Experimental Optimization of Process Parameters in CuNi18Zn20 Micromachining

Abstract

Ultraprecision micromachining is a technology suitable to fabricate miniaturized and complicated 3-dimensional microstructures and micromechanisms. High geometrical precision and elevated surface finishing are both key requirements in several manufacturing sectors. Electronics, biomedicals, optics and watchmaking industries are some of the fields where micromachining finds applications. In the last years, the integration between product functions, the miniaturization of the features and the increasing of geometrical complexity are trends which are shared by all the cited industrial sectors. These tendencies implicate higher requirements and stricter geometrical and dimensional tolerances in machining. From this perspective, the optimization of the micromachining process parameters assumes a crucial role in order to increase the efficiency and effectiveness of the process. An interesting example is offered by the high-end horology field. The optimization of micro machining is indispensable to achieve excellent surface finishing combined with high precision. The cost-saving objective can be pursued by limiting manual post-finishing and by complying the very strict quality standards directly in micromachining. A micro-machining optimization technique is presented in this a paper. The procedure was applied to manufacturing of main-plates and bridges of a wristwatch movement. Cutting speed, feed rate and depth of cut were varied in an experimental factorial plan in order to investigate their correlation with some fundamental properties of the machined features. The dimensions, the geometry and the surface finishing of holes, pins and pockets were evaluated as results of the micromachining optimization. The identified correlations allow to manufacture a wristwatch movement in conformity with the required technical characteristics and by considering the cost and time constraints.

A feasibility study of promoting osseointegration surface roughness by micro-milling of Ti-6Al-4V biomedical alloy

“…The examination of these results, firstly permitted to individuate which medical applications, that are surface roughness dependent [14], are suitable for MM. The choice of analyzing the S a three-dimensional roughness parameter (ISO 25178) instead of the R a one, was related to a lower influence of measurement noise and scratches on S a than R a [20] and to a characterization of the height distribution in combination with spatial parameter that led to an improved description of implant surfaces [14,21]. Secondly, following the need of standardizing evaluation and methodology techniques [14], S a values were statistically investigated by ANOVA to identify the most influencing parameters, letting the development of reliable mathematical models for S a estimation.…”

Analysis of Ti-6Al-4V micro-milling resulting surface roughness for osteointegration enhancement

“…Contingently from the implant typology, roughness needs are different, and can range from values smaller than a micron up to few microns of the parameters Sa [15]. Sa parameter is usually considered instead of the Ra one since less influenced by scratches and measurement noise [16]. Beyond roughness, there are other functional parameters, such as fatigue, wear, and corrosion resistance, to be taken into account for guaranteeing implant permanence inside human body [17].…”