Singeing Process in Textile Industry

In this article, we are going to learn about the singeing process and the machines used in this process. In particular, singeing is a must process before starting another process in the knit sector.

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Introduction

Singeing is a process by which projecting or floating fibers, that stand out on the surface of the fabric, are burned out.

Objectives of Singeing

1. Removing fibers projecting from the surface of the cloth and giving it a smoothened face.

2. To increase the luster in the finished fabric.

3. Preparing the fabric for the next processes.

Types of Singeing Machine

1. Plate singeing m/c.
2. Roller singeing m/c.

3. Gas/Flame singeing m/c.

Plate Singeing Machine

The main parts of the plate singeing m/c

1. Two copper plates
2. Fire clay

Description

Plate Singeing Process
© Textile Pad

Copper plates are set up on a fire clay, which is heated with Furness (gas and oil or oil jet). When the plates become red hot in Furness, the fabric is drawn through a draw roller whose speed is 135.225 m/min. Projecting fibers are burned in contact with a heated plate. In this process, one side of the fabric is singed.

Advantages

• Very suitable for the back filter in the finishing process.
• A certain amount of luster is produced due to friction between the fabric and the hot surface of the curved plate.
• Improves luster.
• Uniform singeing.
• More effective in the case of velvet and pile fabric.

Disadvantages

• It is very difficult to maintain the proper heat control of the plate.
• Only one side of the fabric is singed.
• It is a discontinuous process, so more time is taken.
• Higher labor costs.
• Non-uniform singeing in stitch portion.
• Strength decreases.

Roller Singeing Machine

Roller Singeing Process
© Textile Pad

Description

This is a more improved process than the plate singeing process. In this process, the fabric is singed on one side also by heat, but not red heat. If the fabric is singed by a red heated roller, the heat is not even for this the result is not good.

Advantages

• The surface temp of the cylinder is more uniform than the plate singeing m/c.
• This method is very suitable for velvet and pile fabrics.
• Uniform singeing.
• Luster increases.

Disadvantages

• Only one side of the fabric is singed.
• Due to overuse, a small tiny groove coated the cylinder.
• Local cooling may occur in the cylinder due to contact between the cold fabric and the cylinder surface.

Gas Singeing Machine

Gas Singeing Process
© Textile Pad

This is the most commonly used process for woven fabric. The burners are usually supplied with a suitable mixture of gas and air. Sources of gas include:

1. Coal
2. Petrol
3. Natural gas

Description

This m/c may be a single or double burner. On a double burner, the fabric is singed on both sides. At first, the fabric is drawn onto the guide roller then brushing is done on both sides of the fabric such that, flying and projecting fibers stand sufficiently.

Then the fabric is passed over the burner. The burner should be adjusted to the width of the fabric. The height of the flame depends upon the fineness or coarseness and speed of the fabric.

After singeing, the fabric is immersed in the water in the desizing tank to prepare for the next process. Fabric speed on this m/c is generally 150-250 m/min. The machine may be horizontal or vertical.

Advantages

• Uniform temperature ensures proper singeing.
• Both sides of the fabric can be singed.
• As the process is continuous, there is no hamper in production.
• After singeing, the fabric is cleaned in the water/desizing tank, hence all sparks are easily removed.
• Standard process.
• Ideal for singeing.
• The fabric is inter-stitched with warp and weft are singed.

Disadvantages

• A dirty burner can produce spots on the fabric.
• The process is not suitable for synthetic fabric.
• Due to the inconsistency of the fabric speed, it may be burnt.

Causes of Defects of Gas Singeing and Its Precautions

If any antiseptic/anti-mildew agents (ZnCl or MgCl) are in the size ingredients, then singed fabric produces spots which results in uneven processing.

ZnCl +H2O - ZnO + 2HCl

• Therefore, the fabric must be free from those agents.
• The burner should be cleaned, otherwise, singed fabric will be faulty and as a result, stripes found during dyeing.
• The speed of the fabric must be constant with the flame height, otherwise, the fabric may be burnt.
• The synthetic blend must be handled carefully, otherwise it may shrink in flame and uneven dyeing may occur during dyeing.
• Fabric may be burnt due to power failure. Automatic gas stopping must be with the power failure.
• Fabric must be evenly dried before singeing.
• The singeing may not be even, due to the folding of the selvage.

Controlling Points of Singeing Machine

• Motors and other moving parts.
• Speed of the fabric.
• Electricity supply.
• Air-blowing suction hood.
• Fabric width control.
• Brush.
• Flame height.

Comparison Among Plate, Roller, and Gas Singeing Machine

Plate Singeing	Roller Singeing	Gas Singeing
One side of the fabric is singed	One side of the fabric is singed	Both sides of the fabric are singed
Uniform temp cannot be maintained	Uniform temp cannot be maintained	Uniform temp can be maintained
Extra luster produced due to friction between the fabric and surface	Extra luster produced due to friction between the fabric and surface	No extra luster is produced
Not suitable for dyeing and printing	Not suitable for dyeing and printing	Very suitable for dyeing and printing
The brush is not used for proper singeing	The brush is not used for proper singeing	The brush is used for proper singeing
The plate may decay due to friction	The plate may decay due to friction	No decay

How is scouring and bleaching done?