Knitting Terminologies PDF

Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology) Machine Knitting  Knitted structures are progressively built-up from row after row of intermeshed loops.  The newly-fed yarn is converted into a new loop in each needle hook...

Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology) Machine Knitting  Knitted structures are progressively built-up from row after row of intermeshed loops.  The newly-fed yarn is converted into a new loop in each needle hook.  The needle then draws the new loop head first through the old (fabric) loop, which it has retained from the previous knitting cycle.  The needles, at the same time, release, (cast-off or knock-over) the old loops so that they hang suspended by their heads from the feet of the new loops whose heads are still held in the hooks of the needles.  A cohesive knitted loop structure is thus produced by a combination of the intermeshed needle loops and yarn that passes from needle loop to needle loop. Loop Structure  One loop is the basic repeating unit of knitted fabric just as one point of interlacement is the basic repeating unit of a woven fabric.  A needle loop consists of a head (H) and two side limbs or legs (L).  At the base of each leg is a foot (F), which meshes through the head of the loop formed at the previous knitting cycle.  The yarn passes from the foot of one loop into the foot and leg of the next loop formed by it.  The knitted loop structure may not always be noticeable because of the effect of structural fineness, fabric distortion, additional pattern threads or the masking effect of finishing processes.  Knitted loops are arranged in rows, roughly equivalent to the weft and warp of woven structures. Prepared By: Engr. Shakeel Ahmad Paracha Page 1 of 6  Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology)  These are termed as “courses” and “wales” respectively. The Stitch  The stitch is the smallest dimensionally stable unit of all knitted fabrics.  The knitted stitch is the basic unit of intermeshing which usually consists of three or more intermeshed needle loops.  The centre loop has been drawn through the head of the lower previously-formed loop and is, in turn, intermeshed through its head by the loop above it.  The repeat unit of a stitch is the minimum repeat of intermeshed loops that can be placed adjoining other repeat units in order to build up an unbroken sequence in width and depth.  For a stitch, depending on the position of the legs at the binding points, a technical back and a technical front side is defined.  By changing the type of stitches, various knitted fabric structures can be formed.  The type of stitch is also dependent upon the type of knitting needle used. Needle Loop  It is the basic unit of a knitted structure.  The upper part of the loop produced by the needle drawing the yarn is called the needle loop.  Each stitch or knitted loop consists of a top arc (head), two legs and two bottom half-arcs (feet).  At the base of each leg is a foot, which meshes through the head of the loop formed at the previous knitting cycle, usually by that needle.  The yarn passes from the foot of one loop into the foot and leg of the next loop formed by it. Sinker Loop  The lower part of the knitted loop is technically referred as sinker loop.  It is the piece of yarn that joins one weft-knitted needle loop to the next.  Sinker loops show on the opposite side of the fabric to the needle loops because the needle loop is drawn onto the opposite side from which the yarn was originally fed.  On bearded needle weft knitting machines, loop forming sinkers form the sinker loops in succession between the needles - hence the origin of the term sinker loop. Prepared By: Engr. Shakeel Ahmad Paracha Page 2 of 6  Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology)  On latch needle weft knitting machines, however, the sinker loops are automatically formed as the needles, in succession, draw their new loops. Types of Loops  Face loop o During loop formation, when the new loop emerges through the old loop from back to the face (or front) side.  Back loop o If the new loop passes from the face side to the back side of the old loop, it is called as back loop or weft purl loop.  Open loop o Loop forming yarns does not cross at the bottom of the loop.  Closed loop o The legs of the loop cross so that the loop closing takes place. Technical Face  The side of knitted fabric that consists all of face or knit loops, is called as technical face of the fabric. It is the front side of fabric. Technical Back  The side of knitted fabric having full of back or purl loops, is called as the technical back of the fabric. It is the back side of the fabric. Courses  Courses are rows of loops across the width of fabrics, it is measured in units of (courses / inch).  Courses are produced by adjacent needles during the same knitting cycle.  The number of courses determines the length of fabric.  The courses per inch are denoted by CPI.  Courses per inch would depend upon the stitch length. Wales  Wales are columns of loops across the length of the fabrics, it is measured in units of (wales / inch).  Wales are generally produced by the same needle knitting at successive (not necessarily all) knitting cycles.  A wale commences as soon as an empty needle starts to knit.  The number of wales determine the width of fabric. Prepared By: Engr. Shakeel Ahmad Paracha Page 3 of 6  Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology)  Wales per inch are denoted by WPI.  The wales per inch depend upon the machine gauge, i.e., how close or far the knitting needles are placed. Importance of Courses and Wales  Sometimes when the yarn used for knitting is very fine, or the loops are very closely held together, in such cases courses and wales may not be clearly visible.  The number of wales and courses per inch determines the quality of knitted fabric just as ends and picks per inch determine the quality of a woven fabric.  Greater the number of CPI and WPI, denser will be the fabric, and its weight and cover will be more. Loop / Stitch Length (l)  Loop length, measured in millimetres, is the length of yarn in one knitted loop.  It is one of the most important factors controlling the properties of knitted fabrics.  Generally, the larger the stitch length, the more open and lighter the fabric.  Loop length affects the following parameters: o Stitch Density / Fabric Density o Tightness Factor o Fabric Weight o Fabric Cost o Dimensional Stability o Physical Performance o Piling o Bursting Strength  As loop length decreases, stitch density, tightness factor, fabric weight, fabric cost, dimensional stability increases and vice versa.  There is a definite correlation between the yarn count and loop length of a fabric and this can be defined as the "cover factor."  The cover factor, hence, determines the handle, drape and performance of the fabric. Just as the yarn type dictates the optimum loop length, this in turn dictates the gauge or knitting machine required to knit the yarn. Stitch Density (S)  Stitch density refers to the total number of loops in a measured area of fabric and not to the length of yarn in a loop (stitch length).  It is measured in total number of loops per square centimetre / inch.  The figure is obtained by counting the number of courses or pattern rows in one inch (or centimetres) and the number of wales in one inch (or centimetres), then multiplying the number of courses by the number of wales. Prepared By: Engr. Shakeel Ahmad Paracha Page 4 of 6  Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology) Stitch density( S )  CPI x WPI Cut & Gauge  In knitting, the word gauge, technical abbreviation GG, refers to "Knitting machines" fineness and is the number of needles in a measured space on the knitting machine.  Higher-gauge fabrics (those with more stitches) are made with finer needles; lower-gauge fabrics are made with coarser or larger needles.  Cut and Gauge are expressions of fineness and coarseness (closeness or openness) of stitches in knitted materials.  "Gauge,” is also termed as “cut” and “tension.” This “unit of measure” is equal to the number of needles contained in the “gauge” (size) and it is simply countable on the bed of needles of each knitting machines, flat or circular.  Various types of knitting machines measure gauge over different distances on the machine. For example, circular knit hosiery measures the number of needles in 1.0 inch, full- fashioned knitting in 1.5 inches, and Rachel knits in 2.0 inches.  Because of these differences, it is best to keep in mind the generalized principle that the higher the gauge, the closer the stitches.  The size of the needle and the spacing of the needles on knitting machines determine the number and size of the knit stitches and their closeness.  Each wale is formed on one needle.  The number of needles is equal to the number of wales.  The closeness of the stitches determines whether a knit fabric will be lightweight and open, or heavier and denser.  To describe the stitch density of a single or double knit fabric, the fabric may be designated as an 18, 20, 22, or 24-cut fabric.  Higher the cut: closer the stitches, finer the fabric.  Lower the cut: distant the stitches, coarser the fabric.  The term gauge is also used to describe the closeness of knit stitches.  Given two similar fabrics made from the same fibre and yarn size, the fabric with higher Gauge would be more densely knitted, having stitches more compacted, and would ordinarily considered a better fabric.  If we move clockwise from A to D in the pictures above, we find that the knitted structures are progressively decreasing in gauge and in fineness. Prepared By: Engr. Shakeel Ahmad Paracha Page 5 of 6  Textile Institute of Pakistan, Karachi. TEXT302 (Knitting Technology)  Gauge is very important as everyone knits a little differently; some people knit loosely, while some knit very tight. When the same yarn and the same sized needles are given to two different knitters, there is a good chance that they will come up with a different gauge.  The gauge of a knitted fabric depends on the pattern of stitches in fabric, kind of yarn, size of knitting needles, and tension of the individual knitter. o The coarser the yarn, coarser will be the gauge and the fewer stitches per inch. o The finer the yarn, finer will be the gauge and the more stitches per inch. o The larger (thicker) the needle, coarser will be the gauge and the bigger the stitches. o The smaller (thinner) the needle, finer will be the gauge and the smaller the stitches. o The bigger the stitches, coarser will be the gauge and the fewer stitches per inch. o The smaller the stitches, finer will be the gauge and the more stitches per inch. Technically Upright  A knitted fabric is technically upright, when its course run horizontally and its wales run vertically with the heads of the needle loops facing towards the top of the fabric and the course knitted first situated at the bottom of the fabric. Design Appearance Requirements  The terms technical face, technical back, and upright are purely technically descriptive terms.  They do not necessarily indicate the orientation of the fabric from the designer’s viewpoint e.g., socks and ladies hosiery are usually worn upside down compared to their sequence of production.  The technical back of structures is often used for plush and pile effects e.g., curtains may be hung sideways compared to the wales.  Diagonal stripes may be achieved for dress-wear by cutting the fabric at an angle. Prepared By: Engr. Shakeel Ahmad Paracha Page 6 of 6