method
1.3.1 One-bath Dyeing Method
One-bath dyeing method is a dyeing process whereby, polyester part and cotton part are dyed together in one bath.
1.3.2 Two-bath Dyeing Method
Two-bath dyeing method is a dyeing process whereby, polyester part and cotton part are dyed separately in separate bath.
2.0 Process Requirements
2.1 Equipment used
Three types of Thies machines are used for dyeing process. These are :
Mini-soft
Eco-soft
Luft-roto
2.2 Key Accessories
Key accessories used in dyeing process are :
Mixing tank
Machine Tank
Bohme meter
pH meter
Eye protecting glass
Hand gloves
Sewing machine
Hand lifter for carrying the batch, and
Gum boot.
2.3 Materials / Chemicals used
Following materials/chemicals are used in the dyeing with reactive dyes process :
Water
Steam
Compressed Air
Wetting agent
Detergent
Sequestering agent
Acid
Anti-creasing agent
Dispersing Agent
Gluber salt, and
Soda ash, etc.
3.0 Safety
In order to ensure floor and personnel safety, floor personnel are instructed to follow the safety guidelines given below :
Smoking is strictly prohibited in the factory premises.
Put on the safety masks while mixing or transferring alkali and acid.
During production, after reaching at the optimum temperature (above 800C), in case the lid of machine needs to be opened, operator must depressurise the machine and use hand gloves, eye-protecting glass etc. while performing such task for safety.
4.0 Operation Procedure
4.1 Operation Staff
Operation stuffs for Dyeing Process includes :
Manager
Assistant Manager
Production Executive
Production Executive
Operator
Helper
4.2 Machine Set-up
4.2.1 Machine Set-up for Eco-Soft & Mini-Soft Machine
Machine set-up for Poly-Cotton Blended Fabric Dyeing in Eco-Soft & Mini-Soft Machines are as follows :
Machine Group
Fabric Type
G.S.M.
J.P.(Mb)
R.S. (MPM)
ECO-SOFT
&
MINI-SOFT
Single Jersey
Up to 140
0500
200
140 ~ 180
0600
190
180 & Above
0800
180
Polo Pique
Up to 160
0600
200
Black Pique
160 ~ 200
0700
180
Popcorn
200 & Above
0900
180
.
4.2.2 Machine Set-up for Luft-Roto Machine
Machine set-up for Poly-Cotton Blended Fabric Dyeing in Luft-Roto Machine is as follows :
Machine Group
Fabric Type
G.S.M.
J.P.(Mb)
R.S. (MPM)
LUFT-ROTO
Single Jersey
Up to 140
0700
200
140 ~ 180
0800
200
180 & Above
1000
190
Polo Pique
Up to 160
0800
190
Black Pique
160 ~ 200
0900
190
Popcorn
200 & Above
1000
180
4.3 Checklist Before Operation
Following are the items to be checked before production :
Checking the programme in Beacon Controller
Machine set-up
Fabric weight
Fabric quality
Yarn quality
Collar design (Tipping / Solid)
Rib designs (Normal / Lycra)
Chemical availability
Power availability
Steam availability
Water availability
Compressed air
Manpower availability
Fabric stitch is done properly.
4.4 Operation Procedure
4.4.1 One-bath Dyeing Method
Steps of One-bath Dyeing Process
The sequence for one-bath dyeing process is as follows :
Add Electrolytic agent (G. Salt) and circulate for 5 minutes at 500C
Check pH and S. G. of the Dye bath
Add Dye solution by linear dosing and circulate the fabric for 15 minutes at 500C
Circulate the fabric and raise the temperature at 820C
Circulate the fabric for 25 minutes at 820C
Add Soda Ash solution by curve dosing and circulate the fabric for 30 ~ 50 minutes at 820C
Circulate the fabric and decrease the temperature at 600C
Check the shade with approved shade
Rinse and Drain
Add Acetic acid and circulate for 10 minutes at 700C
Drain
Add Soaping Chemical and circulate for 10 minutes at 950C
Drain
Circulate the fabric for 10 minutes at 700C
Drain
Unload
4.5 Product Quality Check
To check the quality of production, following measures are taken :
Check the pH of the bath.
Absorbency of the fabric.
Hardness of the water.
Iron / Impurities contamination of the water.
Heating and Cooling system of the machine.
Check the shade with customer approved shade.
Check the specific gravity of the bath.
4.6 Q.C. Sample Tests
Not applicable.
4.7 Response to Equipment Faults
Following are the response to be taken in case of equipment fault of dyeing machine :
Equipment Fault
Response
Pump Fault
Call Mechanical Maintenance.
Dosing Fault
Self / Call Mechanical / Electrical Maintenance.
Pump Leakage
Call Mechanical Maintenance.
Filling Problem
Call Mechanical / Electrical Maintenance.
Valve Leakage
Call Mechanical Maintenance.
Program Deleting
Call Electrical Maintenance.
Pressure Fluctuation
Self / Call Mechanical / Electrical Maintenance.
Motor Fault
Call Mechanical Maintenance.
4.8 Machine /Area Cleaning
The daily cleaning for machines are described below :
Clean chemical chambers by water flow.
Clean the floor by water flow.
Machine Oiling by oil or greases done by the Mechanical Maintenance Department.
The Maintenance Department performs the preventive maintenance task as per the PM schedule. Refer to Maintenance Specification for details.
5.0 Applicable Forms & Documents
Document Flow
Document flow for the poly-cotton blend fabric dyeing process can be enumerated as below :
Dyeing Department receives the Process Batch Card (F21-101-1) along with the Job Card (F21-101-2) attached to it from the Batch Preparation Section. Process Batch Card is used for fabrics while Job card is used for Collars & Cuffs.
Different specifications (e.g. Lab dip approval #, Fabric weight and quality, Collar quality, shade, etc.) mentioned in the Batch card and Job Card are checked.
Based on the shade and other specification plans for the machines are prepared.
Print-out of the recipe is taken from the DATA-COLOUR computer. The Recipe Card (F51-301-1) is used as an internal document to keep record of dyeing for a particular batch.
Availability of chemicals and dyestuff is checked and program is put in the Becon Controller.
The Shade Batch Card (F51-301-2) is used to keep track of the dyeing production continuity. Production Officer fills out different areas of the form. This is an internal document of the dyeing department.
The Operator fills out the Production Report (R51-301-1) and it is sent to the Planning department. This report contains information like the Quantity produced, Machine wise production, Amount of re-process, Machine utility percentage (%) and shift wise production.
Upon completion of dyeing for a particular batch, if the dyeing is ‘OK’, the Process Batch Card is stamped as “SHADE APPROVED TO FINISH” in Green, on the other hand, if dyeing is ‘NOT OK’, the card is marked as “SHADE APPROVED TO DRY ONLY” in Red. This Process Card is then sent to the Finishing Department.
Drying is defined as a process where the liquid portion of the solution is evaporated from the fabric. Curing- Curing is a repetitive drying process to cure the cross-linking agent. The operator fixes the expreader as per the required width of the fabric, then sets the temperature, machine speed and over feed (depends on construction of fabric and shades) and then he feeds the fabric to machine for production.
Process Requirements
Equipment used
Following equipment are used for drying process
Ruckh Relax Dryer (Germany)
Computerised Operating Panel
Key Accessories
Following key accessories are used for drying process:
Measuring Tape
Di-Cutter (for yield checking)
Electronic Balance
Expreader
Scissors, and
Materials / Chemicals Used
Safety ofRelax Dryer Machine
Following Do’s and Don’ts are to be followed during operation :
Do not wear loose dress that may entangle with the machine parts while running.
Do not touch the overfeed roller during running the machine.
Be careful about the guiding wheel of expreader during machine operation.
Do not open the chamber doors while running the gas burner and blower.
Wear rubber gloves and facemask while cleaning the screen filter and machine.
Be careful in handling the trolley of fabrics.
Be aware of the first aid treatment procedure.
Operation Procedure ofRelax Dryer Machine
Operation Staff
Operation staffs of Finishing Process includes:
Manager
Textile Technologist / Production Executive
Production Co-ordinator
Operator
Assistant Operator
Helper
Relax Dryer Machine Set-up
Machine set up for the Relax Dryer is as follows:
Machine Parameters
Set-up Value
Temperature Setting
Machine
Blower Fan Setting
Auto
Exhaust Fan Setting
Auto
Machine Speed
3-35 m/m : Depends on the quality of fabric.
Over Feed
0-40 % : Depends on the fabric’s construction.
Width of Expreader Setting
45-114 cm Depends on the required width of fabrics.
Burner Gas Pressure
10-15 M/Bar
Checklist Before Operation
Operator must check the following items before drying or curing the fabric in the relax dryer machine:
Machine parameters are set.
Required manpower is available for production.
Fabric for feed side is ready.
Expreader is guided up ( when needed), and
An empty trolley is ready at delivery side.
Product Quality Check
Shade Check: In delivery side operator checks the shades with the customer approved swatch with the help of Q.C. Inspector. If any deviation is found, he informs the responsible shift officer who takes the necessary action to overcome the problem.
Width Check: Operator measures fabric width by using a measuring tape and compare with the required width which is mentioned in the batch card and verify that required width with the shift officer.
Weight Check: Operator checks the weight by using the GSM cutter and electronics balance and compares with the required finished weight which mentioned in the batch card and then verify that weight with the shift officer.
Compaction Check: Operator checks the compaction (length and width) by using a compaction scale and informs to shift officers.
Fault Check: The operator checks for the knitting fault (e.g. double yarn, missing yarn, yarn contamination etc.), spinning faults (i.e. Barre mark, hairiness, neps etc.), dyeing faults (i.e. Dye stain, shade variation, patches, uneven etc.), and other faults (e.g. Rub mark, dust, etc.) during drying the fabric and are not recorded on the Batch Card, following necessary action to be taken to overcome such problems:
Check the feed side fabric to make sure that these faults did not occur from the previous process.
Stop the machine to identify whether these faults are occurring due to machine fault or the faults are due to the nature of dyes.
Fabric Bow and Slant Check: At the delivery side, the operator checks the bow and slant of fabric. If any abnormality is found, he adjusts the overfeed and speed of expreaders guide wheel.
Q.C. Sample Tests
One-meter sample fabric is cut from each batch (after drying) and sent to the Quality Control Department to check the shade finally as well as other parameters, which is required by the customer. Refer to Off Line Quality Control Tests Specification (Document No. 81-101) for details.
Response to Equipment Faults
Following are the response to be taken in case of equipment fault of Relax Drying machine:
Machine Faults
Response
Teflon Problem
Mechanical Engineer should be called
Expreader Problem
Mechanical Engineer should be called
Plaiter Problem
Mechanical Engineer should be called
Speed, Temperature Problem
Electrical Engineer should be called
Conveyer Problem
Mechanical Engineer should be called
Gas Pressure Problem
Mechanical/Electrical Engineer should be called
Flame Disturbance
Mechanical/Electrical Engineer should be called
Burner Problem
Electrical Engineer should be called
Machine /Area Cleaning
The daily and weekly cleaning works for Relax Dryer Machine are described below :
Clean the sieves that can be reached from the outside of the machine at least once per shift
Clean all the screen filter in every shift.
Clean the trolley properly before using that in delivery side.
Clean the air ducts at least once a week.
Clean all the upper filters at least once a week.
The Maintenance Department performs the preventive maintenance task as per the PM schedule. Refer to Maintenance Specification for details.
Applicable Forms & Documents
Forms & Documents Used
The necessary forms & documents for Relax Dryer process are listed below :
Process Batch Card
Machine Downtime Report
Production Register of Relax Dryer Machine
Document Flow
The document flow of Finishing Process is as follows:
Operator fills out the Batch Card and the concerned officer put his signature on it upon verification. The Batch Card moves with the fabric for the next step of finishing process(e.g. Tubular Compactor, De-water, Drying or Slitting).
Machine Downtime Report is maintained to keep record of any stoppage in production due to machine break down or any other reason. Operator fills this and the responsible officer sign on it upon verification
Production Register of Relax Dryer Machine is used to keep records of date wise production details. Operator fills this out along with his remarks (if any) and this report is recorded for future reference.Attachments
Examples of all applicable forms and documents are attached.
Drying process of Vertical Dryer Vent is defined as the step where the liquid portion of the solution is evaporated from the fabric. In this machine, the tubular fabric is passed through the heated vertical perforated tube and thus gets dried.
Process Requirements
Equipment used
Following equipment is used for drying process:
Steam Heated Vertical Dryer (Bangladesh).
Key Accessories
Following key accessories are used for Vertical dryer:
Scissors,
Sewing machine,
Trolley for loading and unloading, etc.
Materials / Chemicals Used
Not applicable.
Safety of Vertical Dryer Vent
Following Do’s and Don’ts are to be followed during operation:
Do not wear loose dress that may entangle with the machine parts while running.
Always wear rubber shoes.
Be careful in handling the trolley of fabrics.
Be aware of the first aid treatment procedure.
Operation Procedure of Vertical Dryer
Operation Staff
Operation staffs of Finishing Process includes:
Manager
Textile Technologist / Production Executive
Production Co-ordinator
Operator
Assistant Operator
Checklist Before Operation
Operator must check the following items before drying the fabric in the Vertical Dryer machine:
Tubes are properly heated up
Required manpower is available for production
An empty trolley is set for unloading
Sewing machine with thread is available
Feed side fabric is ready
Operation Procedure
Operation procedure for Vertical dryer vent is as follows:
Open the steam valve to heat up the vertical tube/nozzle.
Switch on the blower motor.
When it is heated up, load the fabric through the nozzle/tube, and start loading motor (fabric goes down to the nozzles).
After completing two rolls, cut the fabric and make a knot at the end of the roll, which helps to make the tubular fabric in ballooning form.
After few minutes unload the fabric by passing the fabric in unloading roller to plaiter and start the unloading motor.
Product Quality Check
Design Check : Operator checks the design of fabric in delivery side and matches with the required design, which is written in the batch card.
Fault Check :The operator checks the knitting fault (i.e. Double yarn, missing yarn, yarn contamination etc) spinning faults (i.e. Thick & thin yarn, barre-mark etc) and other faults (i.e. Dye stain, band mark, chemical stain, torn & hole, shade variation etc) during the process.
When minor faults occur within 2-3 rolls which is not resulted from previous process and also not recorded on the batch card, the necessary actions to be taken are as follows:
Check the feed side fabric to make sure that these faults did not occur from the previous process.
Stop the machine to identify the cause or the place where from these faults are occurring.
Q.C. Sample Tests
Not applicable.
Response to Equipment Faults
Following are the response to be taken in case of equipment fault of vertical drying machine:
Machine Faults
Response
Forwards/reverse Problem roller system is not working
Electrical & Mechanical Engineer should be called
Speed control Problem
Electrical & Mechanical Engineer should be called
Plaiter Problem
Electrical & Mechanical Engineer should be called
Steam line Problem
Mechanical Engineer should be called
Machine /Area Cleaning
The daily and weekly cleaning works for Vertical Dryer Machine are described below:
Clean the sieves that can be reached from the outside of the machine at least once per shift
Clean all the perforated holes of each tube properly after each batch.
Clean all the rollers properly after each batch.
The Maintenance Department performs the preventive maintenance task as per the PM schedule. Refer to Maintenance Specification for details.
Applicable Forms & Documents
Forms & Documents Used
The necessary forms & documents for drying process are listed below:
Process Batch Card
Machine Downtime
Production Register of Vertical Dryer Machine
Document Flow
The document flow of Finishing Process is as follows:
Operator fills out the Batch Card and the concerned officer put his signature on it upon verification. The Batch Card moves with the fabric for the next step of finishing process(e.g. Tubular Compactor, De-water, Drying or Slitting).
Machine Downtime Report is maintained to keep record of any stoppage in production due to machine break down or any other reason. Operator fills this and the responsible officer sign on it upon verification
Production Register of Vertical Dryer Machine is used to keep records of date wise production details. Operator fills this out along with his remarks (if any) and this report is recorded for future reference.
Attachments
Examples of all applicable forms and documents are attached.
The Dryer Box is a machine, which is used to dry the collar & cuffs. This drying function can be defined as a process in which the collars are equally hung in improvise carrier and let be heated by circulation of air in a Box chamber.
Process Requirements of Dryer Box
Equipment used
Following equipment are used for drying process:
Four trolley (specially design)
One rolling rod to roll the collar & cuffs (after dry)
Following Do’s and Don’ts are to be followed during operation:
Do not wear loose dress that may entangle with the machine parts while running.
Always wear rubber shoes.
Be aware of the first aid treatment procedure.
Don’t touch the electrical wire.
Always wear hand gloves (during operation)
Dryer Box Operation Procedure
Operation Staff
Operation stuffs of Finishing Process includes :
Manager
Textile Technologist / Production Executive
Production Co-ordinator
Operator
Assistant Operator
Dryer Box Installation Process
The Dryer Box Installation Process as follows :
Machine Parameters
Set-up Value
Temperature Setting
(100-120)0C for White Shade
(120-130)0C for Light Shade
(130-140)0C for Dark Shade
(150-170)0C for Curing
Machine Time/Speed
Auto
Exhaust Fan Setting
Auto
Checklist Before Operation
Before drying the Collars and Cuffs in the Dryer Box the Operator must perform the following items:
Heat up the machine before loading collars & cuffs
Check the exhaust & fresh air devices if working properly.
Check the steam valve for open position.
Set the trolleys’ protection screen firmly.
Check the machine doors whether they are properly locked or not.
Check the graphical device if working properly.
Operation Procedure
At first, hang the collars & cuffs by passing in a series of mini-roller arrangement. If all available rollers of trolley are filled up then load the trolley in the machine. Set the temperature by using the temperature regulator noting the required temperature in the program. Switch on the blower for circulation of hot air inside the machine. Hot air will circulate inside the machine and the evaporated water will be taken out by the exhaust opening (ensure that the exhaust ducting are properly opened). After the set running time is elapsed, attend the alarm and carefully open the machine door and check the dryness. The time and temperature setting can be increased if needed. When the loaded collars/cuffs are fully dry, they are unloaded by rolling it in specially designed roller and allow it for cooling, while the next load are being prepared.
Product Quality Check
Randomly check the product quality with the specification to ensure that the machine is not causing any defect.
Q.C. Sample Tests
After drying the collars & cuffs in Dryer Box, give two pieces of collars/cuffs of a batch to QC Lab to check the shade with body fabric.
Response to Equipment Faults
Following are the response to be taken in case of equipment fault of Dryer Box machine:
Machine Faults
Response
Machine not running
Electrical Engineer should be called
Temperature Display problem
Electrical Engineer should be called
Machine Stoppage Alarm Problem
Electrical Engineer should be called
Steam line problem
Mechanical Engineer should be called
Lower Motor problem
Electrical Engineer should be called
Exhaust & Fresh air device problem
Mechanical Engineer should be called
Hanging Trolley Problem
Mechanical Engineer should be called
Machine /Area Cleaning
The daily and weekly cleaning works for Dryer Box Machine are described below:
Clean the inside portion the machine daily
Clean the exhaust & fresh air devices daily
Clean the safety net daily that covers the blower fan (it is placed inside the machine).
Clean outer surface of the machine daily.
The Maintenance Department performs the preventive maintenance task as per the PM schedule. Refer to Maintenance Specification (Document No. 31-101) for details.
Applicable Forms & Documents
Forms & Documents Used
The necessary forms & documents for Dryer Box process are listed below :
Process Batch Card
Machine Downtime Report
Production Register of Dryer Box Machine
Document Flow
The document flow of Finishing Process is as follows :
Operator fills out the Batch Card and the concerned officer put his signature on it upon verification. The Batch Card moves with the fabric for the next step of finishing process (e.g. Tubular Compactor, De-water, Drying or Slitting).
Machine Downtime Report is maintained to keep record of any stoppage in production due to machine break down or any other reason. Operator fills this and the responsible officer sign on it upon verification
Production Register of Dryer Box Machine is used to keep records of date wise production details. Operator fills this out along with his remarks (if any) and this report is recorded for future reference.
Attachments
Examples of all applicable forms and documents are attached for
Know more about The Dryer Box Installation Process
