The following table provides a quick overview of the property types listed above and is intended as a starting point for understanding why a particular property may be important. Most strength properties are directional, with the potential for widely varying levels in the machine (MD) or cross-machine (CD) directions; the CD is sometimes referred to as the transverse direction (TD). It is important to understand where the MD and CD will be aligned in the final package as you begin to select appropriate properties and levels to match use requirements.
Films and film-based structures are almost always converted in roll form, and generally sent to packaging machines that way, however premade bags and pouches are also extensively used to feed packaging machines.
