Microwave printed-circuit board (PCB) prototypes can be quickly and cost-effectively produced in-house by means of any number of commercial mechanical milling machines or chemical etching. A faster and more accurate approach, however, is to perform the etching and machining by laser. That is the approach used in the new ProtoLaser 100 system from LPKF Laser & Electronics (Wilsonville, OR), which can mill and drill both laminated ceramic materials and soft substrate materials such as polytetrafluoroethylene (PTFE) circuit-board materials. The system generates circuits directly from computer-aided-design ( CAD ) and computer-aided-manufacturing (CAM) software and is compatible with a wide range of layout file formats, including Gerber, HPGL, and DXF files.

The ProtoLaser 100 system represents a high-speed laser-based PCB prototyping system that can also be used for production runs. The system can be used to create high-resolution lines and spacing in high-frequency PCBs in a fraction of the time of a mechanical milling/drilling system . It can also be used in conjunction with a mechanical system to form a full-featured PCB prototype production center.

The new system overcomes a shortcoming of earlier laser systems: the fast and efficient removal of large areas of conductive layers from standard FR 4 to soft PTFE substrates. Traditionally, these areas are removed from a laminate to leave behind circuit traces and other structures on the substrate. Laser ablation of large areas was known as a very slow process and the quality of final results was usually not acceptable. Laser was therefore normally applied only to produce the finest features on the boards and the remaining parts of the boards were produced by standard chemical methods. This has resulted in highly increased complexity and price of the production of the boards.

The ProtoLaser 100 overcomes this limitation using a single laser to produce complete RF and high-density circuits in a single production step. The same laser used to form precise lines and high-frequency circuit features is used in a different operating mode to remove the unwanted sections of conductive-layer material. Traditionally, laser-based systems have employed different laser hatching algorithms for removal of large conductive areas from a laminated substrate. By this approach, subsequent laser channels are lying closely together or partially overlapping to achieve ablation of complete hatched area. The main problem with this technique, however, is that ablated conductor material (commonly copper) is deposited to the left and/or right of the channel structured by the laser, since the conductive material does not completely vaporize from the surface of the laminated substrate. When channels overlap or even approach each other, the extra material tends to be deposited back into the newly formed channel, forming irregularities in the channels and channel sidewalls that result in uneven high-frequency performance. In some cases, the laser energy can cause overheating and damage to a sensitive PCB substrate.