The traditional method of manufacturing carpets is by simultaneously weaving the backing cloth and pile yarns and looms.
Cotton backing thread is first stretched along the length of the loom. These threads are called chain warps.
Thicker backing thread is then interlaced across the widths of the loom by a ‘shuttle’.
These threads are called wefts.
The vertical pile yarn is introduced around each weft shot which is compacted by a comb like device called the reed. This action is called beating-up and ensures that the weft is firmly compacted at exact right angles to the warp.
Additional warps, called stuffer warps, are often added. These are thicker and straighter than chain warps and improve strength and rigidity.
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 used.
The names Axminster and Wilton are derived from the English towns where the processes first originated and are now used throughout the world to describe the type of weaves used.
Axminsters are woven on looms which lock the tufts into a warp and weft and makes the backing at the same time.
A synthetic adhesive finish is then often applied to the woven carpet backing to hold the tufts more securely to prevent detufting.
The pile fibre is often wool or a blend of wool with nylon but there are quite a number of Axminster carpets with synthetic fibres.
Axminster carpets range from high to low prices.
One of the great advantages of the Axminster carpet is the large number of colours that can be woven into the design.
Wiltons are woven on looms similar to cloth looms. They may be plain or patterned.
Unlike an Axminster the yarn of a Wilton is not cut off where a particular colour does not appear.
Instead some of the pile yarn is woven into the backing of the carpet (dead yarn), adding to the firmness and the quality of the carpet.
Wilton carpets are based on the ‘Brussels’ method which the Flemish weavers brought to England in the 18th Century and can be used for carpets of one to six colours.
Patterned Wiltons are relatively expensive because the dead yarn buried in the body of the carpet has to be paid for. This is not wasted as it gives the carpets the increased weight and quality for which they are noted.
The pile fibres used are the same as used in Axminster.
The term non-woven is applied to all carpets which are not produced by weaving, but by inserting the pile into a pre-manufactured backing.
Until the 1940’s all carpet was traditionally woven but today, non-woven carpets account for 90% of the UK carpet industry.
The main non-woven manufacturing process is tufting, but modern fibre technology has permitted the development of other products, including bonded, needle punch and flocked carpets.
Tufted carpets were introduced from the USA after the Second World War.
The principles of their manufacture are based on threading cotton fibre through loosely woven material, producing a tufted appearance.
This developed into the machine production of ‘tufted’ fabrics.
Tufted carpets are relatively inexpensive as they can be produced at a much faster rate.
In tufting, the base cloth or primary backing is pre-manufactured separately as a woven or bonded cloth in polypropylene, jute or other materials.
This is then mounted and passed through a tufting machine which, in simple terms, operates like a giant sewing machine with hundreds of needles mounted side by side on a bar.
Pile yarn is threaded through the each needle and the needles move down simultaneously, forcing the yarns through the primary backing.
Beneath each needle is a hook-like device called a lopper which catches the tuft as the needle retracts, thus forming a loop.
The pile height is determined by the distance between the looper and the backing.
In the case of loop-pile tufting, the looper retracts, releasing the yearn loop.
In the case of cut-pile tufting, each looper has an accompanying knife blade which acts against its side in a scissor-like action.
Several loops at a time are held on the looper, the knife always cutting the loop farthest along it.
The tufting operation is repeated 450-650 times per minute, thus producing a carpet upside down.
HIGH AND LOW LOOP DESIGN
If the yarn feed to a particular needle is reduced a low loop will result.
By feeding yarn at two or three speeds, in a controlled way, patterns can be formed by the different pile heights.
Different coloured yarns, next to each other, can be brought into the pattern effect using a high loop, or removed from sight by a low loop close to the backing fabric.
To control the supply of yarn at different tensions various electronic or mechanical pattern attachments are used, varying in complexity and versatility.
A further enhancement of this technique is that of shearing, where the ‘tips’ are cut off leaving a cut and loop pile finish. The primary backing material is then coated in latex which anchors the pile yarn in place. If the carpet is to be secondary backed type a layer of jute or polypropylene is applied whilst the latex is still wet, ensuring a firm bond and giving extra stability to the carpet.
In the case of foam backed carpet a foamed latex coating is applied in an accurately measured thickness.
This provides additional support and an integral cushion underlay.
Modern technology permits a wide variation in foam density and composition. The greatest disadvantage of the tufting process is the colour limitation.
Some plain carpets are tufted using pre-dyed yarn, but coloured carpets are usually produced using white yarn that is completely dyed, or a pattern is sprayed onto the surface.
This type of floor covering is also known as needle loom or needle felt.
Unlike other types of carpet it does not usually have a pile, but a fibrous, felt-like surface.
Layers of lose fibres are placed on the backing material or scrim and punched by barbed needles which oscillate up and down
The underside of the carpet is then covered with a layer of latex, bitumen or PVC.
Needlepunch floor coverings are produced either as continuous lengths of conventional width roll stock or as carpet tiles.
Jumbo cord is a ribbed Needlepunch type carpet with a light gel foam backing.
BONDED CARPET (INCLUDING ADHESIVE BONDED)
Bonding is a process of securing pile yarn or fibres to the surface of a pre-manufactured backing material.
This is most frequently achieved with adhesives or by applying heat to fuse the fibres to the backing materials.
A popular example of adhesive bonded carpets is non-woven cords where the fibres are pressed into a rigid form and then bonded to a hessian backing with latex adhesive.
Common styles and textures:
A cut pile carpet made from yarn which has a high degree of twist or ‘kinkiness’.
This gives the pile an overall textured effect.
It can be produced by either the weaving or tufting process and is generally a plain carpet.
SCULPTURED/CUT & LOOP:
This style combines cut pile and loop pile of varying height which creates a subtle patterned effect.
Shadow styles are produced by using darker tones on the base of the pile.
Gradually lightening towards the top. This is produced as a tufted carpet.
A cut pile carpet in which the tufts are tightly packed and closely sheared, resulting in a very smooth velvety appearance.
Velour carpet can be produced by both the weaving and tufting process and is generally a plain carpet.
Many plain Wiltons are made with a velour finish.
BERBER & CORD:
The Berber was originally made from undyed wool by nomadic Berber tribesman of North Africa.
Today this name is used to describe a style of carpet, usually loop pile, which has this natural ‘flecked’ effect.
Cords have a fine gauge low level loop pile with very hard wearing qualities and a very dense finish.
AXMINSTER & WILTON
These are the two different types of traditionally woven carpet where backing and piles are interwoven together in manufacture.
This process is very lengthy and costly but gives a superb finish.
The Axminster method of weaving allows carpet designers to use an almost unlimited number of colours.
Wiltons, which tend to be plain or tonal, may come in a variety of textures, i.e. twist pile, cut pile and even sculptured.
SAXONY & SHAG PILE:
Saxony is a cut pile carpet made with densely packed relatively long tufts which give a luxurious feel and appearance.
The Shag pile is a cut pile carpet made with extra long tufts-very luxurious but generally not suitable for areas of very hard wear.