A process for manufacturing a plastic hollow body including extruding a molten plastic parison through a die. At least one longitudinal cut is made in the parison. The parison is introduced into a mold comprising two cavities. The hollow body is molded by conforming the parison to the mold cavities. The die includes a passage for the molten plastic which gradually modifies the shape of the parison so that it is substantially flattened on exiting.

A method for controlling the temperature of a polymer melt in an extrusion tool includes flowing the polymer melt via at least one flow channel from an input to an output and around at least one temperature-control element in the at least one flow channel. The temperature control element includes a plurality of temperature control units. The temperature of the polymer melt flowing around the temperature-control element is controlled by individually controlling each of the temperature-control units so as to vary a degree of temperature control of the temperature-control element such that a degree of temperature control is controllable to be the same or different at locations throughout the temperature control-element.

Disclosed is a device and method for dynamic extrusion molding of plastic articles having variable micro-channel. The device mainly includes a single-screw extruder, a dynamic extrusion die, a fluid source, a water sink, a tractor, a winding device, and a data acquisition and control system. Near outlet of extrusion die, when the end portion of a syringe needle is at different positions, the inner diameter of the micro-channel of the extrusion molded plastic article is also different. When the hollow syringe core within the dynamic extrusion die performs a high-frequency short-range vibration along an extrusion direction, the inner diameter of the micro-channel of the extruded plastic articles is dynamically variable. The plastic articles of variable micro-channel of the present invention has novel structure with high dimensional accuracy, and a variety of varying patterns, it can be stably produced by simple processing equipment with high level of automation.