Search results for "Machining"
showing 10 items of 180 documents
Physics based modelling of interface temperatures in machining with multilayer coated tools at moderate cutting speeds
2004
Abstract A new thermal model is presented for turning with tools with multilayer coatings. In the previous paper [Int. J. Mach. Tools Manuf. 43 (2003) 1311] devoted to the thermal problems in dry turning of steels with tools treated with multilayer coatings with an intermediate Al 2 O 3 layer new analytical models for estimating the heat partition to the chip and the average interface temperature were derived and the predictions were compared with experimental results. In this paper, a physics based modelling concept has been applied to both the individual layer and the composite layer approach to develop an estimate of the average and the maximum steady-state chip-tool interface temperatur…
Impact of Superfinish Turning on Surface Integrity of Pure Copper
2011
Abstract The presented study deals with comprehension of relationships between machining cutting conditions and physical-chemical properties linked with surface integrity. A multi-physics model is presented to calculate residual stress, temperature and dislocation fields in the machined material. This model includes both thermal-mechanical, structural evolution and dynamic recristallisation approaches. The model was applied to pure copper after superfinish turning. Good agreement was found between numerical values and experimental ones. This paper also presents a work on the impact of mechanical and microstructural changes induced by machining on the electrochemical behaviour and corrosion …
A physical-based constitutive model for surface integrity prediction in machining of OFHC copper
2017
International audience; Due to the rising interest in predicting machined surface integrity and sustainability, various models for metal cutting simulation have been developed. However, their accuracy depends deeply on the physical description of the machining process. This study aims to develop an orthogonal cutting model for surface integrity prediction, which includes a physical-based constitutive model of Oxygen Free High Conductivity (OFHC) copper. This constitutive model incorporates the effects of the state of stress and microstructure on the work material behavior, as well as a dislocation density-based model for surface integrity prediction. The coefficients of the constitutive mod…
Influence of cutting process mechanics on surface integrity and electrochemical behavior of OFHC copper
2014
The authors gratefully acknowledge the support received from IC ARTS and CEA Valduc; International audience; Superfinishing machining has a particular impact on cutting mechanics, surface integrity and local electrochemical behavior. In fact, material removal during this process induces geometrical, mechanical and micro-structural modifications in the machined surface and sub-surface. However, a conventional 3D cutting process is still complex to study in terms of analytical/numerical modeling and experimental process monitoring. So, researchers are wondering if a less intricate configuration such as orthogonal cutting would be able to provide information about surface integrity as close as…
Dual phase titanium alloy hot forging process design: experiments and numerical modeling
2015
Titanium alloys are considered desirable materials when both good mechanical properties and weight reduction are required at the same time. This class of materials is widely used in those fields (aeronautics, aerospace) in which common steels and light-weight materials, e.g., aluminum alloys, are not able to satisfy all operative service conditions. During the last decade, forging of titanium alloys has attracted greater attention from both industrial and scientific/academic researchers because of their potential in providing a near net shaped part with minimal need for machining. In this paper, a numerical model of the forging sequences for a Ti-6Al-4V titanium alloy aerospace component is…
TECHNOLOGICAL PERSPECTIVES REGARDING THE APPLICATION OF THE CONTACT BREAKING ELECTRICAL DISCHARGE MACHINING PROCESS USING AS ELECTRODE-TOOL - METAL B…
2020
The scientific paper presents the most important aspects of theoretical and practical nature regarding the possibilities of processing metallic materials using the contact breaking electrical discharge machining with transfer object-metal band. The exposed research is based on the experience gained over the years by a team of Romanian researchers and university professors who managed to patent a metal material cutting plant using the process of contact breaking electrical discharge machining with transfer object-metal band. The scientific paper presents a radiography of some studies and research carried out over the years in the previous field presented.
Evaluating Safety Systems for Machine Tools with Computer Numerical Control using Analytic Hierarchy Process
2019
Computer numerical control (CNC) machine tools are complex production systems with fully automatic machine parts. Nowadays, high feed rates and machining speeds are used during the machining process. Human operators are still needed to set-up the machine, load/unload workpieces and parts, load the machining code, and supervise the machining process. The operators work in an environment where automated high-speed motions occur, and consequently, CNC machine tools have to be equipped with safety systems. The approach presented in this paper was to evaluate the main safety systems of CNC machine tools based upon the analytic hierarchy process (AHP). The analyzed systems were divided into six m…
The Effect of surface topographical changes of two different surface treatments rotary instrument
2018
Background One of the major innovations in endodontics has been the introduction of nickel-titanium (NiTi) alloy. This study evaluated the surface topographical changes of two different surface treatments rotary instrument after instrumentation and sterilization. Material and Methods 240 Extracted teeth were included in this study. 90 new AlphaKite and Revo-S NiTi rotary instruments were selected and divided into two groups (Group A 45 AlphaKite and group B 45 Revo-S). Each group were divided into three subgroups: (A1, B1) n=5 files were used as a control, (A2,B2) n=20 files were used to prepare three root canals using endodontic rotary motor then sterilized by autoclave for one cycle under…
Fracture and fatigue of titanium narrow dental implants: New trends in order to improve the mechanical response
2019
Sixty-four fractured commercially pure titanium (cp-Ti) narrow dental implants (NDIs) with similar macrogeometry and connection designs were studied after different implantation times in humans in order to determine their reliability and to evaluate the causes of the fracture. These NDIs were compared with other similar implants, made with alloyed titanium with 15% Zr and with 12% strained titanium. Original implants were tested under static and fatigue conditions, simulating the tri-axial loads in the mouth by means of a Bionix hydraulic test machine. Fractography was studied using field-emission scanning electron microscopy (FSEM). The results showed that cp-Ti NDI exhibits low strength f…
ELECTRICAL DISCHARGE MACHINING - A HIGH FUTURE NONCONVENTIONAL PROCESSING PROCESS
2021
Electrical discharge machining is one of the most common processes for processing metallic materials. This process is characterized by the lack of mechanical pressure on the object that ensures the macroscopic location of the erosive agent. This scientific paper highlights a study based on experimental data processing as well as modeling the most important technological parameters for dimensional processing by electrical discharge machining with and without magnetic activation. In this context, the modeling and optimization of process parameters is approached, which can lead to the quality increasing of the processed surface, to an increase of the processing productivity and to a reduction …