This paper focuses on the analysis of tool wear mechanisms in finishing turning of Inconel 718, one of the most used Ni alloys, both in wet and dry cutting. Cemented carbides, ceramics and CBN tools are suitable for machining Ni alloys; coated carbide tools are competitive for machining operations of Ni alloys and widely used in industry. Commercial coated carbide tools (multilayer coating TiAl/TiAlN recommended for machining Ni alloys) were studied in this work. The feasibility of two inserts tested for dry cutting of Inconel 718 has been shown in the work. Experimental test were performed in order to analyze wear patterns evolution. It was found great influence of side cutting edge angle in tool wear mode.The financial support of this work to the Ministry of Economy and Competitiveness of Spain (under project DPI2008–06746).Publicad
This paper focuses on the effect of the drill geometry on the drilling of woven Carbon Fiber Reinforced Polymer composite (CFRPs). Although different geometrical effects can be considered in drilling CFRPs, the present work focuses on the influence of point angle and wear because they are the important factors influencing hole quality and machining forces. Surface quality was evaluated in terms of delamination and superficial defects. Three different point angles were tested representative of the geometries commonly used in the industry. Two wear modes were considered, being representative of the wear patterns commonly observed when drilling CFRPs: flank wear and honed cutting edge. It was found that the crossed influence of the point angle and wear were significant to the thrust force. Delamination at the hole entry and exit showed opposite trends with the change of geometry. Also, cutting parameters were checked showing the feed’s dominant influence on surface damage.
1 April 2015 in Journal of the Mechanical Behavior of Biomedical Materials
Common practice of surgical treatments in orthopaedics and traumatology involves cutting processes of bone. These operations introduce risk of thermo-mechanical damage, since the threshold of critical temperature producing thermal osteonecrosis is very low. Therefore, it is important to develop predictive tools capable of simulating accurately the increase of temperature during bone cutting, being the modelling of these processes still a challenge. In addition, the prediction of cutting forces and mechanical damage is also important during machining operations. As the accuracy of simulations depends greatly on the proper choice of the thermo-mechanical properties, an essential part of the numerical model is the constitutive behaviour of the bone tissue, which is considered in different ways in the literature. This paper focuses on the review of the main contributions in modelling of bone cutting with special attention to the bone mechanical behaviour. The aim is to give the reader a complete vision of the approaches commonly presented in the literature in order to help in the development of accurate models for bone cutting.
Cutting operations in bone are involved in surgical treatments in orthopaedics and traumatology. The importance of guaranteeing the absence of damage in the living workpiece is equivalent in this case to ensuring surface quality. The knowledge in this field is really far from the expertise in industrial cutting of mechanical components. Modeling of bone cutting is a challenge strongly dependent on the accurate modeling of mechanical behaviour of the bone. This paper focuses on modeling of orthogonal cutting of cortical bone. The intrinsic anisotropic nature of the cortical bone that makes it comparable to a composite material is taken into account. The influence of anisotropy is analysed comparing this behaviour with an isotropic approach. It is shown that both chip morphology and temperature are affected by the anisotropy of the cortical bone that acts as a workpiece.This work was supported by the the Ministry of Economy and Competitiveness of Spain under the Project DPI2011-25999 and DPI2013-46643-RPublicad