Principles of loom motions
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This document discusses the operational principles of loom motions. It begins by defining a loom and classifying the main types. It then describes the important parts of a loom, including the heald shaft and shuttle. The document explains the weaving process and the primary loom motions of shedding, picking, and beating up. It also discusses the secondary motions of take up and let off, and the auxiliary motions including warp stop, weft stop, and warp protector.
Principles of loom motions
- 1. 1 FABRIC PRODUCTION 1 ND 1 LECTURE SERIES ON OPERATIONAL PRINCIPLES OF LOOM MOTIONS BY Muhammed Raji, Abdulwasiu. Department of Polymer & Textile Technology Yaba College of Technology, Lagos Nigeria. Correspondence: [email protected] REFERENCES 1. Lord, P.R., Mohamed, M.H., (1992). Weaving: Conversion of yarn to fabric. Durham, England: Merrows Publishing Co. Ltd. 2. Gokarneshan, N., (2004). Fabric Structure and Design. New Delhi, India: New Age International (P) Ltd, Publishers. 3. Gordon, S., Hsieh, Y-L, (2007). Cotton: Science and Technology. Cambridge, England: Woodhead Publishing Ltd. 4. Adanur, S., (2001). Handbookof Weaving. Pennsylvania, USA: Technomic Publishing CO. Inc. 5. Marks R. and RobinsonA.T.C. (1976). Principles of Weaving. Manchester, UK: The Textile Institute.
- 2. 2 LOOMS/WEAVING MACHINE A loom is a device that causes interlacement of two sets of threads, namely, warp and weft threads, to form a fabric. The very first loom in history is the pit loom. Subsequently the handloom was developed and then the power loom. After the advent of power looms, a number of developments have taken place. The chart below shows the broad classification of the various types of looms.
- 3. 3 DESCRIPTION OF IMPORTANT PARTS OF A LOOM 1. Heald Shaft: This is made of wood or metals such aluminium. It carries a number of heald wires through which the ends of the warp sheet pass. The number of heald shaft depends on the warp repeat of the weave. Handloom Powerloom Shuttle loom Shuttlelessloom
- 4. 4 WEAVING Weaving is the process ofmechanically interlacing two sets of yarns at right angles to one another in a designated order. In a woven fabric, the longitudinal or warp yarns are called ends and the transverse or weft yarns are called picks. The order or pattern of interlacement of ends and picks is called the weave or fabric design. The most basic and extensively used woven fabric is the plain weave in which the warp and weft (filling) yarns are interlaced in alternate order. Woven fabrics differ according to interlacing pattern and yarn structure and composition. LOOM MECHANISMS/MOTIONS The basic mechanisms in any type of loom can be classified as follows: (a) Primary motions (b) Secondary motions, and (c) Auxiliary motions. The primary motions can further be divided as shedding, picking and beat up motions. Shedding opens the warp sheet into layers to facilitate passageof shuttle. The figure below shows a shed. Figure : A shed
- 5. 5 The picking motion causes the shuttle carrying weft to be propelled from one end of loom to another. Figure : Picking SHUTTLE: The filling yarn is inserted through the shed by a small carrier or device called a shuttle. The shuttle is normally pointed at each end to allow passage through the shed. In a traditional shuttle loom, the filling yarn is wound onto a quill or pirn
- 6. 6 Figure : A shuttle with quill or pirn. The beat up motion lays the previously laid weft to the fell of the cloth ( i.e. pushing the newly inserted length of weft, known as the pick) into the already woven fabric at a point known as the fell. Figure : Beat up/Beating-up
- 7. 7 The secondarymotions comprise of take up and let off motions. Take up motion helps to wind the cloth on to the cloth roller and also influences the pick density in the cloth. Figure : Take up/Cloth control. Let off motion helps to let the warp from the weaver’s beam ( i.e. delivers warp to the weaving area) at a uniform rate thus maintaining the warp tension constant throughout the weaving process. Figure below: Let off
- 8. 8 The auxiliary motions consistof the warp stop motion, weft stop motion and warp protectormotion. The warp stop motion is used to stop the loom in the event of warp breakages. This is necessary to prevent fabric defects such as missing ends and floats. Weft stop motion is used to stop the loom in the event of weft exhaustion or weft breakages. This is necessary to prevent missing weft threads called cracks in the fabric. The warp protector is used to prevent multiple warp thread breakages in the event of shuttle getting trapped in the middle of the warp sheet