WHAT IS A CARPET?

Carpet is a cloth backing material with yarn arranged in a vertical or horizontal position to form the pile. Therefore the backing material serves as an achorage for the pile, which forms the upper surface of the carpet. Basically, carpets can be split into two main complimentary components:

(A) PILE FORMING YARN - To walk on

(B) CLOTH BACKING MATERIAL - To secure and support the pile. A
secondary backing is sometimes used to give additional stability.



When carpets are laid, or displayed, only the pile is visible but it should not be forgotten that the backing material is equally important, and influences both the quality and price of the finished product.

There are various methods of inserting and securing the pile yarn into or onto the backing during manufacture, but essentially these methods can be divided into two categories;

WOVEN & NON-WOVEN



WOVEN CARPETS

This is the traditional method of manufacturing carpets by simultaneously weaving the backing cloth and pile yarns on looms.

Cotton or Polypropylene backing threads are first streched a long the length of the loom, these threads are called chain warps, and bind the carpet together.

Additional warps, called stuffer warps of jute or polypropylene threads are added between every two chain threads, these stuffer warps are thicker and straighter than chain warps and improve strength and rigidity.

A simular thickness of jute or polypropylene thread is then interlaced at 90 degrees to the warps across the width of the loom by a 'shuttle' or 'needle', these threads are called wefts.

The vertical pile yarn is introduced around alternate weft shots, which are compacted by a comb-like device called the reed. This action is called beating-up and ensures that the weft is firmly compacted at right-angles to the warp.





All conventional woven carpet is produced by either the AXMINSTER or WILTON weaving process. Both types consist of warps, wefts and pile - the difference really lies in the manner in which the material is woven and the design of the looms.

The names AXMINSTER & WILTON are derived from the English towns where the processes first originated, and are now used throughout the world to describe the types of weave used.



AXMINSTERS

There are two distinct common methods of Axminster weaving, Gripper Jacquard Axminster and Spool Axminster.

The components of the carpet are usually identical but the form of contruction is different, depending on the type of loom used.

The Axminster contruction process allows for a variety of colours to be incorporated into the design, therefore the majority of Axminsters are multi-coloured and intricately designed.

Plain Axminsters can be produced but this is not cost effective.

Both Axminster weaving processes only produce a cut pile surface as each tuft is cut and inserted seperately.

The pattern design for all woven carpet is traditionally hand painted onto square grid paper, each tiny square representing a single carpet tuft.

This process has been updated by the use of computer aided design, which allows colour, pattern and dimension changes at the touch of a button, printing similar full-colour designs in a fraction of the time.

The density of the weave is a major factor in determining a woven carpets quality and durability.

An Axminster may have 5 - 14 tufts per inch, forming rows along the length of the carpet (the beat up).

A typical beat up of 7 tufts per inch; with a pattern repeat every 36 inches; would mean that 252 different rows are woven for each yard of carpet, which in turn, means 252 pattern changes are required.

The number of tufts across the width of the carpet (the pitch) is normally between 6 and 9 inch; which means for each square inch of carpet; with a beat up and pitch of 7 tufts per inch; would give a "square" pile density of 49 tufts per square inch.



SPOOL AXMINSTER

Spool Axminster takes its name from the many individual spools of yarn used on the loom. The great advantage of spool axminster is that the process permits almost any number of colours, but for reasons of cost and other practical considerations they seldom exceed 25 different colours.

Each row of coloured squares representing a row of tufts across the carpet is then transposed into a 27" or 36" spool using coloured yarns, one spool for each different row of the pattern.

Each spool is finished by clipping on a tuft tube which is like a comb with hollow teeth. The individual yarn ends are drawn through the hollow tubes in readiness for inserting between the warp threads. The pattern is built up by clipping each spool differently wound in specific order between endless chains.




Broadloom carpets are produced by using identically wound spools laid side by side which allows the manufacturer to produce widths of either 6ft, 9ft, 12ft or 15ft.

Because of the cost of setting up the different designs, Spool Axminster is normally used only for long production runs. During weaving, each spool is consecutively taken from the endless chains and its tubes dipped between the cotton chain warps.

A double strand jute weft is then inserted by a long needle representing the shuttle. The pile is then pushed up from below by the combs to form a 'U' around the weft. This U shaped tuft varies in length from 15 - 25mm the most common length being 22mm.

Two blades then cut the tuft to the required length, and the spool is returned to the paternoster.

The more double stranded jute wefts are inserted and the pile yarn and all three wefts are beaten-up by the reed.

The next spool is advanced by the endless chain and the above process repeated until all the spools in the pattern repeat length have had a row of tufts cut off them. The cycle repeats itself.

Spool Axminster constructed carpets can be identified by the smoother backing, the pattern outline showing through the backing, and the greater number of colours included in the design.

The Spool Axminster process does have some disadvantages, it is notoriously wasteful in unconverted yarn due to the guillotining and trimming of the spool tubes, this could account for a wastage of yarn as high as 10% - 15%.

Efficiency is also lost if the spools are unevenly wound, certain colours can run out, causing production downtime and costly repair by hand.