The new drilling and milling system features a proprietary laser source, designed and manufactured by LPKF. The ProtoLaser 100's infrared (IR) dye-pumped laser provides the type of structuring control not associated with traditional laser sources, using a fine 25-μm (1-mil) diameter laser beam to achieve minimum track width of 50 μm (2 mils) and minimum track spacing of 25 μm (1 mil). The laser operates at a wavelength of 1064 nm, pulse repetition frequencies (PRFs) of 10 to 100 kHz, and minimum laser pulse length of 35 ns at a PRF of 30 kHz.

With a ProtoLaser 100, PCB production takes place in two phases: the laser-structuring phase and the laser-rubout phase. In the structuring phase, CAD software guides the laser beam to outline all the features of the final circuitry. During this stage, the conductive areas which are to be ablated from the board are divided into many small subareas or stripes . All generated lines are then structured by the laser. Laser-beam parameters (beam diameter on the working field, laser wavelength, pulse frequency, energy, and length) are carefully chosen in a way that isolation channels are reliably structured in the conductive layer without significantly damaging the substrate.

The width of the stripes depend on the parameters used later in the rubout process; however, after the structuring phase is completed, the established subareas are no longer in direct electrical and thermal contact with each other. Thermal contact only remains via the substrate, a poor thermal conductor.

In the rubout phase, laser parameters are changed so that the laser beam no longer reaches the threshold for the ablation of the conductive layer (average power remains high but peak power is sharply reduced). The laser beam is then guided along the stripes and its energy is absorbed in the conductive layer. Since the structured channels do not allow transversal diffusion of the absorbed energy into the surrounding material, the temperature of the illuminated stripes increases dramatically and eventually the adhesion force between the conductive layer and the substrate diminishes significantly. By applying an adequate external force, the complete stripe is removed as a single piece from the substrate. The mechanism that allows the stripe removal is a combination of the strong temperature raise at the metal-insulator interface and a mechanical shock originating from the expansion of the metal layer.

The advantages of the new rubout method are obvious. Since the conductive-material stripes are removed as single solid pieces, no particles are deposited on the substrate during the stripe-removal process, resulting in a substrate that is clean and undamaged. The width of the stripe and the speed of the laser beam moving along the stripe depend on the applied laser power but, in general, the process speed exceeds the conventional laser-rubout methods by at least a factor of 10.

The ProtoLaser 100 system has a work area measuring 420 × 380 mm (16.5 × 14.9 in.). The laser beam covers a scan field measuring 100 × 100 mm (4 × 4 in.) and works with materials as thick as 150 mm (6 in.). It can be used with a variety of substrate materials, such as FR3, FR4, ceramic-filled soft substrates (TMM and RO4000), and PTFE substrates. The system operates with a wide range of CAD/CAM file formats, including Gerber, HPGL, Sieb & Meier, Excellon, DXF, Barco, and ODB++ files. The system itself measures 2,000 × 1350 × 2150 mm (78.7 × 53.1 × 84.6 in.) and weighs between 600 and 700 kg (1320 and 1540 lbs.).

The ProtoLaser 100 can be combined with the company's ProtoMat series of mechanical milling and drilling PWB prototyping CNC machines for extended functionality in a prototyping or small-production environment. Since the machines operate without hazardous chemicals, they can be operated even in environmentally sensitive areas.