8.The Drawing-in Process.pdf

Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) The Drawing-in Process The process of passing each warp yarn through its drop wire, heald eye and reed dent is called as drawing-in process. The drawing-in process is usually carr...

Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) The Drawing-in Process The process of passing each warp yarn through its drop wire, heald eye and reed dent is called as drawing-in process. The drawing-in process is usually carried out away from the loom in a drawing-in area where all necessary components, i.e. drop wires, heald frames and reed are mounted on the specially designed frame. Prepared By: Shakeel Ahmad Paracha Page 1 of 10  Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) Components of Drawing-in Process Components of drawing-in process are: o Dropper Wire o Heald Frame o Reed The Dropper Wire Dropper wires are used for warp stop-motion on the loom. Each warp yarn is passed through an individual dropper wire which remains lifted due to the tension in the yarn. As the warp yarn breaks, the dropper falls and due to some arrangement, the loom is stopped. Dropper wires are made of aluminum, copper or stainless steel. The Heald Frame Heald frames are used to create a shed in the warp yarns so that weft yarn can be passed through it. Heald frames have number of heald wires and each heald wire has a small opening called as heald eye. Each warp yarn is passed through an individual heald eye. Heald frames are given up and down motion through tappet, cams or dobby shedding mechanism. Prepared By: Shakeel Ahmad Paracha Page 2 of 10  Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) However, in jacquard shedding mechanism, no heald frames are used and warp yarns are moved up and down by controlling individual harness wires. Drawing-in Draft (DID) The order of passing the warp yarns through different heald frames is called as drawing-in draft (DID). The drawing-in draft is obtained from a particular weave design. The drawing-in draft also shows the number of heald frames required to complete a particular weave design. The Reed Reed is an essential part of the loom which is made up of a wooden or plastic frame holding number of vertical steel wires placed at a fixed distance. The gap between the two consecutive wires of a reed is called as a dent. One or more warp yarns are passed through each dent of the reed depending upon the required warp thread density. The main purpose of the reed is to perform the primary motion of beating-up. In addition to beating-up, reed performs the following functions: o To control the warp thread density. o To keep the warp yarns straight & parallel to each other. Prepared By: Shakeel Ahmad Paracha Page 3 of 10  Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) Count of the Reed or Reed Count The count of the reed shows the number of dents present in a unit width of the reed. The count of the reed to be used depends upon the warp thread density required in the fabric. The Stockport reed counting system is the most commonly used. It is defined as the number of dents per two inches of the reed. There are two systems of reed counting: o Reed count determined by the number of groups of dents in a given space. o Reed count determined by the number of dents in a given space. Types of the Reed Counting Systems Prepared By: Shakeel Ahmad Paracha Page 4 of 10  Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) Reed Count Conversion Two different reed counts can be converted using the following formula: Dents of known system Required Count = inch x Count of known system Dents of unknown system inch Example 1 Convert 20 Irish reed count into Stockport. Dents of known system = 100 = 2.5 inch 40 Dents of unknown system = 1 = 0.5 inch 2 Count of known system = 20 Dentsof known system Required Count = inch x Count of known system Dents of unknown system inch 2.5 Required Count = x 20 = 100 Stockport 0.5 Example 2 Convert 72 Stockport reed count into Radcliff. Dents of known system = 1 = 0.5 inch 2 Dents of unknown system = 1 = 1 inch 1 Count of known system = 72 Dentsof known system Required Count = inch x Count of known system Dents of unknown system inch 0.5 Required Count = x 72 = 36 Radcliff 1 Example 3 Convert 100 Blackburn reed count into Leeds. Dents of known system = 20 = 0.444 inch 45 Dents of unknown system = 19 = 2.11 inch 9 Count of known system = 100 Dents of known system Required Count = inch x Count of known system Dents of unknown system inch 0.444 Required Count = x 100 = 21 Leeds. 2.11 Prepared By: Shakeel Ahmad Paracha Page 5 of 10  Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) Reed Plan (RP) The number of ends passing through each dent of a reed is called as the reed plan (RP). Reed plan is also called as ends per dent/reed denting/denting order/reed filling. The warp thread density required in the fabric is controlled by altering the reed count and reed plan. Types of Reed Plans Reed plans are of two types: o Regular reed plan o Irregular reed plan If the same number of ends per dent is used throughout the width of the fabric, then such type of reed plan is called as regular reed plan. In irregular reed plan different number of ends per dent at different places across the fabric width is used. Controlling Warp Thread Density Warp thread density of a woven fabric is controlled on the loom by: o Reed count o Reed plan (denting order) Example 1 What is the warp thread density of fabric with the following reed plan if count of the reed is 36 dents/inch? Reed plan = 3 Ends dent Reed count = 36 Dents inch Ends = Dents x Ends inch inch dent Ends = 36 x 3 = 108 inch Prepared By: Shakeel Ahmad Paracha Page 6 of 10  Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) Example 2 What is the warp thread density of fabric with the following reed plan if reed count is 60 Stockport? Reed plan = 4 Ends dent Reed count = 60 Stockport Dents = 60 = 30 inch 2 Ends = Dents x Ends inch inch dent Ends = 30 x 4 = 120 inch Example 3 What should be the reed plan in order to get 72 ends per inch if the reed selected is 36 Stockport? Ends Required = 72 inch Reed count = 36 Stockport Dents = 36 = 18 inch 2 Ends = Dents x Ends inch inch dent Ends Ends = inch dent Dents inch Ends = 72 = 4 dent 18 Example 4 What should be the Stockport reed count in order to get 56 ends per inch if the reed plan utilized is 2 ends per dent? Reed plan = 2 Ends dent Ends = 56 inch Ends = Dents x Ends inch inch dent Ends Dents = inch inch Ends dent Dents = 56 = 28 inch 2 Stockport Reed count = 28 x 2 = 56 Prepared By: Shakeel Ahmad Paracha Page 7 of 10  Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) Example 5 For the reed plan shown below calculate the average warp thread density if count of the reed used is 72 Stockport. Reed count = 72 Stockport Dents = 72 = 36 inch 2 Total ends in reed plan = 24 Total dents in reed plan = 16 Ends = 24 = 1.5 dent 16 Ends = Dents x Ends inch inch dent Ends = 36 x 1.5 = 54 inch Example 6 For the reed plan shown below calculate the average warp thread density if count of the reed 30 dents/inch. Dents = 30 inch Total ends in reed plan = 18 Total dents in reed plan = 13 Ends = 18 = 1.384 dent 13 Ends = Dents x Ends inch inch dent Ends = 30 x 1.384 = 41.5 inch Prepared By: Shakeel Ahmad Paracha Page 8 of 10  Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) Types of Drawing-in Process The process of drawing-in can be carried out: o Manually o Automatically Manual drawing-in is carried out by two operators who sit opposite to each other, one facing the heald frames and the other facing the reed. Automatic drawing-in is carried out automatically using special machines. Manual drawing-in is a tedious and time-consuming process which takes hours whereas automatic drawing-in can handle 6000 ends per hour. Manual Drawing-in Automatic Drawing-in Prepared By: Shakeel Ahmad Paracha Page 9 of 10  Textile Institute of Pakistan, Karachi. TEXT202 (Fabric Technology) The Tying-in Process In case of mass production if the new warp beam has the same drawing-in arrangement as that of the last beam, then the process of drawing-in can be avoided and instead knotting or tying-in is used to save time. In tying-in, the warp yarns from the new beam are knotted or tied together with the corresponding warp yarns of the last exhausted beam. Tying-in can be carried out: o Manually o Automatically The speed of automatic knotting machine goes up to 600 knots per minute. Prepared By: Shakeel Ahmad Paracha Page 10 of 10