Denim weight and construction

  

The typical construction of a bottom-weight 14-ounce denim is 55 to 64 warp ends per inch and 38 to 42 filling picks per inch. The number of warp ends per inch is sometimes referred to as the “sley.” The size of the yarn used, the fabric weave design, and the fabric tightness will influence the weight, as well as the amount of size left on the finished fabric.

 As a rule, denim is woven as 3x1 twill, 2x1 twill, 2x2 twill, 3x1 broken twill or 2x2n broken twill. The weights of the finished fabrics vary between 3 ½ and 16 ½ ounces per square yard. The fabrics weighing 3 ½ to 8 ounces per square yard are typically used to manufacture blouses, tops, and shirts. Trousers, jeans and jackets tend to use heavier weight denim fabrics ranging between 8 and 16 ½ ounces per square yard. Numerical notations for different denim designs such as 3x1 twill denote what each warp yarn is doing relative to the filling yarns interlacing with it.

In this example, if you look at the end marked number one, this warp yarn is going over pic 1,2, and 3. And then under pic 4. With the end mark number 2, the same sequence is being repeated but advanced up one pic. This means that the warp yarn is under pic 1 and goes over pics 2, 3, and 4. This upward advanced sequence continues thus giving the characteristic twill line.

       

In this example the twill line would be rising from the lower left to the upper right and the fabric would be  classified as a 3x1 right hand twill weave. If the twill lie was made to rise to the left, then the design is a left hand twill weave.

Broken twills are created by breaking up the twill line at different intervals thus keeping it from being in a straight line