I claim the ornamental design for a 3D printer assembly, as shown and described.
FIG. 1 is a first front isometric view of the 3D printer assembly in accordance with a first variant;
FIG. 2 is a left side elevational view of the 3D printer assembly shown in FIG. 1;
FIG. 3 is a right side elevational view of the 3D printer assembly shown in FIG. 1;
FIG. 4 is a top plan view of the 3D printer assembly shown in FIG. 1;
FIG. 5 is a bottom plan view of the 3D printer assembly shown in FIG. 1;
FIG. 6 is a front elevational view of the 3D printer assembly shown in FIG. 1; and,
FIG. 7 is a rear elevational view of the 3D printer assembly shown in FIG. 1.
The ornamental design which is claimed is shown in solid lines in the drawings. The broken lines in the drawings are for illustrative purposes only and form no part of the claimed design.