Sizing || Control Point || Gas/Electricity || Ingredient || Developments

Sizing || Control Point || Gas/Electricity || Ingredient || Developments

Importance of sizing:

Sizing imparts the additional strength to the sized yarn which helps the yarn to withstand weaving tension. The sizing helps to bind the protruding fiber on the surface thereby makes the sized yarn more uniform and smooth. Sizing also increases the abrasion resistance to the yarn.

Factors affecting size pick up:

  • Those belongs to the yarn particulars.
  • Those that depend on certain properties of the size paste.
  • Those due to some characteristics of the equipment and waxing of the sizing machine.

Important sizing ingredients and their functions:


The main function of adhesive is to bind the protruding fibers along the axis to the yarn.

There are two types of Adhesive:-

1) Natural Adhesive- Maize starch and potato starch

2) Synthetic adhesives- PVA, PVC


The main function of the softening agent is to give soft feel and pliability to the yarn. Examples of the lubricants/softeners are mineral waxes, vegetable waxes, mutton tallows, mineral and vegetable oils.

Hygroscopic substances:

Hygroscopic substances have the property of absorbing moisture from the atmosphere. It will maintain natural moisture content in the sized yarn. Magnesium chloride and glycerin are the examples of the hygroscopic substances.


Antiseptics prevent the growth and development of mildew. They will attack the fibers and thus weakens or damage the fabric. Examples are zinc chloride, copper sulphate, salicylic acid.

Weighing agent:

Weighing agent will increase the extra weight and cover to the sized yarn. Examples are china clay, sodium sulphate, Epsom salt.

Bluing and brightening agent:

Its main function is to overcome a dull yellow tint colors, bluing and brightening agents are used in the size mixing.

Control points:

Stretch control:

It is the difference between the length of the warpers beam and that on the weavers beam and then calculate the stretch percentage on the warpers beam length. Modern sizing machines equipped with mechanical or electronic stretch control devices. The permanent stretch in the yarn causes decreases in elongation at break of the sized yarn. Stretch is expected to be in the limit 0.5 to 1%.

Moisture control:

Moisture control in the sized yarn is up to 7.5% in the sized yarn.  Electronic moisture  control devices on sizing machine have the facility to preset the desired moisture content and is connected to drive of the cylinder.

Temperature control device:

The temperature of the size mixture determine the viscosity of the size paste which determines the percentage of the size addon, size penetration and further the end breaks during weaving. On modern sizing machine, temperature control devices automatically adjust the steam inlet in the size box.

Size level control:

On modern sizing machine, electrically operated controlling devices uses two electrodes located in the size mixture, with the help of electric circuit it operates the opening and closing of size inlet valve.


Over and under creel:

In over and under creel, the yarn sheet passes over the surface of the beam in top tier of the creel and then passes under the beams in bottom tier. This creel can be easily load and unload, easy to supervise all beams. Demerits of this creels are beams are under greater tension than those from the beams ahead of them, it occupies more space.

Vertical creel:

It overcomes some problems of over and under creel. It require limited floor space. In this beams are place din bottom and upper tie. The warp may be drawn into a sheet form, from the top of the creel. In this it is easier to locate the lappers but it is difficult to cut the lappers.

Inclined creel:

In inclined creel beams are place in an inclined stand. The withdrawal of the yarn sheets in the ascending order or descending order and warp sheet will enter to size box. In this it is easier to locate lappers but it is difficult to cut the lapper.

Developments in Sizing:

  • Positive feed roll mechanism.
  • Motorized movement of immersion rollers.
  • Auto pressure release for squeeze rolls.
  • Automatic size paste circulation system.
  • Wet squeezing arrangements and auto squeezing pressure control device in relation top speed.
  • Heavy duty chain and sprockets to avoid slippages beams with a flange diameter up to 1250mm.
  • Motorized comb movements to avoid burns on reed cents.
  • Hydraulic/pneumatic beam pressure, moisture indicator and controller.
  • At creel pneumatic breaking on warp beams.
  • Telescopic creel brackets and pre wetting sizing system, PIV gears.

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