Wednesday 14 March 2012

Drafting Plan


The process of drawing the warp yarn through the eye of heald frames according to design is called drafting, and the plan which indicates how drafting needs to be done is called drafting plan. The drafting plans shows the number of heald frames required and which warp yarn should pass through which heald frame to produce the design.

Methods of representing drafting plan

1.     By ruling line: here horizontal lines represent the heald frames and vertical lines with arrow head represent the warp yarn. The intersection point is the position of the warp yarn in heald frame

2.     By Design Paper:



Above is a representation of drafting plan by design paper
1.     The vertical lines (columns) represents warp yarn
2.     The horizontal lines (rows) represent a heald shaft
3.     The ‘x’ shows the heald shaft occupied by the warp yarn (here warp yarn 1 occupies heald shaft 1warp yarn 2 occupies heald shaft 2 and so on)




3.     By numbering: as shown below, here the heald frame number is written below the warp yarn under a weave plan.



Different systems of drafting    

1.     Straight Draft:
·       It is the simplest form of draft system where individual warp yarn in a repeat is place in individual heald frame.
·       Number of heald frame required is equal to the number of warp yarn in the repeat.
·      Mostly used in twill design




2.     Skip Draft
·      This draft is use when EPI is high.
·      This draft reduces the friction between the yarns.
·      Number of heald frames used is two times the number of warp yarn in a repeat.





3.     Pointed Draft
·      This draft is used to make fabric with symmetry design e.g. zig zag, twill, diamond.
·      This draft is used when the repeat size is too large.
·      In this draft system a straight draft is returned in the opposite direction after a certain point.
·      The number of heald frames used is equal to half the number of warp yarn in a repeat.




Above three is the most common drafting system. Other drafting systems are as follows

4.     Broken draft
5.     Divided draft
6.     Grouped draft
7.     Combined draft
8.     Curved draft
9.     Sateen draft
10.  Bed fort cord draft

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