TDO Machine

Plastics orientation is the straightening and aligning of polymer chains that occurs in a variety of manufacturing processes used to produce many everyday plastic items. It is the intended outcome when stretching plastic sheet in width to produce transverse direction oriented (TDO) products such as shrink sleeve film, or when combined sequentially with machine direction orientation (MDO) to produce products such as BOPP film. This is accomplished by using a tenter frame to convey material through an oven while concurrently stretching it transversely at optimal process conditions to achieve the desired level of polymer orientation. One of the key components of this system that makes this possible is the tenter rail hinge, but not all hinges are created equal.

In a TDO machine, the rails that guide the tenter chain are typically manufactured in rigid straight lengths that are joined by a hinge that allows the rail sections to articulate relative to each other.These hinges are mounted on translating cross members that allow the distance of the rails relative to the centerline of the machine to be adjusted inward and outward to accommodate various widths of products and to achieve the desired rail profile to provide the required stretch ratio and strain rate.