Feasibility study of micromilling for AISI 316L microneedles arrays

Abstract

Microneedles market is expected to grow and the study of micromilling capabilities to meet medical requirements represents an opportunity of vast applications on this area. It is suggested that the limitations of this manufacturing process may lead to affect geometrical features of importance for insertion compliance. A study of the impact of the final geometric and surface features of the micromachined product on its functionality is necessary to fully understand this manufacturing technique in the medical area, especially the microdevices market. In this work, micromilling process with aid of Minimum Quantity Lubrication (MQL) system was used to manufacture AISI 316L square pyramidal (i.e., base length and height of 0.5 mm by 0.5 mm) microneedles arrays, and analysis of precision and reproducibility of measurements of height, base length, tip radius, tip angle, roughness and tool wear of ball nose micro end milling tool were performed. Based on the used cutting parameters, an optimal quantity of 30 microneedles can be manufactured to obtain values closed to those of design and guarantee insertion in skin. Simulations presented maximum radius tips of 50 microns to accomplish piercing