The most cost effective cavities land on unetched areas of a metal layer. Utilizing appropriate energy delivery of IR wavelengths, the dielectrics absorb the laser energy but the metal reflects the energy to leave a clean surface for plating, wire bonding, or solder reflow.
Creating cavities that stop on etch circuit layers is accomplished with MLT control depth cavity skiving. MLT control depth, cavity skiving delivers an even distribution of energy across the cavity area through custom programming techniques and utilizing the right spatial and temporal laser beam profiles. As the laser cavity processes to within 25um - 50um of the desired depth, the ablation switches from higher energy or 'coarse' delivery to a multi-pass of lower energy or 'fine' delivery. This fine ablation skiving cleans the dielectric from the circuit surface and stops just below the etched circuit plane.
The process times or cost of laser produced cavities are based on the total volume of material removal. When cavity depths exceed .008", mechanical pre-milling the cavity to within 5mils of the target layer prior to laser can greatly reduce the laser cavity skiving costs. Laser skiving of PCB cavities can have limitations with some material stackups and tolerances. Please contact our sales staff to discuss your PCB cavity requirements.
CAD or Data Requirements
CAD system integration and custom file converters enable flexible, laser manufacturing from customer-provided data. Although most file types are accepted, the preferred file types are Gerber, Excellon, DXF, or other 2D formats. In most cases, non-scaled data is required as MLT will make the appropriate scaling or offsets to meet part dimensions.
If concerned about compatibility of your data format or CAD/CAM tool, please contact MLT Sales for more information. For more CAM/CAD guidelines and detailed requirements, click CAD Requirements.
Cavity Skiving Standard Tolerances
|Infrared (CO2)||Ultraviolet (UV)|
|Positional:||+/-.002” (50um)||+/-.001” (25um)|
|Dimensional:||+/-.002” (50um)||+/-.001” (25um)|
|Depth:||Application Dependent||Application Dependent|