Three Dimensional Seamless Garment Knitting on V-Bed Flat Knitting Machines
Volume 4, Issue 3, Spring2005
THREE DIMENSIONAL SEAMLESS GARMENT KNITTING ON V-BED FLAT KNITTING MACHINES
Wonseok Choi, Ph. D. Student Nancy B. Powell, Associate Professor College of Textiles North Carolina State University 2401 Research Drive Raleigh, N.C. 27695-8301 (919) 515-6578
ABSTRACT
Since the introduction of seamless garment knitting techniques on V-bed machines in 1995, this technology has been considered an innovative process and is currently growing in its commercial application around th e world. By eliminating the cutting and sewing processes, complete garment knitting provides a variety of advantages in knitting production such as savings in cost and time, higher productivity, quick response production and other advantages.
The purpose of this research is to review the principles of seamless knitting on V-bed machines and to compare the machines from two major flat-knitting machine suppliers, Shima Seiki and Stoll. This paper will also discuss characteristics and applications of complete garment knitting in various products. This research was accomplished through interviews and a review of the literature. It has implications for academicians and industrial personnel who require information in three dimensional knitting technology and rela ted machinery.
Keywords: Knitting, tubular, seamless, complete garment
1. INTRODUCTION Through this research, principles of seamless knitting techniques are discussed, Seamless knitting technology creates one and two major suppliers for V-bed entire complete garment with minimal or no machines, Shima Seiki and Stoll, and cutting and sewing process. This innovative machine characteristics will be introduced. technology eliminates post labor work, In addition, advantages and disadvantages of which saves production time and cost. In this type of production are revealed. In addition, the technology offers knitwear order to understand the seamless knitting consumers more comfort and better fit by technology, it is important to review the eliminating seams. Thus, seamless fundamentals of the knitting process. By a technology provides benefits to review of the evolution of the knitting manufacturers as well as end users. process, an explanation of knitting methods, Seamless knitting technology has entered and the description of knitting machines’ the mainstream in the knitwear market. characteristics, the distinctiveness of seamless knitting will be better understood. Article Designation: Refereed 1 JTATM Volume 4, Issue 3,Spring 2005 This research was achieved through a review according to type of fabric, type of needle, of the literature and additional primary data and form of needle bed. In the circular was collected through interviews, company knitting machine, needles are set radically or visits, etc. parallel in one or more circular beds [3]. On the other hand, a flat knitting machine 1.1. Knitting Fundamentals employs straight needle beds carrying independently operated needles, which are To fully examine the developments in usually of the latch type [3]. seamless knitting, a basic foundation of knitting construction and characteristics Compared to flat knitting machines, circular should be discussed. Knitting is defined as weft knitting machines provide higher “the process of forming a fabric by the productivity. Thus, circular knitting intermeshing of loops of yarn” [22] and machines have more rapid production knitting accounts for more than 30% of total speeds than weft knit flat bed machines. fabric production [24]. The end use of However, flat knitting machines have knitted fabrics, created either in tubular or greater versatility in loop structure flat form, can be apparel and other products combinations and patterning because their inc luding sweaters, underwear, hosiery, machine cams can be changed after every socks and stockings. course (even after every stitch), and they are able to knit one or both beds easily [52]. It Knitting is classified into two fields, weft should also be noted that electronic circular knitting and warp knitting. In weft knitting, machines have the same capability. loops are formed in a horizontal direction whereas in warp knitting, loops are formed in a vertical direction [1] (Figure 1.1a and 1.1b). Weft knitting is more resilient, more open and has additional design possibilities as compared to warp knitting. Conversely, warp knitting has less resilience, more cover, lighter weight and higher productivity. Weft knitting can be divided into circular knitting and flat knitting
Figure1.1a. Weft knitting Figure 1.1b. Warp knitting (Black, 2002
Article Designation: Refereed 2 JTATM Volume 4, Issue 3,Spring 2005 Knitting
Warp Weft
Tricot Raschel Flat Circular
V-Bed Purl Single needle Bed Cotton Patent
Seamless
Figure 1.1c. Knitting Classification Diagram
Spencer defines cams as “the devices which The latch needle, the most widely used convert the rotary machine drive into needle in weft knitting, is mainly composed suitable reciprocating action for the needles” of a needle hook, a latch, and a needle stem [42]. Figure 1.1d shows the knitting action (Figure 1.1g). The major advantage of the of latch needles for the cam track on a V- latch needle is that it self acts or controls the bed knitting machine. According to the loop so that individual movement and position of needle butts moving up and control of the needle permits loop selection down through the cam system, the loop can to be accomplished [42]. The sinker is be formed sequentially [34]. another primary element in knitting. Main purposes of the sinkers are loop formation, holding down, and knocking-over [42]. However, the role of sinkers on a V-bed knitting machine with latch needles is chiefly a holding-down function. Therefore, holding down sinkers are capable of tighter fabric structures with an improved appearance. The purpose of the brushes is to open the latches at the first course when the machine starts to knit and to avoid any closing of the latches [21]. The yarn carrier or yarn feeder is pulled along the needle bed by the carriage and introduces and feeds yarns required for knitting. The yarn carrier is assembled on a dovetail-profiled rail [34]. Figure 1.1d. Knitting action of Take down rollers are needed to prevent the latch needle though cam track previous loop, which is located in the hook (Raz, 1991) enclosure, from riding up with the needle Figures 1.1e and 1.1f illustrate the basic ascension. This is very crucial for loop knitting machine parts on a flat bed machine formation because without take down including a carriage, latch needles, sinkers, tension the previous loop will not slide brushes, yarn carriers and take down rollers. under the latches and new loops will not be A carriage that has cam boxes travels along formed without the operation of the take the beds forcing the needle butts in its way down rollers [34]. to follow the curved shape of the cam [34].
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4. 1. Latch needles 3. 2. Sinkers 2. 2. 3. Brushes 4. Yarn Carrier (Feeder)
1. 1.
Figure 1.1e. Knitting machine system on flat V-bed machine (Shima Seiki Manual [37])
Carriage
Cam box
Figure 1.1f. Yarn Carriers, Carriage and Take-down Rollers (Raz, 1991)
Transfer spring Needle hook
Needle stem Latch
Figure 1.1g. Latch needle on Shima Seiki Machine
Flat bed machines have four different 1.2. Historical Events Contributing to the classes; (i) V-bed flat machines which have Development of Seamless Knitting two inverted V-formed needle beds; (ii) Purl machines which have double ended needles; In the evolution of seamless knitting it is (iii) machines that have a single bed of important to review the developments in needles which include most domestic knitting that directly affect three- models and a few hand manipulated intarsia dimensional knitting techniques. Kadolph machines [40]; and (iv) Cotton patent and Langford [12] explain that historical machines which are single -bed machines remnants of knit fabrics have been dated with bearded needles arranged vertically [1]. from A.D. 250 in the Palestine area. Bearded needles are the needles having an Knitting was accomplished by a hand extended terminal hook or beard that can be process until 1589, when William Lee in flexed to close the hook [22]. England invented a flat-bed weft-knitting frame to create hosiery [12]. The first operational V-bed flat knitting machine using latch needles was invented in 1863 by Article Designation: Refereed 4 JTATM Volume 4, Issue 3,Spring 2005 Issac W. Lamb [34]. William Cotton of 1960’s, the Shima Seiki company further Loughborough took out a patent in 1864 for explored the tubular-type knitting principle his rotary-driven machine that used a flat commercially to produce gloves. Also, in bed to produce fully-fashioned garments the mid1960's, engineers at Courtaulds in [16]. According to Hunter [9], in the the UK established British patents on the 1800’s, the flat knitting machine was fitted idea of producing garments by joining tube with sinkers, which controlled loops in order knitting. However, the method was too to knit single jersey tubular articles such as advanced to be commercialized at that time. gloves, socks and berets. In 1940, the By 1995, Shima Seiki fully developed manufacture of shaped knitted skirts was shaped seamless knitting [9]. Recently, by patented in the USA. This permitted darting employing more advanced computerized on knitted skirts using a technique called systems, simpler programming was possible, "f lechage" (See glossary). The flechage and the computerized systems enabled the technique not only improved drape and fit, production of more complicated and but cut production cost. In 1955, the sophisticated knitted structures and Hosiery Trade Journal reported on the products. Table 1 introduces the historical automatic knitting of traditional berets events of seamless knitting. through the shaping of components. In the
Year Historical Events Contributing to Development of Seamless Knitting
1589 William Lee in England invented the first flat-bed frame to create hosiery. Issac W. Lamb invented the first operational V-bed flat knitting machine including the latch 1863 needles. William Cotton of Loughborough patented his rotary-driven machine that used a flat bed to 1864 produce fully-fashioned garments The flat knitting machine was fitted with sinkers, which controlled stitches in order to knit 1800’s single jersey tubular articles such as gloves, socks and berets. The manufacture of shaped knitted skirts using a “flechage” technique was patented in the 1940 USA. The Hosiery Trade Journal reported on the automatic knitting of traditional berets through 1955 the shaped sections. Shima Seiki company further explored the tubular-type knitting principle to produce gloves 1960’s commercially. Courtaulds established British patents on the idea of producing garments by joining tube 1960's knitting.
1995 Shima Seiki introduced seamless entire garment knitting at ITMA.
Table 1. Historical Events Contributing to Development of Seamless Knitting Seamless entire garment knitting was productivity, quick response production and introduced in 1995, at ITMA, the other advantages. In Section 2, numerous International Textile Machinery Association advantages of seamless garment knitting are [24]. Seamless knitting, or complete discussed. knitting, whic h produces one entire complete garment without a sewing or linking process, provides a variety of advantages in knitting production such as savings in cost and time, higher
Article Designation: Refereed 5 JTATM Volume 4, Issue 3,Spring 2005 2. ADVANTAGES OF SEAMLESS yarn consumption can be minimized by GARMENT KNITTING complete garment knitting as well as by effectively analyzing yarn feed through the In general, V-bed knitting process has more computerized system on the machine [7]. flexible needle selection capability and more The DSCS (Digital Stitch Control System) design possibilities compared to warp on Shima Seiki machine predetermines how knitting process [2]. Through computerized much yarn is required for the each stitch. flat bed knitting, more variety of knit Loop size can be controlled accordingly and patterns and structures can be created and there is much less stress on the yarn at the designs can be instantly and efficiently sinker. According to Mowbray, this device changed through a computer-aided design not only permits a variety of types of yarns system. Furthermore, seamless garment to be used but also offers maximum knitting makes it possible not only to create production efficiency because higher speeds several types of tubular formed knitting but can be achieved [26]. The range of gauges also to build diverse design structures on the for complete garment machines varies from tubular knitted garments simultaneously. 5 gauge to 18 gauge. Seamless garment knitting technology adds flexibility through Complete garment knitting offers a variety gauge conversion and multi-gauge knitting of benefits in technical aspects as well as in [20]. The capability of multi-gauge the market demands. For benefits to the application allows the conversion of gauges market, quick-response production and just- in the same machine. As a result, it saves in-time production are possible. The time and cost for investing in different required number of products can be quickly machines for every gauge. knitted in less time to meet the needs of the market. It also enables mass customization In garments, three-dimensional knitting is for many markets. Onal states “Mass purported to give lightness and softness in customization is the use of technology and knitwear because there is no linking and management methods to offer product sewing production [39]. In addition, there variety and customization through flexibility are no bulky and annoying stitches at the and quick response. It owes its success underarm points, shoulders and neck lines partially to computer-based information, [39]. For finished edges, the garment can design and manufacturing technology” [29]. have better trimmed edge lines through a In certain markets, seamless knitting could machine binding-off process instead of a be considered for mass customization by sewing or linking operation. rapid design changes according to customers’ requirements through In decreasing the number of production computerized knitting systems. Seamless processes such as the cutting or sewing knitting systems may be utilized for steps, the risk of defects and damages can sampling prototype and for niche market also be minimized. A single entire piece limited production items. production method is claimed to provide more consistent product quality [20]. For the focus of this paper, the benefits of Consequently, seamless knitwear is seamless technology are mainly discussed. promoted to look better, fit better and is First, there is no longer the traditional labor- believed to be much more comfortable than intensive cutting and sewing process a traditiona l fully-fashioned piece of because of eliminating seam production. knitwear. Seamless knitting also allows knit Hence, the tubular-typed seamless knitting designers to create design structures and results in potential savings in terms of patterns across the entire garment. Designers production time and cost. For instance, can easily program and style both more according to Melliand International, in the sophisticated design structures and shaped case of a complete woman’s knit sweater, a patterns through the computerized design time saving of about 35% can be achieved system. with seamless knitting [20]. Additionally, Article Designation: Refereed 6 JTATM Volume 4, Issue 3,Spring 2005 Finally, in the global environment, utilized for complete garment knitting [11]. according to Shima, seamless garment Cotton is also a popular fiber used in knitting puts less stress on the environment seamless apparel. by minimizing waste disposal and reducing the need to grow as much as cotton, wool Another issue for complete garment knitting and other natural raw materials [26]. is that if the garment has a defect during knitting such as a hole or a barre’ problem, 3. TECHNICAL ISSUES the entire garment is useless and must be discarded. Pratt explains “Barre’ means a Although seamless garment knitting continuous visual barred pattern or stripiness technology provides a variety of advantages parallel to the yarn direction in a knit fabric” for the knitting industry, it still has several [32]. Compared to fully-fashioned knitting, technical issues to be considered. The main there would be more waste when the problem in complete garment knitting has complete knitted garment has any defect. In been fabric take-down [10]. To keep equal cut and sewn production pattern pieces tension of each loop (i.e., stitch), diverse could be placed for cutting on a flat piece of sinker systems and take-down tension fabric to avoid any defects. systems have been utilized. Finally, the novel sinker systems such as a spring-type 4. APPLICATIONS OF SEAMLESS moveable sinker system and a computerized KNITTING take-down tension system, appropriate to complete garment knitting, have been Seamless garment knitting on the V-bed developed to solve the problem. Even machine has primarily been used for though the systems have brought higher apparel. However, in recent years, this new stability for knitting, there is the opinion of three-dimensional knitting technique has users that it still is not easy to control an been extended in other areas such as fashion, exact take -down tension for the complete upholstery, industrial, automotive, and garment. medical textiles.
Complete garment knitting also has a 4.1. Apparel (Figure 4.1) problem caused by the alternate needle selection. The alternate needle selection A diverse range of seam-free products can knitting makes fabrics more open and less be created such as hand gloves, hats, socks, elastic than conventional fully-fashioned and sweaters according to the machine garments [27]. This problem occurs in the gauge and types of machine. Additionally, welt or the cuff areas. A welt in knitting patterns for knitted trousers and skirts are means “a secure edge of a fabric. The welts available on the complete knitting machines. are usually at the starting end of the fabric” As far as design structures, most knit [22]. To solve the looser fabric problem, it structures knitted on fully-fashioned is critical to select appropriate yarns for the machines can be created on the seamless machine gauge; and in this context, elastic, garment machines such as cable stitches and flexible and durable yarns are recommended even intarsia structures. such as wool. For instance, a Yorkshire (See glossary for structures.) [33] spinning company in the UK uses the elastic Spirol® lamb-wool on the cuffs and the 4.2. Upholstery (Figure 4.2) collars, which can be knitted tighter like a fully-fashioned product [27]. In the current Several upholstery companies are utilizing global knitting industry, natural fibers, such three-dimensional seamless seat upholstery as wool, cashmere and angora, and production. The Teknit Company offers manufactured fiber such as acrylic are three-dimensional knit upholstery for the mainly used to create seamless garments for office chair market. Teknit creates shaped outerwear [11]. Viscose and polyamide three-dimensional polyester seat covers that with Lycra® or other elastomerics are also compete against woven fabric, which Article Designation: Refereed 7 JTATM Volume 4, Issue 3,Spring 2005 requires a cutting and sewing process [43]. a predictive computer model which reduced According to Teknit, lead times are the time needed for seat design by 25% [31]. substantially lower than conventional woven Seamless knitting for automotive also fabric and the office chairs covered with provides a potential for designing a more seamless knitted fabric are their fastest ergonomic seat through the ability to alter selling line. The company also has the the knitted tube size. capability of promoting rapid design changes by using sophisticated CAD 4.4. Medical textiles systems [46]. Additionally, seamless shaped knitting with its inherent stretch Recently, specialty textiles created by three- characteristics follows the contours of the dimensional flat bed knitting machines have seat, providing better seat trimming [46]. It also been applied to medical textiles. enhances appearance and enables users to Tubular typed knitted structures such as feel more comfortable by eliminating ridges bandages, orthopedic supports, and medical caused by a sewing or a linking process. compression stockings have been developed. In the future, it is expected that more 4.3. Automotives advanced and sophisticated medical textiles created by seamless knitting technology Courtaulds and General Motors Corporation would be produced. The incorporation of developed the three-dimensional knitting high performance fibers and additional technique to produce seat covers in 1985 sensors or electronics could provide further [40]. Marjorie Sorge proposed that opportunities for seamless products in automotive seat covers made by seamless healthcare applications. knitting also provide great potential for the automotive market in that the three dimensional knitting process cuts lead time by eliminating cut-and-sew operations, brings down warranty costs and adds quality [40]. Lear Corporation which owns patents on three-dimensional knitting technologies claimed the ability to design new seats using
Figure 4.1. Seam free Figure 4.2. Claud garment created on 9™ Chair created Shima Seiki by WholeGarment® NeutralPosture® Machine (NeutralPosture, (Shima Seiki, 2003) 2004)
Article Designation: Refereed 8 JTATM Volume 4, Issue 3,Spring 2005 Each of these market applications has need stitching. The Shima Seiki Company specific performance requirements and explains that with cut and sew production, specialized aesthetics. In order to use this up to 40% of the original fabric can be waste technology to fulfill these market needs, the [39]. principle s of knitting and knitwear production, and the evolution of seamless 5.2. Fully-Fashioning knitting need to be reviewed.
5. EVOLUTION OF THE KNITTING PROCESS FROM CUT AND SEWN PRODUCTION TO SEAMLESS GARMENT KNITTING
As described in Table 1, the knitting industry has gradually developed since Front Body Back Body Sleeves William Lee of Calverton successfully Figure 5.2. Fully-fashioning production converted the actions of hand knitting with two needles into a mechanical process. Lee’s work was the first attempt at Fully-fashioned knitting means “shaped mechanizing hosiery knitting in 1589 [16]. wholly or in part by widening or narrowing Since the invention of the frame-knitting of piece of fabric by loop transference in machine, knitting technology has progressed order to increase or decrease of the number from hand flat machines to complete of wales” [3]. Thus, as the number of loops garment-knitting machines. Section 5.1, 5.2, are increased or decreased, the fabric can get and 5.3 will explain the evolution of the shaped areas as seen in Figure 5.2. To knitwear process from cut-and-sew achieve fully-fashioned knitting, loop production to seamless knitting. transference is necessary. The loop transference is the process that moves 5.1. Cut and Sew Production stitches (i.e., loops) from the needles on which they were made to other needles [49]. Figure 5.2a illustrates the mechanism of loop transference on a V-bed flat knitting machine.
In addition, the following stitch notation (Figure 5.2.1) describes how widening or narrowing occurs by loop transference on fully-fashioned machines. The fully- Front Body Back Body Sleeves fashioning process allows the separate Figure 5.1. Cut and sew production creation of shaped front and back body parts (Shaded area: Cutting Waste) and sleeve parts by increasing or decreasing Cut and sew production is created by the use the number of loops (Figure 5.2); this of one entire panel of fabric . Figure 5.1 eliminates the cutting operation. However, shows the cutting layout for the front and because all parts of the garment are knitted rear body portions and also the sleeve separately, the fully-fashioned knitting still portions required to create a sweater. requires a post sewing or linking process. Through the cutting and sewing process, the Linking is defined as a process of joining finished garment is created. However, this side seams or edges of fabric pieces together garment production process requires several with a row of knitting on a linking machine post-knitting processes including cutting and [19]. sewing. Additionally, in this process, separately knitted trimmings and pockets
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a. The delivering needle is raised by a cam in the carriage. The loop is stretched over the transfer Transfer spring spring.
b. The receiving needle is raised slightly from its needle bed. The receiving needle enters the transfer spring of delivering needle and penetrates the loop that will be transferred.
c. The delivering needle retreats leaving the loop on the receiving needle. The transfer spring opens to permits the receiving needle to move back from its closure. Finally, loop transference is completed.
Figure 5.2a. the mechanism of loop transference on V-
bed flat knitting machine (Raz, 1991)
Back bed
1. Single jersey stitch notation Front bed Code Transfer four stitches 2. from the font to back bed : Back loop
: Face loop
3 Transfer complete : Needles
Racking one stitch in a : Gating
4. right direction and transfer again from the : Transfer
back to front bed
5. Loop transference is finished for the front bed
Figure 5.2.1. Narrowing process by loop transference on flat V-bed machine
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5.3. Seamless garment knitting minute [41]. Complete garment knitting can be achieved either on a circular knitting machine or a flat (V-bed) knitting machine. However, seamless circular knitting machines are different from seamless flat knitting machines in that circular machines such as the Santoni create only a single tubular type of garment. Seamless flat knitting machines such as the Shima can Figure 5.3. Complete garment production create more than one knitted tube at the by a seamless flat knitting machine same time, and the tubes are joined together on the machine (Figure 5.3a). The complete “Seamless” garment knitting creates a garments knitted on circular machines may complete garment by several different also need minimal cutting as seen in Figure carriers (feeders) with minimal or no cutting 5.3a. In addition, the complete garments and sewing processes (Figure 5.3). Thus, created by circular knitting machines still seamless knitting has the capability for require minimal seam joining on one body production time and cost saving by tube and two sleeve tubes as well as the removing post-knit processes such as the finished edges. Santoni has recently linking or sewing and cutting operation [39]. introduced the SM4 TL2 machine, which shapes the knitted tube and will eliminate It also minimizes yarn consumption by the cutting process [35]. Consequently, reducing the cutting waste and can achieve seamless knitting on circular machines is not higher productivity. Machine productivity true seamless knitting. in knitting is expressed in pattern rows per
1. 2.
Body Sleeves
Figure 5.3a. Complete : Cut area for a body part : Cut area for sleeve parts garment production by a seamless circular knitting machine 3.
: Seam joining area
Article Designation: Refereed 11 JTATM Volume 4, Issue 3,Spring 2005 In recent years, several companies have On the flat machine, the three tubes are developed seamless or complete garment knitted on a pair of front and back needle machines such as Santoni, Sangiacomo, and beds. The flat machine knits and transfers Orizio Santoni, part of the Lonati Group, is loops between the front needle bed and the the biggest supplier of the circular knitting back needle bed with different yarn carriers machinery. Lonati has recently acquired for one body tube (Feeder 2) and two sleeve Sangiacomo, and its expanded seamless tubes (Feeders 1 and 3) (Figure 6.1). The circular knitting technology is in the three-tube knitting continues to the forefront of the industry. Santoni, whose underarm point. At the underarm point, the customers include Nike, Adidas, Sara Lee et two carriers knitting sleeve parts (Feeders 1 cetera [30], offers 14 different models of and 3) are taken out of the knitting zone. circular knitting machines, from 7 to 32 The remaining carrier (Feeder 2) that knitted gauge. The machines produce swimwear, the main body part knits together the three sportswear, outerwear, underwear et cetera. tubes into one tube [10] (Figure 6.2). The [35]. tubes are joined at the underarm points, shoulders and neck points. In this manner, However, in the strict sense of the word, seamless garment knitting is accomplished. seamless flat V-bed knitting actually creates However, in order to make loop transference complete garments, which do not require for performing shaping or design structures, any kind of cutting or sewing process. For loops should be formed by selecting Section 6, the knitting method of multi- alternate needles [17] (Figure 6.3). tubular knitting techniques created on a V- bed knitting machine will be discussed. Figure 6.4 reveals how loop transference occurs on complete garment knitting by 6. V-BED MACHINE KNITTING OF using empty needles. By loop transference SEAMLESS GARMENTS using the alternate needles, single jersey tubes as well as rib type tubes can be knitted As mentioned earlier, seamless garments on on the complete garment machine. Figure a flat V-bed machine can be create d in three 6.5 depicts how the 2X2 rib structure can be separate tubular forms by knitting one wider created on the complete garment V-bed tube for the body part and two narrower knitting machine. However, due to the tubes for the sleeve parts. Tubular knitting alternate needle selection on seamless is created on both needle beds but front and machines, the garment tends to be more back bed knitting are done alternately [23]. open and less elastic than a traditional fully- The continuously alternate knitting of all fashioned garment [27]. This requires the needles on front and back needle beds use of more elastic yarns on the seamless creates a single plain tube. Tubular type knitting machine compared to the other knitting is not a new technique. Since the regular V-bed machines such as fully- 1800’s, single jersey tubes have been fashioned machines. produced on flat machines [8]. However, seamless garment knitting can be seen as a In addition, the number of tubes knitted on more advanced technique in that it can the machine depends on the desired type of connect the three tubes together to create a knitted product. The complete garment sweater [6] and has the capability to increase machine does not have to create three tubes and decrease the dimensions of the tubes all the time. For instance, to create a [44]. Moreover, various structures such as sweater, it requires three tubular typed plain, rib, and purl can be created within the forms. On the other hand, a seat cover may seamless garment at the same time. require only one type of tube for the complete cover, but could also provide an integrated attachment tube.
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Feeder 1 Feeder 2 Feeder 3 Feeder 2
Neck point Shoulder point
Underarm point Underarm point
Figure 6.1. Three-dimensional Figure 6.2. Three-dimensional complete garment knitting until complete garment knitting after underarm point (Shima Seiki) underarm point
Figure 6.3. Alternate stitch notation on complete garment knitting
Back bed Alternate loop notation 1. Front bed
Transfer two stitches from the front to back 2. bed by using empty needles
3. Transfer complete
4. Racking two stitches in a right direction and transfer again from the back to front bed
5. Loop transference is finished for the front bed
Figure 6.4. Loop transference on complete garment knitting
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1. Carriage traverse
Transfer( ) two loops for each back rib knitting(red colored yarn) from front to the back bed. Then, knit 2x2 rib for front body knitting(red colored yarn). After knitting, transfer ( ) stitches back to the original position (red colored yarn).
2. Carriage traverse
Transfer( ) two stitches for each front rib knitting(green colored yarn) from back to the front bed. Then, knit 2x2 rib for back body knitting(green colored yarn). After knitting, transfer ( ) stitches back to the original position(green colored yarn)
3. Repetition of the steps 1 and 2 creates 2x2 rib tube.
* The upper figures show 2x2 rib tubular type knitting. Green colored yarn and red colored yarn represent the same yarn. In order that loop notation is seen easily, two different colors are utilized in this diagram. Figure 6.5. Tubular knitting of 2x2 rib on complete garment machine
7. SEAMLESS MACHINES Association) [24]. Since the beginning of WholeGarment® machine production, about For seamless flatbed knitting machines, two 3500 WholeGarment® machines have been suppliers, Shima Seiki and Stoll, are the manufactured and sold worldwide [11]. The leaders in machine manufacturing. They seamless garment machines of Shima Seiki offer solutions for the knitting of complete have different range of gauges from 5 to 18 garments on computerized V-bed knitting gauge (needles per inch) and knitting widths machines. In Section 7, the two companies, ranging from 50 inches to 80 inches. Shima Shima Seiki and Stoll, and their seamless Seiki produces five versio ns of the knitting machine systems will be introduced innovative WHOLEGARMENT® machine and compared. that can produce a one-piece three- dimensional complete garment with no 7.1. Shima Seiki stitching, linking or sewing processes. Figure 7.1 illustrates the SWG-V The Shima Seiki company invented the WholeGarment® knitting machine system WholeGarment® machine and introduced that shows various machine features such as the commercial complete garment knitting a machine tuning screen, a computer (SWG-V machine) in 1995 at ITMA controller, top tension devices, yarn (International Textile Machinery carriage, et cetera.
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Top Tension Equipment Machine Tuning
Computer Controller Carriage Fig ure 7.1. SWG-V® machine
7.1.1. Shima Seiki CAD system and machines Figure 7.1.1 shows the Shima Seiki® Seiki knitting machine and the machine can knitting machine system. In general, knit be operated. The machine-tuning screen patterns can be created on the CAD allows operator interface with the settings of (Computer-Aided Design) system and all the machine. Finally, one complete three- data can be saved to a diskette. The saved dimensional garment can be knitted on the data can then be transferred to the Shima machine.
Diskette
SDS ONE® CAD Complete garment machine system
: Set-up yarn (See explanation of comb system in Section 7.1.2) Production of Complete garment
Figure 7.1.1. Shima Seiki Knitting machine system
Article Designation: Refereed 15 JTATM Volume 4, Issue 3,Spring 2005 7.1.2. Shima Seik i CAD system CAD system, each different type of knitting loop is represented by different colored The Shima SDS ONE® CAD system is a squares (Figure 7.1.2a). For example, as totally integrated knit production system that seen in the following figure 7.1.2a, color allows all phases including planning, design, number 1(red) indicates a jersey (face loop) evaluation and production [44]. and color number 2 (green) indicates a Specifically, the loop simulation program reverse jersey (rear loop). Thus, the permits quick estimation of knit structures following red colored figure shows how a without any kind of actual sample making single jersey structure can be displayed on [8]. The program provides an opportunity to fully-fashioned CAD system of Shima Seiki see knit problems and to try out diverse knit machine. structures on the computer system before beginning the actual knitting. In the Shima
Single Jersey
6 5 4 3 2 L1 : Comb on R1 2 3 4 5 6 7 8 9 10 Option lines Option lines
: Float loop : Face loop : Rear loop : All needle knitting (1X1 Rib)
Color number 0 Color number 1 Color number 2 Color number 3
* A Comb on a V-bed knitting machine is used to set up the yarn required to knit. The comb hooks the set-up yarn, and moves up and down, pulling down the set-up yarns connected with a knitted garment. * Option line is used to control the data for a knit structure on the CAD system. For example, the right side of option line number 1 is utilized to decide repetition of a pattern area. Each option line represents specific functions of the machine knitting.
Figure 7.1.2a. Shima Seiki CAD system for fully-fashioned The CAD patterning of the seamless loop transference for complete garment garment knitting is more complicated than knitting can occur and how it can be that of the fully-fashioned knitting due to displayed on the CAD system. The empty alternate needle selection. The bottom needles thus can be used for the loop figure (Figure 7.1.2b) depicts a single course transference. For the loop transference on notation of the tubular-formed knitting. In complete garment knitting, at least two Figure 7.1.2b, the first row indicates front loops are transferred in a right or a left bed knitting (color number 1) and the direction due to alternate needle selection second row indicates back bed knitting such as Figure 7.1.2c. Note that only even (color number 2). Accordingly, continuous number of loops can be transferred for knitting in a lateral direction between the seamless knitting on V-bed knitting front and back needle beds forms a tubular- machines. typed fabric. In Figure 7.1.2c, it shows how
Article Designation: Refereed 16 JTATM Volume 4, Issue 3,Spring 2005
: Miss : Face loop : Rear loop
Figure 7.1.2b. Stitch notation for seamless knitting and CAD design on Shima Seiki CAD system
: Miss : Face loop : Rear loop
: Knit front and transfer 2 stitches in a right direction
Figure 7.1.2c. Loop transference on front bed for seamless garment knitting
By utilizing the principle of the alternate 7.1.2d displays a whole garment designed on stitch notation, two-dimensional design can the Shima Seiki CAD system. be created on the CAD system as seen in Figure 7.1.2d. This represents a three- dimensional tubular typed garment. Figure
Figure 7.1.2d. Design for complete garment on Shima Seiki CAD system Binding-off: The process that sequentially moves the stitches to the next loop from the edge [38]. This technique is generally utilized to finish edge lines. Article Designation: Refereed 17 JTATM Volume 4, Issue 3,Spring 2005 The interface between the knitwear 7.1.3. Types of Shima Seiki Seamless designers and the knit technicians is critical knitting machines to the success of new sample development. The designer’s concept sketch must be Shima Seiki offers a line of machines realized through the capabilities of the capable of seamless knitting. These five machine governed by the technical expertise different machines have special attributes, of the technician. Shima Seiki addresses which can be selected according to this interpretative process through its application or end use. Gauge and needle enhanced Shima Seiki SDS ONE® CAD type are the primary distinguishing factors. system. “Knit designs created in the paint program are simultaneously converted to 7.1.3.1. SWG-V® knit programming data, so that designers and technicians can keep in close The Shima Seiki's SWG-V® machine, communication with each other over the which comes in 5 gauge and 7 gauge, is the same job” [39]. The combination of knit first commercial application of structures and yarn selections available in Wholegarment® technology (See Figure the design system will allow virtual 7.1) [39]. The SWG-V® machine uses a simulation of potential garments without latch needle where the latch closes into the actual knitting. hook of needle as it pulls the yarn through a loop to form a new loop [33] (Figure Recently, Shima Seiki created a large 7.1.3.1a). The latch needles used in flat bed pattern structure database of knitted parts machines require an additional attachment, a including collars, plackets, cuffs et cetera. transfer spring, in order to transfer a loop as Knit and garment designs can be easily can be seen in Figure 7.1.3.1a. However, changed at will (Figure 7.1.2.e and 7.1.2f) due to the transfer spring, the needles cannot [39] be located in the center of the needle groove, which results in a slightly asymmetrical loop formation. This will be discussed on Sections 7.1.3.4 and 7.1.3.5.
Figure 7.1.2e. Figure 7.1.2f Structure Virtual sampling pattern (Shima Seiki) database
Article Designation: Refereed 18 JTATM Volume 4, Issue 3,Spring 2005
Transfer spring Needle hook
Figure 7.1.3.1a. Needle stem Latch Latch needle on SWG-V® machine
Shima Seki introduced a version of the loop transference requires two sets of SWG-V® machine, with its enhanced needles, for the front and back of the technical capabilities such as the yarn carrier garment, unlike a traditional single jersey kickback device and increased memory tube that has only one set of needles [10]. capacity [39]. The New SWG-V® machine Therefore, this twin needle configuration also has a special twin gauge needle allows the needles to more effectively create configuration (Figure 7.1.3.1b) that includes widening or narrowing as well as diverse a pair of needles working together in each knit structures for complete garment needle slot. Complete garment knitting with knitting.
Figure 7.1.3.1b. twin gauge needles (Shima Seiki)
7.1.3.2. SWG-X® Actually, a machine that includes four The SWG-X® machine is used to produce needle beds and four cam plates is much fine gauge knitwear, which has either 12 more expensive to produce than a V-bed gauge or 15 gauge. Fine gauge knitting is machine with two needle beds [10]. The produced by the slide needle and pull-down reason Shima Seiki chose the more device, which independently controls expensive four-bed route for fine gauge is in takedown tension for front and back body that if the machine was to take the half- portions. Specifically, the SWG-X® is gauge route for the fine gauge, the gauge configured for complete garment knitting would be just too fine for flat knitting with four separate needle beds and an technology [10]. The half gauge route on additional loop presser bed [39]. This is the two needle beds for 12 or 15 gauge knitting reason why the SWG-X® machine is the is too fine to endure rigorous racking or only machine that can knit complete transferring for complete garment knitting. garments without alternate needle technique. The needle hook is also too small to accept As can be seen in Figure 7.1.3.2, front body the yarn required for 12 or 15 gauge knitting can be achieved on needle beds 1 knitting. and 2, whereas back body knitting can be done between beds 3 and 4.
Article Designation: Refereed 19 JTATM Volume 4, Issue 3,Spring 2005 This multi-needle bed configuration permits tubular ribs. In addition, various knit complete garment production with sufficient structures can be knitted at the same time stitch density. Moreover, stitch transference with required stitch densities (Figure can be more easily accomplished to create 7.1.3.2).
1. 3.
Figure 7.1.3.2. Cross section Diagram of the SWG-X® four-needle bed configuration 2. 4. (Shima Seiki)
7.1.3.3. SES-S.WG®
As with the SWG-V® machine, the SES- ends, and blocks of different gauges of S.WG® has the capability to knit complete needles each working with its corresponding garments with latch needles. However, count of yarn and yarn carriers [44]. Shima unlike the SWG-V's twin-needle Seiki explains that this capacity responds to configuration, the SES-S.WG® uses the the change of seasons and trends without standard latch needles and spring-type investing in a machine for every gauge. As sinkers at the same pitch. This enable s the a result, it saves time by eliminating the task machine to knit fine-gauge shaping as well of gauge conversion from one machine to as integral knitting, and it also makes another machine. Product variety can be possible multiple -gauge knitting. In greatly enhanced by achieving more multiple -gauge knitting, a number of interesting and sophisticated design patterns different gauges can be knitted in a single [39]. course. Multiple -gauge knitting is different from fixed gauge knitting in that an assortment of gauge sizes may be knitted in a single garment [39] (Figure 7.1.3.3). The multiple gauges contain a combination of techniques, such as half-gauging, intarsia technique, using different numbers of yarn
Figure 7.1.3.3. multiple-gauge knitting sample with 12G and 7G mixed side by side (Shima Seiki)
Article Designation: Refereed 20 JTATM Volume 4, Issue 3,Spring 2005 7.1.3.4. SES-C.WG® needle unlike a latch needle . The slider moves up and down by the movement of the The SES-C.WG® is a flexible machine in cam system, which is timed to work closely that it can achieve quality knitting in a range with the movement of the needle. This of production styles. The SES-C.WG® increases the stability of knitting, and there machine has the capability to perform are no brushes to be worn out. shaping and integral knitting similar to the other SES-series. In addition, this machine Another feature of the compound needle is can knit coarser gauge complete knitwear. that it does not have to be raised as high By using compound needles and a take because there is no latch that must be down system featuring a pull-down device, cleared which increases knitting stability at the SES-C.WG® can produce a high-quality higher speeds. However, one drawback of coarse gauge seamless garment. The both the latch and the compound needle is compound needle, in which the hook and that both needles have to be off center in the hook closing portions are separately trick wall to allow for the transfer spring. controlled [22], is generally used in warp This puts the needle hook closer to the knitting machines [13] (Figure 7.1.3.4a). knock-over bit on one side, resulting in a However, Shima Seiki applied the concept slightly imbalanced stitch. To solve the of compound needles to the flat bed problem of imbalance, the Shima Seiki machine. developed the slide needle [50]. The slide needle will be discussed in Section 7.1.3.5.
7.1.3.5. First®
This machine executes all types of Figure 7.1.3.4a. production from fully fashioning and three- Compound needle dimensional shaping to seamless production. (Kadolph and All this capability is accomplished through Langford , 1998) the development of the slide needle instead of the latch needles, which uses a unique two-piece, slide mechanism [39] (Figure 7.1.3.5a).
Compared to traditional latch needles, the Fig 7.1.3.5a. Slide needle compound needle is more complex and (Shima Seiki) expensive to manufacture [44]. However, the compound needle gives higher operational stability, which is required for larger needle sizes. According to Shima Seiki, the compound needle offers Shim Seiki points out “A flexible two-piece significant reduction in needle stroke to slide mechanism splits and extends beyond allow for similar reductions in needle bed the needle hook for increased potential and carriage size [39]. Thus, the short stroke especially in complex transfers. Using the knitting helps reduce space in the carriage slider mechanism for transfer effectively and permits smaller and lighter carriage [6]. eliminates the transfer spring, allowing the According to John Ward [50], a technician needle to be mounted in the center of the at Shima Seiki USA Inc., the compound needle groove. The slide needle thereby needle eliminates the necessity for a brush achieves perfectly symmetrical loop on the carriage, because the needle has a formation for knitting the highest possible slider that opens and closes the hook of the Article Designation: Refereed 21 JTATM Volume 4, Issue 3,Spring 2005 quality fabrics (Figure 7.1.3.5b and slider on the slide needle [51]. In 7.1.3.5c)” [39]. Accordingly, by using the consequence, the additional equipments slide needle, the machine provides better make the machine with slide needles more quality and stable knitting as well as higher expensive than a machine with latch productivity. However, in order to transfer needles. loops by slide needles, the First® machine needs an additional transfer bed that can only move stitches [51]. The machine also requires an extra cam system to control the
Fig 7.1.3.5b. Conventional latch needles offset slots Fig 7.1.3.5c. Slide needles centered in slots (Shima Seiki)
Another distinctive feature of the First® takedown tension permits 3-dimensional machine is its takedown system. “Precision shaping of complete garment items” [10]. pull down of the garment is independently The following Table 2 shows the five- controlled by tiny pins mounted on front and versions of Shima Seiki WholeGarment® rear panels which feature adjustable working knitting system. All sources are cited from width through individually controlled 1.5 the Shima Seiki company website, inch wide sections. This precise control of www.shimaseiki.co.jp.
Article Designation: Refereed 22 JTATM Volume 4, Issue 3,Spring 2005 Shima Seiki WholeGarment® Systems (Sources from www.shimaseiki.co.jp, 2004)
First® New SWG-V® SWG-X® New SES-S.WG® New SES-C.WG®
Knitting 126-181cm Max 183cm Max 172cm 183cm 203cm Width 50-72” 72” 68” 72” 80”
8, 10, 12, 14, 16 5 gauge(capable of Gauge 12 - 18 gauge 5, 7 gauge 12, 15 gauge gauge producing 3G fabric)
Knitting Max 1.3m/sec Max 1.3m/sec Max 1.3m/sec Max 1.3m/sec Max 1.1m/sec Speed
Max 1.5-inch Max 1.5-inch Max 1.5-inch Max 1.5-inch Max 1.5-inch racking racking in each racking in each racking in each racking in each Racking in each direction (3 direction (3 inches direction (3 inches direction (3 inches direction (3 inches inches total) total) total) total) total)
3 system Ultra-compact 2- Triple Knitran ® Triple Knitran ® Knitting (1 knitting system system (1 knitting 3 or 4 system system. Single system. Single system + 2 transfer system + 1 transfer carriage carriage system) system)
Simultaneous Simultaneous Simultaneous Simultaneous Simultaneous
Transfer, Transfer, Transfer, Transfer, Transfer, Transfer Independent of Independent of Independent of Independent of Independent of carriage direction, carriage direction, carriage direction carriage direction, carriage direction, Split stitch Split stitch Split stitch Split stitch
Spring-type Spring-type Spring-type movable Fixed sinker Spring-type movable Sinker system movable full sinker movable full sinker full sinker system system full sinker system system system
Yarn Carriers 12-16 13 12 13 16
Special pulldown Special pulldown
Main/sub rollers, mechanism with Main/sub rollers, mechanism with Take down Main/sub rollers, Changeable 31 independent Changeable 31 independent device Changeable 31 levels levels operation on front levels operation on front
and rear and rear
Needle Electromagnetic Electromagnetic Electromagnetic Electromagnetic Full-jacquard selection direct selection direct selection direct selection direct selection solenoid selection
Latch needle Needle Slide needle Latch needle Slide needle (Standard layout of Compound Needle needles)
Everything from full- Fine-gauge shaping
fashioning, rib and integral High quality fine Coarse gauge Production knitting, even shaping to 3- gauge knitwear knitting dimensional shaping, multi-gauge
as well as seamless knitting
Table 2. The Shima Seiki WholeGarment® machine Systems
Article Designation: Refereed 23 JTATM Volume 4, Issue 3,Spring 2005 7.2. Stoll 7.2.1. Stoll CAD system
According to Spencer [44], the Stoll SIRIX® (M1) CAD system is a complete design, patterning, and programming system, and it utilizes two windows to graphically develop knitting programs for the Stoll machines. In the Stoll CAD system, all knit structures are displayed by real modules. Figure 7.2.1 shows how 2X2 rib and single jersey can be displayed on the Stoll M1 CAD system. 2x2 Rib
Figure 7.2. STOLL Knit and Wear® Machine (Stoll) Single Jersey
The other major machinery producer for seamless knitting considered in this research is Stoll. The Stoll system is examined in comparison with the Shima Seiki based on 2X2 rib research at Cotton Inc. with Emmett Hylton, Knitting Manager [5]. This section considers the CAD system, the knitting equipment and the seamless systems Figure 7.2.1. 2X2 Rib and single available. Seamless garment knitting jersey displayed on the Stoll M1 systems from Stoll and Shima are similar, CAD system and a comparison of the complete garment knitting systems offered by Shima Seiki and As in the Shima CAD system, Stoll’s M1 Stoll are considered in this section. Stoll has CAD system offers two different windows manufactured flat knitting machines for for designers and technicians who need more than 130 years and has today more different information for the same design than 1,100 employees worldwide [45]. The (Figure 7.2.2). The technical window shows Stoll machine also markets complete the developing design in the form of running garment knitting machines called “Knit and yarn notations and technical data, while the Wear®”. The range of gauge for Stoll Knit design window presents design as a knitted and Wear® machine is from E2.5 to E9.2 structure [44]. Both windows can be easily gauge and the knitting width is from 72 displayed and automatically converted. inches to 84 inches. The Stoll Company Therefore, it is expected to minimize also has a multiple gauge system, which miscommunication between designers and permits different gauge areas to be knitted in technicians in knitting industry. By one single course [45]. understanding the knit structures, it is possible to improve collaborative efforts and resulting samples.
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Figure 7.2.2. Linked windows options of fabric design view and technical view (Spencer, 2001)
7.2.2. Types of Stoll seamless knitting gauge knitting in order to create an machines interesting knit structure between finely knit areas knitted with all needles and coarser 7.2.2.1. CMS 330 and CMS 340 TC Knit areas knitted only with every second needle and Wear® machines [45].
CMS 330 TC and 340 TC knit and wear® 7.2.2.3. CMS 330 TC-C Knit and Wear® machines have a 72-inch (183 cm) knitting width. The CMS 330 TC knit and wear® CMS 330 TC-C knit and wear® machine machines cover three systems and a gauge has a three-system capability and a working range from E6.2 to E7.2. E6.2 provides a width of 84 inches (213 cm). This width can range from E6 to E12 and E7.2 gives a range easily produce coarse gauge knitwear in from E7 to E14. On the other hand, the extra-large sizes. The gauge E2,5.2, in CMS 340 TC knit and wear® machine has conjunction with knitting and transferring four systems that combine the knitting and systems designed especially for this the transfer system, and a gauge range from application and a new type of holding-down E2, 5.2 to E9.2. Technically, the CMS 330 technology, allows the production of TC machine is capable of producing fully seamless garment knitting [45]. fashioned, multiple gauge as well as intarsia fabrics. An intarsia fabric is a flat knit 7.2.2.4. CMS 340 TC-M Knit and Wear® fabric with patterns knitted in solid colors (or textures), so that both sides of the fabric This machine is equipped with a new extra are equal [48]. Its three systems yield a high wide working width of 84 inches (213 cm) level of production. The CMS 340 TC for producing triple XL sized seamless machine has the capability of multiple - sweaters [13]. The four system model gauge knitting such as Shima Seiki New features a gauge range from E2, 5.2 to E7.2 SES-S.WG [45]. (up to 14 cut) and the machine also offers gauge conversion capability. It also can be 7.2.2.2. CMS 330 TC-T Knit and Wear® used efficiently for fully-fashioned, multiple -gauge and intarsia fabrics. Thus, it This machine offers a 72-inch (183 cm) joins the advantages of the comb machines knitting width and the range of the gauge is with those of multi piece knitting. between E6.2 and E7.2. By using its three Consequently, profitability can be enhanced systems and two additional needle beds with and even multi-piece fully-fashioned transfer elements and independent racking knitting can be achieved [45]. For instance, front and rear, fine gauge knitting is possible two front pieces, two back pieces, and four in gauges E12 and E14 with all needles [45]. sleeve pieces can be sequentially knitted in This machine is also capable of multiple - the necessary sizes. In two-piece knitting,
Article Designation: Refereed 25 JTATM Volume 4, Issue 3,Spring 2005 the left fabric can be knitted by the two left the front and back body portions of the knitting systems, and the right fabric can be garment not in the middle of the shoulder knitted by the two right knitting systems but at the top of the back. This new knitting (Figure 7.2.2.4). This figure also shows the sequence demonstrates that the shoulder part two separate yarn carriages. Two-piece of the garment can be produced with greater knitting significantly increases productivity quality with a wide range of possible compared to one-piece seamless knitting variations in terms of visual appearance and [45]. “This machine knits complete garment elasticity [45]. Table 3 shows the five- panels as multi-layer applications and also versions of the Stoll Knit-and-Wear® as racked and structured patterns in multi knitting system. All sources are cited from layer knits and an absolute novelty in the the Stoll website, www.stoll.de. sector – two gauges in one fabric” [36]. In addition, this machine is capable of producing ultra-coarse gauge garments with the fabric appearance of 2-gauge with a hand-knitted look [13]. With new take-down technology, this machine offers a new shoulder solution, the so-called “French shoulder”. This style of shoulder features the connection between
Figure 7.2.2.4. Two piece fully fashioning (Stoll)
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Type of Knit–and–Wear® machines (Sources from www.stoll.de, 2004)
CMS 330 TC CMS 340 TC CMS 330 TC-T CMS 330 TC-C CMS 340 TC-M
Knit and Wear Knit and Wear Knit and Wear Knit and Wear Knit and Wear
Knitting 183 cm 183 cm 183 cm 213 cm 213 cm Width 72” 72” 72” 84” 84”
Gauge E2,5.2- E7.2 E2,5.2- E9.2 E6.2-E7.2 E2,5.2- E2,5.2 E2,5.2- E7.2
Knitting Max 1.2m/sec Max 1.2m/sec Max 1.2m/sec Max 1m/sec Max 1.2m/sec Speed
Racking Max 4” Max 4” Max 4” Max 4” Max 4”
Independent Independent knitting systems Independent knitting Independent knitting Independent knitting knitting systems with split function systems with split systems with split systems with split Knitting with split function function for for optimum function for optimum function for optimum system for optimum system system allocation optimum system system allocation system allocation allocation (4 combined allocation (3 systems) (3 systems) knitting/transfer (4 systems) systems)
Simultaneous Simultaneous Simultaneous Simultaneous transfer Simultaneous transfer Transfer transfer in both transfer in both transfer in both in both directions in both directions directions directions directions
Moveable holding- down spring loaded
Moveable Moveable sinkers: enables Moveable Sinker Moveable holding- holding-down holding-down manufacturers to holding-down system down sinkers knit ultra coarse sinkers sinkers sinkers garment with a hand-made look (Mowbray, 2004).
Yarn Carriers 16 16 16 16 16
Main / Main / Main / Main / Main / Take down upper take-down upper take-down upper take-down and upper take-down and upper take-down device and take-down and take-down take-down comb take-down comb and take-down comb comb comb
Needle Electronic Electronic Electronic selection Electronic selection Electronic selection selection system selection system system system selection system
Coarser gauge Coarse gauge Multi-gauge, Multi-gauge, Fine gauge knitting, knitting, Production knitting, Fully-Fashion, Intarsia fabric Flexible gauge Multi-gauge Multi-gauge, Intarsia fabric
Table 3. The Stoll knit and wear® machine system
Article Designation: Refereed 27 JTATM Volume 4, Issue 3,Spring 2005
7.3. Comparison of Complete Garment between two offerings is that Shima Seiki Knitting Systems between Shima Seiki & machines employ three different types of Stoll needles for complete garment knitting such as latch needles, compound needles and Table 4 compares seamless garment knitting slide needles, whereas Stoll machines systems between two companies, Shima employ only latch needles. Table 4 shows Seiki and Stoll. The characteristics of the the machines of two companies have quiet machines are generally comparable except similar characteristics. in a few features. The main difference
A comparison of complete garment knitting systems between Shima Seiki and Stoll (Sources from www.shimaseiki.co.jp and www.stoll.de, 2004)
Shima Seiki WholeGarment® Stoll Knit-and-Wear® Machines Machines
Knitting Width 50” – 80” (126 – 203 cm ) 72” – 84” (183 – 213 cm)
Gauge 5 - 18 gauge 5 -18 gauge
Knitting Speed Max 1.3m/sec Max 1.2m/sec
Racking Max 3” total Max 4” total
Knitting System 3 – 4 systems 3 – 4 systems
Transfer Simultaneous transfer Simultaneous transfer
Spring-type movable full sinker Spring-type moveable holding- Sinker System system down sinker system
Yarn Carriers Up to 16 Up to 16
Take-down Device Main/sub take down rollers Main/upper take down rollers
Needle Selection Electric selection system Electric selection system
Latch needles, Compound needles, Needle Latch needles Slide needles
Integrated knit production system Complete design, patterning, and CAD system allowing planning, design, programming system evaluation and production
Table 4. Comparisons of complete garment knitting systems between Shima Seiki and Stoll
Article Designation: Refereed 28 JTATM Volume 4, Issue 3,Spring 2005 8. CONCLUSIONS conventional fully-fashioned garments. Nevertheless, complete garment knitting Seamless garment knitting on V-bed provides major benefits for the market as machines creates one entire complete well as for technical production. (See Table garment by using several different carriers 5) Manufacturers do not have to rely on the eliminating the need for additional cut and cutting and sewing process. As a result, it is sewn operations. The garment can be believed to offer savings in terms of created in tubular forms: one wider tube for production times and cost, and it minimizes the body portion and two narrower tubes for yarn consumption. In addition, seamless the sleeve portions. Two leading garment knitting provides more consistent companies, Shima Seiki and Stoll, and homogeneous product quality, which manufacture seamless or complete garment gives lightness and comfort in the garments. V-bed knitting machines. Both companies It also offers knit designers more creative develop various complete garment machines knit possibilities. according to the machine gauge, types of needles, sinker systems, take down systems, Three-dimensional seamless knitting with its and application of knit structures. diverse capabilities can be applied to numerous products such as fashion, For seamless garment knitting, the machines upholstery, automotives, aerospace, medical have the capability not only to create shaped textiles, et cetera. Seamless knitting is knitting, but also to make various knit forecasted to continue growing and could be design structures in the complete garment by one of the largest next generation knitting utilizing alternate needle selection. technologies. Alternate needle selection, however, creates fabrics more open and less elastic than
Potential benefits of seamless knitting
1. Minimizing or eliminating labor intensive cutting and sewing process 2. Savings in production times and cost 3. Minimal yarn consumption 4. Higher productivity 5. Multi-gauge knitting 6. Lightness and softness 7. No bulky and irritating stitches/seams 8. More constant product quality 9. Better trimmability for finished edge lines 10. Better look, better fit and more comfortable 11. More creative possibilities for knitwear designers 12. Quick-response production for size and pattern changes 13. Just-in-time production 14. Mass customization
Table 5. Potential proposal for seamless garment knitting
Article Designation: Refereed 29 JTATM Volume 4, Issue 3,Spring 2005 9. REFERENCES 19. Linda, G. & Leggett, N. (1990). The Machine Knitter’s Dictionary, Batsford Ltd , 1. Black, S. (2002). Knitwear in Fashion. London, p.114. Thames & Hudson, New York. p.174-175. 20. Legner, M. (2003). 3D-Products for 2. De Arajo M. D. (2002). Weft-Knitting Fashion and Technical Textile Applications Fabric Design for Technical Application. from Flat Knitting Machines. Melliand Textile Asia, 33(3). p.23-27. International, 9(3). p.238-241. 3. Denton, M J. & Daniels, P. N. (2002). 21. Maison, L. (1979). Flat knitting Textile Terms and Definitions. The Textile Machines. ITF Maille , France. p.B-4. Institute , Manchester, UK. 11, p.383, p.65, 22. McIntyre J. E. & Daniels, P. L. (1997). p.138, p.308, p.176. Textile Terms and Definitions, The Textile 4. Groz-Beckert. (2004). Groz-Beckert Institute, 10. p.180, p.270, p.213, p.225, Needles(Manual). p.120-121. p.383. 5. Hylton, E. G. (2005). Personal interview. 23. Merle, M.L. (2003). Developments in Cotton Inc. February 28, 2005. Three-Dimensional Knitting for Preforms 6. Hunter, B. (2004). Technology Transfer. and Clothing, Proceedings: International Knitting International, 111(1311). p.35-39. Textile Design and Engineering Conference, 7. Hunter, B. (2004). Loop Tension and Edinburgh, Scotland, Heriot-Watt Fabric Quality. Knitting International, University, Netherdale, Galashiels TD1 111(1312). p.40. 3HF, UK. 8. Hunter, B. (2004). Is Knitwear Software 24. Millington, J. (1996). Knitting: a High too Rigid? Knitting International, Technology Industry. Textile Outlook 111(1318). p.19-20. International, p.98, p.105. 9. Hunter, B. (2004). Complete Garments - 25. Mowbray, J. (2003). Oswal Shapes up to Evolution or Revolution?(Part I). Knitting the Challenge. Knitting International, International, 111(1319). p.18-21. 110(1307). p.28. 10. Hunter, B. (2004). Complete Garments- 26. Mowbray, J. (2004). Complete Knitwear Evolution or Revolution?(Part II). Knitting Solutions. Knitting International, International, 111(1320). p.22-23. 111(1311). p.42. 11. Hunter, B. (2004). Complete Garments- 27. Mowbray, J. (2004). A New Spin on Evolution or Revolution?”(Part III). Knitting Knitwear. Knitting International, 111(1312). International, 111(1321). p.20-22. p.34-36 12. Kadolph, S. J. & Langford, A. L. (1998). 28. NeutralPosture. (n.d.). Retrieved January Textiles, Merrill Prentice Hall, New Jersey, 22, 2005, from 8. p.217, p.219-220. http://www.neutralposture.com. 13. Knit Americas. (2001). Seamless 29. Onal, L. (2003). The Relation of Seam- Sweaters Here to Stay, Winter, p.22-23. free Garments and Mass Customization, ITB 14. Knitting International. (2004). Lonati International Textile Bulletin, 49(3). p.44. buys Sangiacomo, 111(1313). p.19. 30. Powell, N.B. (2003). Italian Textile 15. Knitting international. (2004). Technology. Textile World, 153(6). p.40-41. Technology Spurs Further Growth. 31. Powell, N.B. (2003). Mass 111(1318). p.59. Customization in Transportation Textiles 16. Knitting Together. (n.d.). Retrieved through Shaped Three-Dimensional December 20, 2004, from Knitting. Proceedings: International Textile http://www.knittingtogether.org.uk. Design and Engineering Conference, 17. Kobata, et. al. (2001). Method of Edinburgh, Scotland, Heriot-Watt Knitting 3-D Shape Knit Fabric. United University, Netherdale, Galashiels TD1 States Patent: 6,318,131. 3HF, UK. 18. Lehrich, R. (2004). Shima Seiki training. 32. Pratt, H. (1972). Knit Barre Cause and NCSU. From March 8, 2004 to March 12, Cures. AATCC Symposium. New York. p.3. 2004. 33. Raul, J. (1998). Dictionary of Textiles. Anmol Publications PVT. India, p.84, p.24.
Article Designation: Refereed 30 JTATM Volume 4, Issue 3,Spring 2005 34. Raz, S. (1991). Flat Knitting : The New 50. Ward, J. (2004). Email interview. Shima Generation. Meisenbach Bamberg, Seiki USA Inc. November 29, 2004. Meisenbach. p.34-37, p.14, p.62-63. 51. Ward, J. (2005). Email interview. Shima 35. Santoni. (2004). Know-How : Santoni. Seiki USA Inc. January 6, 2005. Gruppo Lonati, Brescia, Italy, p.2-29. 52. Young, E. A. (1985). Knitwear 36. Schlotterer, H. (1998). Stoll-Pattern Manufacturers’ Use of Electronic V-bed Innovations from Pitti Imagine Filati. Knitting Machines with Presser Foot. A Knitting Technology, 20(3). p.97-99. thesis submitted to the Graduate Faculty of 37. Shima Seiki. (2004). Shima Seiki North Carolina State University, Raleigh. Instruction Manual, Shimatronic p.26. WholeGarment® Machine SWG-V, Wakayama, Japan, p.1-4. Glossary 38. Shima Seiki. (2004). Creating Shaping Guide. SDS-ONE Knit Barre’ : Barre’ means a continuous visual Paint(Shaping_HelpE), Version A-38. barred pattern or stripiness parallel to the 39. Shima Seiki Mfg. (n.d.). Retrieved yarn direction in a knit fabric. September 9, 2004, from http://www.shimaseiki.co.jp. Bearded needle: the needles having an 40. Sorge, M. (1994). A Stitch in Time: extended terminal hook or beard that can be Inland Fisher Guide’s Low-cost, High-tech flexed to close the hook. Seat Covers. Ward’s Auto World , p.52. 41. Spencer, D. (1983). Knitting Binding-off: The process that sequentially Technology. Pergamon Press, New York. moves the stitches to the next loop from the p.42. edge. This technique is usually utilized to 42. Spencer, D. (1989). Knitting finish edge lines. Technology, Woodhead Publishing Limited, Cambridge, England. 2. p.13-14, p.202, Brushes: The aim of brushes is to open the p.26, p.18, p.24, p.25, p.72-73 latches at the first course when the machine 43. Spencer, D. (1996). Sitting Pretty, starts to knit and to avoid closing of the knitting International, 103/1232-(32). p32 latches. 44. Spencer, D. (2001). Knitting Technology, a Comprehensive Handbook Cable stitch: Cable stitch is a stitch formed and Practical Guide. Woodhead Publishing by small groups of plain wales plaited with Limited, Cambridge, England. 3. p.106, one another in ropelike fashion. p.76, p.238, p.144, p.140, p.234, p.27 45. Stoll. (n.d.). Retrieved October 11, 2004, Carriage: Carriage that has cam boxes from http://www.stoll.de. travels along the beds forcing the needle 46. Stoll, H. (2001). New Approach to the butts in its way to follow the curved shape Design Automobile Interiors using Three- of the cam. dimensionally Knitted Fabrics. Melliand International, 7(6). p.127. Cam: The device which converts the rotary 47. Teknit, (n.d.). Retrieved November 11, machine drive into suitable reciprocating 2004, from action for the needles. http://www.teknit.com/Pages/summary.htm# ecol. Circular knitting machine: Needles are set 48. Tortora, G. P. & Robert, S. M. (1996). radically or parallel in one or more circular Fairchild’s Dictionary of Textiles. Fairchild beds. Used without further qualification, the Publication, New York. 7. p.287. term generally refers to a weft-knitting 49. Tubbs , M. C. & Daniels, P. N. (1991). machine of this type. Textile Terms and Definitions. The Textile Institute , Manchester, UK. 9. p.132-133, Comb: Comb on V-bed knitting machine is p.79, p.184. used to set up a yarn required to knit. The comb hooks the set-up yarn, and moves up Article Designation: Refereed 31 JTATM Volume 4, Issue 3,Spring 2005 and down, pulling down the set-up yarns Knitting: The process of forming a fabric by connected with a garment. the intermeshing of loops of yarn.
Compound needle: The hook and hook Knocking over: Knocking over is one of closing portions are separately controlled. functions of sinkers. It supports the old loop The compound needle gives higher as the new loop is drawn though it. operational stability at higher speed compared to latch needle. Latch needle: It has a latch or swinging fingers that closes into the hook of needle as Flat knitting machine: Flat knitting machine it pulls the yarn through a loop to form a employs straight needle beds carrying new loop. independently operated, usually latch needles. Linking: Linking is a process of joining side seams or edges of a piece of fabrics together Flechage: Course shaping in knitting. A with a row of knitting on a linking machine. term increasingly used to define two and three-dimensional shaping of knitted fabric Loop transference: Loop transference is the by increasing and/or decreasing the length of process that moves stitches from the needles succeeding knitted courses to a pre-planned on which they were made to other needles series. Beret knitting is also a term used to for the purpose of shaping or design. describe this process. The term is derived from the French for wedge. Mass customization: It is the use of (http://www.resil.com/dictionary/f.htm) technology and management methods to offer product variety and customization Fully-fashioned knitting: Fully-fashioned through flexibility and quick response. It knitting is shaped wholly or in part by owes its success partially to computer-based widening or narrowing by loop transference information, design and manufacturing to increase or decrease of the number of technology. wales. Miss stitch: A knitting cycle where a needle Gauge (cut): Gauge indicates the number of or needles do not take a yarn and produce a needles per inch. float loop either intentionally or as the result of knitting fault. Holding down: Holding down is one of functions of sinkers. It prevents previous Multiple -gauge knitting: Multiple -gauge loops from riding with needles. Thus, it knitting is a number of different gauges can gives tighter structures with improved be knitted in a single course. appearance. Productivity: Machine productivity is Intarsia fabric: An intarsia fabric is a flat expressed in pattern rows per minutes. knit fabric with patterns knitted in solid colors (textures), so that both sides of the Racking: Racking is the lateral movement of fabric are equal. a needle bed or point bar across a predetermined distance on a flat knitting Interlock: a double -faced rib-based structure machine. consisting of two 1X1 rib joined by interlocking sinker loops. Rib gating: The alternate alignment of one set of needles with the other on a machine Interlock gating: The opposed alignment of equipped with two sets of needles arranged one set of needles with the other on a to knit rib fabrics. knitting machine.
Article Designation: Refereed 32 JTATM Volume 4, Issue 3,Spring 2005 Sinker: Sinker helps loop formation, Tubular knitting: Tubular knitting is created holding-down, and knocking-over on a on both needle beds but front and back bed machine. knitting are done alternately.
Slide needle: A flexible two-piece slide Warp knitting: Warp knitting is composed of mechanism splits and extends beyond the loops formed in a vertical direction. needle hook for increased potential especially in complex transfers. Using the Weft knitting: Weft knitting is composed of slider mechanism for transfer effectively loops formed in a horizontal direction. eliminates the transfer spring, allowing the needle to be mounted in the center of the Welt: Welt in knitting is a secure edge of a needle groove. fabric. The welts are usually at the starting end of the fabric. Take down rollers: Take down rollers are required in order that the previous loop Yarn carrier (feeder): The yarn coming from which is located in the hook enclosure is a single yarn feeder is feeding the needle in prevented from the riding up with ascending a sequential order and by doing so connects needle. the adjacent loops into a course.
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