A method for producing a foamed extrudate comprises a device containing a main melting device and an auxiliary melting device. A first melt is generated in the main melting device, a second melt is generated in the auxiliary melting device from a meltable starting material. At least one reactive additive is added to the meltable starting material, wherein the at least one reactive additive being selected from the group consisting of a chemical blowing agent and an active nucleating agent is mixed in the auxiliary melting device with the second melt, so that an additive-containing second melt is obtained in the auxiliary melting device which is added to the first melt.

A sizer for cooling an extrudate, which includes a core and a housing. The core includes an extrusion channel which accommodates the extrudate, a core cooling channel, and a core vacuum channel in fluid communication with the extrusion channel. The housing includes a housing cooling channel and a housing vacuum channel. The core cooling channel is in fluid communication with the housing cooling channel, and the core vacuum channel is in fluid communication with the housing vacuum channel.

A sizer for cooling an extrudate, which includes a core and a housing. The core includes an extrusion channel which accommodates the extrudate, a core cooling channel, and a core vacuum channel in fluid communication with the extrusion channel. The housing includes a housing cooling channel and a housing vacuum channel. The core cooling channel is in fluid communication with the housing cooling channel, and the core vacuum channel is in fluid communication with the housing vacuum channel.

A carriageless print head assembly, for use in extrusion-based additive construction is disclosed. The carriageless print head features a cold end equipped with one or more timing belt attachment slots and bores for receiving bearings to achieve linear motion. The carriageless print head may be optionally equipped with a fluid channel for aiding in the regulation of the temperature of the print head cold end, and one or more thermal monitors for monitoring the temperature of the cold end of the print head.

A print head assembly, for use in extrusion-based additive construction is disclosed. The print head may be optionally equipped with a fluid channel for aiding in the regulation of the temperature of the print head cold end, and one or more thermal monitors for monitoring the temperature of the cold end of the print head.

A method of using a carriageless print head assembly, in extrusion-based additive construction is disclosed. The carriageless print head features a cold end equipped with one or more timing belt attachment slots and bores for receiving bearings to achieve linear motion. The carriageless print head may be optionally equipped with a fluid channel for aiding in the regulation of the temperature of the print head cold end, and one or more thermal monitors for monitoring the temperature of the cold end of the print head.

A method of using a print head assembly, in extrusion-based additive construction is disclosed. The print head may be optionally equipped with a fluid channel for aiding in the regulation of the temperature of the print head cold end, and one or more thermal monitors for monitoring the temperature of the cold end of the print head.

An extrusion die is disclosed. The extrusion die can include a body member defining a passage therein, and the passage configured to receive heated material at an ingress end of the body member. A mandrel can be disposed within the passage and configured to divert the heated material around the mandrel within the passage as the heated material traverses the passage from the ingress end to an egress end of the body member. The mandrel can define an interior hollow portion that is configured to receive coolant.

An extrusion die is disclosed. The extrusion die can include a body member defining a passage therein, and the passage configured to receive heated material at an ingress end of the body member. A mandrel can be disposed within the passage and configured to divert the heated material around the mandrel within the passage as the heated material traverses the passage from the ingress end to an egress end of the body member. The mandrel can define an interior hollow portion that is configured to receive coolant.

A carriageless print head assembly, for use in extrusion-based additive construction is disclosed. The carriageless print head features a cold end equipped with one or more timing belt attachment slots and bores for receiving bearings to achieve linear motion. The carriageless print head may be optionally equipped with some combination of an air conduit for cooling the top layer of the constructed product, a fluid channel for aiding in the regulation of the temperature of the print head cold end, and a thermal monitor for monitoring the temperature of the cold end of the print head. A computer-mediated method of monitoring the cold end of the print head to limit jams due to overheating is also disclosed.