Weft Knitted Fabrics

It is not possible to discuss the technology of knitted garment manufacture without describing the constituent fabrics that influence the construction and properties of garments made from them. At the same time it must be stated that this is not intended to be a comprehensive treatise on knitted fabric.

Looped fabrics

There are three recognised looped constructions: warp knitting, weft knitting and crochet (Fig. 2.1).
Warp knitting is characterised by the structural threads of the fabric running along the length of the fabric approximately parallel with the selvedge. One horizontal row of loops, or course, is made from many threads.

Weft knitted fabrics are characterised by the structural threads being perpendicular to the selvedge of the fabric. One horizontal row of loops (course) is made from one or very few threads.

Crochet, unlike the other two constructions, is solely hand-made. One thread is used which chains upon itself, and cross links are formed with previously formed chain to generate fabric.
This book is solely concerned with weft knitting.

Weft knitting

Knitted fabrics are formed from loops. The constituent loop of weft knitting is of the general shape shown in Fig. 2.2. It is said to have length (€), i.e. the length of the thread forming it from a to b. This is its most important dimension and in fact decides the area the loop covers and its width and height within a construction.

The loop in fact consists of two bends, an upper one and a lower one, half of which is on either side of the overall construction. The loop can vary in size, that is its length (€) can alter. It is rather obvious that as the loop length increases the area the loop occupies gets larger. Such a relationship is independent of the diameter of the constituent yarn, although usually within a knitted construction the yarn size increases commensurate with the loop size (Fig. 2.3).

We can describe such loops by relating them to familiar articles, so that the small loop represents the constituent part of a ladies hose or tights fabric, (loop length 0.2 cm), the medium loop the constituent part of a ladies fully fashioned classic sweater (loop length 0.55 cm) and the coarse loop a man's heavy outerwear sweater (loop length 3 cm).

Loops can be related to one another and can be intermeshed with one another to form fabrics. In a horizontal direction the relationship is a simple one of a series of loops formed by the same thread diagram (Fig. 2.4). In the vertical direction loops can be joined together by intermeshing (Fig. 2.5), whereby individual loops are connected by drawing subsequent loops through previously formed loops. The result is a fabric of matrix-like construction, having vertical and horizontal series of loops (Fig. 2.6).

Course  A horizontal row of loops is known as a course.
Wale  A vertical row of loops is known as a wale.

Plain fabric
In the simplest fabric construction all the units are of the same sort, i.e. each loop is the same shape and is pulled through the previously knitted loop in the same manner or direction. This simplest fabric is called plain weft knitted fabric, usually abbreviated to plain fabric (Fig. 2.7). Because all the loops intermesh in the same direction the fabric has a different appearance on each side. The side to which the loops appear pulled through is known as the 'face' or 'technical face'. The side from which the loops appear pushed away is known as the 'back' or 'technical back'.

Another characteristic of constructional appearance is that it is impossible to differentiate between the top of the fabric and the bottom.

Properties

The fabric is extensible in a course-wise direction and in a wale-wise direction. However, the degree of extensibility is different when pulled top to bottom from when pulled side to side. The course-wise extension is approximately twice that of the wale-wise extension due to the degree of constraint imposed on each loop by ifs intermeshing.

The loop pulled vertically extends by half its length while the loop pulled horizontally extends by its whole length, € (Fig. 2.8). The degree of recovery from stretch is not a property of the construction but depends on the nature of the raw material and yarn construction.

This is the first of the properties related to the Hsu-al and historical use of the fabric; garments made from plain fabric are constructed so that the minimum stretch is placed vertically on the human body and arms, and maximum stretch around the body. Present and past fashions usually demand garments that do not sag readily. Periodically there have been exceptions to this usage where the wales of the fabric have run from side to side of the garment. The Dolman sweater of the 1950s and more recently is one such usage.

The Dolman fashion was essentially draped, with folds developing under. the arms and around the tightly constrained waist. The draping was aided by another differential property of plain fabric: that the ease of bending the fabric is dependent on which side the bend is occurring, and whether the bend is wale wise or course wise (Fig. 2.9).

On the face of the fabric, bending takes place most readily along the wale outwards. On the back of the fabric bending takes place more readily along the course outwards. These subtleties of mechanical performance are very important in dictating the overall appearance of a garment. In a piece of unprocessed, unpressed plain fabric, the outer edges curl vigorously. The top and bottom curl in towards the face of the fabric and the sides towards the back of the fabric. Curling towards the face tends to diminish the forces causing the curling at the sides; likewise curling towards the back diminishes the tendency to curl towards the face. A few seconds play with a piece of fabric will show this to be true. In fact in the literal sense the fabric can be said to be most in a state of equilibrium when it is in a roll or sausage form.

Pressing or other heat/water processes are used to minimize or eliminate such curling which is caused by the directionality of the loop . formation. A cross section of the fabric cut vertically between wales (Fig. 2.10) shows that each loop bends in the same direction, towards the face, and is constrained in that form by being intermeshed with the loop below. However, the loop at the top is not constrained and is free to straighten, releasing the next loop, and so on, the guiding principle being that no loop or portion of yarn wishes to remain strained by bending.

A cross section through the fabric along the course (Fig. 2.11) shows a similar situation, all loops being curved towards the back. Again a release of the bending forces on the loops results in them straightening and curling towards the back of the fabric.

This property has a major influence on the design and construction of garments made from plain fabric. Obviously all the edges must be constrained in some way unless curling is deliberately desired. This is achieved by seams, welts and the use of other fabrics of a more stable

nature, especially ribs.

In addition, almost all garments made from plain fabric are constructed with the face outwards as the 'effect side', with the back inwards as the `reverse side'. This is primarily because of the difficulties of constructing side seams from pieces of unprocessed fabric. It is much more difficult to uncurl the edges of fabric when they are trapped between two layers, than when they are on the outside (Fig. 2.12). Neatness of appearance also plays a part in this choice.

The constituent loops of plain fabric can readily be disconnected from the structure, course by course, by merely pulling at the most exposed thread. This can take place either from the end first knitted or the end last knitted and is known as unroving. A related disconnection of loops leading to a breakdown of the structure is caused by a series of loops being sequentially unmeshed down one or a group of wales. The resulting fault is known as a ladder. Plain fabric incorporated into garments must be firmly locked into seams, or the structure changed into a different non/laddering, non/unroving form, such as the rib of a waistband or cuff of a sweater.

All knitted fabrics, including plain fabric, are relatively thick compared to the diameter of their constituent yarns, and are composed largely of air space. Because of this, knitted fabrics have excellent heat insulating properties. However their openness leads them to being very air/ water permeable, and therefore neither waterproof nor heat retentive under conditions involving air movement.

Plain fabric is the commonest weft knitted fabric and is produced by widely different sorts of knitting machinery in all forms from circular fabric piece goods to fully fashioned panels. Other structures are covered here using the same terms and concepts as in the discussion of plain

fabric.

Rib fabrics

Rib fabrics are composed of loops formed in opposite directions, so when viewed from one side both hack and face loops are apparent. All the loops of any one wale are of the same sort, either hack or face. The name rib is derived from the ribs of animals, whose contours rib fabrics resemble.

The simplest rib fabric is the 1 x 1 (one by one or one and one). This is formed by alternating wales of back and face loops. (Fig. 2.13a) is purely schematic and does not show the fabric in its normal relaxed form. When the fabric is relaxed (Fig. 2.13b) and under no strain in the direction of the courses, it collapses to a situation of alternate wales touching one another. The wales in between are hidden but show on the opposite side of the fabric.

The fabric therefore looks the same on both sides and appears to casual viewing to be composed solely of face loops. This collapse of the fabric is caused by the portion of the loops that bridges the face loops and the back loops within the structure. When the fabric is placed under strain by stretching along the course, the bridging portions are twisted into an S form by the legs of the loops. This twisting forms a storage of energy and the structure acts like a spring, quickly regaining its collapsed form when the strain is released.

Because of this, rib fabrics are used where portions of garments are expected to cling to the shape of the human form and yet be capable of stretching when required. Waistbands, cuffs and collars are typical applications, together with whole garments of a fitting nature.

Extensions of up to 120% can be obtained along the course, with normal constructions. Along the wale, rib fabric behaves very much like plain fabric, with very limited extensibility. As already mentioned, the fabric has no back or front, the appearance being similar on both sides. The fabric is also stable as a plane structure with no tendency to curl.

Other constructions of rib are possible and are widely used, such as two wales of face loops alternating with two wales of back loops to form

2 x 2 rib (Fig. 2.14). On the same basis there are 3 x 3, 2 x 1, 3 x 2 etc.

As the number of wales in each rib increases, the elasticity decreases 

because the number of change overs from back to front diminishes. Over

3 x 3 rib the fabric more and more behaves like plain fabric, even curling in favour of the dominant rib. Such structures are known as 'broad ribs' (Fig. 2.15).

Rib fabrics will only unrove from the end last knitted and l x 1 rib will only ladder from the end last knitted (Fig. 2. 16). All other rib constructions will ladder from the end first knitted. Such a property reinforces the argument for using ribs on the extremities of garments.

Purl fabrics
The simplest type of purl fabric consists of courses of face loops alternating with courses of back loops. This is known as 1 x l purl (Fig. 2.17). This, like 1 x 1 rib fabric, is balanced: for every face loop there is a back loop generating equal and opposite forces. The fabric is stable with no tendency to curl. It does, however, have a relaxed and extended form, collapsing in a vertical dimension so that each course lies at an angle to the plane of the fabric. Looked at from the side, the fabric, and indeed each wale, appears like a concertina. The fabric therefore has a large vertical extensibility which is largely elastic, depending on the fibre used and the yarn construction. The fabric is very bulky and has excellent thermal insulation properties.

As with rib fabrics there are other combinations of simple purls, such as 2 x 2, 3 x 3 etc. These are uncommon, however, and not particularly useful.

Unlike the rib fabric however, the classification 'purl' covers any fabric with face and back loops in the same wale. This covers a vast range of fabrics with designs in back and face loops, known as 'fancy purls'. Another term used, particularly in the USA is 'links-links'.

The three classifications discussed in this chapter — plain, rib and purl — are absolute ones and all weft knitted fabrics can be categorised into one of these classes. To summarise:

(1) Plain — all the loops in the fabric are of the same sort, face or back, depending on which side is                         looked at.
(2) Rib --the loops are of two sorts, face and back, but in any wale all the loops are of the same sort.
(3) Purl — some if not all the wales contain loops of both sorts, front and back.

It is of course possible to manipulate, modify and displace the loops in a fabric, but this does not alter the basis of the above classification.

Within the classification it is possible to modify the structures by various means. It is also possible to introduce design into a fabric without changing the structure, by such means as yarn type, colour, lustre etc., or by striping and plating (see Glossary). Some structures can be described as hybrids with, in particular, combinations of rib and plain to form milano ribs or ripple (bourelet) fabrics.

Others are unique structures like interlock and eightlock which fall into the rib category. Interlock consists of two 1 x 1 rib fabrics knitted in so that they are locked together. Eightlock is similar in construction but involves 2 x 2 rib. Interlock fabric is extremely stable; knitted in soft cotton yarns it is widely used in men's underwear, and leisurewear.

The main modifications used to alter knitted structures fall into three categories: tuck stitches, miss stitches, and transferred and displaced loops. It is not the purpose of this book to be a knitted fabric manual, but brief descriptions of these three categories are given here with mention of their significance in garment construction.

Tuck stitches

A tuck loop is a loop that is incorporated into a knitted structure without actually passing through or intermeshing with the loop immediately below it, but is intermeshed with the succeeding loop. Because the tuck loop is missing from the structure, the loop below it is stretched slightly to bridge the gaps. This loop is known as the held loop (Fig. 2.18). When a series of tuck loops are formed one after another in one wale, the structure distorts and a `knop' occurs (Fig. 2.19). When a series of tuck loops are formed adjacent to one another in a course, they form a float on the back of the fabric (Fig. 2.20).

One of the most interesting consequences of incorporating tuck loops into a knitted structure of any classification is the widening of that fabric. The more tuck loops the more the fabric widens relative to a similar structure containing no tuck loops. This is caused by the sides of the tuck loop, which would normally be constrained by the previously knitted loop, straightening out and exerting outward pressure on the neighbouring loops. The widening effect can be used in garments to 'stitch-shape' portions of the garment where extra width is required.

Common constructions include 1 x 1 cross tuck in plain fabric with its variations, and half and full cardigan in 1 x 1 rib fabric. Tucking can also be a colour pattern method, particularly in plain fabric fully fashioned outerwear. The colour patterning is based on the premise that tuck loops side by side in a course generate a float which is not seen on the face side of the fabric.

Miss stitches

A miss loop is generated when a loop is missed out of a knitted structure altogether, and does not pass through the loop below nor intermesh with the subsequent loop. The yarn that would have formed the loop lies as a float across the back of plain fabric (Fig. 2.21). As in the tuck stitch, the loop that stretches across the gap is known as the held loop.

Miss stitches can be used for generating structural interest as floats on the technical back of plain fabric, or as held stitch designs on the face, or to create 'relief' effects on rib fabrics. Their main use, however, is as the colour patterning medium of knitted fabrics, both plain and rib. In the simplest situation two threads form complementary loops; where one knits the other misses, and vice versa (Fig. 2.22).

More complex variations of this simple structure are used to generate rib jacquards, in which one side of the fabric contains the pattern, and the other — the reverse side — has various structures to create balance or imbalance with the face. Some of the structures can be so imbalanced (i.e. more loops on one side than the other) as to cause the surface of the fabric to bubble within a pattern. Such fabrics are known as 'relief'.

The extensibility of fabrics is reduced but not eliminated by the introduction of miss stitches. Such reduction is considered desirable in jersey fabrics used as alternatives to woven fabrics in outerwear garments.

Transferred loops

A loop that is displaced after being formed so that it combines with an adjacent loop, or so that it appears in a different wale, is said to have been transferred.

Transferring is used to generate holes in fabric to form lace-like effects. Fig. 2.23 shows a structure and draft of a typical lace fabric, formed by transferring loops on a plain fabric. Transferring can be used to produce structural effects by inclining wales of both plain and rib fabrics. Fig. 2.24 shows a structure and draft of an inclined wale plain fabric. This is also used to produce cables by exchanging two or more groups of wales with one another.

Most structural and colour designs in weft knitted fabric fall into the above three categories of modification. These influence the nature of the garments subsequently produced from them, largely because they modify the physical properties of the basic fabrics. They also give a wealth of visual interest to the fabrics.

Other factors contribute to the complexity of knitted fabrics and to the appearance and properties that characterise them. The following is by no means a comprehensive list:

• fibre type, size, colour, lustre, cross-sectional shape etc.;
• yarn type, size, colour, surface nature, contrived irregularities (fancy yarns etc.);
• loop size;
• constructional details generating colour patterns or structural patterns;
• making a construction with specific properties of weight, insulation, abrasive or washing                     capabilities etc;
• wet finishes applied to fabrics, e.g. shrink resist, softening, stiffening, anti-creasing, moth                     proofing etc;
• dry finishes such as pressing, brushing, calendering, setting etc.

Knitted Garments

The principal feature of garments made from knitted fabric is that the nature of the final garment and the processing it goes through are affected in a major way by the primary knitting process. It is possible to have four knitted garments which look superficially similar but have been produced by four differing processes (Fig. 1.1). This chapter defines these processes and discusses the relative methods and use of them.

All knitted garments can be classified into four categories according to general production methods:

(1) fully cut;
(2) stitch shaped cut;
(3) fully fashioned;
(4) integral.

Fully cut (Fig. 1.2)

The term 'fully cut' describes the processes most akin to making garments from woven fabric. Garments are cut from piece goods fabric, laid up (spread) on to cutting tables. All parts of the garments other than the trims are cut from the ray. Each garment piece has all edges cut, hence the term fully cut.

The garments are assembled by seaming machines, often of a specialist nature, and trims are added where appropriate. The fabric for this process is invariably knitted on circular knitting machines. Such machines come in a wide range of types but are mostly classified under two headings:

(1) single jersey or plain web machine;
(2) double jersey or rib machine.

FULLY CUT GARMENTS , PRODUCTION SEQUENCE.

Circular knitting of fabric 

 ↓

Scouring, bleaching and/or dyeing

 ↓

 Pressing, calendering or decatizing 

or stentering

 ↓

Laying up (spreading) of fabric 

 ↓

Marking and cutting 

 ↓

Assembly

 ↓

Examine and mend

 ↓

Finish press

Fig. 1.2 Production sequence of fully cut garments

These machines vary in diameter, the number of needles per inch/ centimetre (gauge), the number of courses they can knit in one revolution (number of feeders), and their fabric patterning capabilities. Modern circular machines are capable of extremely high production rates (300 m²/hour).

The fabric varies according to the type of garment to be made and the knitting machinery is usually designed specifically for a particular class of garment: specialist sports clothes and leisure activity clothes, jersey dresses, suits, slacks and other outerwear. Exceptionally 'knitwear' is sometimes produced.

As already suggested, fully cut is analogous to the processing of woven fabrics but there is one important distinction that influences the whole range of processing. All knitted fabrics and the garments made from them are extensible. Care must be taken with the wet and dry finishing processes to avoid stretching and thus inducing shrinkage potential into the fabric. Care must also be taken with laying up, cutting and finally the making up processes, to avoid distortions.

Making up of the garments is usually carried out with a three thread overlock stitch (BS stitch type 504), although multi thread chain stitch seams are increasingly being used on underwear, swimwear and leisure-wear.

CUT STITCH- SHAPED GARMENTS,

PRODUCTION SEQUENCE

flat or circular knitting of blanks

↓

rough press

↓

cutting

↓ 

assembly

↓

examine and mend

↓

finish press

Fig. 1.3 Production sequence of cut stitch-shaped garments

Sewing machine attachments are of major importance for speeding work times. There are general and specific attachments to seaming machines for hemming, binding, elasticating and other seam forms.

The attractions of fully cut processes are:

(1) the relatively low costs of the fabric produced at high speeds with low labour input;

(2) the opportunity for scale of production which particularly shows benefits at the cutting stage.

The disadvantages are:

(1) the relatively high waste factors that occur even with small garment pieces. Such wastage ranges from 17% to 50% and is a significant cost burden on the garments produced;

(2) the high labour cost of assembly of the garment.

Cut stitch shaped (Fig. 1.3)

The majority of knitwear is produced by this method, together with a very small production of ladies vests. The general method involves knitting rectangles of fabric relating to the size of the portions of the garment to be made. The pieces, known as 'blanks', have the lower edge of the fabric sealed with a structure known as a 'welt' that prevents laddering and distortions of waistbands and cuffs.

The term 'stitch shaped' derives from different stitch structures within the length of the blank that distort it from the rectangle into a shape associated with the human body. Commonly such shaping involves engineered rib waistbands and cuffs that restrict the lower extremity of the garment but are extensible. In ladies vests such waistbands Occur in the middle of the garment blank.

These blanks require minimal preparation for seaming. Cutting involves trimming for length and sometimes for width, followed by cutting neckholes and armholes, lower arms and shoulder shaping.Cutting is still largely carried out by hand, using shears on individual or doubled pieces. Template press cutters capable of dealing with up eight blanks at a time are also employed. Such labour intensive operations are offset by the low wastage figures achieved — 10-20%.

It pays to make the blank as near as possible to the exact size of the garment portion, or a width multiple of the garment portions. The knitting machinery employed to produce the blanks is in its mechanised form the most complex of all, although it must he admitted that simple hand flat knitting machines can produce highly complex blanks, with the `programme' being in the brain of the operative.

There are two types of knitting machine employed: flat and circular. Both are usually rib machines, with two knitting beds and two sets of needles. Some are purl type, with two beds sharing one set of needles. Flat knitting machines knit blanks with selvedges on the side of the fabric. The blank can be any width up to the total width of the machine bed. Two or more blanks can be knitted at the same time.

Flat machines are relatively slow and even with five knitting systems the most advanced machinery makes very few blanks in an hour — 24 maximum and 12 normally. The labour of machine minding and the high capital cost of the machines feature significantly in the cost of a garment.

Flat machines vary in their complexity with the simple types being used for relatively simple garments. Most machines now are computer controlled and programmed and are built for prodigious versatility of fabric type and patterning. Other mechanical developments of this type of machinery also allow the production of fully fashioned and integral garments, although at the expense of the production rate.

The circular machines produce blanks in the form of tubes, the circumference of the tube being related to the diameter of the machine. A particular size of tube may be used to produce a certain size of garment, with minimal waste on the side seams. Various diameters of machines are assembled in a plant to produce a range of garment sizes.

Production management of such a plant is extremely difficult as changes of structure in the fabric of the blanks change the circumference of the fabric produced. An 18 in diameter machine may produce a 44 in (112 cm) width of one fabric type and a 38 in (96 cm) width of another. Inevitably either some of the plant remains idle or the plant is fully employed with added wastage of raw materials when cutting small garments from large blanks.

The approach now employed to minimise the problems is to have very large diameter machines producing large circumference tubes that are split down the side, opened out and cut into a series of

and sleeves to fit the production requirements and mini f widths mise waste. Such bodies a
machine is the Jumberca TLJ-5E, produced in a diameter of 33 in and producing fabrics from 2.5 m to 3 m wide.

Yet a further approach is the variable circumference machine. This type still knits in a continuous revolving manner but some of the needles around the circumference do not knit. The number of these can vary and they are situated in a block on either side of a space 60° in circumference, that contains no needles. In each revolution of the machine, yarn is cut and trapped when it reaches the gap and knitting recommences on the other side of the gap. Thus the fabric is produced not as a circle but as an open width blank, the width of which can be varied to suit the production requirements, with minimal waste. The patents for this machine type are held by Mecmor who produce the Varitex garment length machine, TEJ 180, with a 33 in diameter and 12 feeders, and the TEJ 2500 with a diameter of 40 in (101 cm), 18 feeders and a maximum knitting width of 110 in (280 cm).

Like the flat machines, circular garment length machines have been subject to electronic development; computer controls have been fitted to them to handle the complexity of information required to knit a garment blank. Separate programming computers with a Computer Aided Design (CAD) facility are used to produce the tape or disk that is 'read' by the knitting machine.

The garments are assembled almost entirely by the .use of three and four thread overlock machines (BS stitch types 504 and 506). Seam covering stitches (BS 602) are sometimes used on the facings or 'stoning' of cardigan and back neck seams. Collars are often attached by linked, or increasingly, mock linked seams (BS 101 or 401). Lockstitch seams are used when attaching inextensible trims such as ribbon facings, plackets, leather and woven fabric decorative portions, and tabs and labels.

Often, in the initial stages of production prior to cutting, the blanks are steamed on an open bed — in the case of acrylics — or pressed — in the case of wool and cotton. To facilitate ease of handling and maintenance of size, two similar blanks are often seamed together temporarily with chain stitch before the steaming. Heavy, rectangular, wire frames are sometimes used to. hold the blanks to prescribed dimensions.

Fully fashioned (Fig. 1.4)

Fully fashioning is the process whereby portions of a garment are shaped at the selvedges by progressively increasing or decreasing the number of loops in the width of the fabric. Such narrowing and widening produces the shape of a piece of garment that would otherwise be generated by
cutting.

FULLY FASHIONED GARMENTS, PRODUCTION SEQUENCE

Knitting ribs and garment portions

↓

Rough assembly

↓

Scour, dye, mill, shrink-resist finish

↓

Press

↓

Cut, neckholes etc.

↓

Attach collar

↓

Examine and mend

↓

Finish press

Fig. 1.4 Production sequence of fully fashioned garments.

Fashioning has two obvious advantages over the two previously described categories of garment making:

(1) there is little or no cutting waste;
(2) the edges of the garment pieces are sealed and not liable to fraying, so can be joined by simple non-bulky seams.

Fully fashioned garments are usually associated with knitted outerwear of a particular classical type and with a particular type of machinery: the `straight bar' or 'Cotton's Patent' knitting machine. However, knitted underwear is made on a fully fashioned basis, although the quantity is now very small compared to that made in the 19th century. A similar situation applies to ladies hose which suffered a dramatic eclipse in the early 1960s when a fashion change wiped out an enormous industry virtually overnight.

Men's heavy rib sweaters are also fully fashioned on hand flat knitting machines, as are fine gauge ladies suits and dresses.

Increasingly the fashioning capabilities of modern electronically con¬trolled V-bed flat machines are being used for making fully fashioned garments with scope for embellishment using a wide range of patternings. Such a use, with savings of material and making up costs, Will increasingly feature as a development of the stitch shaped industry.

INTEGRAL GARMENT (1/2-HOSE) PRODUCTION SEQUENCE

Knit half hose

↓

Seam toes

↓

Wet finish, scour, dye

↓

Examine and mend

↓

Finish press, set

Fig. 1.5 Production sequence of integral garment (half hose).

Making up traditional classical fully fashioned garments takes place in two stages:

(1) rough making up;
(2) finished making.

The rough making up is carried out to join the basic portions of the garment together: front, back and sleeves along the selvedge. Cup seamers are used to provide a single or double chain stitch for these seams. With some styles — saddle shoulders and set-in sleeve jumpers — linking is used to join the shoulder seams, loop for loop.

The rough made up garment can at this stage be wet processed. This is carried out on the majority of garments that are single coloured, and on some that are multi-coloured. Wet processing involves some or all of the following: scouring, milling, shrink resist and dyeing.

After drying, hoarding and pressing the finishing making up is carried out, including cutting of necklines, fronts of cardigans and shirts, attaching collars, facings, stollings and buttons, buttonholing etc. Linkers, mock linkers and lockstitch machinery are used.

Fully fashioned garments made on V-bed machinery are not normally wet processed, and making up is usually by cup seamers, linkers and mock linkers.

Integral garments (Fig. 1.5)

Integrally knitted garments are those that are essentially knitted in one piece with little or no seam. The archetypal example is the beret, which is knitted sequentially in a series of triangles, leaving the beginning and the end to be joined into a three dimensional shape. This principle has also been used to make skirts and jumpers and is used to produce a large proportion of ladies and gents millinery.

Another integral garment using a combination of tubular knitting and shaping is the men's sock or half hose. To shape the heel and toe of a sock, pouches are formed from extra rows of knitting.

The third common type of integral garment consists principally of joined tubes — the glove. Tubes are constructed for each of the digits, sometimes with shaped tips, and merge together into the palm portion, (also a tube). Such gloves can now he knitted fully automatically (Shim, Seiki) with no subsequent making up procedures.

Integral concepts are proposed from time to time for upper body outer-wear garments, and have been the subject of patents. Inhibitory factors to their introduction include lack of competent designers and development technicians, and sheer conservatism on the part of producers.

The rewards could be considerable, saving both raw material anti labour costs at the expense of lower machine output. There is little question that the electronic V-bed knitting machines in their present state of development, with presser foot or holding sinkers, are easily capable of producing garments in all the integral garment categories.

Introduction

When most people. arc confronted with the term 'knitting' they immediately think of Aunt Agatha's Christmas jumpers, in excruciating colours, the necks of which will not stretch over the head. This book is not about Aunt Agatha's jumpers. Knitting is one of the most important processes for producing garments and world wide represents a considerable and increasing percentage of the population's apparel.

Knitting is used to produce garments that cover every part of the human body, in a wide range of garment types from socks, caps, gloves and underwear to upper and lower body garments varying from T-shirts to formal jackets. In spite of this range, the treatment of the fabric to produce various garments and the properties of the garments produced have a great deal in common, and it is the intention of this book to explore that commonality.

This common theme is connected with the knitted fabric property of extensibility. This is in sharp contrast to the general rigidity of most woven fabrics. The industries dealing with the production of knitted garments remain separate from those dealing with woven garments, except for the overlap occurring with dresses, suits and other outerwear garments produced from jersey fabrics.

Within Government industrial statistics the firms producing knitted " garments are not classified as part of the clothing industry but as part of the textile industry. Nevertheless, in spite of the separateness of the knitted garments industry, within the fully cut sections there is a considerable sharing of production technique with the industry using woven fabrics, in pattern generation, lay planning, cutting, and production planning and organisation. Many hooks have been written about woven fabric clothing technology; a few mention some of the areas of overlap between woven and knitted fabric, but there are no books dealing with the particular and general. techniques of producing clothes from knitted fabric. It is the intention of this book to begin to redress the balance.

There are indeed very few books dealing with the industrial aspects of-knitting (see bibliography) and these tend to deal primarily with knitting machines and their 'products, not the subsequent processes that create garments. The primary production of knitted fabric is not dealt within this book, although an introductory chapter on knitted fabric structures is included.

There are many books covering hand-knitting techniques and the production instructions for creating garments. This is to be expected, for hand knitting is one of the oldest of man's construction techniques, and is also one of the world's most popular pastimes.

Hand knitting

Hand knitting precedes machine knitting as a technique by many hundreds, if not thousands, of years. Its area of origin and time of invention are unknown. There is conjecture that the mountainous areas of Persia, now Iraq, Iran and Afghanistan were the origin. Similar claims have been made for the Holy Land, Israel, Jordan, Syria and Lebanon; also the Atlas mountains of North Africa provide a likely site. These are all areas associated with the domestication of sheep, and the likely connection between wool fibre and knitting. Wool fibre, which is composed of protein, would decay rapidly in the sorts of climate associated with mountain areas. This would help explain the lack of early examples of knitting. Archeological investigation in these areas has tended to concentrate on the great civilisations, not peasant culture. It is also possible that references to knitting in early writings have been missed or misinterpreted.

In medieval Europe hand knitting was an important industry and socks, caps and knitted gloves were common products. Hand knitting had many obvious advantages, i.e. the simplicity and portability of the production apparatus, the lack of a cutting and making up process needed to complete a garment, knitted in the round (integral), the lack of complex finishing techniques, the simplicity of fit, and the stretch allowing various shapes and sizes of people to be able to wear one size of garment.

By the second half of the 16th century hand knitting had developed into an advanced craft, with stockings for the gentry and nobility being knitted from extremely fine silk threads on pins that were little more than fine wire. These stockings were usually richly embroidered and embellished with threads of coloured silk, gold and silver. The prices were very high and and the hose were regarded as the most important part of a gentleman's wardrobe. The lower orders wore stockings of worsted sun

wool or linen or hemp, knitted or bias cut from woven fabric.

Knitting machines

In 1589, in the reign of Queen Elizabeth I, the Reverend William Lee, a curate of Calverton in Nottinghamshire, presented himself at the Court of the Queen with a request for Letters Patent for his newly invented knitting machine. This machine was remarkable in many ways: it was the product of lateral thinking in that it used an entirely different method to produce a familiar product; it employed complex interacting motions unlike any other machine in existence; and it was arguably the first machine to concentrate on increasing the productivity of a process for its own sake (i.e. the start of the Industrial Revolution).

This first machine produced coarse knitting — peasant hose — and although it reportedly caused a sensation at Court and was the object of marvel, Elizabeth dismissed the application with the following words:

           'My Lord I have too much love for my poor people who obtain their bread by the employment of knitting, to give my money to forward an invention, that will tend to their ruin by depriving them of employment, and thus make them beggars. Had Mr Lee made a machine that would have made silk stockings I think 1 should have been somewhat justified in granting him a patent for that monopoly, which would have affected only a small number of my Subjects; but to enjoy the exclusive privilege of making stockings for the whole of my Subjects, is too important to be granted to any individual'.

Under the patronage of Lord Hunsdon, Lee persisted and produced in 1598 a refined version of his frame, able to produce silk stockings. This machine contained, it is thought, 20 needles to the inch rather than the 8 needles per inch of the original. He still did not acquire the desired document from Elizabeth, or James I, and, enticed by the French envoy the Marquis de Rosny, he moved to France with his brother James, six frames and nine knitters. The frames were set up in Rouen and succesfully operated as a small industry.

William Lee stayed in Paris, where, after the murder of Henry IV, he was declared persnnna non grata. He died in Paris in 1610, destitute and in low spirits before his brother James could rescue him.

Knitting industry

James, on learning of the death of his brother in such lowly circumstances, removed the machines back to London where the changed economic and political climate enabled an active industry to be started, with people clamouring to be apprentices to the new pursuit. James made a modest profit from the sale of the machines, returned to Nottinghamshire and with Aston, a miller of Thornton, produced frames improved with Aston's invention of a fixed additional sinker bar.

The industry was now set for rapid and consistent expansion, lasting for 200 years until the slump initiated by the French Revolution and subsequent Napoleonic wars produced the first experiences of industrial recession (Thomis 1969.)

Such was the completeness of the frames conception that frames of virtually identical construction were still used in a productive capacity in Nottinghamshire in the 1970s, to produce shawls.

The industry during the 17th century developed as a typical Guild-organised cottage industry. The Framework Knitters Company, established by Royal Charter and based in London, regulated the industry in England and Wales but not in Ireland and Scotland.

The restrictive nature of the Guild system in respect of knitting become intolerable by the beginning of the 18th century, and moves were made to escape its strictures. Initially such moves were confined to the establishment of branches of the industry in Dublin and the Scottish Borders, but eventually they led to the breakdown of the Guild authority in the Midlands, aided by a Parliamentary sanction of 1753. During this period the Framework Knitters Company took legal action to attempt to control
the trade and move it back to London.

By 1750 the distribution of frames in the country was:

London                                                                 1000
Surrey                                                                   350
Nottingham                                                          1500
Leicester                                                               1000
Derby                                                                    200
East Midlands rural sites                                      7300
Other English towns and Scotland                       1850
Ireland                                                                   800

A total of 14 000 - a considerable industry.

The 18th century represented two interconnected revolutions for the knitting industry, with a subsequent effect on the whole of the textile industry. The first was a spate of inventiveness that modified the frame. The second was the diversification of the product into articles other than hose. Both these trends led to rapid expansion of the industry.

Modifications to frames

The modifications of the frames were numerous and many inventions were aimed at circumventing the inventions of others. Most of the modifications and inventions occurred in or near Nottingham town.
Among the most important modifications were:
(1) the rib frame;
(2) selection devices to aid patterned loop transfers, including pin drums and jacquard's;
(3) the warp frame;
(4) selection devices to produce tucked fabrics.
These led ultimately to the evolution of warp knitting and of true twisted lace. Such expansion led to a shortage of yarn, particularly of the newly introduced short staple cotton. (The first cotton, from India, was knitted in Nottingham in 1730.)

First Hargreaves (1767)„ind then Arkwright (1769/72) set up their spinning mills in Nottingham. Both men were from Lancashire but were attracted to the Nottingham area by the demand for yarn, the availability of capital, the skill of local engineers and the theoretical availability of a workforce used to working with machines. What was lacking, however, was power. Watts' steam engine was invented in 1769 and was not available to Arkwright until much later. His Nottingham frames were driven by horse or mules: Hargreaves' machines were powered by hand. Felkin (1967) is of the opinion that, if the steam engine had preceded Arkwright's frame, the cotton industry would have been located in the East Midlands.

Arkwright moved to Derbyshire for water power and eventually hack to Lancashire where calico and Fustian weaving expanded rapidly.

Diversification of product

The diversification of the product was connected to the inventions: sometimes an invention suggested a product and sometimes a perceived market led to an invention. Such see-sawing was to become the characteristic of knitting industry development up to the present time.

The other associated characteristic, which is not exclusive to knitting but is more exaggerated than in any other industry, is the tendency to produce multiple solutions to one problem. This can best be explained in an example. At the height of the double-jersey/jacquard fabric boom of the 1960s, every knitting machine builder produced an exclusive, patented, needle selection mechanism to carry out the function of lifting needles to knit or leaving them down to miss. There were possibly over 20 different mechanisms available at the same time to carry out the same function.

Examples of this can still be found in electronically controlled V-bed knitwear machinery, where every machine builder has progressed along separate lines and produced different machines, computers and, most important, languages to deal with the same problems and functions.

This dates back to the mechanics and engineers in Nottingham (and Saxony) all trying to circumvent one another's mechanisms to produce the same product. It is said that Nottingham was the largest outlet in Europe for powerful telescopes and can lay claim to another first in industrial development industrial espionage! In no other industry is it possible to make a seemingly identical product by so many alternative routes.

The original purpose of the frames was to take advantage of the demand for hose. The wearing of hose (defined here as tight fitting leg covering) by men became firmly entrenched in Italy during the Renaissance, and rapidly spread to the rest of Europe. This fashion during the 15th century involved the wearing of what we would recognise as tights - close fitting garments enveloping the whole of the lower body from the waist downwards. Such garments were constructed from bias cut woven fabrics, or leather, but it is not impossible that sonic were knitted. They were called `breeches' and were often worn with `hosen' - short socks or lightweight hoots worn over the tights.

Later, as the fashion progressed into the 16th century, the hoses covered most of the leg and the breeches became ballooned shorts. This fashion was to dominate men's dress of all classes up to the start of the 19th century.

From approximately 1540 the hose were almost exclusively knitted. During the reign of Elizabeth 1, richly embellished hose became one of the most important items of men's dress. Contemporary accounts speak of men spending half their annual income on J single pair of hose.

I am sure that such commercial implications were not lost on William Lee, although he was not to benefit personally. William Lee's frame was flat and could therefore only produce flat pieces of fabric. These could he shaped at the edges and garments could he built up of several pieces to produce complexity of shape, or to remove seams from awkward places such as the soles of the feet. Essentially, however, the hose were seamed together by hand and were of the type that we now know as fully fashioned, with a main seam down the back of the leg. The hand knitters were not restricted to the flat form and could produce hose in the round
(integral garments).

After the wide introduction of Lee's frame, from 1620 onwards, hand knitting of hose diminished except for the very coarsest of articles. Nevertheless, hand knitting was still used to produce items like hats and gloves and possibly seamen's jumpers.

Tradition has it that with the break-up of the Spanish Armada, and the subsequent blockade of the English Channel, ships of the Armada headed northwards to round Scotland and head back for home via the Atlantic ocean. This part of the story is undoubtedly true as wrecks and founderings are reported all along the route.

The Spanish sailors carried their knitting skills with them and there are highly developed patterned knitting skills in all the seaboard places where the Armada ships could have called or foundered, including the Scottish east coast, Orkneys, Shetlands, Faroes, Norway, Iceland and the Irish Aran Islands. In the coastal ports of the North sea and North Atlantic, the upper body garments that we now know of as knitwear developed. They never became fashion in the widely worn sense of the word and were not, until recently, the objects of commerce, but they produced for fishermen and seamen essential items of protective clothing.

The product of the frame, i.e. the major output of knitting, was one type of garment - hose - until early in the 18th century when some diversification's took place; other garments, normally the province of hand knitting, were produced such as gloves, hats, scarves and shawls. These were essentially shaped garments made like the hose, either fully fashioned or integral.

There were other interesting developments. After the introduction of cotton into Nottingham in 1730 frame-work knitters began knitting lengths of simulated lacework using loop transfer techniques. Such 'point lace' created a boom, both in the commercial sense and in a spur to inventiveness.

Also over the same period other garments were made from knitted fabric, which was cut and treated in a similar way to woven fabric. Jackets, breeches and waistcoats are all items produced during this period of which there are examples in existence.

Later, in the period 1790 to 1820, such cut techniques when applied to hose to cheapen them were a major factor in the Luddite Rebellion in the Nottingham area. The knitters strongly objected to the implied productivity improvements, the subsequent lowering of reward to themselves and the lowering of the quality of the goods produced. A copy of their petition has recently been published (Knitting International) and provides a remarkable insight into the problems of the day.

The industry was also experiencing another unique event — a major change in fashion for men, away from the weaving of full hose to the wearing of trousers.

In the 19th century power was applied to the knitting machine, the first circular machines appeared, William Cotton's patent revolutionised fully fashioned hosiery production, and Matthew Townsend's latch needle enabled consecutive knitting and selection to knit and miss to take place.

The product diversified still further during this period and knitted underwear became a reality, followed at the end of the century by sportswear and swimwear (exposed underwear) followed closely by knitted outer garments (knitwear).

During the period 1880 to 1910 knitwear became established as an item of female fashion. The basic methods and division of production were established during this period and are still with us today. These basic methods are:

(1) Fully fashioned Knitting shaped portions of fabric in the flat;
(2) Cut stitch shaped Knitting of made to size portions of fabric, with some shaping introduced by changing of stitches;
(3) Fully cut knitted piece goods Lengths of fabric from which garments are cut in masses;
(4) Integrally knitted The shape is generated in the round during knitting, leaving little or no seaming.

Twentieth century developments

Development in the 20th century has largely involved increasing the productivity of knitting machines and making them more versatile in their patterning scope. The knitted garment is now established as part of everyday dress and most people, irrespective of age or gender, are usually wearing two or more knitted garments most of the time.

Fashion or society in its cycles sometimes decrees that knitted garments are the main form of clothing for females. The polyester clothes of the 1960s and early 1970s are an example, and the knitwear-dominated late 1970s and early 1980s are another. Such cycles in fashion prove concerting, if not plain disastrous, to the knitting industry. The industry contributes to its vulnerability by divisions into specialist sectors. Such sectors tend not to respond to fashion changes readily, either because of technical limitations and lack of expertise in technical and design development, or a complete failure to recognise market opportunity.

Some sectors remain aloof from fashion directly for long periods of time, but are subject to other trends. The manufacture of basic under-wear, for example, trades on the basis of a utilitarian necessity but is subject to pressure from alternative production sources, being ideally located in areas of low labour costs.

Even basic underwear is slowly subject to fashion changes and some-times itself evolves into fashionable items of clothing. The T-shirt that is currently ubiquitous wear all over the world evolved from vests.

There is currently a discernible trend in production techniques that may, over a long period, have important consequences for the knitting industry and its products. There has always been concern over the waste of raw material that results from cutting garment shapes out of flat materials. This can, in extreme cases, represent 40-50% of the whole.

It is recognised that knitting in the fully fashioned or integral modes enables the waste of value-added raw material to be largely eliminated. For a long time, however, the technology of knitting machinery has limited the range of garments that can be produced by these methods. Fully fashioned outerwear, for example, has long been confined to plain fabric with embellishments of stripes, loop transfer, tuck stitches and intarsia.

The advent of computer controlled V-bed knitting machines has changed the situation dramatically. The ability to fully fashion on a wide range of fabric types is now possible. Inhibitory factors, however, are:

(1) the added skills needed on the part of the designer and machine programmers to cope with the complexities;
(2) the increase in machine production time involved in making fully fashioned garments as opposed to cut stitch shaped.

This second factor is seen by most manufacturers as the biggest stumbling block because such decreases in productivity raise the proportion of the cost of the garment that is involved with the high capital value of the knitting machines and the fixed overheads. This is a highly debatable subject, balancing the savings on raw material and making-up labour costs against the loss of overall production.

The next step in this progression is to begin to lower the seaming content of the garment. Again, development of the latest computer con¬trolled V-bed knitting machines to include fabric controlling sinkers (Stoll SMC and Shima Seiki SES) allows garments to be integrally shaped by a wide variety of methods. Such developments have potentially more savings than fully fashioned. But there are inhibitory factors:

(1) the added skills needed of the designers and programmers;

(2) the consequent decrease of production from capital invested;

(3) the argument that a fault occurring during knitting damages a whole garment.

It is my contention, however, that production will move strongly in a progression, initially for knitwear but ultimately for all knitted articles, of:

                  Fully cut → stitch shaped cut → fully fashioned → integral

I am strengthened in my argument in that three garment types have moved along this progression successfully. These are half hose and hose, gloves and hats.

These principles will be looked at in a separate chapter devoted to integrally knitted garments.