Simple quality assurance in an apparel industry

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fashion manufacturing, a product development approach

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markers

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fabric spreading

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Spreading methods

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Terminology describing sewing operations

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Animation of a chain stitch machine

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Animation of a lock stitch machine

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Jeans Specification sheet

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How are jeans made

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pinking types etc.

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feed types

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sewing bed types

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Seam types

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stitch classes

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Laundry guide

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more textile terms

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Ergonomics in the clothing industry

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Apparel trade terms

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Systems of Cutting

  1. Hand Shears   :   Hand shears are normally used when cutting only single or double plies. The method is flexible enough to accommodate any fabric construction and pattern shapes. It is appropriate for made-to-measure garments. But it consumes a lot of time and the consequent high labour cost per garment.

Straight Knife

It consists of a base plate, usually on roller for ease of movement, a stand carrying a straight vertical blade with varying edge characteristics and an electric motor above it, a handle for the cutter to direct the blade and a sharpening device. The base plate on its roller slider under the glazed paper which is spread below the bottom ply of fabric in the lay.

Two kinds of power are required to operate a straight knife. Motor power drives the reciprocating blade and operator power drives the knife through the lay.

Advantages: It is most common means of cutting lays because it is versatile, portable, cheaper then a bent knife, more accurate on curves than a round knife, relatively reliable and easy to maintain.

Round Knife

Blade diameter vary between 6 cm to 30 cm

Advantage: It is a fast machine , excellent for cutting straight lines or gradual curves.

Disadvantages: It is difficult for a circular blade to negotiate a tight curve, such as an arm hole

Bend Knife

It consists of an electric motor with a continuously rotating steel blade. The blade knife passes through a slot in the cutting table in a fixed position, and the section of lay to be cut is moved past it.

Advantages: Bend knifs are used when a higher standard of cutting accuracy is required. They are used more in mens wear than in women’s wear as they are often used to cut large garment parts, such as large panels of jackets and overcoats.

Computer Controlled cutting

The input for this operation comes from the markers generated on computerized marker planning systems. The marker planning is transferred to the cutting unit by means of tapes or floppy discs etc.

Advantages: Computerised cutting is six to eight times faster than any manual method and produces cut components with a consistent level of accuracy.

Disadvantages: Requires a substantial initial investment.

Methods of cutting

The following points should be taken care of while cutting:
1. The blades must present very thin edge to the fibres so that high pressure may be presented to the fibres enough to shear them without stretching or deforming them. 
2. All fibres must be severed to allow the blade to pass through the fabric and produce free standing cut parts
3. the Act of cutting dulls the blade, so blade must be regularly sharpened to renew the thin sharp edge. 
4. The methods of cutting must not remove any material between the cut parts
5. Fabrics should return to their original shape after cutting
                                                                                      

The Cutting of the Fabric

The objective of Cutting

The objective of cutting is to separate fabric parts as replicas of the pattern pieces in the marker. In achieving this objective, certain requirements must be fulfilled.

1. Precision of the Cut

The garments must be cut with as much precision as possible.

2. Clean Edges

The raw edges of the fabric should not show fraying or snagging. Such defects come from an imperfectly sharpened knife

3. Unscorched, unfused Edges

The built up of heat in the knife blade comes from the friction of the blade passing through the fabrics. Solutions to this problems lie in well sharpened blade, the use of antifusion paper, spraying the blade with silicon lubricant, slowing down the speed of the cutting blade and reducing the height of the lay.

4. Support of the Lay

The cutting system must provide not only to support the fabric but also to allow the blade to penetrate the lowest ply of a spread and sever all the fibres

5. Consistent Cutting

The cutting system must cut accurately irrespective of the height of the pile.

The Cutting of the Fabric

spreading of the fabric-2

5. Elimination of Static Electricity



In spreading plies of fabric containing man made fibres, friction may increase the static electricity in the fabric.The spreader will experience in laying a ply neatly on top of the others due to either attraction or repulsion of those plies according to how they are charged.



Method to reduce static electricity



- Change the method of threading the fabric through the guide bars

- increase the humidity of the atmosphere in the cutting room

- arrange to earth the lay



6. Avoidance of distortion in the spread



A layer of glazed paper, laid glazed upside down, is normally placed at the bottom of the spread. This helps to avoid disturbing the lowest plies on the material in the spread when the base plate of a straight knife passes underneath. Also gives stability to the lay if it is to be moved on a table.



7. Avoidance of Fusion during cutting



Anti-fusion paper may be used in the same way as interleaving. It contains a lubricant which lubricates the knife blade as it passes through the spread.



Method of Spreading



1. Spreading by hand onto a horizontal table



In this process, the fabric is drawn from its package. The operator work back from the end, aligning the edges and ensuring that there is no tension and there are no wrinkles. The ply is cut with hand shears.



Typical fibres which are spread by hand are checks, crosswise stripes and other regular repeating patterns.



2. Spreading by hand and hooking up: This method uses a table with a horizontal surface at normal height. The table incorporates a swivel device which enables the table to be tilted so that the surface is about 10 degree off the vertical. The top edge of the table carries a series of hooks. The spreader hooks the selvedge of the fabric onto these hooks, while maintaining the correct tension down the length of ply. He begins at one end and works towards the other. whenthe spread is complete the table is returned to the horizontal position, the hooks are retracted and the marker is positioned on the top.

This method is used when it is difficult to lay the plies on a horizontal table or when it is wished to align checks along one selvedge.

3. Spreading using a travelling machine

these carry the piece of fabric from end to end of the spread, dispensing one ply at a time on to the spread

Consideration in Spreading (number 3, No.1 is requirement, number 2 is method of spreading)

The nature of fabric package

The fabric packages vary in length, width and make up. The forms of fabric piece that can be used are as follows:

1. Open face rolled: Most fabrics are rolled as a single ply on to a disposable tubular cardboard core about 7 to 8 cm in diameter. The packages are suitable for spreading by machine.

2. Tubular knitted fabric rolled
this is usually used for the manufacture of garments such as sports shirts or t-shirts

3. Folded fabric rolled
This form is traditional with the woollen and woollen fabrics used in tailored garments

4. Folded fabrics- cuttled
This form occurs usurally with check fabric to avoid the distortions which may ensue from tight rolling.

5. Velvet-hanging
Some velvets may be delivered wound on specially constructed frames to prevent the pile becoming crushed

Spreading of the Fabric-1

Objective

The objective of spreading is

1. To place a number of plies of fabric under the marker according to the planning process.

2. in the colour required

3. correctly aligned as to length and width

4. at correct tension

Limitation of Spreading

1. It requires strongly constructed tables usually with steel legs and braced frames

2. Spreading itself is a time consuming process

Remember

Spreading is no more than a sophisticated method of material handling, it adds nothing to the manufacture of garments. In conventional cutting rooms it is a technological bottleneck.

Considerations in Spreading

a. The requirements of the spreading process

Spreading must achieve a number of specific objectives:

1. Alignments of the plies

Every ply must comprise at least the length and width of the marker. In addition it should have minimum possible extra outside those measurements. Because nature of fabric is such that fabric width varies piece to piece

2. Elimination of the Fabric Flaws

Fabric flaws may be identifies by the supplier or by the spreader. It must be eliminated by different methods.

3. Correct Ply direction

For fabrics designated both one way only and one way either way, the spread should contain plies whose surface direction is compatible with the pattern facing of the marker.

4. Correct Ply Tension

If the plies are spread with too slack a tension they will lie in ridges with irregular fullness. If plies are spread in a stretched state they will maintain their tension while held in a lay, but will contract after cutting or during sewing, thus shrinking the garment parts to a smaller size than the pattern pieces. Thus tension in the plies should be optimum.

cutting-4

The requirement of quality in Cutting

Wherever a knife blade is used, the placement of the pattern pieces in the marker must give freedom of knife movement. It should not restrict the path of knife so that it leads to inaccurate cutting.
For example, a blade, which has width, cannot turn a perfect right angle in the middle of a pattern piece. Space must be allowed for a knife to turn such corners.


A pattern count must always be made at the completion of a marker. This is done to check that the complete menu of patterns has been included. For example, a 12 size trouser marker, where each trouser size has 16 pattern pieces, signifies a complete menu of 192 pattern pieces.

Correct labeling of the cut garment parts is essential. It is the responsibility of the marker planner to code every pattern piece with its size as the marker is made.

2. The requirement of the production Planning

When an order is placed for a quantity of garments , it normally specifies a quantity of each size and color. Size is often given as a ration. For best utilization of cutting room resources, a high lay rather than a low lay gives a lower cutting labour cost per garment. It will also give lower overall cutting time.

Scrambling

The mixing of sizes in a marker is termed as scrambling. Upto a point, the more sizes that are included in a marker, the greater the scope for fabric savings.

Stepped Lay

Some times single, sized markers are used in a stepped lay

Marker Efficiency
It is defined as


A marker planner can improve the marker efficiency by
a. suggesting alterations to pattern
b. suggesting alterations in cloth

Alteration to pattern: In this the seam location is examined and best possible placement of pattern in the marker is made. This is done by shifting the seam so that small parts can be placed in areas which are otherwise wasted
Alteration to cloth: In this the marker planner can select the fabric width.

Methods of marker planning

Manual Marker Planning

It is used for short marker or single sized markers
In this the planner works by moving around the full sized patterns, either directly or on paper.

Manual marker planning in miniature

In this a miniature of marker is produced. With the help of plenimeter, marker efficiency is calculated. After getting the highest marker efficiency, the pattern is again marked back to full size.

Computerised marker planning

In this the planner specifies the following parameters to the computer:

- The width of the fabric
- The pattern pieces to be used
- Size to be included
- Other constraints eg. Matching of the checks.

The system can produces the marker either
- automatically
- interactively

In automatic marking, the placement of pieces are previously defined in computer. That arrangement is called up that gives the highest marker efficiency.

Advantages

Rapid method of obtaining a relatively efficient marker

Disadvantages

There is no guarantee that the best marker is achieved

In interactive marker making, the operator plans markers by interacting directly with the system through a graphic display terminal

Advantages of computerized marking

The quality of marker planning is more consistent than with manual method because
Instructions regarding grainlines are always followed
Butting of patterns is precise with no overlapping
Pattern count is automatic
It provides grading facility
It enables the reproduction of as many copies of a marker as are required.

Disadvantages

Cost of computer equipment is very high

Methods of drawing and duplicating markers:

Once the planning of a marker has been completed, there is need for it to be drawn out in a way that cutter can use and which can be duplicated if multiple copies of the same plan is needed.

The method of drawing markers can be classified as

Drawing the shape of the patterns onto paper by marking around the patterns by hand.
Drawing the shape of the patterns onto paper using a plotter linked to the computer on which the marker was planned
Recording the shape of the patterns, hence its edge on paper by photographic method
Marking directly onto fabric by drawing round the patterns or by spray marking

Hand drawing round patterns onto paper

In this method the marker maker lays out the pattern on paper, the order already planned. He then draws the pattern pieces with a pencil or ball point pen and identifies each pattern with a size code.

Advantages: Most common method of marker making in bulk production

Disadvantages: It cannot be used readily with check fabrics. Because checks are not easily seen through paper, when it is put on the lay

Computer Controlled plotting on paper

After planning the marker on a visual display unit, the marker maker instructs the computer to trace the marker automatically onto paper. Any number of copies can be produced

Photographic system for paper markers

These create paper markers which show pattern shapes but avoid the need to draw round them by hand. In one method marker maker positions the pattern pieces on a light sensitive paper. Ultra violet lamps travel over the marker to expose the pattern which is then developed in ammonia vapour. Accuracy is high. High capital investment is required.

Marking Directly onto fabric

Marking round pattern pieces

Chalk or pencil is here used to mark round pattern pieces by hand. It is most traditional and simplest method. It is economical for single garments and check fabrics. It allows manipulation of the patterns during the marking process. It requires considerable skill. It takes the longest time. Dark coloured chalks can stain light coloured fabrics.

Spray Marking

In this after the pattern pieces are placed on the fabric, the marker maker lowers a net, held taut by a frame, onto the fabric to secure the position of the pattern pieces. A machine with a pump ejecting a fine spray is parsed over the marker. With the whole marker sprayed, the marker maker removes the patterns to leave an unsprayed silhouette. Very good on check fabrics. This method does not work satisfactorily on more sheer, less absorbent fabrics. Machine requires a lengthy cleaning process. While duplicating, successive layers of paint build up on the patterns, until they become so thick they lose accuracy.

Duplicating the patterns on paper

Carbon Duplicating: In this the marker maker lays out the number of plies of paper, interlaced with carbon. As the marker maker marks the top ply, an impression is simultaneously transferred to other copies.
Advantages: It can create upto six or eight copies in addition to the original
Disadvantages: It is a dirty process, particularly when the carbons are new. It can be less accurate in practice, since papers can be moved out of alignment during marking. Cutting lines can become less clear on the lower plies of a high stack. It is not always possible to predict the number of copies required as the time the marker is made.
Non Carbon Duplicating Papers.
Advantages: More copies can be achieved. It saves time by not having to roll out and re-roll carbons.
Disadvantages: Paper cost is high.
Paper combined with disposable carbons
It delivers more copies and saves time. When the cutting room uses only a few copies of each marker, this method pays best because of low capital costs and manual costs. It can provide an acceptable definition of lines, if too many copies are not attempted simultaneously.
Spirit Duplicating or hectograph carbon system
In this carbon is transferred to the underside of the master during marking. This carbon is released onto copy paper during reproduction.
This method can produce upto 40-50 copies per minute. The costs are reduced as more copies are required. It is a wet and messy process. Accuracy can be reduced due to twisting, creasing, shrinking or stretching of paper. Consumes time as copies should be left to dry for five minutes. It is sometimes necessary to remark parts of the marker after a few copies have been run off. It is very difficult to use wider marker as size of machine and difficulties of operations increase.
Pressurised Duplicating
In this method the carbon in the master is transferred to the pressure sensitive paper of the copy by pressurized roller. This method can produce upto 50-60 copies per master. It is more accurate as there is less likelihood of paper twisting and creasing. Paper is more expensive. Special marking pen does not produce very thin line.

Photographic Method
The original marker is copies using ultraviolet light on light sensitive paper. The image is then developed by means of ammonia vapours.
It is the quickest copying method. It ensures good definition of line. It is a cleaner process. The system can duplicate an unlimited no. of copies. It is also convenient to duplicate small quantities as they are required for current production. Removal of ammonia vapors is a problem. It is expensive for a small number of copies.

Perforated markers
In this the marker maker lays out the pattern pieces on light weight pattern card, draws round each piece with pencil and identifies each piece with a size code using a long arm sewing machine which carries a punch in place of a needle, the marker maker punched a series of perforations around the periphery of all the pattern pieces, and punches out the outlines of the size codes. The perforated marker, placed on top of the lay, is dusted with French chalk. The perforated marker can be used many times. Line definition can be poor unless great care is exercised. The cutting knife can cause the chalk dots to vibrate, thus sometimes dissipating the lines. It involves about twice the time of producing a hand drawn marker plus the cost of dusting.

cutting-3

The requirement of quality in Cutting

Wherever a knife blade is used, the placement of the pattern pieces in the marker must give freedom of knife movement. It should not restrict the path of knife so that it leads to inaccurate cutting.
For example, a blade, which has width, cannot turn a perfect right angle in the middle of a pattern piece. Space must be allowed for a knife to turn such corners.


A pattern count must always be made at the completion of a marker. This is done to check that the complete menu of patterns has been included. For example, a 12 size trouser marker, where each trouser size has 16 pattern pieces, signifies a complete menu of 192 pattern pieces.

Correct labeling of the cut garment parts is essential. It is the responsibility of the marker planner to code every pattern piece with its size as the marker is made.

2. The requirement of the production Planning

When an order is placed for a quantity of garments , it normally specifies a quantity of each size and color. Size is often given as a ration. For best utilization of cutting room resources, a high lay rather than a low lay gives a lower cutting labour cost per garment. It will also give lower overall cutting time.

Scrambling

The mixing of sizes in a marker is termed as scrambling. Upto a point, the more sizes that are included in a marker, the greater the scope for fabric savings.

Stepped Lay

Some times single, sized markers are used in a stepped lay

Marker Efficiency
It is defined as


A marker planner can improve the marker efficiency by
a. suggesting alterations to pattern
b. suggesting alterations in cloth

Alteration to pattern: In this the seam location is examined and best possible placement of pattern in the marker is made. This is done by shifting the seam so that small parts can be placed in areas which are otherwise wasted
Alteration to cloth: In this the marker planner can select the fabric width.

Cutting-2

Processes involved in a cutting room

1. The planning, drawing and reproduction of the marker
2. The spreading of fabric to form a lay
3. The cutting of the fabric

1. The planning, drawing and reproduction of the marker:

It has three parts:

1. Marker Planning
It is the placement of the pattern pieces:
1. To meet technical requirements
2. To economise material

2. Marker drawing

It is marking the oulines of the pattern on the marker by pencil, chalk or some autometic method.

3. Reproduction of the marker

It is dublicating the original marker in required quantity for
a. To reduce the time
b. reduce the cost of repeatedly marking in patterns

Marker Planning

Why Important
Marker planning is important because when the cutting room cuts cloth, it spends around half of the company's turnover. Therefore any reduction in the amount of cloth used per garment will lead to a increased profit.

Aim
The aim of the marker planning is to try a number of pattern placements, selecting the one which gives the shortest marker.

Constraints in the work of marker planning

1. Nature of the fabric
2. Desired results in the finished garment
3. Requirements of quality in cutting
4. requirements of production planning

1. Nature of the fabric

a. Pattern alighment in relation to the grain lines

grain
It is the direction in which a fabric is woven (lengthwise grain or warp, crosswise grain or weft)

Lenth Grain (warp)- Yarns parallel with the selvedge and at right angle to the cross grain. This is the strongest grain and drapes best when perpendicular to the floor.

Cross Grain (Weft)- Yarn woven across the fabric from selvedge to selvedge. It is the filling yarn of woven fabric. Cross grain yields to tension.

Bias- A slanting line or diagonal line cut or sewn across the weave of the cloth.

True Bias (45o angle)
The angle line that intersects with the length and cross grains at a 45 degree angle. True bias has a maximum give and stretchability, easily conforming to the figures' contours.

The pattern must be laid down within the stated rules, f0r grain lines. If this is not followed then the finished garment will not hang and drape correctly when worn.

Rules for conforming to the grain lines

1. The grain line should lie either parallel to line of warp or weft and not in between
2. For bias cutting, the grain lines will normally be at 45 degrees to the warp.

The designer or pattern cutter may define a tolerance which allows the marker planner to swing the grain line a small amount from the parallel

b. Symmetry or asymmetry

Symmetrical or Either way fabrics: Most fabrics can be turned around and retain the same appearance. These are known as "either way" or "symmetrical " fabrics

Asymmetrical or oneway-eitherway fabrics
These are those fabrics, whose ply, if turned around, does not retain the same appearance. However, as long as the pattern pieces of an individual garment all lie in the same direction, which direction they lie does not mattern.

One way only fabrics
This applies to fabrics with a design object which can only be used one way up, eg. velvet.

Here the marker must ensure that the top ends of the pattern pieces all face the same way

c. Design Characteristics:
E.g. if a vertical stripe does'nt show a complete mirror image repeat, the right and left side fo the garment may be designed to be mirror images of each other. In this case a marker is planned which uses a half set of patterns, and the required effect is created in the spreading of the fabric which places pairs of plies face to face.

Cutting

Objective of the cutting room

1. To cut the garment parts accurately and economically

2. To cut the garments in sufficient volume to keep the sewing room supplied with work

Necessity of Cutting

1. A garment is made of several pattern shapes, whereas the cloth supplied is of single width and length. Cutting is necessary to introduce shape in the garment.

2. A fabric has only one width. The width may be small or large. Thus cutting is necessary to overcome the limitations of fabric width

3. A piece of fabric wrapped around the body must be joined somewhere. Therefore, cutting is necessary to locate appropriately the position of the joint.

Steps in Cutting

1. To cut a single garment, the garment pattern is attached to one or two piles of the fabric

2. Care is taken to match the design on the fabric

3. The garment parts are then cut with hand shears, electric cutters or die

To cut large quantities of garments

1. To cut large quantities of garments, a lay is created. A lay consists of many piles of fabrics spread one over the another.

2. On top of this lay, a marker is placed. A marker consists of a length of paper. All the pattern pieces for all the sizes of the garment are drawn on it.

3. Care is taken to interlock closely all the pattern pieces. This will ensure minimum fabric usage.

4. The piles of the fabric in the lay are of the same length as the marker.

The number of piles in the fabric in the lay depends upon:

1. Requirement of the order for the garment. If the order is bigger, no of piles are more.

2. Availability of the material

3. Constraints of physical equipment: Capacity of the cutting scissors.

Back ground to the clothing industry

Garment companies employ as large and as small number of people. This wide variation is due to two special features of the the fashion industry.

1. Fashion requires quick response

Clothing is of two types
- Fashion or couture garments- made in small quantities at high cost
- staples- underwear, shirts, schoolwear - influence of fashion is minimal and there is a constant demand for large quantities.

Remember that level of technology used in clothing manufacture are closly related to the quantity and length of the manufacturing run of a style of garment that is made

2. The fashion industry is labour intensive and does not require fixed capital

Entry into clothing industry is relatively easy. The reason for this relates to the simplicity of the central process in clothing manufacture whcih is sewing.

It is the process of sewing which dominates the output of a clothing factory, however large or small it is.

A sewing factory produces low added value, becasue it is generally limited to a one operator-one machine organisation

Remember that sewing technology occupies only about one-fifth of the time of the average sewing operation. The other four-fifth of the time are occupied in activities such as preparing the fabric to be sewn, trimming, folding, creasing, marking and disposal after sewing and bundling.

Why this industry is labour intensive

1. Fabrics are limp

They bend in all directions. It is therefore difficult to invent jigs and autometic equipments for performing sewing operations.

2. Fabrics vary in extensibility

A minimum extensibility of yarn is needed in order that the needle may penetrate the fabric satisfactorily. Extensibility which is less than minimum and very high extensibility both give trouble in making up of the garment

3. Fabrics vary in thickness

4. Joining must achieve compatibility with the flexibility, drape and handle of the fabric, no substitute of sewing has yet been generally applied. Mechanically, a stitch is the only type of joing whose properties approach those of the fabrics

Cutting room mechanisation can be done and it is being done

Difference between cutting and sewing activities

In cutting room: As half of the wholesale cost of a garment is in material, the cutting process consumes half of the companies turnover when it cuts cloth and therefore economy of material is a major area of concern there.

Textile Finishing

Finishing is the general term for a multitude of processes and treatments which a fabric may undergo after it has been made (woven or knitted) and coloured (dyed or printed). It is the final processing of the cloth and its purpose is to make the fabric suitable for its intended end use. That may mean. for example, making the fabric shrinkproof, softer, stiffer, water repellent, crease resistant or a combination of these properties.

CLASSIFICATION OF FINISHES

Textile finishes and finishing are classified in several ways. Persons concerned with end products (designers, merchandisers and sales personnel) usually categorize finishes as aesthetic finishes and functional finishes. The former modify the appearance and/or hand (feel) of fabrics, while the latter improve the performance of a fabric under specific end use conditions.
Persons concerned with textile processing (chemists and finishers) categorize finishes into chemical finishes and mechanical finishes. These are also called wet finishing and dry finishing, respectively.

Finishes are also categorized by their degree of permanence. These finishes are called permanent, durable, semi-durable and temporary.

Permanent finishes usually involve a chemical change in fibre structure and will not change or alter throughout the life of a fabric.

Durable finishes usually last throughout the life of the article, but effectiveness becomes diminished after each cleaning, and near the end of the normal use life of the article, the finish is nearly removed.

Semi-durable finishes last through several launderings or dry cleanings and many are renewable in home laundering or dry cleaning.

Temporary finishes are removed or substantially diminished the first time an article is laundered or dry cleaned.

PRE-TREATMENT PROCESSES

Pre-treatment processes consist of cleaning operations to rid the fabric of all soil and additives used during the weaving or knitting process. These processes are usually the first treatments a fabric undergoes after leaving the loom or knitting machine and are required before any dyeing, printing or finishing can be accomplished.

The processes consist of various types of cleaning actions, depending upon the fibre, the impurities present and the fabric construction. In cottons, cotton blend, silk and man-made fibres, the processes are, known generally as the boil-off. In woolens and worsteds, it is called a scour or scouring.


RESINS

Resins are the chemical group used in many of the finishes.

Resins are the most widely used chemicals in the textile industry. They are used for many purposes, primarily on cellulosic and cellulosic blend fabrics.

Resins have a profound effect on and cause changes in the hand (feel), drapability and physical characteristics of textiles. While many benefits are achieved through these changes, there are also some shortcomings. Resins modify fabrics in the following ways:

A. They add stiffness to fabrics and are thus used as stiffening agents or to create a firm hand.

B. Resins stabilize fabrics in the same shape or configuration as when the resin was cured. Fabrics cured m a smooth, nonwrinkled condition will return to that shape after being wrinkled in wear, while fabrics cured with creases in garments will retain these creases.

C. Yarns in fabric will be stabilized and will resist shrinkage in laundering.

D. Fabrics will become less moisture absorbent, thus drying more rapidly. They will also be less comfortable in warm, humid weather.

E. Resins combine chemically with cellulosic fibres (cotton, rayon,ete.) to cause significant reductions in abrasion resistance, breaking strength and tear strength. This reduction can be as high as 50%.

F. Most resins produce an offensive "fish-like" or formaldehyde odour in fabric. This odour eventually disappears on exposure to air and/or laundering.

G. Resins have an affinity for oily soils, creating a soiling problem. Soil release finishes help alleviate this objection.

IMPORTANT FINISHES

Anti-static Finishes

Anti-static finishes are chemical substances applied at the textile finishing mill for the purpose of reducing or eliminating static. These chemicals are actually substances which absorb small amounts of moisture from the atmosphere, thus reducing the dryness of the fabric.
Anti-static finishes are not a truly satisfactory method for coping with the problem of static in textiles because they are merely semi-durable. These finishes wash out or wear out in several launderings or dry cleanings. Permanent anti-static efrects are obtainable, however, with the man-made fibres which have been especially modified for this purpose.

Antiseptic Finishes

Antiseptic finishes are chemical agents inhibiting the bacterial growths which cause irritation and odour in shoes, luggage, underwear fabrics and similar items. These finishes are low in cost, easily applied and are durable to laundering and dry cleaning.

Calendering

Calendering is not a single type of finish. There are various types of calender machinery, each producing different types of finished fabrics.

Fundamentally, a ealender is a mechanical device consisting of two or more large rotating cylindrical rollers stacked on top of each other and usually heated. The cylindrical rollers are in contact with each other under pressure. Fabric being calendered passes around and between these cylinders. The specific type of calendered finished fabric varies with the nature of the cylinder surface, the speed of the cylinders and the nature of the fabric being finished.

The various types of calendering finishes include the following
(a) Simple calendering (b) Glazing calendering (c) Embossed ealendering (d) Moire calendering (e) Schreiner calendering

Crease Resistant Finishes

Crease resistant finishes are popularly known as CRF finishes. They are used on cotton, rayon and linen because these three fibres wrinkle easily. CKF finishes are resin finishes; the fabric is saturated with resin and then the resin is cured at temperatures of about 360°F. The fabric becomes stiffer, less absorbent and more resistant to wrinkling. Resin treatments also results in tensile strength loss and reduction of abrasion resistance in cellulosic fibres. Most CRF finishes are durable.

Flame Resistant Finishes

There are two systems to make fabrics flame resistant. The first is to use selective fibres which have characteristic flame resistant properties. The second is by the use of flame resistant finishes.

All of the many types of flame retardant finishes now available suffer from at least one of the following shortcomings : (a) they cause stiffening and loss of fabric drapability; (b) they result in significant strength loss in fabric; (c) they are easily removed in laundering (nondurable); and (d) they become ineffective when laundered in household bleach, with soaps or with water softeners.

Fulling

Fulling is a permanent finish used on wool fabrics; it is also known as milling or felting. The process is a carefully controlled scouring or laundering process to induce felting shrinkage in wool fabrics. The resultant fulled fabric is smoother, more compact and has yarns more tightly embedded than an unfulled fabric. Woolens are frequently heavily fulled.

Mercerization

Mercerization is one of the most important of all cotton finishes. This finish imparts luster to the cotton, increases its strength by nearly 25% and improves dye affinity, producing brighter shades than unmercerized cotton. It also enhances the hand as well as uses less dye to achieve the same depth of shade. The finish consists of treating the material while under tension with cold, concentrated sodium hydroxide solution. Both fabrics and yarns can be mercerized, but fibres cannot. Mercerization is a permanent finish.

Napping

Napping is a mechanical finish in which woven or knitted fabrics are passed against rotating, bristled wire-covered brushes. This action results in fibres actually being raised from the fabric. The overall effect is a fabric with raised fibre surface.

Napped fabrics have a softer hand and provide better insulation than the same materials unnapped because they can entrap more air; hence, their wide use in blankets, sleepwear and winter clothing. However, the insulating value of cotton and rayon napped fabrics is not long lasting. The low resilience of these fibres causes premature flattening of the fibre nap.The nap can partially be restored by frequent brushing.

Plisse

Plisse is the name of a finish as well as the name of a fabric treated with this finish. It is a permanent finish, produced on cotton by the action of sodium hydroxide; but unlike mercerizing, no tension is used. The sodium hydroxide is printed on the fabric in the form of a paste.The fabric shrinks only where the sodium hydroxide is applied, producing a puckered effect.

Shearing

Shearing is a process used to cut off surface fibres on fabrics. It makes uniform the surface of napped fabrics. Most cut pile fabrics are also sheared to provide uniform pile height.

Soil Release Finishes

Soil release finishes in fabrics permit relatively easy removal of soils (especially oily soils) with ordinary home laundering.

There are several types of soil release finishes. All of them accomplish the end result of making the fibre more absorbent (hydrophilic), thus permitting better “wettability" for improved soil removal.

Most soil release finishes are applied at the same time that the resins are applied to textiles. Most are durable through 40 to 50 launderings and are routinely applied to fabrics for work clothes and table cloths. They are also often applied to fabrics for slacks and skirts.

Several other benefits arise from the use of soil release finishes in durable press fabrics because of their increased absorbency. These include: improved antistatic properties, improved fabric drapability and somewhat greater comfort in hot weather.

An interesting FAQ about textile finishing can be found here. 

Textile Printing-1

Printing has often been described as dyeing in a localized, patterned design. Textile printing utilizes the same dyes or pigments applied to produce a dyed fabric.The same principles of specific dye classes having select fibre affinities and the general fastness characteristics apply equally to printing as to dyeing.

Dyes or pigments used in dyeing are usually in a water bath solution. When the same dyes or pigments are used for printing, they must be thickened with gums or starches to prevent the wicking or flowing of the print design.The thickened solution, about the consistency of heavy buttermilk, is called the print paste.

Many dyes cannot be used in printing pastes. Some of the reasons include insufficient solubility, Low colour yield and poor print paste stability.

METHODS OF PRINTING
There are several methods for printing of textiles. Two are of significant commercial importance: the roller print method and the screen print method. A third method, heat transfer printing, is of less significance. Other printing methods, not widely used in commercial production of textiles, are block and batik printing.

Roller Printing

This method of printing is comparable to newspaper printing. It is a high speed process, capable of producing over 6000 yards of printed fabric per hour. The method is also known as machine printing.

In roller printing, the design is put into fabric by copper engraved rollers (sometimes called copper engraved cylinders). The roller engravings match exactly the artist-designer's creative sketch. A separate engraved cylinder is required for each colour in the print. The size of the engraved cylinders is governed by the printing machine and the design.

HOW ROLLER PRINTS ARE MADE

1. The Engraved Copper Roller A in rotation makes contact with Colour Furnisher B (whose surface is much like that of a paint roller used in house painting). The entire surface of Roller A becomes covered with print paste.

2. Colour Furnisher B, also in rotation, picks up a constantly fresh supply of print paste from Colour Box E.

3. Meanwhile, Engraved Copper Roller A in rotation comes in contact with Doctor Blade C. This is a steel blade which functions somewhat like a squeegee. It scrapes off all the print paste on the surface of Roller A, but cannot clean off the print paste from the engraved portion, and thus leaves behind the print paste inside the etched copper.

4. The cloth to be printed is drawn and guided between the Cylinder Roller and Engraved Copper Roller A. The pressure created at the point of contact causes the print paste to be transferred from inside the etched copper to the cloth. The pattern is now on the cloth.

5. Engraved Copper Roller A continues in rotation and comes in contact with Lint Doctor D, a steel blade which comes in contact with Roller A and removes any lint picked up from the fabric being printed.

6. The cloth being printed continues its path around the Cylinder Roller. If a 2nd, 3rd or 4th colour is to be printed on the same fabric, then Steps 1 through 5 will be repeated for the respective 2nd, 3rd or 4th sets of Engraved Copper Roller, Doctor Blades, Colour Box and so forth. The fabric makes only one pass through the roller printing machine. Successive colours do not become smudged because the pressure of the engraved roller on the fabric being printed literally squeezes the print paste into the fabric and the surface colour dries instantly.

7. The printed cloth on leaving the machine is immediately dried so that the fabric can be touched without smudging the print. Afterwards, the fabric is transferred to a steam chamber where moisture and heat will set the dyes. If pigments rather than dyes are used, the fabric is entered into a dry heat curing oven at temperatures up to 400°F.

8. 'The Back Grey is a fabric that moves through the print machine along-with and in back of the fabric being printed. Its function is to absorb the excess print paste which may strike through and stain the Cylinder Roller cover. The Back Grey is later washed out and used over and again. It eventually takes on a dingy grey colour, hence its name.

Screen Printing

Screen printing is a method whereby an open, but closely meshed screen, mounted in a wooden or metal frame, is placed in contact with the fabric to be printed and the print paste forced through the screen by a squeegee (implement edged with rubber for sweeping water from surfaces). The design is created by painting out or otherwise making opaque portions of the screen, thus preventing the print paste from passing through. Those areas where the print paste does pass through will register as the printed pattern.

There are actually three methods of screen printing, each of which embodies the same principle. The first, hand screen printing, the second method is automatic screen printing or flat bed printing or automatic flat printing and the third method is the rotary screen printing or rotary printing.

Hand Screen Printing

Hand screen printing is done commercially on long tables (up to 60 yards in length). The roll of fabric to be printed is spread smoothly onto the table, whose surface has first been coated with a light tack adhesive. The print operators then move the screen frames, by hand, successively along the whole table, printing one frame at a time, until the entire fabric is printed. Each frame will contain one colour of the print. A three colour print, for example. will require three frames and three applications to the fabric. The rate of production ranges from 50 to 90 yards per hour by this method.

Automatic Screen Printing (Flat Bed Printing)

Automatic screen printing (flat bed printing) is like hand screen printing except that the process is automated and therefore, faster. Instead of the long table on which the fabric to be printed is spread (as in hand screen printing), the fabric is moved to the screens on a wide rubberized belt. Like hand screen printing, it is an intermittent rather than a continuous process. In this instance, the fabric moves to the screen, then stops for the screen squeegee action (which is done automatically). After the squeegee action, the fabric moves again to the next screen frame. The rate of production is about 500 yards per hour. Automatic screen printing is utilized for whole rolls of fabric only.

Rotary Screen Printing

Rotary screen printing is different from the other methods of screen printing in several important respects. Rotary printing is continuous like roller printing. The fabric being printed is moved on a wide rubber belt under the rotary screen cylinders which are in continuous movement. Rotary screen printing is the fastest method of screen printing, with production of 2500 to more than 3500 yards per hour. Seamless, perforated metal or plastic screens are used. The largest rotary screens have a circumference of about 40 inches and the maximum repeat size of patterns is, therefore, about 40 inches.

Heat Transfer Printing

Heat transfer printing is sometimes called thermal transfer printing. In this method, the design is first printed on paper with printing inks containing dyes of the disperse dye class. The printed paper (called transfer paper) is then stored until ready for use by the textile printer or converter.

When fabric is to be printed, it is passed through a heat transfer printing machine which brings paper and fabric together face to face and passes them through the machine at about 400°F. Under this high temperature, the dye on the printed paper sublimates and is transferred onto the fabric.The process, resembling somewhat the familiar decal transfer, is relatively simple and does not require the expertise necessary when producing roller or rotary screen prints.

Disperse dyes are the only dyes which can be sublimated. and thus the only ones which will respond in a way that permits heat transfer printing. The process is therefore limited to fabrics which are composed of fibres having affinity to this class of dyestuff. This includes acetate, acrylics, polyamides (nylon) and polyesters.

The Above table give a list of the printing methods and their advantages and disadvantages.

PRINTED FABRIC IMPERFECTIONS

The following is a listing and description of the more frequently occurring imperfections that may result from printing processes. These imperfections may result from faulty or improper printing procedures, faulty or improper preparation of the fabric prior to printing or to imperfections in the material being printed.

Since the printing of textiles is in many respects similar to the dyeing of textiles, many of the imperfections found in dyed fabrics are also found in printed fabrics.

A. Colour Drag- Colour of the print smears or smudges from rubbing against an object before it becomes dry.

B. Colour Splatter-The print paste instead of being placed on the fabric is thrown or splattered onto the fabric surface.

C. Fuzzy Pattern - The edges of patterns are not sharp, clear lines, but are instead rather fuzzy lines. Most frequently caused by improper singeing or improperly thickened print paste.

D. Off-register- Printing rolls or screens improperly aligned so pattern parts do not meet properly. This imperfection is also called out-of-fit or out-of-register.

E. Stop Mark- Colour streak across the fabric resulting from the printing machine being stopped during the printing process and then starting again.

F. Tender Spots- In printed fabrics, one or more colours of the print may cause weakened areas where they were printed. Usually due to excessive use of injurious chemicals in the print paste. May also be found in the discharged area of discharge prints.

Textile Dyeing -3

Dyeing and Types

Dyeing can be done during any stage in the manufacture of a textile. They may be dyed as fibre, as yarn, as fabric or as garments, depending on the type of fabric or garment being produced.

Stock dyeing refers to the dyeing of fibres or stock, before it is spun into yarn.

Sliver of worsted known as top is sometimes dyed in the stage of manufacture between fibre and worsted yarn.

Skein dyeing consist of immersing large, loosely wound hands of yarn into dye vats which are specially designed for this purpose.

In package dyeing, about a pound of yarn is wound on a small perforated spool or tube called a package. Many spools fit into dyeing machine in which the flow of the dye bath alternates from the centre to the outside and then from the outside to the centre of the package

In Beam dyeing, an entire warp beam is wound on a perforated cylinder, which is then placed in the beam dyeing machine where the flow of the dye bath alternates as in package dyeing.

The main reason for the dyeing of yarn is for the manufacture of plaids, stripes, checks and other multicoloured designs.

Cross dyeing

It is a special type of dyeing in which a yarn, a fabric or even a garment made with two or more kinds of fibres having different dyeing qualities is dyed in a single bath containing two different classes of dyes. Each kind of dye colours only one type of fibre. Two different colours can be dyed in one dye bath or either type of fibre may be dyed, leaving the other white.

Textile Dyeing-2

Classes of Dyes

Textile Dyeing-1

Textile Dyeing

There are three distinct categories by which color is imparted to textiles . These are:

By Dyeing
By Pigment Application
By Solution or Dope Dyeing

Of the three categories, the most widely used is dyeing.

Essentially, dyeing involves the use of highly complex organic chemical dyestuffs, which will under proper conditions, actually combine with the textile fibre molecule. Usually the fibre, yarn or fabric is immersed in a water solution of the dye, frequently under carefully regulated high temperature, untile the dye in the bath combines with the material to reproduce the desired colour.

Textile colouring by use of pigments differs from dyes in that pigments do not combine with the fibre molecules as dyes do. Pigments physically hold onto the textile material with resin binders in much the same way that paint holds to a wall.

Solution dyeing differs from the previous two categories mentioned because the coloration of the textile is part of the fibre manufacturing process of man-made fibres. In solution dyeing, appropriate coloring agents are added to the man-made fibre solution before it is extruded from the spinnerette.

Selling Points of Different fibres

Cotton - see the fabrics made from cotton here

• Economical
• Versatile
• Easy to care
• styled attractively
• comfortable- absorbant
• durable

More of them here

Linen

• Versatile
• sacrce
• cool- vegetable fibre
• easy to care fro and hygenic- does not spoil as easily as cotton
• durable- fibres are stronger and longer than cotton

Silk

• Attractive- can be made in sheer and dainty textures
• finest
• easy to drape- in graceful folds
• warm- in proportion to weight
• durable- strongest natural fibre in commercial use

Wool

• Soft- short elastic wool fibres, slack twisted carded yarn, fuzzy or hairy surface
• comfortable- the thermoelastic, elasticity of fabric, ease in tailoring
• Attractive- soft cushionlike texture, deep rich colors, good draping quality

Worsted

• Firm- longer fibres, tighter twisted yarn, harder surface
• durable- highly twisted, close weave, clear surface
• easy to keep pressed because- highly twisted yarn, close weave, hard surface

Rayon and Acetate

• Take dye well
• dont change lustre during washing
• dont yellow with age
• resist light better than silk
• do not mold or mildew/ sea water
• look like natural fibres
• as the fibres lack elasticity, garments may bulge or break at the point of strain
• Acetate should be ironed with a warm iron- not hot
• Acetate rayons are warmer than rayons

Nylon

• Elastic- v. good for knitting
• nylon filaments- when dry are stronger than any other fibres ( twice as strong and 1/2 as heavy than aluminium wire of same size)
• Nylon hosiery can be very sheer yet strong
• dont mildew
• can be dyed
• dries quickly- v. good for hosiery bathing suits
• wear and tear resistant
• can be heat set.

Acrylic

• Soft when made of spun
• warm when 'high bulk yarn'
• bulky but not heavy
• comfortable
• varied textures
• good resistant to sunlight, soot, sm0ke, flames
• easy to care for
• good colorfulness

Modacrylics

• Warm and soft to touch
• Non allergic- used for pillows and stuffing
• Resilient- matting
• non absorptive- doesnt weaken or flatten, used for coat collars or mittens
• resistant to UV, fire, inorganic acids, bacteria, abrasion

Polyesters

• very wrinkle resistant
• resistant to dirt, stains and moisture
• smoooth and crisp looking even in humid weather
• easy to care for- drip dry/ no ironing
• resistant to sun/ abrasion and moths
• non allergic
• light weight and strong

Vinyl Plastic

• tough and strong- tennis raquet string
• quick drying and easy to clean
• resistant to moth, dirt, soil, grease and chemicals

Spandax

• resilient/ form fitting

Metallic

• luxurious appearance
• resistance to sunlight/ abrasion chemicals
• durable

Glass

• Fireproof- theatre lobbies
• Non absorptive
• strong- limited stretch
• resistant to microorganism or insect/ sunlight
• water repellent

Rubber

• Elastic and enduring form fitting

Selling Points of Different fibres

One pointers for Fibres

Silk: The Luxurious fibre
Wool: the warm fibre
Cotton: The economical fibre
Flax: The hygenic fibre: launders easily- hot water and soap don't harm- stronger wet than dry
Acetate: The beautiful fibre
Azlon: the soft blender
Glass: The non flammable fibre
metallic: The luxury look
Nylon: the strong fibre
Acrylic: warm, lightweight fibre
Modacrylic: Fleecy, furlike fibre
Polyester: The resilient fibre
Saran- V. resistant to hard wear and suited for auto seat covers also
Vinyon- The industrial Fibre
Olefin- The lightweight fibre
Spandax- The expendable fibre

New Denim Project

Operating Profit Review

If sale = 100 Rs.

Raw Material= 56 Rs.
Color and Chemical= 6 Rs.
Packing = 1 Rs.
Power= 8 Rs.
Fuel = 2 Rs.
Transport = 2 Rs.
Sales Commission = 5 Rs.
Working Capital Interest = 3 Rs
Salary= 0 Rs.
Wages= 1 Rs.
Stores= 1 Rs
Spares = 2 Rs.

Total = 54 Rs.

So Profitability = 16 Rs.

Some Terminology

Voile : It is a doubled yarn, high twiested with count range >60's . It has an square and open construction. The fabric made from it is light weight, transparent crispy and granular feel. It can be either cotton or p/c. Its trade name is 2x2 Rubia. 72 epi and 72ppi

Cambric: It is a single yarn, rest properties are same as cambric.

Shiffon: Here weft is highly twisted polyester filament (tpm 1440) and textured and warp is P/C ratio is 67:33

Oxford Classical : Warp 2/40's , weft 2/30's

Oxford Pinpoint: Both warp and weft 2/80's, 144 ends/inch in grey and 60-62 ppi.