NOVELTY - The device has first three-dimensional (3D)-printing head that selectively discharges conductive 3D-printing material. The second 3D-printing head is provided to selectively discharge insulating 3D-printing material. A processor (116) is configured to control operations of the first and second 3D-printing heads based on a CAD scheme describing a multi-layer printed circuit board (PCB) intended for 3D-printing. The functional PCB is 3D-printed in a lamination-free process. The first and second 3D-printing heads are to 3D-print a functional electromagnetic waveguide.    USE - Device such as three-dimensional printer for three-dimensional printing of such as 3D-printed printed circuit board (PCB), 3D-printed electronic circuit or integrated circuit (IC) or electronic component such as resistor capacitor or coaxial component or cable or mesh and waveguide. Can also be used in connector, pad or conductive pad, rheostat, potentiometer, opto-electronic component or device, digital IC, analog IC, sensor, LED, battery and power cell, etc.    ADVANTAGE - The inter-layer transition placement module automatically optimizes or enhances the distribution of such inter-layer transitions, or determines or modifies the location of such inter-layer transitions, and thus reduces the overall thickness of the PCB, to maintain an overall thickness of the PCB under or within a threshold value. By utilizing an on-the-fly trace thickness/trace width modifier to modify in real time and while 3D-printing of a trace, the width and/or the thickness of the conductive material is 3D-printed and maintains constant current-carrying capacity. The 3D-printing allows sequential or continuous creation of via or transition within the 3D-printing process that fabricates the 3D-printed PCB, and thus maintains or enhances electrical performance while providing three-dimensional options to optimize routing.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block-diagram illustrating the 3-D printer and the components and modules of printer.    Printing head (101)    Printing material (102)    Processor (116)    Printing program (119)    Housing (157)