Basic Woven Structure | Classification of Basic Woven Structures

The form of interlacing of warp and weft yarns can be divided basically into three categories- plain, twill and satin/sateen weave. These three kinds of forms are called basic weaves.

1. Plain Weave: 

The simplest of all weaves is the plain weave. Each filling yarn passes alternately over and under one warp yarn. Each warp yarn passes alternately over and under each filling yarn. Some examples of plain-weave fabric are crepe, taffeta, organdy, and muslin. The plain weave may also have variations, which include the following:

Warp rib weave- Warp rib weaves may be described as plain weave in which two or more picks are inserted in the same shed. Warp rib weaves are normally used in warp faced constructions. The warp cover factor and the warp crimp are substantially higher than the weft cover factor and the weft crimp. The intention is to produce fabrics with prominent weft-way rib formed by the crowns of the warp threads.
 

Weft rib weave- Weft rib may be described as plain weave in which two or more ends weave together as one. It is difficult to achieve very high weft cover factors in weft faced plain-weave cloths. By using two finer ends weaving as one, it becomes possible to achieve higher weft cover factor. Such cloths are expensive to weave and not very common.
 

Basket, matt or hopsack weave- In matt, basket or hopsack weaves two or more ends and two or more picks weave as one. The simplest and commonest of these weave is 2/2 matt.
(Refer to Annex 2 for weave diagrams)

2. Twill Weave: 

A weave that repeats on 3 or more ends and picks & produces diagonal lines on the face of the fabric. A twill weave is characterized by diagonal rib (twill lines) on the face of the fabric. These twill lines are produced by letting all warp ends interlace in the same way but displacing the interlacing points of each end by one pick relative to that of the previous end. In twill weave line moves sinisterly (Right - Left, Z twill) and dextrally (Left - Right, S twill). Common derivatives of twill weave are as follows:
 

Zigzag Weave- If the direction of the diagonal in a twill fabric is reversed periodically across the width, a zigzag effect is produced. Zigzag weave is achieved by simply combining two S and Z twill weaves of equal repeat.

Diamond weave- Diamond weaves are achieved by combining two symmetrical zigzag weaves of equal repeat. Diamond designs are vertically and horizontally symmetrical.
 

Herringbone weave- In Herringbone weave also the twill direction is reversed periodically like zigzag weave but at the point of reversal the order of interlacement is also reversed and then twill line commence as usual.
 

Diaper weave- Diaper weaves are produced when we combine two Herringbone designs. Diaper designs are diagonally symmetrical. (Refer to Annex 2 for weave diagrams)

3. Satin/sateen Weave: 

The satin weave is characterized by floating yarns used to produce a high luster on one side of a fabric. Warp yarns of low twist float or pass over four or more filling yarns. The low twist and the floating of the warp yarns, together with the fiber content, give a high degree of light reflection. Weights of satin fabrics range from chiffon satin to heavy duchesse satin. The sateen weave is similar to a satin construction except that in the sateen weave, the filling yarns float and are visible on the surface of fabric. Examples: cotton sateen, and damask.

Textile Softening | Fabric Softening Process | Types ofSoftener/Softening Agents

Softening
As a general rule, each fibre has its specific softness value, which depends on its chemical composition and physical structure (less crystallinity = greater softness). The fineness of the fibre or of the filament directly affects the softness of the yarn (woollens, worsteds, microfibers etc.). The yarn twist ratio is inversely proportional to its softness.

The weave also contributes to reducing (closer weave = cloth) or increasing (looser weave = satin) the fabric softness. Furthermore, a greater number of yarns per centimetre increase the stiffness of the fabric, thus reducing its softness.

Softening is carried out when the softness characteristics of a certain fabric must be improved, always carefully considering the composition and properties of the substrate. It is also worth underlining that no standard methods have been developed and established to determine exactly what the softness of a fabric is. This evaluation is therefore almost personal and carried out on the basis of operator.s experience. It is anyway possible to distinguish between many types of softness:

a) surface softness,
b) surface smoothness,
c) elasticity (to compression and stretching).

Fabric Softening Process:
To change the hand properties of a fabric, we can apply mechanical, physical, chemical or combined techniques; some of these methods (sueding, raising) have already been explained in detail in previous sections of this handbook, while some others refers to machines that give different degrees of softness, by means of high-speed rope processing in wet or dry conditions, with the drying stage carried out during the treatment (with or without softeners or enzymes.)

The functional core of these machines are the two tunnels where the fabric is fed through two Venturi tubes. The energy applied for drawing the material is produced only by air and pressure. The fabric flowing through the Venturi tubes is pushed at high speed against a grid on the machine rear side; the fabric then slides on Teflon-coated chutes and reaches the machine front side to start the cycle again; the fabric can reach a speed of 1000 m/min., depending on the type and weight of the different textiles to be processed and according to the desired results. 

Schemes of fabric softening machines

This unit applies physical and mechanical principles on fundamental elements such as: 

• air, which is the fabric propeller and drawing element; 
• the mechanical stress exerted on the fabric inside the Venturi tubes and the stress due to the impact against the rear grid; 
•  the eventual action of heat.

It is also worth noticing that water is not a crucial element for the process; it is only a medium for carrying dissolved non biodegradable chemical additives (if required.) The combination of all these elements, almost free of polluting charge, cause the structural modification of the fibres making up the fabric.

They result in more or less marked surface modifications, which can radically change the appearance and the sensorial properties of the fabrics. The complexity of the finishing action starts inside the Venturi tube where the tail of the fabric is subjected simultaneously to a compressive action and to a subsequent series of vibrating pulses which tend to “random-modify” and compact the textile structures, eventually giving them different properties.

The one-way thrusting force is transformed into a impact force against the grid on which the fabric is pushed when emerging from the Venturi tube; this causes other modifications of the fabric and add structural and surface effects.

This simple treatment that combines physical and mechanical principles, carried out at a precise temperature set by the operator, is sufficient to create particular effects on the morphology of fibres and the weave. The modifications produced by this treatment are very different and not only affect the colour, appearance and hand properties of the fabric, but also add new properties, e.g. modifying the refraction and diffraction of light on the fabric surface.

The most notable effects in terms of style and added value are obtained on linen, a precious delicate fibre, particularly difficult to process without using chemicals.

The combination of a chemical product or an enzyme liquor with the mechanical treatment can be carried out not only on linen but also on many other widely used fibres such as Tencel and polynosic fibres, imparting a draping, full and lively hand.

All these effects are obtained thanks to the air thrust and to the following impact against the grid, or to the pressure of rollers on the fabric rope. Comparing the effects of this treatment on a Tencel fabric and on a similar treatment carried out on a dyeing machine, we can see that, as previously explained, this finishing process not only affects the appearance of the fabric, but also .cleans up. the fabric surface homogeneously, as a result providing good anti-pilling properties.

The best softness results can be obtained by carrying out the above mentioned physical mechanical processes and by applying a special chemical softening agent.

As a general rule, the softening agents applied are hygroscopic or lubricating agents, which facilitate the fibre sliding within the fabric structure, thus granting easier deformation and creasing of the fabric. In most cases, the duration of the effect is limited since the products applied during the treatment are eliminated by subsequent washing; for this reason they must be applied in the final stage of the treatment. The most common softeners are below:

1. Non-ionic Softener
2. Anionic Softener
3. Cationic Surfactants
4. Silicone-Based Softeners
5. Reactive Softeners

Non-ionic Softeners: 

Generally ethers and polyglycol esters, oxiethylates products, paraffins and fats. These softening agents are generally less efficient than anionic and cationic ones but they withstand the effects of hard waters, acid or basic environment and also in presence of cations and anions, therefore the normal fabric care conditions.

Anionic Softeners: 

Sulphoricinates, anionic surfactants produced by the condensation of fatty acids. They have good characteristics as lubricating softening agents and give the fabric a full hand; they are unstable in hard water and acid environment. In addition, they must not cause yellowing at condensation temperatures.

Cationic Surfactants: 

Usually they are quaternary ammonium salts, amino-esters and amino amides; they are recommended for all types of fibre, and can be also applied with exhaustion process in acid environment (pH 4-5). These are the best softening agents and are also called molecular velveting. Agents because they form bonds with the cationic group on the surface of the fibre generally with negative electric potential. They can give some problem in presence of large anions, and they can cause dye toning, or a reduction in fastness to light values in the presence of direct and reactive dyes; they also have a high polluting charge as waste water (bactericides).

Silicone-Based Softeners: 

These are generally polysiloxane derivatives of low molecular weight. They are insoluble in water, and therefore must be applied on fabrics after dissolution in organic solvents, or in the form of disperse products. They feature quite good fastness to washing. They create a lubricating and moderately waterproof film on the surface and give fabrics a velvetysilky hand (desirable for velvets, upholstery fabrics and emerised fabrics)

Reactive Softeners: 

N-methylol derivatives of superior fatty amides or urea compounds replaced with fatty acids. The products have to be cross-linked and provide permanent softness and water repellency.

As explained previously, even though some softeners can be applied with exhaustion processes on yarns, when softening fabrics, the best technique is the continuous pad-wetting process followed by a drying stage in a stenter. This treatment must be carried out at the end of the finishing process; for this reason, softening is usually performed simultaneously with other dimensional stability processes (width stabilisation, weft and warp straightening). It is worth remembering that the use of softeners can reduce the fastness to rubbing of synthetic fibres dyed with disperse dyes, as the fatty surface layer tend to attract the dye molecules after hot treatments. 

Wool Glazing Machine | Process of Wool Glazing

Wool Glazing Machine

This special machine is used to perform functional finishing on wool fabrics after raising finishing. The machine is made up of two different units. 

1.Starching Unit

2.Glazing Unit

The Starching Unit Includes:
1) a vat containing water and silicones;
2) a variable-speed extracting cylinder to reduce the quantity of liquid to be passed onto the fabric;
3) a brush coated with horsehair adhering to the extracting cylinder and passing the liquid onto the fibre ends of the fabric, simultaneously combing and lining up the fibres.

The Glazing Unit Includes:  

•  A crenellated polishing cylinder (made of steel and coated with hard chrome) heated by means of electric resistances at temperatures up to 220°C and four spiral grooves on which hard-steel combs are assembled. These combs have very fine teeth to enhance the efficiency of fibre ironing during the process;

• A felt sleeve, rotating at the same speed of the fabric, presses the fabric onto the polishing cylinder. The contact arc on the polishing cylinder can vary and the cylinder can reach a temperature of 130°C.

Wool glazing machine

The fabric with the fibre ends already combed and wet come under the polishing cylinder, which dries and irons the pile, and confers a lustrous appearance by giving a soft and smooth hand, also thanks to the silicones added to the starching vat (thanks to this process the fabric acquires a hand similar to the precious wool one).

By adjusting the temperature and the speed of the polishing cylinder, the contact arc of the fabric on the cylinder and the contrasting pressure of the felting material, it is possible to obtain different types of finishing (from the laid down to the perfectly lined up one).

Raising or Napping Finishing | Working Process of Raising FinishingProcess

Raising or Napping

A finishing process that raises the surface fibers of a fabric by means of passage over rapidly revolving cylinders covered with metal points or teasel burrs. Outing, flannel, and wool broadcloth derive their downy appearance from this finishing process. Napping is also used for certain knit goods, blankets, and other fabrics with a raised surface.

The raising process is a very old technique known also to Romans (as pictured in some paintings found in Pompeii). This operation is particularly suitable for wool and cotton fabrics; it gives a fuzzy surface by abrading the cloth and pulling the fibre end to the surface. During those last years this process has also been applied on polyester/viscose blends and acrylic fabrics. 

By means of this process a hairy surface can be given to both face and back of the cloth providing several modifications of the fabric appearance, softer and fuller hand and bulk increase. This enhances the resistance of the textile material to atmospheric agents, by improving thermal insulation and warmth provided by the insulating air cells in the nap. The fuzzy surface is created by pulling the fibre end out of the yarns by means of metal needles provided with hooks shelled into the rollers that scrape the fabric surface. The ends of the needles protruding from the rollers are 45°-hooks; their thickness and length can vary and they are fitted in a special rubber belt spiral-wound on the raising rollers. These rollers are generally alternated with a roller with hooks directed toward the fabric feed direction (pile roller), and a roller with the hooks fitted in the opposite direction (counterpile roller).

Raising rollers

The machine also includes some rotating brushes, which suction-clean the nibs in pile and counterpile directions. Actually the trend goes towards a ratio of raising rollers/pile rollers equal or 1/3. The two series of rollers have independent motion and can rotate with different speed and direction thus carrying out different effects.

Raising (napping) machine

1: roller; 

2: rollers equipped with hooks;
3: fabric;

4: nib cleaning brushes;

5: fabric tension adjustment

The action of these systems is almost powerful and the results depend upon the effects and the type of fabric desired . The raising effect can be obtained by adjusting the fabric tension (5) or by adjusting the speed and the roller rotation direction (2).

Once a certain limit has been exceeded, the excessive mechanical stress could damage the fabric: it is therefore better, when carrying out a powerful raising, to pass the wet fabric through the raising machine many times (dry when processing cotton fabrics) and treat the fabrics in advance with softening-lubricating agents. 

Raising the face of the fabric

The pile extraction is easier when carried out on single fibres: it is therefore suitable to reduce the friction between the fibres by wetting the material or, in case of cellulose fibres, by previously steaming the fabric. For the same reasons, it is better to use slightly twisted yarns.

The same machine allows different options of independent motions:  

1. Fabric moving between entry and exit 

2. Motion of large drum 

3. Motion of raising rollers

The raising intensity can be adjusted by suitably combining the above mentioned independent motions, the tension of the textile material, the number of .pilewise. or . counterpile. raising rollers and their relative speed. It is possible to obtain .combed pile. raising effect, “semi-felting” effect with fibres pulled out and re-entered in the fabric, and complete felting effect.

The raising machine is equipped with two overlapping drums each one featuring 24 rollers, which can process two faces or face and back of the same fabric. The drums assembled on a standard machine can rotate separately one from the other in the fabric feeding direction or in the opposite direction by carrying out a counter rotation. In this model all the functions are carefully monitored and controlled by a computer system; in particular all the commands are driven by alternating power motors controlled by “Sensorless” vector inverters. 

The control electric system features:
1).  PLC programmable controller for machine and alarms automation; 

2).  Touch screen to program and update all processing parameters; 

3). Operating conditions of each single raising process (up to one million .recipes”) that can be stored to facilitate the batch reproduction. 

Furthermore, a series of special pressure rollers can be assembled on the feeding cylinders to prevent the fabric from sliding, thus granting an extremely smooth raising. The raising process ability lies merely in raising the desired quantity of fibre ends without excessively reducing the fabric resistance. For this reason, the technique applying the alternated use of pile and counterpile rollers is the most widely used since it minimises the loss of fibres from the fabric and the consequent resistance reduction.

Standard raising machines have been designed to work with fabrics powerfully tensioned essentially because they are not equipped with an efficient and reliable tension control. 

This gives rise to the effects detailed below:

1) The contact surface between the fabric and the raising cylinders is quite small;
2) The hook nibs work only superficially on the fabric and the raising effect is quite reduced;
3) The fabric width is drastically reduced.

The above mentioned inconveniences have now been eliminated thanks to the last generation of raising machines, which reduce the number of passages and carry out the raising process by gently tensioning the fabric.

Introduction of Merchandiser/Merchandising | Objects of Merchandising |Qualities of Merchandiser | Function of Merchandisers

Merchandise means goods bought and sold; and trading of goods. Merchandising is an activity of selling and promoting the goods.

Merchandiser is a person who interacts with the buyer and seller, and also puts efforts into proper relation between buying offices/ buying agents/ agency and seller/ exporter in terms of executing an order.

A garment export unit generally has many departments like stores, cutting, production, packing, checking etc. Merchandising department is the star of the department among all the working departments in the Export concern, because Merchandising is the only department having maximum control over the departments and total responsible for Profit and loss of the company.

The job of a merchandiser is to co ordinate with the entire department in the office as well as the customers. Merchandiser meets the buyers and collects the details of their requirements etc., to develop the relationship with the customer.

Objects of Merchandising
Merchandising denotes all the planned activities to execute and dispatch the merchandise on time, taking into consideration of the 4 Rs to replenish the customer.

Right Quantity: To dispatch right quantity of product what buyer ordered.
Right Quality: It should be with right quality as accepted both parties.
Right Cost: Everybody wants more from what they are paid.
Right Time: No one wants to wait idle even in a Restaurant. Keeping delivery schedule is mandatory.

Qualities of Merchandiser

Planning Capability: Merchandiser should be capable of planning, based on the planning the order is to be followed. If the planning is not done properly it will directly affect the delivery time of the order.

Decision making: For a Merchandiser, decision making power is most important. He should think about the decision to be taken and to act in a right way.

Communication Skill: The communication is very much important to promote the business activity. The merchandiser should remember that communication must be lurid and should having face to face conversation with the buyer.

Loyalty: Loyalty is an essential character of human beings. Especially for the business people like merchandiser it is a must.

Knowledge about the field: Merchandiser should have adequate knowledge about the garments, Computer knowledge, and technical knowledge to communicate with different people in the business is a must.

Co-ordinate & Co-operate: Merchandiser is the person who is actually co-ordinate with the number of departments. To Co-ordinate with different people in the industry he should be co- operative.

Monitoring ability: Merchandiser should monitor to expedite the orders.

Other qualities: Education, Experience, Situational Management, Ability to Evaluate, Dedication, Knowledge of expediting procedures.

Function of Merchandisers

1. Developing new samples, execute sample orders
2. Costing
3. Programming
4. Raw materials / Accessories arrangement
5. Production scheduling (or) route card drafting
6. Approval of various Process, Pattern and size set
7. Pre production follow up
8. Meet Inspection Agencies
9. Production controlling
10. Identifying shortages and make arrangement for the shortages
11. Following quality assurance procedures, quality control procedures
12. Monitoring the in-house, sub-contractors and junior activities
13. Buyer communication
14. Communication with sub-contractors, processing units & other 3rd parties
15. Proper reporting
16. Highlighting to the management
17. Record maintenance
18. Developing samples
19. Placement of orders to suppliers
20. Taking measures for consistent production
21. Taking preventive action to maintain the targeted performance in all areas of activities
22. Attending meeting with superiors and furnishing the required details about merchandising

Purchase order (PO) is received from the buyer which includes:
• PO no/date
• Buyer/Consignee
• Garment no
• measurement
• the description of the garment
• L/C date
• Last date within which shipment to be reach the destination.
• Sign and seal
• Order validity date

After receiving PO from the buyer merchandiser issues PO for the fabric unit, buttons, thread, dyeing unit, printing, embroidery and other raw materials. These raw materials’ are checked and color, quality and size approved by the merchandiser.

Skein Dyeing Machine/Arm Dyeing Machine | Working Process of SkeinDyeing Machine

This is the most suitable machine for dyeing delicate yarns (Silk, Bemberg, etc.) since it prevents the material being too tightly packed; in fact other skein dyeing systems frequently produce an excessive packing of the dyed material. The machine is equipped with horizontal arms perforated in the upper part; skeins are stacked and suspended on this rack. The liquor, forced through the arm holes, penetrates the skeins and is then collected in an underlying vat. Standard machines are equipped with a rod which moves the skeins at preset times, changing the bearing point to obtain a more uniform dyeing. During the skein motion, the flow of the liquor is stopped to avoid the formation of tangles in the yarn; since yarns are not fixed to rigid supports, they can thoroughly shrink. This machine does not run under pressure. It is possible to dye at steady temperatures since the liquor is contained in a separate tank. 

Skein Dyeing Machine

Modular skein dyeing machine with pullout arms. Pullout arms also allow the loading and unloading of skeins far from the dyeing machine, without manually intervening in the intermediate dyeing, squeezing and drying operations. It can be used for silk, cotton, viscose and Cashmere yarns.

The operating costs of this machine are generally very high because it require a very high liquor ratio (1:15 . 1:25 . 1:30 ). Standby times for loading and unloading operations are also very high and the arms must be often cleaned. This machine can be used also for scouring and finishing processes.

Some machine manufacturers have designed machines with slant covers to avoid unwanted liquor dripping on the skeins; the skein rotation is determined by the perforated arms, and not by the rotation of the skein-lifting device when the arm is stopped; it is therefore possible to eliminate the sliding contact with the skeins and preserve them perfectly.

There are also package dyeing machines with triangle-shape arms, arranged radially on a variable-speed rotor. When the dyeing process has terminated, the material can be centrifuged and dried, by forcing a hot air flow into the arms and through the skeins.

Winch Dyeing Machines | Working Process of Winch Dyeing Machines |Advantages/Limitations of Winch Dyeing Machine

A dyeing machine consisting essentially of a dye vessel fitted with a driven winch ( usually above the liquor level) which rotates and draws a length of fabric, normally joined end to end, through the liquor.

Winch dyeing machine

Winch dyeing machine is a rather old dyeing machine for fabrics in rope form with stationary liquor and moving material. The machine operates at a maximum temperature of 95-98°C. The liquor ratio is generally quite high (1:20-1:40). Winch dyeing machines are a low cost design that is simple to operate and maintain, yet versatile in application proving invaluable for preparation, washing or after treatments as well as the dyeing stage itself. In all winch dyeing machines a series of fabric ropes of equal length are immersed in the dye bath but part of each rope is taken over two reels or the winch itself. The rope of fabric is circulated through the dye bath being hauled up and over the winch throughout the course of the dyeing operation. Dyestuff and auxiliaries may be dosed manually or automatically in accordance with the recipe method.

A winch dyeing machine

Description and Dyeing Method on Winch Dyeing Machine
The basic principle of all winch dyeing machines is to have a number of loops or ropes of the fabric in the dye bath, these ropes are of equal length , which are mostly immersed in the liquor in the bath. The upper part of each rope runs over two reels which are mounted over dyebath. At the front of the machine , above the top of the dye liquor , is a smaller reel, which is called jockey or fly roller.

The fly roller remain free wheeling along with fabric rope. At the back of winch tank is the winch wheel, which pulls the fabric rope from the dye bath over the jockey reel for dropping in the dye bath for immersion. From the dropped location , the fabric rope travels back . to be lifted and fed to winch wheel.

The dyeing process on winch dyeing machines is based on higher M:L as compared with other dyeing machines. The process is conducted with very little tension . The total dyeing time is lengthier as compared to other machines.

Advantages of Winch Dyeing Machine
1. Construction and operation of winch are very simple.
2. The winch dyeing machines are suitable for types of wet processing operations from desizing to softening.
3.The winch dyeing machine is suitable for practically all types of fabrics ,which can withstand creasing in rope form processing.
4. Thr tension exerted on winch is less than jigger dyeing machine,the material thus dyed is with fuller hand.
5. The appearance of the dyed goods is clean and smooth on winch dyeing machines.

Limitations of Winch Dyeing Machine
1. Batch dyeing operations needs trimming, sewing, opening out the rope , loading and unloading for individual lots separately.
2. Since several lengths of fabric are run over the winch reel into the liquor and sewn end to end,Continuous length processing is not possible in a single batch.
3. Fabric is processed in rope form which may lead to crease marks , particularly in heavy , woven , thin and light synthetics.
4. Most of the machine work under atmospheric conditions.