SHEDDING SYSTEM

SHEDDING SYSTEM

There are four shedding systems used to provide manipulation to the warp yarns:

1. Crank Shedding
2. Cam Shedding
3. Dobby Shedding
4. Jacquard Shedding

CRANK SHEDDING:

This is the simplest shedding system. In this system, the crankshaft of the weaving machine provides the harness motion. This system is used only for plain weave and its derivatives.

CAM SHEDDING:

A typical cam system can handle weave patterns with up to 14 different harnesses. Cam shedding mechanisms are relatively simple. A pair of cams is sufficient to weave plain fabric. A cam is a disk that transforms a rotational motion of its own to a reciprocating motion of a follower. The transfer is done by means of the cam’s edge or a groove cut in its surface.

DOBBY SHEDDING:

Dobby mechanisms are more complicated than cam systems. They are normally built to control up to 30 harnesses. Picks per repeat are virtually unlimited in dobby. Basically there are two separate functions in dobby mechanism: 1) power transmission, 2)connection and disconnection of the harnesses from the power source at the proper time. Dobby mechanisms are classified as negative, positive and rotary dobby. They can be mechanical or electronic.

JACQUARD SHEDDING:

Jacquard Shedding offers unlimited patterning possibilities. The Jacquard machines offer the highest level of warp yarn control. This versatility is due to the separate control of each warp end or groups of similarly interlacing warp ends within the pattern repeat across the fabric width. They enable the most sophisticated patterns, such as pictures, to be produced in the woven fabrics. Jacquard machines can be mechanical or electronic with single lift or double lift mechanisms; the new machines are all double lift. Most Jacquards heads generally are equipped to handle over 2000 harness cords or hooks with pattern repeating on about on about 9000 picks and multiple heads can be employed over a single weaving machine to increase the weave pattern capability. Jacquard systems are placed on top of the weaving machine.