Nonwoven machines do not make uniform fabric. There are always differences between the machine direction, abbreviated MD, and the cross machine direction, abbreviated CD. These differences show up as differences in tensile strength, elongation, tear strength, and fiber orientation. Most of the time we want the material to behave the same in both directions in the finished product, but this is seldom possible. So we often have to settle for trade offs in the various fabric characteristics to make an acceptable fabric for the customer. It is important for production employees to know the process parameters of their machines that cause changes to the various MD and CD characteristics of the fabric. Many of these process parameters have to do with stretching the fabric.