Process: WI-DYEING Author: A
Document type: WI-Work Instruction Reviewer: B
Title: DYEING MACHINE OPERATION Approver: C
PURPOSE
1.0 PURPOSE
This document describes the processes of dyeing machines operation with fabric to ensure high Right First Time and machine Utilisation with utmost efficiency as well as ensure required safety measures.
2.0 SCOPE
The scope of this WI covers the operations includes pre-treatment & Dyeing of the fabric into the dye vessel and is managed by;
Shift Executive.
Shift Supervisor.
Senior Machine Operator.
Machine Operator.
3.0 APPLICABLE REFERENCE/DOCUMENTS
3.1 Batch Processing Card
Batch processing Card is used to record all batch details, customer, EKL #, construction and operational actions
3.2 Batch Recipe
A list of pre-determined dyes and chemicals used to precise weights to achieve a specific colour.
3.3
WI-EPY-PRD-006 Recipe Sheet Preparation.
The process of developing a recipe using colour, fabric weight, origin of fabric, machine name/number
3.4
WI-EPY-DYG-005 Dye & Chemical Distribution.
A process of preparation and distribution of chemicals prior to the demand from the machine.
3.5
WI-EPY-DYG-007 Dyeing Machine Operation
Operate the machine according to the company best practice process to ensure high colour quality and Right First Time.
3.6
WI-EPY-DYG-008 Addition or Topping.
The process required for improving colour or fabric quality by adjusting the treatment process to compensate for the drop in quality.
3.7
WI-EPY-DYG-009 Colour Assessment.
A visual or digital assessment carried out against a physical standard to determine the colour variation.
3.8
WI-EPY-DYG-010 Unloading Machine.
The process to efficiently unload the machine to maximise machine operational hours.
4.0
APPLICABLE SAFETY PRECAUTIONS& DOCUMENTATION
Personal Protection Equipment
Worn at all times whilst working in the Chemical Store
4.1
Footwear Protection
Worn to eliminate continued wet feet, eliminate chemical burns and eliminate slippage on wet floors.
4.2
No Smoking
Smoking is not permitted on the production floor or offices.
4.3
Eye Protection
Used to eliminate corrosive burns from chemicals.
4.4
Hand Protection
Used to eliminate corrosive burns from chemicals and to improve grip of chemical containers.
1.0
5.0 EMPLOYEE QUALIFICATIONS
5.1 The Machine Operator must be literate and have achieved SS2 grade.
5.2
The Machine Operator is to receive 4 weeks formalised training before being released to operate the machine unsupervised.
6.0 EQUIPMENT USED / APPROVED MATERIALS
6.1 High Pressure Fabric Dyeing Machine.
6.2 Atmospheric Fabric Dyeing Machine
6.3 JET Fabric Dyeing Machine.
6.4 PH PAPER
Indicate the PH of any specific process.
6.5
RESIDUAL PEROXIDE TESTER
Indication of residual peroxide after pre-treatment.
7.0 RESPONSIBILITIES
Position Responsibility
Shift Executive Provide recipe and nominate program to be followed
Shift Supervisor Ensure proper execution of process as well as maintain safety measures
Senior Machine Operator Assist in faster execution of machine operation
Machine Operator Execute machine operation as per WI
8.0 PROCEDURE
8.1
Following the production plan the machine operator first checks the recipe, the batch card for the same batch number as the production plan. If they are incorrect the Operator will speak with the Supervisor to identify the problem and locate the correct batch/fabric/recipe.
8.2
The Machine operator will check to ensure the chemicals are available before beginning the machine loading routine.
8.3
Once the information is confirmed as correct the operator first checks the machine for any operational issues such as stains, contamination (inside the machine) or leaks.
8.3
Machine Controller
The controller is used to run the dye vessel and requires the machine operator to enter the batch details such as water volume, Liquor Ratio, Pump pressure, winch speeds etc.
8.4
Once the review has been completed the operator will select the machine program for required desired process. The commonly required process are as below:
8.4.1 Semi-bleach (for pre-treatment)
8.4.2 Full Bleach (for white)
8.4.3 All in Method (Reactive Dyeing)
8.4.4 Cool Down Method (Reactive Dyeing)
8.4.5 Disperse Dyeing Method
8.5
In the machine monitor operator will add the following data;
The volume of water required to maintain a 1:5 or 1:8 Liquor Ratio (L;R).
Length of fabric as taken from the batch card.
The carry over.
The Winch Speed.
The Pump Pressure.
Set the winch speed at a level to maintain cycle time below/equal to 3 min.
8.6
With all the data entered the operator will select the required process program and then dose the first chemicals required (as per the recipe) into the stock tank. This is either used from manual process (WI-EPY-DYG-001) or can be from the ColorSystem chemical delivery system (WI-EPY-DYG-003).
8.7
The water is then fed into the machine to top the volume of the water to maintain the required L:R.
8.8
The machine will run by start button.
8.8.2
The operator will then turn the pump on to assist the feeding of the fabric through the nozzle.
8.8.3
When the rope is tied onto the fabric the operator will feed the rope/fabric over the winch and through the nozzle.
8.9. Semi-Bleach process
8.9.1 Bleaching Process
The steps for Bleaching Process are as follows:
Take water in bath at required level
Load fabric in the machine
Add Detergent, Sequestering Agent, Anti-Creasing Agent, Stabilizer
Add Caustic Soda Solution
Circulate the fabric and raise the temperature at 600C
Add Hydrogen per Oxide Solution
Continue circulating the fabric for 5 minutes and raise the temperature at 980C
Continue circulate the fabric for 45 minutes at constant temperature (980C)
Continue circulating the fabric and decrease the temperature at 800C
Rinse and Drain
Add Acetic acid, Hydrogen per Oxide Killer and raise the temperature at 550C
Continue circulating the fabric for 10 minutes at constant temperature (550C)
Rinse and Drain
Add Detergent and raise the temperature at 800C
Continue circulating the fabric for 10 minutes at constant temperature (800C)
Rinse and Drain
8.9.2 Semi-Bleaching Process Recipe:
The recipes for Scouring & Bleaching process are given below:
The Semi-Bleaching Process can be graphically represented as follows:
Enzyme Treatment:
The main objective of enzyme treatment is to obtain clearer fabric surface by removing protruding fibre from fabric surface.
Here we use two type of Enzyme:
1. Neutral Enzyme: To obtain moderate enzyme effect upon treated fabric. It is done in neutral condition.
2. Acid Enzyme: Applied when more clean fabric surface is required. Here required PH level to be maintained is 4.5-5.0
Enzyme is normally done at a temperature at 550C for 60 minute.
After any enzyme treatment a hot treatment must be maintained to deactivate enzyme function by raising the bath temperature at 800C for 10 minute.
8.10 Reactive Dyeing Process:
8.10.1 Reactive Dye-Stuff
Reactive groups are present in the molecules of the reactive dyes. These dyes chemically react with fibres hence it is called The Reactive Dyes. These type of dyes posses reactive groups which during the process of dyeing, reacts chemically with the fibre substrate to form a covalent bond so that chemically speaking it becomes a part of the fibre itself.
The reaction is as follows:
D-F-CH = CH2 + Cell-OH D-F-CH2-CH2-O-Cell
8.10.2 Properties of Reactive Dyes
The properties of reactive dyes are as follows:
Anionic in nature
Soluble in water
It forms strong covalent bond with fibre
Their wet fastness and light fastness are good
They have better substantivity
They are used in alkaline condition
8.10.3 Influencing Factors for Dyeing
During dyeing with reactive dyes, following important factors are to be considered:
The pH of the bath
The temperature of bath
The concentration of the electrolyte
The time of dyeing
The liquor ratio
Program followed:
1. All in method (for Extra Dark)
2. Cool Down Method
Steps of Reactive Dyeing Process with All in Method Program
The sequence for dyeing process with All in Method is as follows:
Take water in bath at required level
Load fabric in the machine
Add Detergent, Sequestering Agent, Anti-creasing Agent
Check pH of the Dye bath
Circulate the fabric for 5 minutes at 600C
Add Electrolytic agent (G. Salt) and circulate for 5 minutes at 600C
Add Dye solution by linear dosing and circulate the fabric for 20 minutes at 600C
Add Soda Ash solution by curve dosing and circulate the fabric for 45 minutes at 600C
Continue circulating the fabric for 30 50 minutes at constant temperature (600C)
Check the shade with approved shade
Rinse and Drain
Add Acetic acid and circulate for 10 minutes at 500C
Drain
Add Soaping Chemical and circulate for 10 minutes at 950C
Drain
Circulate the fabric for 10 minutes at 500C
Drain
Unload
Graphical Representation (All in method)
The sequence for dyeing process with Cool Down Method is as follows:
Take water in bath at required level
Load fabric in the machine
Add Detergent, Sequestering Agent, Anti-creasing Agent
Circulate the fabric for 5 minutes at 600C
Check pH of the Dye bath
Add Dye solution by linear dosing and circulate the fabric for 20 minutes at 600C
Add Electrolytic agent (G. Salt) and circulate for 10 minutes at 600C
Raise temperature 800C and circulate for 15 min
Cool temp at 600C 10 min
Add Soda Ash solution by curve (Progressive) dosing and circulate the fabric for 45 minutes at 600C
Continue circulating the fabric for 30 60 minutes at constant temperature (600C)
Check the shade with approved shade
Rinse and Drain
Add Acetic acid and circulate for 10 minutes at 500C
Drain
Add Soaping Chemical and circulate for 10 minutes at 950C
Drain
Circulate the fabric for 10 minutes at 500C
Drain
Unload
Graphical Representation (Cool down method)
The sequence for dyeing process with Disperse dyes is as follows:
Take water in bath at required level
Add Detergent, Sequestering Agent, Anti-creasing Agent, Dispersing Agent
Circulate the fabric for 5 minutes at 500C
Add Acetic acid and circulate for 5 minutes at 500C
Check pH of the Dye bath
Add Dye solution by linear dosing and circulate the fabric for 10 minutes at 500C
Circulate the fabric and raise the temperature at 1300C (1.50C/min after 800C)
Continue circulating the fabric for 30 40 minutes at constant temperature (1300C)
Circulate the fabric and decrease the temperature at 800C
Check the shade with approved shade
Rinse and Drain
Add Caustic Soda and circulate for 3 minutes at 500C
Add Hydrose and raise the temperature at 800C
Continue circulating the fabric for 15 minutes at constant temperature (800C)
Drain
Add Acetic acid and circulate for 10 minutes at 600C
Drain
Graphical Representation (Disperse Dyeing)
Steps of Whitening Process for 100% Cotton
The sequence for whitening process for 100% cotton fabric is as follows:
Take water in bath at required level
Add Detergent, Sequestering Agent, Anti-creasing Agent, Stabilizer
Circulate the fabric for 5 minutes at 500C
Add Caustic Soda and circulate for 5 minutes at 500C
Add Hydrogen per Oxide and circulate for 5 minutes at 500C
Add Optical Brightener agent and raise the temperature at 1000C
Continue circulating the fabric for 50 minutes at constant temperature (1000C)
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 500C
Drain
Unload
Graphical Representation (Whitening process)
9.0 TERMS AND ACRONYMS
Acronym Term
Batch Card A physical card generated to record full batch details from customer name, Fabric and construction.
Recipe A piece of computer generated (excel/auto) printed copy of required dyes and chemicals as well as all information regarding the Batch being processed e.g. fabric specification, L:R, fabric weight etc.
Cycle time The amount of time required for one complete rotation of fabric rope in a machine nozzle.
All in Method A specific type of dyeing program which maintain isothermal process during dyeing operation
Cool down Represents migration of temperature at higher degree other than isothermal in dyeing operation
PH Important parameter need to be maintained to ensure good product quality with good reproducibility. Generally number ranging from 0-14, where 0-6 indicate acidic media, 7 is neutral and 8-14 is alkaline medium.
Semi-Bleaching Combined Scouring & Bleaching treatment upon greige fabric to attain fabric absorbency with required level of fabric whiteness prior Dyeing.
Wetting Agent Reduces the surface tension and impart wet ability of fabric at semi-bleaching.
Anti-crease Act as lubricating to reduce friction
Hydrogen Peroxide (H2O2) Bleaching agent
Stabilizer Stabilizes H2O2 at semi-bleaching to obtain better bleaching performance
Peroxide Killer Act to destroy residual peroxide after semi-bleaching
Detergent Act as wetting agent or wash off agent.
Sequesterent To deactivate metal ion as well as reduce hardness of water.
Electrolyte (SALT) Act exhausting agent
Enzyme Process involved with Biocatalyst to remove protruding fibre from fabric
Levelling Control dye bath
Alkali Act as dyes fixation at dyeing operation
OBA Act as optical Brightening agent.
Dispersing Agent For well dispersion of disperse dyes
Reduction Clean Highly alkaline treatment to remove unfixed dyes from fabric.
ISIONS
10.0 OUT OF CONTROL ACTION PLAN (OOCAP)
If the program is incorrect the operator will seek out the Supervisor on appropriate action.
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.
11.0 REVISIONS
Revision Date Author of Change What Alterations were Made
1 13/03/2016 A 1st Generation of WI.
Signature
Author: A
Reviewer B
Approver C
