In order to interlace warp and weft threads to produce fabric on any type of weaving machine, three operations are necessary:
- Shedding: separating the warp threads into two layers to form a shed.
- Picking: passing the weft thread, which traverses across the fabric, through the shed.
- Beating-up: pushing the newly inserted weft, known as the pick, into the already woven fabric at a point known as the fell.
These three operations are often called the primary motions of weaving and must occur in a given sequence, but their precise timing in relation to one another is also of extreme importance and will be considered in detail.
Two additional operations are essential if weaving is to be continuous:
- Warp control ( or let-off): this motion delivers warp to the weaving area at the required rate and at a suitable constant tension by unwinding it from a flanged tube known as the weaver’s beam.
- Cloth control (or take-up): this motion withdraws fabric from the weaving area at the constant rate that will give the required pick-spacing and then winds it onto a roller.