Patent attributes
A 3D printer includes a gantry configured to move in a plane substantially parallel to a x-y build plane and a print head configured to extrude molten material to print a 3D part in a layer-by-layer process. The 3D printer includes a platen configured to support the part being printed in the layer by layer process and positionable with a primary Z positioner along a z-axis substantially normal to the x-y build plane. The 3D printer includes a local Z positioner moved by the gantry, the local Z positioner comprising a linear motor configured to move the print head in the z-direction and having an operable range of motion extending from a nominal build position at which a nozzle of the print head is positioned in the x-y build plane to a raised position above the x-y build plane.