Roughness evaluation of Ti6Al4V bulks produced by laser powder directed energy deposition and micro-milled for biomedical applications.

Abstract

Laser Powder-Directed Energy Deposition (LP-DED) has excelled as a technology that can produce parts with large dimensions in less time. Furthermore, the micro-milling process can be combined to provide a uniform surface and a high quality of roughness that directly impacts osteointegration and cellular adhesion. This paper aimed to manufacture bulks produced by LP-DED with two different powders and different laser powers. In sequence, the milling process was used to create six channels and evaluate the influence of the feed per tooth (f_z) on the bulk surface. The values obtained from the as-built bulks revealed the impact of the laser power and powder features on the surface of the bulks, obtaining values around 30-55 ?m for the Sq and 20-45 ?m for the Sa, respectively. These values were reduced when applying micro-milling from 1.0 to 1.5 ?m in terms of Sa and 1.5 to 2.5 ?m for the Sq. Regarding Skewness and Kurtosis, the results revealed Ssk > 0, indicating a surface with greater valley concentration, and in most cases, Sku > 3, describing the prevalence of sharp peaks or valleys. This surface microtopography can provide cell housing and form a bone matrix around the implant.