Singeing machine is the process passed out for removing loose hairy fiber protruding from the surface of the cloth there by giving it a clean looking surface. If the fabric is to have a smooth finish than singeing is essential. Singeing and desizing is a dry process used on woven goods that removes the fibers protruding from yarns or fabrics.
These are burned off by passing the fibers over a flame or heated copper plates. Singeing and desizing improves the surface appearance of woven goods and reduces pilling. It is really useful for fabrics that are to be printed or where a smooth finish is desired. Pollutant outputs associated with singeing include relatively small amounts of exhaust gases from the burners.
Objective of Singeing Machine
- To remove loose hairy fibers.
- To obtain a smooth Surface.
- In order to impart a clearly defined & sharp design.
- To prepare fabric for next process.
The process to remove the size material applied in weaving section and increase the absorbency power of the fabric is called desizing.
- Gas singeing machine:
- Name: Osthoff-(Senge-Desize m/c)
- 42327 wuppertal
- Origin: Germany
Machine description with process
Fabric inlet section: Gray fabrics are directly feed into the inlet of singeing machine. Where the fabric is passed over some free roller, guider & expander to ensure open width entry. Here there is a control panel to control fabric speed.
Cleaning unit 1: Through fabric inlet then fabric is passed through cleaning unit which contain a brush as well as provide a vibrating motion for effective cleaning. From this unit dust are collected through duct in which suction is occurred by a high power motor. Big dusts are collected in dustbin and inferior particles are released in environment.
Singeing unit: After passing cleaning unit then fabric comes into contact of flame for singeing. Fabric is passed over the water roller & in water roller flame is attacked tangentially or horizontally depending on fabric type & quality required.
Cleaning unit 2: when singeing is occurred, the fabric contains few flame sparks on its surface & selvedge. Those are removed by cleaning unit & the dusts are passed through water because they contain fire spark. The inferior particles are moved away through duct in environment.
J Box: if fabric is feed as roll form then two j box is required one after inlet & another before cleaning unit. In continuous process j box is required for the continuity of fabric processing without machine stoppage which saves time.
Desizing unit: finally the fabric is passed through desizing unit. Its contain desizing liquor. For desizing wetting agent, Enzyme, sequestering agent, acetic acid is required. Temperature is maintained around 80-100’C.
Chemical mixing unit: Beside desizing unit there are two chemical tank one of them is called reserve tank where chemical is mixed & circulated, another is storage tank where agitated chemicals are stored for using in bath. From this chemical entered in bath as required for even immersion.
Batching unit: After desizing fabric is collected in rolled in batcher in uniform tension. Then the fabric goes for rotation of 10-12 hours. For proper decompose of starch it is essential.
Rotation: After batching the fabric is packed by poly bag. Then it goes for rotation for 8 to 12 hours. In this time water react with starch in presence of enzyme & decomposestarch as water soluble glucose.
A typical Recipe for Desizing
Solid dyed fabric desize Recipe-
- Wetting agent: Rucolase F.W.K– 7 gm/lt
- Enzyme: Rucolase H.C.H – 8 gm/lt
iii. Dearting agent: Rucowet V.L-1g/lt
- Sequestering agent: Verolaw N.B.O – 1 gm/lt
- Acetic acid – as required to maintain pH
Yarn dyed fabric desize Recipe-
- Wetting agent: Rucolase F.W.K – 5 gm/lt
- Enzyme: Rucolase H.C.H – 5 gm/lt
- Enzyme: Enzyme can make soluble the sizing chemical in H2O.
- Wetting agent: it is used to increase the wettability of textile substrate and dye-stuff in water to easy penetration and obtain smooth paste. i.e. T.R oil.
- Sequestering agent: It is used to minimize the impact of hardness of the water. i.e EDTA.
- Dearating agent: It is used as antifoaming agent and increase the penetration of wetting agent.
Note: – In woven fabric processing Gas singeing machine is widely used. -The singeing is not applied above 45 count of fabric.
Material and Chemical used
Steam, compressed air, water, natural gas, Desizing agent, wetting agent, sequestering agent and dearating. Sizing Machine also work similar process.
Check list before production
Operator must check the following before starting production of the fabric named bellow:
- All cotton colored fabric = Singing & Desizing.
- All cotton colored peach finish fabric = Desizing.
- Yarn dyed & P.C/C.V.C fabric = Singing & Desizing.
- P.C/C.V.C fabric = Singing & Cold bleach.
- P.C/C.V.C / yarn dyed peach finish fabric = Desizing.
- Bull-Twill / Heavy fabric = Singing & Cold bleach.
- White cotton fabric & Special yarn dyed (PC-015) fabric = Singing (Without Chemical)
Basic parameter of m/c
- Fabric Speed: 80m/min
But normally 65-70m/min
- Flame intensity:
For fine fabric= 10-11 mbar
For coarse fabric= 16-17 mbar
For pocketing fabric= 6-7 mbar
Some condition for Flame intensity
GLM: 410-570= 18 mbar
GLM:300-400= 16 mbar
GLM: 100-132= (8-10)
Note: When tension is increased flame intensity is also increased . Otherwise flame intensity is decreased with low tension.
- Pick up %:
For coarse fabric mainly taken-100%
For fine fabric mainly taken-80%
- Temperature: Bath – 50’c
- Cold bleach:cold bleach is done at room temperature.
- Chamber temperature: 85-100’c
- Desizing temp- 80-100’C
Flow chart of Singeing & Desizing
Cleaning unit 1
Cleaning unit 2
Here also has,
- Compensation roller: If compensation rollers down fabrics move and if compensation roller up fabrics fixed.
- Bow roller: which is moved ups to downs.
- Padded: only squeeze is done.
- Free rolle
- Bend pipe: Shrink will not occur
- Padded Pressure: Maintain tension.
- Sochor roller
The total amount of chemicals which are absorbed by fabrics.
It is the ratio weight (wet fabric to dry fabric) to dry fabric and expressed in percentage.
Wet fabric – Dry fabric
Pick up% = × 100%
Procedure of Singeing Machine and Desizing Machine
- pick up% is measured from left, centre, right.
- At first 3 sample are cut from the above of padder pressure or after squeeze roller.
- Then the samples are packed in polybags with vapour
- We will have to take the weight of polybag frome left, centre and right side.
- Then we take the weight the fabrics with poly
- By removing the value of 2nd to 1st value , we get the value of /weight of wet fabrics
- Then the samples are washed by 1-2% CH3COOH and water
- To dry these, we will have to give samples in the oven. i.e Rapid (Labortex Ltd)
- After drying these, we will have to do conditioning for better result.
- Then we will have to calculate the value of dry fabric weight.
Pick% = (polyethylene+ fabric weight) – polyethylene weight
=Wet fabric weight – dry fabric weigh
= result/ dry fabric weight * 100%
But we will have to ensure that every side can absorb equal amount of chemical.
The amount of times which are fabrics take in passing the desizing chamber can be calculate as-
By dissolving test:Here 1’’ grey cloth with square cross section (□) will have to take in a 500ml pot. Then we will have to take the times which the fabric takes to dissolve in this solution.
Clip test: Here a clip is used to measure the times which the fabrics take in desizing chamber. In this process we will have to pass the clip from pressing roller to padder cylinder and have ti calculate the passing time of clip by stop watch.
Problem of Singeing Machine and Desizing Machine
During operation there are several problem occurred such as:
- Sometime fire comes out unevenly due to breaking of burner surface. This can make uneven singeing.
- Problem in bearing of roller. This is the most common problem.
- High temperature in singeing machine section that occurred when even cold water is not flowed. When temperature is so high machine stopped automatically.
Dr. Joshep, DGM, Textile Division, Seotex Limited, USA