Er . Bhushan Kumar www.er-bhushan.in Shedding Mechanism ….. www.er-bhushan.in erbhushan@2015 Er . Bhushan Kumar Weaving Executive Raymond Textiles Ltd Vapi, Gujarat, India erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Shedding Mechanisms: Shedding is a process of raising and lowering of warp yarns by harnesses to make an opening for the filling (weft) yarn to pass through.  All weaving machines control the warp yarns to create a shed. This can be accomplished with the following systems: Crank shedding Cam shedding or tappet shedding Dobby shedding Jacquard shedding www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Crank Shedding: Crank shedding mechanisms can only be used for plain weave fabric constructions. In this system the harnesses are controlled by the crank shaft of the weaving machine. For each crank shaft revolution a wheel is rotated half a turn, which changes the harness position.   www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Cam Shedding: A cam is a disk which has grooved or conjugated edges which corresponds to the lifting plan. The lifting plan controls which harnesses are lifted. The disadvantage of cam shedding is that when the woven design has to be changed the cams have to be rearranged to suit the new design. Pattern design is also limited due to the amount of harnesses the cams can control. cams convert the rotary motion of the main shaft of the weaving machine into the reciprocating motion of the Heald frame . It has two types Positive cam shedding Heald shaft raised or lowered by the cam or eccentric system Negative cam shedding Heald shaft raised by the mechanism but returned by the external devices such as spring. www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Jacquard Shedding: In jacquard weaving a device called a ‘jacquard’ selects and lifts the warp yarns individually.  It has types. Mechanical Jacquard Electronics Jacquard www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Dobby Shedding www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

Path followed by the warp threads in an open shed is longer www.er-bhushan.in Shed Geometry and shed characteristics require a great consideration and precision because it is the zone in which the yarns are converted into fabric . The basic function of weaving are performed in this area Path followed by the warp threads in an open shed is longer www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in The path followed by the warp threads in an open shed is longer. The additional length required for warp ends should be taken either by the warp extension or by the regulation of the yarn delivery (in this case the warp yarns are withstood the higher tension forces when the shed is opened) (In this case tension acting on the warp yarn is constant but position of the cloth fell is moveable). www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Longer back shed is preferable to get a less degree of warp tension in open shed Shorter back shed length assists in separation of the upper and lower warp sheet and formation of clear shed , preferable for weaving fabrics from hairy coarse yarns www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

The means of weft insertion www.er-bhushan.in Size of shed Shed opening is determined by The means of weft insertion Beat up motion It is desirable to have a small shed opening in order to reduce the lift of Heald frames and therefore to reduce the stress non the warp www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Raising Back Rest If the back rest is above normal position alternate warp threads will be relatively slack and therefore free to move laterally to achieve a more uniform spacing www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Types of Shed www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Timing of shedding Shedding timing is synchronized with picking and beat-up timing There are three shedding timing Normal shedding Early shedding n Late shedding www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Normal shedding www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in Heald staggering is done ton reduce the abrasion between the warp yarns when healds are crossing each other. www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in During the weaving of heavy fabric like denim , canvas, satin duck, etc. the force required to push the weft is high. so there may be bumping of fabric To avoid this weaving resistance, asymmetric shedding is used. In this shedding the time and duration of movement of the tap and bottom shed line is so adjusted that they cross below the mid lift position. At this point of crossing the yarns at the bottom shed line are under high tension and those at the top shed line. as the reed beats up the weft , the slack top shed line yields and permits the weft to be pushed to the fell of the cloth with relative ease. So it is easy to weave even heavy fabric. www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015

A vision of Textile learning & sharing views....... www.er-bhushan.in * Er.bhushan@2015 * for any queries or suggestions email at: bhushan.aec@gmail.com dear reader your suggestions are valuable for me.*this article is just for information…any type of dispute will not be considered…I have tried to keep matters original *all right reserved* www.er-bhushan.in erbhushan@2015 www.er-bhushan.in A vision of Textile learning & sharing views....... erbhushan@2015