Effect of overlap and overscan number in laser surface texturing of medical needles

Micro-features are frequently created on medical needles to improve the visibility and friction behavior in ultrasound-guided percutaneous procedures. Ultra-short pulsed laser ablation is the front runner among the current material micro-processing technologies. In this paper, the effect of process parameters in laser surface texturing (LST) of medical needles was studied by experiments based on Taguchi methodology. The evolution of ablation dimension and surface roughness with different process parameters was measured by optical microscope. Based on response surface regression, mathematical models for correlating the machined depth and surface roughness with the overlap and overscan number were developed. Analysis of variance (ANOVA) was carried out to access the adequacy of the developed mathematical models. The results indicate that the developed mathematical models can predict the machined depth and surface roughness during LST operation satisfactorily. Analyses were made to study the effect of the process parameters on the machined micro-channel. From the analysis, it was found that the overlap and overscan number have great influences on the machined depth and surface roughness.