Removing Component Markings in Printed Circuit Board Assembly

Printed circuit board assembly can be a very long process involving trial and error. All components and terminals should have identification markings to ensure that they are laid out correctly according to a designer’s schematic. Such markings include serial numbers and company logos. Problems occur when the design changes to improve the efficiency of the final circuit or to correct any errors. This involves a continuous erasing process, when the positions of any components change. The standard erasing procedure is to manually grind the marking away from the component. But this is not just time-consuming - it can also damage the component and causes stress damage to solder joints. Security is another reason for removing component markings during printed circuit board assembly. Many companies like to ensure that their competitors cannot find out too easily what kind of components make up the circuit board. In this case, the marking removal is also usually done manually after the board has been assembled, with the same potential damage to components and solders. One solution to this problem is to use carbon dioxide laser markers. Lasers are usually used to mark the solder resist. This is a covering on the circuit board that protects certain areas from accepting any solder. This means that the only areas on the board that can be soldered are those that are free of the resist. The main advantage of this is to reduce any short-circuiting. The laser provides a clear marking on the PCB surface that is permanent. It can provide a code that can be read with a specific machine as well as logos, graphs and various graphics. To the naked eye these areas show up as white spaces. Rather than manually erasing component markings, the carbon dioxide laser marker over-writes identification numbers and logos on the components. It uses a “sea of numbers” pattern. This adds a further level of security, as it is difficult to discern any specific pattern within the numbers. As well as eliminating any potential damage to components or stress to solder, this is a very speedy and accurate process. The laser markers have an accuracy within plus or minus 0.1 mm. It is also an automated process that reduces the time needed previously to erase markings.