PCBs

For this high-throughput application, it is basically possible to use both CO2 and Nd:YAG lasers. As the end results are very much dependent on the further manufacturing process, the system must be selected accordingly.

CO2 markings usually alter the soldering mask on printed-circuit boards to produce a grey to white marking on the mask. It forms a contrast which is adequately visible by the naked eye and by means of automatic image recognition systems. As only a minimum amount of material is eroded, this type of marking is ideal when the next process consists in printing the PCB or inserting components, because no additional cleaning step is required. Since the marking results are not very much dependent either on the carrier material or the soldering mask, a set of parameters covers most materials to be processed.

Nd:YAG lasers ablate the soldering mask material down to the copper layer. Given correct adjustment of the parameters, this makes for a good contrast. The process is material-dependent and different sets of parameters are required for different materials. Good contrast is helpful when reading bar codes.