An Overview of Doffer in Carding Machine

An Overview of Doffer in Carding Machine

Bhavdip Paldiya
Dept. of Textile Technology
Sarvajanik College of Engineering & Technology, Surat, India
Cell: +91 9662020909
Email: bhavdipk9009@gmail.com

What is Doffer?
Doffer is a revolving cylinder, or a vibrating bar, with teeth, in a carding machine, which doffs, or strips off, the fiber from the cards.

Doffer in carding machine

Object of Doffer:
The main object of the doffer is to take off the fibres that lie more or less evenly distributed between the cylinder wires, and to condense them so that they constitute a coherent web.

Types of Doffer:
There are two types of doffer in carding.

1. Single doffer
2. Double doffer

Specification of Doffer:

• DIAMETER:-27’’dia
• SPEED:-45rpm/minute
• WIRE POINT PER INCH:-300-400 
• SURFACE SPEED ratio:-53.3 
• DIRECTION:-CLOCKWISE

Doffer Wires:
The doffer strips the fibres from the cylinder. The rate of transfer is called the transfer ratio. The transfer needs to be optimised to reduce the re-circulation on the cylinder to a minimum. The specification of the doffer wire, together with the card settings will define the correct operation of the transfer of the fibres from doffer to cylinder.

Doffer Wire Maintenance:

• Doffer is still working with a concept of Land formation. A normal grinding machine will be good for doffer grinding. All the wire points should be touched by the grinding stone. A slow and gradual grinding with the grind-out concept will give the best results. Harsh grindings will result in burr formation on the land. This will increase the number of hooks in the fibre; thereby the effective length of the fibre from this card will be reduced. 

• Flat tops grinding is very important. Every time a flat top is ground, yarn quality is improved. It is better to use a grinding machine with the emery fillet. Frequent flat tops grinding will result in less neps and the yarn quality will be consistent. 

• Some mills increase the life of the flat tops compared to cylinder wire. But it is better to change flat tops and cylinder wire together for better and consistent yarn quality. 

• It is a good practice to check the individual card quality before changing the wire

Uses and Characteristics of Doffer:
Suitable for carding of 1.5D-20D*38-65mm artificial fiber. Single cylinder high-speed carding and double-doffer outputting has high production capacities. Cotton stripping has been used stripper bar,the cotton feeding roller is controlled by frequency conversion.

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