Warp Knitting & Latest Techniques
Warp knitting is a stitch forming technique in which we supply the yarns to the knitting zone in the direction of the Wales, i.e. parallel to the selvedge of the fabric. While carrying on the process of warp knitting, we provide at least one separate yarn to every knitting needle. Then the yarns have to be deflected laterally in between the needles, to connect the stitches to create a fabric. Therefore in warp knitting, the knitting needle draws a new loop of yarn through the knitted loop being produced in the previous knitting cycle by the other end of yarn. Process of Warp Knitting A warp knitted structure mainly consists of two parts. The first part of the structure is the stitch, which we form by wrapping the loop of yarn around the needle. This wrapping of the yarn is called overlap. Then we draw the yarn through the previously knitted loop. The second part of the structure is the length of yarn which connects together the stitches. We term this portion of the warp knitted fabric, being produced by the lateral movement of the yarns across the needles as the under lap. To determine the length of the under lap we take into consideration the needle spaces. Longer the under lap, more are the chances of its lying at the right angles to the fabric length axis. If the under lap is longer for a given warp, then there occurs an increase in lateral fabric stability. Conversely, if the length of yarn connecting the stitches is short, then it will reduce the width-wise stability and strength of the fabric. Shorter under lap enhances the lengthwise stability of the fabric. The length of the under lap also affects the weight of the fabric. When we have longer under lap, then we need to supply more yarn to the knitting needles. Moreover, the under lap has to cross and cover more no. of Wales coming on its way, thus making the fabric thick, heavy and dense. Due to the warp tension, the under lap can result in the lateral displacement of the root of the stitch as it connects to the root of the stitch.
As there occurs the reciprocating actions of the yarn, therefore it causes the stitch of each knitted course to incline alternately to the left and then to the right, i.e. in the same direction. We usually employ a second set of yarns to control the lateral as well as the longitudinal properties of the knitted fabric. By making use of the second set of yarn, we can improve the appearance of the fabric by getting erect loops. The second set moves in the direction opposite to that of the first set, thus helping to balance the lateral forces acting on the needles. It is not necessary to keep the length of the under lap same for both sets of yarns. By using the technique of warp knitting, we can form several types of knitted fabrics, including tricot, Raschel knits, and Milanese knits. All warp-knit fabrics are resistant to tears and comparatively simple to sew. Tricot is very common in lingerie. Milanese is durable, more stable, softer and more expensive than tricot and, hence, we use it for making better lingerie. Milanese is now virtually obsolete. Raschel knits do not expand significantly and are often bulky; therefore we consider using them as an unlined material for coats, dresses, jackets and straight skirts. The largest outlet for the Raschel Warp Knitting Machine is for lace fabric and trimmings. Warp knitting offers us the following advantages: • Higher production rates than weaving. • Large working widths • A wide variety of fabric constructions. • We can knit three-dimensional structures on double needle bar raschels. By using weft insertion technique, we can manufacture uni-axial, bi-axial, multi-axial as well as composite structures on single needle bar raschels. • Warp knitting process offers a low-stress rate on the yarn thus facilitating careful handling of the fibres such as glass, aramid and carbon (mainly when using weft-insertion techniques).
• We can produce conventional warp knitted structures can directionally.
The principle of Warp Knitting: Composite lapping actions are responsible for the generation of warp knitted fabric. The compound lapping action comprises of two separate movements which are as follows: • Swinging motion, i.e. backward & forward motion • Shogging motion, i.e. the lateral action or sideways movement Main cam shaft of the knitting machine produces the swinging motion whereas the pattern wheel or pattern drum present at one side of the machine generates the shogging motion. During the shogging motion there occur the lateral movement of the guide bars along the needle bars or parallel to the needle bar. The no. of endless chain links or pattern wheels that are present in the knitting machine is equal to the no. of guide bars employed in the machine. We call the amount of yarn supplied to the guide bar for a definite number of courses as a run-in. In other words, we term the amount of yarn required in inches to 480 courses, i.e. 1 rack as a run-in. We call the ratio of Run-in present between two guide bars as termed as Run-in ratio. Run-in ratio depends on the length of the loop as well as on the structure of fabric thus determining the appearance & knitting performance.
Warp Knitting Categories: Warp knitted fabrics created by using the technique of warp knitting have various applications. We can use these fabrics for producing a wide variety of items such as: Automotive textiles Sportswear Outerwear
Plush fabrics Shoe fabrics Terry fabrics Nets Blankets Medical textiles
Contact us: Our company, Bharat machinery works, is one of the preeminent manufacturer and supplier of all sorts of knitting machines. Our knitting machine manufacturing unit in India holds an extensive experience of over 60 years. We at Bharat Machinery Works creates highly effective knitting machines that perform at a higher pace. We improve our knitting machines to advanced technology from time to time. Our knitting machines are perfect for increasing productivity. Moreover, all the components of the machine are readily available, that would never stop your working production process. We always satisfy our customers by providing them with the excellent quality of knitting machines.