Twin screw extruders transfer mechanical energy through turning two screws or rotors. It may be co-rotating or counter rotating, intermeshing or non-intermeshing. The basic parts of twin screw extruders are the barrels, the screw elements, and the shafts on which they are staged and driven. They are widely used in pharmaceutical and food processing industries. Nonintermeshing twin screw extruders are less common for mixing applications because of weaker screws interaction and being less self cleaning. Low speed, late fusion, counter rotating twin screw extruders often use on piece barrels and screws.
Twin Sheet Forming is a thermoforming process whereby two sheets of plastic are molded at the same time, creating hollow parts fused together into a structural assembly. Different shapes and contours can be molded on opposite sides of the part, along with differing color, material types and material thickness.