Shedding Principles and Mechanisms

Abstract

This chapter will focus on shedding principles and mechanisms which are used for achieving shedding. This step is essential for the weaving process as it is necessary for weft insertion. Thanks to frame motion order and design resulting from it, shedding is also primordial for the woven fabric integrity. Shedding principle consisting in separating warp yarns into two layers, it leaves an empty space used for pick insertion. As a consequence, an opened shed may be considered as a geometric shape composed of the strained warp yarns. The parameters of shed geometry, their setting as well as their influence on yarn strain and stress will be discussed. Another part is concerning the several shedding mechanisms available: tappet, cam, dobby and Jacquard systems. In each case, a presentation of the mechanism principle is made on the base of original or basic examples; classification is made according to operation parameters, modern mechanisms composition and operation are precisely described and discussed and finally practical exercises are proposed all along the chapter.