Friday 30 November 2012

Figuring with extra warp/weft threads


Extra Weft Figuring
Principles of Figuring with extra threads
A distinguishing feature of fabrics in which extra materials are employed is that the withdrawal of the extra threads from the cloth leaves a complete ground structure under the figure.One of the advantages of figuring with extra materials is that bright colors-in sharp contrast with the ground-may be brought to the surface of the cloth in any desired proportion.Pleasing color combinations may thus be conveniently obtained,since the extent of surface allotted to the figuring color may be readily proportioned in accordance with the degree of its contrast with the ground shade,without the latter being affected.
The extra yarns for figuring can be introduced in a fabric either as warp or weft,or in a combination of these two.For an extra warp weaving a separate warp beam is employed because of the different take up rates and tension employed during weaving process.For the case of extra weft figuring the weaving machine must have the capacity of inserting two or more weft. threads to be inserted in continuous order with the ground threads,or intermittent order ,while where they are introduced the arrangement of the figuring and ground threads may be 1 and 1,1 and 2,1and 3 etc,according to the structure of the cloth and solidity of the figure required.The visibility of the figures largely depends on this factor.
Method of disposing of the surplus extra threads
The extra yarn is allowed to float loosely on the back in the ground of the fabric.This method is used when the space between the figures is not excessive,when the ground is dense and when the fabric is used in situations that do not render the long floats on the back objectionable.It is not applicable to cloths in which the ground is so light and transparent that the positions of the extra threads on the back can be perceived from the face side.
The extra yarn is allowed to float loosely on the back,and is afterwards cut away.This method is suitable for light ground textures,but if the extra threads floats somewhat loosely on the surface in forming the ornament,it is necessary for them to be found in at the edges of the figure,or the loose figuring floats will readily fray out from the surface.The firm interweaving of the extra yarns at the edges,however,makes the outline of the figure less distinct,and is rather objectionable unless employed in such a manner as to assist in forming the figure.
In compact fabrics the extra threads are bound in on the underside of the cloth,either between corresponding floats in the ground texture,or by means of special stitching threads.
The extra threads are interwoven on the face of the cloth in the form of small auxiliary figures or floats thus adding to the fullness of the texture.
Extra Warp figuring
The chief advantage of the extra warp method is in productivity but at present it is mostly utilized for continuous styles arranged one end of ground,one of extra,except dobby effects which are still produced in a considerable variety of intermittent figuring arrangements.The reason for the decline of the fancier Jacquard stripe styles lies in the fact that each different design frequently requires the harness to be re-tied or otherwise modified which is costly itself and which often leads to further costs by increasing the length of the weaving machine downtime.Additional costs are incurred by the need to draw-in new warp into the newly re-tied harness which is more expensive than knotting in,a procedure used when standard harness setts remain unchanged between one warp and another.Many elaborate styles similar in appearance to extra warp can be produced by means of extra weft figuring using standard harness setts and achieving the necessary variety by weft pattern changes.
Extra Weft Figuring
Extra weft figured fabrics may be formed with one,two or more extra weft picks in addition to the ground weft.Only one series of warp threads is used and the effect is obtained by floating the extra weft where desired on the face of the ground cloth produced by the interlacing of the warp with the ground weft in plain or in some other simple weave order.Weaving machine used for this purpose must have the capacity to insert more than one kind of weft.
Figuring With Extra Warp and Weft Yarns

Comparison of extra warp with extra weft figuring
In extra warp figuring ,there are two or more series of warp threads to one series of of weft threads, and the method has the following advantages and disadvantages,as compared with the extra weft principle.
Advantages
1)The productivity of a loom is greater because only one series of pick is inserted,and a faster running loom can be used.
2)No special picking,box,and uptake motions are necessary
3)There is theoretically no limit to the number of colors that can be introduced
4)In an intermittent arrangement of the extra ends either spotted or stripe patterns can be formed,whereas a similar arrangement in the weft can only be used to form spots(except in special cases)because of the objectionable appearance of the horizontal lines.
Disadvantages
1)Two or more warp beams may be required instead of one
2)If an ordinary jacquard and harness are employed a smaller width of repeat is produced by a given size of machine,because the sett of the harness requires to be increased in proportion to the number of extra threads that are introduced in a design
3)In a dobby weaving the drafts are usually more complicated
4)Stronger yarns are required for figure,and the threads are not so soft,full and lustrous,extra ends are subjected to greater tension during weaving than extra picks,and as a rule,there is less contractio  in length than width,and the result is that extra warp effects usually show less prominently than extra weft figures.
5)If extra threads have to be removed from the underside of the cloth,it is more difficult and costly to cut away extra ends than extra picks.
Hope you enjoyed it!expecting your comments and suggestions. 

24 comments:

  1. THE BEST
    I GOT ALL THE INFORMATION NEEDED

    ReplyDelete
  2. Thanks for information. Extra weft insertion for motif weaving is now much more faster, easier and sporty with extra weft insertion device CHANEKEE. Pl log on www.chanekee.com for details

    ReplyDelete
  3. Hi Ninder
    Thank you for your comments, keep in touch!

    ReplyDelete
  4. Nice Work. It was easy to understand and compare.Thanks...i need it!

    ReplyDelete
  5. It was just so easy made by u to understand.... Thnx

    ReplyDelete
  6. The post is useful and it would really help for those who search for Handloom Fabrics | Chinese Fabrics

    ReplyDelete
  7. What is the reference of this book??

    ReplyDelete
  8. Good note for textile students...

    ReplyDelete
  9. This whole article has been Fully copied(each and every word) from Watson's Advanced Textile design compound woven structure.
    Disappointed that the writer did not use his/own language.

    ReplyDelete