Knitted Loop Structures PDF

Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology) Knitted Loop Structures  Formation of loop structures o The weft knitted structures composed of knitted loops, which are produced whenever the needle c...

Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology) Knitted Loop Structures  Formation of loop structures o The weft knitted structures composed of knitted loops, which are produced whenever the needle clears the old loop, receives the new yarn and knock-over the old loop from the previous knitting cycle. o Fig. shows the three possible positions of the needle at the time of feeding the yarn. They are referred to as knit, tuck and miss positions. o These different stitches are produced by controlling the height of the needles and the individual selection of needles enable knit, tuck or miss stitches to be formed. o For different stitch requirements, swing cams or auxiliary cams are placed between the rising cams and the stitch cams to change the path of the needle butts to form a raceway and the needle butts travel in this restricted path accordingly to form knit, tuck and miss stitch. Knit Stitch  The knit stitch is the basic stitch.  It is also called the plain stitch.  A knit stitch is produced when a needle receives a new loop and knocks over the old loop that it held from the previous knitting cycle.  The old loop then becomes a needle loop of normal configuration.  Knit stitch is formed when the needle carries out a complete stroke, reaching the maximum height on the looping plane. Tuck Stitch  A tuck stitch is formed when a knitting needle holds its old loop and then receives a new yarn.  Two loops then collect in the needle hook.  The previously formed knitted loop is called the held loop and the loop which joins it is a tuck loop.  The tuck loop will always lie at the back of the held loop.  The numbers of consecutive tucks on any one needles limited by the amount of yarn that the needle hook can hold, with the maximum usually being between four to five loops. Prepared By: Engr. Shakeel Ahmad Paracha Page 1 of 3  Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology)  Fig. 1 shows the technical face of the tuck stitch along with the knitting notations.  The resultant stitch is elongated.  Tuck stitches appear on the back of a fabric and may be recognized as an inverted V; sometimes elongated for two or more courses, depending on how many times the stitched was tucked.  Fig. 2 shows a single tuck viewed from technical face and back of the fabric.  Fig. 3 shows a single tuck viewed from the technical back and, in addition, how this structure is represented using conventional stitch notations.  Tuck stitches tends to reduce the length of the fabric and increase its width (wales are pushed apart), resulting in the fabric being thicker (yarn from the tuck stitch lies on top of the preceding stitch) with less extension in the width.  The tuck stitch is used in knitted fabric to create design effects in colour, raised surface texture, or a hole or eyelet effect. Miss Stitch  A miss stitch is created when one or more knitting needles are deactivated and do not move into position to accept the yarn.  The yarn merely passes by and no stitch is formed.  The float will lie freely on the reverse side of the held loop, which is the technical back, and in the case of rib and interlock structures it will be inside the fabric.  Fig. 4 illustrates that the float will extend from the base of one knitted or tucked loop to the next.  Miss stitch is also known as float stitch or welt stitch.  Fig. 5 shows the face and the back of the miss stitch.  Fig. 6 shows a four needle float viewed from the technical back, together with the conventional stitch notation used to represent this structure. Prepared By: Engr. Shakeel Ahmad Paracha Page 2 of 3  Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology)  The introduction of miss stitches results in the fabric becoming narrower in width, since the wales are pulled closer together and the held loop ‘robs” yarn from adjacent loops.  This tends to improve fabric stability.  The miss stitch also has a tendency to increase fabric weight, and reduce both stretch, and width.  A miss stitch is used to create colour and figure designs in knitted fabric since it permits the selective positioning of yarns in a fabric.  Knit, tuck and miss stitches can be used in any of the four fabric types - single jersey, rib, purl or interlock - to produce a wide range of structural effects.  Fig. 7 shows the combination of all three stitches. Prepared By: Engr. Shakeel Ahmad Paracha Page 3 of 3