Aesthetic laser marking assessment using spectrophotometers

In this paper, the use of spectrophotometers in quantitatively assessing four types of surfaces marked using an Nd:YAG laser is investigated. Mixed results were obtained regarding its assessment efficacy. The spectrum reflectance trace could not effectively distinguish the degrees of marking in anodized aluminium; whereas with stainless steel, assessment could be achieved by observing the reflectance peak signatures. With poly-butylene tetra-phthalate (PBT) and phenol formaldehyde, the spectrum reflectance traces were flat with discernible changes in the average reflectance being obtained as a result of marking at different speeds.