US 12,257,776 B2
Pellet extruder for 3D printing
Jacob Jan Saurwalt, Alkmaar (NL)
Assigned to Admatec Europe B.V., Alkmaar (NL)
Appl. No. 17/913,167
Filed by Admatec Europe B.V., Alkmaar (NL)
PCT Filed Mar. 24, 2021, PCT No. PCT/EP2021/057511
§ 371(c)(1), (2) Date Sep. 21, 2022,
PCT Pub. No. WO2021/191244, PCT Pub. Date Sep. 30, 2021.
Claims priority of application No. 20165465 (EP), filed on Mar. 25, 2020.
Prior Publication US 2023/0139210 A1, May 4, 2023
Int. Cl. B29C 64/209 (2017.01); B29C 64/393 (2017.01); B33Y 30/00 (2015.01); B33Y 50/02 (2015.01)
CPC B29C 64/209 (2017.08) [B29C 64/393 (2017.08); B33Y 30/00 (2014.12); B33Y 50/02 (2014.12)] 15 Claims
OG exemplary drawing
 
1. Extruder based print head for 3D printing, comprising
a material feed unit for providing material in granular and/or liquid feed form,
a material extrusion unit arranged to receive the material in granular and/or liquid feed form and transform the material into liquefied material in print form, and
a nozzle unit in fluid communication with the material extrusion unit, the nozzle unit comprising an output channel and a nozzle arranged to output the liquefied material,
further comprising an internal volume enlargement unit in fluid communication with the output channel of the nozzle unit,
wherein the internal volume enlargement unit has a first internal volume in a first operational status and a second internal volume in a second operational status, wherein the second internal volume is larger than the first internal volume, and
wherein the internal volume enlargement unit comprises an expansion volume within the material extrusion unit, and an actuator connected to an extrusion screw, which actuator is arranged to linearly move the extrusion screw within the expansion volume to retract the liquefied material into the expansion volume.