A melt processing plant is provided that includes a melt charger for charging a processing head, in particular a pelletizing head, with melt, in which a diverter valve for discharging the melt during a starting and/or retooling phase is associated to the melt charger upstream of the processing head. A splitter divides the discharged melt into melt portions with the melt channels of the splitter head having at least one step-like cross-sectional enlargement of their inflow portion, a cross-sectional shape different from the outlet cross-section of the discharge channel, and an open orifice region out of the splitter.

A conveyance portion, a barrier portion, and a path are provided at places of a screw main body in which a kneading portion is provided. In at least one of the places, the path is provided inside the screw main body, and includes an entrance and an exit. The entrance is opened to urge the raw materials having the conveyance limited by the barrier portion to increase pressure on the raw materials, to flow in the entrance. The raw materials flowing from the entrance flow through the path in the same direction as a conveyance direction of the conveyance portion.

A conveyance portion, a barrier portion, and a path are provided at places of a screw main body in which a kneading portion is provided. In at least one of the places, the path is provided inside the screw main body, and includes an entrance and an exit. The entrance is opened to urge the raw materials having the conveyance limited by the barrier portion to increase pressure on the raw materials, to flow in the entrance. The raw materials flowing from the entrance flow through the path in the same direction as a conveyance direction of the conveyance portion.

Systems (200) and methods for making different plastic products (202, 204) in a single melting process are provided. A method includes melting a plastic resin in a first extruder (104) to form a melt (106) and transferring at least a portion of the melt to a second extruder (114). Any portion of the melt (106) that is not transferred to the second extruder (114) is formed into a first plastic product (202). Additives (116) are blended with the melt in the second extruder to form a second melt (118), and a second plastic product (204) is formed from the second melt (118).