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DUET Journal Vol. 1, Issue 3, June 2012
Dhaka University of Engineering & Technology, Gazipur 12
Effect of Machine Paramet...
DUET Journal Vol. 1, Issue 3, June 2012
Dhaka University of Engineering & Technology, Gazipur 13
underwear, a typical weig...
DUET Journal Vol. 1, Issue 3, June 2012
Dhaka University of Engineering & Technology, Gazipur 14
Table 1: Typical Selectio...
DUET Journal Vol. 1, Issue 3, June 2012
Dhaka University of Engineering & Technology, Gazipur 15
differing for the differe...
DUET Journal Vol. 1, Issue 3, June 2012
Dhaka University of Engineering & Technology, Gazipur 16
Fig-9: Needle in knitting...
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Effect of machine parameters on knit fabric specifications

Effect of Machine Parameters on Knit Fabric Specifications
Cotton knit fabrics of yarn count 16Ne, 20Ne, 26Ne, 30Ne, 40Ne and 120-200 GSM for plain, 165-280 GSM for rib, 205-250 GSM for interlock were investigated with different machine parameters. The investigation developed a way so that it can be visualized or can forecast the resulting fabric specification with required configuration. The research emphasized on the adjustable points on which fabric GSM, stitch length, fabric width, and compactness directly or indirectly depends. It can be approached that the yarn count increases with the machine gauge. At different ranges of GSM the variation of the finished fabric diameter with the machine diameter is different. From a constant, VDQ number can be obtained for a particular stitch length and fabric design. Key Words: GSM, Stitch length, Yarn count, Fabric Width, Machine gauge, Needle.

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Effect of machine parameters on knit fabric specifications

  1. 1. DUET Journal Vol. 1, Issue 3, June 2012 Dhaka University of Engineering & Technology, Gazipur 12 Effect of Machine Parameters on Knit Fabric Specifications Shekh Md Mamun Kabir1 and Mohammad Zakaria2 1 Lecturer, Dept. of Wet Processing Engineering, Bangladesh University of Textiles, Tejgaon, Dhaka-1208, Bangladesh 2 Lecturer, Dept of Textile Engineering, Dhaka University of Engineering & Technology, Gazipur, Bangladesh E-mail: zakariate@duet.ac.bd ABSTRACT Cotton knit fabrics of yarn count 16Ne, 20Ne, 26Ne, 30Ne, 40Ne and 120-200 GSM for plain, 165-280 GSM for rib, 205-250 GSM for interlock were investigated with different machine parameters. The investigation developed a way so that it can be visualized or can forecast the resulting fabric specification with required configuration. The research emphasized on the adjustable points on which fabric GSM, stitch length, fabric width, and compactness directly or indirectly depends. It can be approached that the yarn count increases with the machine gauge. At different ranges of GSM the variation of the finished fabric diameter with the machine diameter is different. From a constant, VDQ number can be obtained for a particular stitch length and fabric design. Key Words: GSM, Stitch length, Yarn count, Fabric Width, Machine gauge, Needle. 1. INTRODUCTION Fabric or cloth is a flexible artificial material that is made by a network of natural or artificial fibers. The example is thread or yarn which is formed by weaving or knitting or felting. So, fabric is a manufactured assembly of fibers and/or yarns that has substantial surface area in relation to its thickness and sufficient cohesion to give the assembly useful mechanical strength. There are three principal methods of mechanically manipulating yarn into textile fabrics-interlacing, intertwining and interloping. All three methods have evolved from hand manipulated techniques through their application or primitive frames into sophisticated manufacturing operations on automatic machinery. Knitted fabric specification which are related to knitted fabric production. In case of knitted fabric specification GSM, stitch length is mainly considered. The common problem of all industries is to produce knitted fabrics of required GSM. Other specification like fabric width, thickness is generally maintained in industries by previous data sheet. So, problem occurs when an order comes which never produced in previous. The goal of our project is to find out easy process or method to take decision about the selection of yarn count, loop length, machine gauge and diameter for producing single jersey, rib and interlock fabric of ordered GSM. Many research works were carried out on the behavior of fabric with machines specifications both experimentally & numerically all over the world from different angle of views. Iyer I., Mammel B., Schach J. [4], Ghazi Saeidi R., Latifi M., Shaikhzadeh Najar S., and Ghazi Saeidi A. [5], Shady E., Gowayed Y., Abouiiana M., Youssef S. and Pastore C [6] are some of the researchers who worked on according to the “Circular knitting: technology process structure yarn quality”, "Computer Vision-Aided Fabric Inspection System for On-Circular Knitting Machine", “Detection and Classification of Defects in Knitted Fabric Structures”. Although a variety of research work carried out from different perspective but the investigation of fabric specification with the change of machine parameters is relatively limited. 2. GENERAL DISCUSSION 2.1. Plain Structure Plain is the base structure of ladies‟ hosiery, fully fashioned knitwear and single-jersey fabrics. Its use in ladies‟ suiting is known as the „Jersey Lily‟ (see in Fig.1). Other names for plain include stockinet, whilst in the USA the term „shaker stitch‟ is applied to it when knitted in a coarse gauge of about 31– 32 needles Per inch (25mm). 2.2. Rib Structure The simplest rib fabric is 1 X 1 rib. The first rib frame was invented by Jedediah Strutt of Derby in 1755, which used a second set of needles to pick up and knit the sinker loops of the first set. It is now normally knitted with two sets of latch needles. 1 X 1 rib is production of by two sets of needles being alternately set or gated between each other. Relaxed 1 X 1 rib is theoretically twice the thickness and half the width of an equivalent plain fabric, but it has twice as much width-wise recoverable stretch. In practice, 1 X 1 rib normally relaxes by approximately 30 percent compared with its knitting width (see Fig. 2). 2.3. Interlock Structure Figure 3 shows that interlock was knitted almost solely in cotton on 20 gauge (needles per inch) machines for
  2. 2. DUET Journal Vol. 1, Issue 3, June 2012 Dhaka University of Engineering & Technology, Gazipur 13 underwear, a typical weight being 5oz per square yard (170 g per Square meter) using 1/40‟s s cotton, but from the 1950s onwards, 18 gauge machines were developed for knitting double-jersey for semi-tailored suiting because the open-width fabric could be finished on existing equipment. As the machines became more versatile in their capabilities, the range of structures became greater. Fig. 1: Structure of single jersey knitted fabric. Fig. 2: Structure of 1X1 Rib fabric. Fig. 3: Structure of interlock fabric 2.4. Circular Knitting Machine Most single-jersey fabric is produced on circular machines whose latch needle cylinder and sinker ring revolve through the stationary knitting cam systems that, together with their yarn feeders, are situated at regular intervals around the circumference of the cylinder. The yarns is supplied from cones, placed either on an integral overhead bobbin stand or on a free-standing creel, through tensioners, stop motions and guide eyes down to the yarn feeder guides (see Fig. 4). Fig. 4: Circular knitting machine Machine Parts: 1. Yarn feeder guide, 2. Latch needle, 3. Holding-down sinker, 4. Needle cylinder, 5. Cylinder driving wheel. 6. Cylinder driving gear, 7. Sinker-operating cams, 8. Sinker cam-cap, 9. Sinker trick ring, 10. Needle-retaining spring, 11. Needle-operating cams, 12. Cam-box, 13. Cam- plate, 14. Head plate, 15. Cylinder driving pinion attached to the main drive shaft. 3. MACHINE PARAMETERS 1. Machine gauge. 2. Machine Diameter. 3. V.D.Q Pulley 4. Needle gauge. 3.1. Machine Gauge No. of needles per inch present in a needle bed of a knitting machine is called machine gauge for that knitting machine. Selection of machine gauge depends upon the following: Yarn count, Fibre type, Yarn twist, Yarn finished. General practices of machine gauge and yarn count in different industries in Bangladesh are shown in Tables- 1, 2 & 3. From this study of the data collected from the different factories we can see that the gauge increases with the English count (Ne) of the yarn. 3.2. Machine Diameter Machine diameter is mainly diameter of m/c cylinder. It is important for fabric width. Only diameter does not fetermi- Cylinder loops Dial loops Course
  3. 3. DUET Journal Vol. 1, Issue 3, June 2012 Dhaka University of Engineering & Technology, Gazipur 14 Table 1: Typical Selection of M/C Gauge for Different Count Yarn: Gauge Count (Ne) Low High Limit 32 32/1 46/1 60/1 28 30/1 46/1 60/1 24 20/1 46/1 50/1 22 20/1 40/1 20 20/1 40/1 18 20/1 40/1 16 10/1 24/1 Table 2: Relation between machine gauge and yarn count (Single jersey): S/J M/C gauge Count (Ne) M/C gauge Count (Ne) 18 30 24 30 20 26 24 30 22 20 24 40 24 30 24 28 24 34 24 28 24 28 24 30 24 30 24 34 24 30 24 34 24 30 24 26 24 30 28 40 24 34 28 50 Table 3: Relation between machine gauge and yarn count (1X1 Rib & Interlock) 1X1 Rib Interlock M/C gauge Count (Ne) M/C gauge Count (Ne) 18 30 24 46 16 28 24 46 16 30 24 40 18 26 24 40 18 24 24 34 18 28 24 36 16 30 24 36 ne the fabric width. It also needs machine gauge and wales space which is depends upon yarn count and loop length (see Tables- 4, 5, 6 & Fig.5, 6, 7). Tables show that same machine with the specific diameter can produce fabrics with different width. 3.3. V.D.Q (variable dia. for quality) Pulley V.D.Q pulley is a pulley which drives several smaller pulleys by a tooted belt. These smaller pulleys are at the driven position and drive a clutch device which engages with the yarn wheel. By varying the dia of the V.D.Q pulley, which is at the driver position, the amount of the yarn feeding can be controlled. This variation in the yarn feeding varies the stitch length and the G.S.M (see Fig.8). V.D.Q a Stitch length (when needle is same) V.D.Q a No. of Needle (when stitch is same)  From the above two expression we get, V.D.Q a Stitch length X Needle Constant, Kv = This constant Kv varies with the diameter of the machine, type of the machine (single or double jersey), different brand of machines. [Shown in Table-7] Table 4: Relationship between M/C diameter and fabric diameter (single jersey) M/C Finished dia. of fabric (inch) M/C Dia. (inch) M/C Gauge Count- 20/1 Ne & Fin GSM- 190- 200 Count -24/1 Ne & Fin GSM- 175- 185 Count -26/1 Ne & Fin GSM- 155- 165 Count -40/1 Ne & Fin GSM- 110- 120 20 24 23.2 21.7 20.8 16.1 20 20 19.6 18.4 18 18 24 24 27.4 25.7 24.6 19.1 28 24 32.6 30.8 29.3 22.7 30 24 35 32.8 31.5 24.4 36 24 42 39.6 38 29.4 38 24 44.5 41.7 40 31 40 24 46.7 43.8 42 32.5 42 24 48.9 45.8 44 34.1 3.4. Needle Gauge Thickness of needle express by the needle gauge. It is important for selection of machine gauge. Needle gauge is Fig. 5: Change of fabric diameter with machine diameter with respect to GSM.
  4. 4. DUET Journal Vol. 1, Issue 3, June 2012 Dhaka University of Engineering & Technology, Gazipur 15 differing for the different needle types and different Brand (see Fig. 9). According to the result of study Machine gauge is 24 then Needle thickness is 0.52mm and Machine gauge is 28 then Needle thickness is 0.41mm. Fig. 6: Change the fabric diameter with M/C diameter with respect to GSM Fig. 7: Change the fabric diameter with M/C diameter with respect to GSM Table 5: Relationship between M/C diameter and fabric width (1X1 Rib) 1X1 Rib M/C Finished dia. of fabric (inch) M/C Dia. (inch) M/C Gauge Count- 20/1 Ne & Fin GSM- 270- 280 Count- 24/1 Ne & Fin GSM- 230- 240 Count- 26/1 Ne & Fin GSM- 215- 225 Count- 40/1 Ne & Fin GSM- 155- 165 30 18 34 32 31 26 36 18 40 38.5 37 32 40 18 44 43 41.5 36 42 18 46 45 43.5 38 Table 6: Relationship between M/C diameter and fabric width (Interlock). Interlock M/C Finished dia. of fabric (inch) M/C Dia. (inch) M/C Gauge Count- 30/1 Ne & Fin GSM- 250-260 Count- 34/1 Ne & Fin GSM- 225-240 Count- 40/1 Ne & Fin GSM- 205-215 30 22 26 26.5 29 36 22 31 34 35 38 22 33 36 37 Fig. 8: V.D.Q pulley. 4. RESULTS AND DISCUSSION We have got some result from different experiment of various fabric parameters. From the research we have found some relation among the fabric Specifications with the machine parameters. The result is based on the data collected from the factories. 4.1. Selection of the gauge corresponding to the yarn count In the industry there is a range of yarn counts that a particular gauge of a machine can accommodate. They follow the range to select the precise gauge. Now we have analyzed the data to see the variations of yarn count with machine gauge. The table is as follow: [Table-8] Usually the yarn count increases with the machine gauge. 4.2. Relation between M/C dia and fabric dia The fabric dia is the width of the fabric in the tubular form. The finished fabric dia varies with the M/C dia. At different ranges of GSM the variation of the finished fabric dia with the M/C dia is different. Different fabric structures show different variation. But same structure follows a particular path of variation.
  5. 5. DUET Journal Vol. 1, Issue 3, June 2012 Dhaka University of Engineering & Technology, Gazipur 16 Fig-9: Needle in knitting machine. 4.3. V.D.Q pulley constant There is a relation of V.D.Q number, stitch length and needle number. It is, Constant, Kv = This constant is dependent mainly on the M/C. Different machine type, brand; diameter can vary the value of the constant. For a given machine the constant is same. For Single jersey fabric the V.D.Q pulley constant is 41.20825 & for Rib fabric the V.D.Q pulley constant is 68.76084. With these values a better selection of VDQ number can be obtained for a particular stitch length. Table 7: The value of Kv for different M/Cs M/C Dia. X Gauge No. of Needle V.D.Q Stitch Length (mm) Constant, Kv = S/J 1 23*24 1728 125 2.90 40.0896 2 23*24 1728 110 2.60 40.8436 3 24*24 1800 118 2.75 41.9499 Rib 1 38*24 2136X2 151 2.55 72.1430 2 38*24 2136X2 100 1.70 72.624 3 34*24 1920X2 102 2.55 78.336 Table 8: Relation of Machine gauge with yarn count Gauge Count (Ne) Low High Limit 32 32/1 46/1 60/1 28 30/1 46/1 60/1 24 20/1 46/1 50/1 22 20/1 40/1 20 20/1 40/1 18 20/1 40/1 16 10/1 24/1 5. CONCLUSIONS In this research we tried to analyze and observe different characteristics of the fabric specifications and machine parameters and to build up some relations among those. Most of the relations are building with the help of the data collected from the mills and factories. Some of the data are collected gained by experiments. In some cases our data was limited. The limitation of data may create some undesirable consequences. More data have to be collected to obtain a precise result. Experiments have to be done on the common fabrics and other fabrics to get a better understanding of the fabric specifications and machine parameters. REFERENCES [1] David J. Spencer, Knitting Technology by “Wood head Publishing Limited”- Third Edition. [2] Horrocks & Anand, Handbook of Technical Textile [3] Professor J E Mclintyre & P N Daniels, Textile Terms & Definitions published by “The Textile Instute”- Tenth Edition. [4] Iyer I., Mammel B., Schach J., Circular knitting: technology process structure yarn quality, Second Edition, Meisenbach GmbH, Bambreg, Germany, 1957. [5] Ghazi Saeidi R., Latifi M., Shaikhzadeh Najar S., and Ghazi Saeidi A., "Computer Vision-Aided Fabric Inspection System for On-Circular Knitting Machine" Textile Research Journal, 75(6), 492497, 2005. [6] Shady E., Gowayed Y., Abouiiana M., Youssef S. and Pastore C., Detection and Classification of Defects in Knitted Fabric Structures, Textile Research Journal, 76(4),295-300, 2006. [7] Abouiiana M., Youssef S., Pastore C. and Gowayed Y., Assessing structure changes in knits during processing, Textile Research Journal, 73(6), 535-540, 2003.

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