The most important improvement in metal the cutting industry is the continuous utilization of cutting tools and tool condition monitoring system. In the metal cutting process, the tool condition has to be administered either by operators or by online condition monitoring systems to prevent damage to both machine tools and workpiece. Online tool condition monitoring system is highly essential in modern manufacturing industries for the rising requirements of cost reduction and quality improvement. This paper summaries various monitoring methods for tool condition monitoring in the milling process that have been practiced and described in the literature.

Tool condition monitoring techniques in milling process — a review

Monitoring and controlling of metal cutting processes is an essential task in any modern precision machining setup. The implementation of proper monitoring process leads to promising results in terms of cutting tool life, machining costs, and production rates. Several techniques have been used to detect, monitor, and analyze different parameters associated with the cutting processes such as cutting tool wear, chip breakage and fracture, chatter vibrations, and formation of built-up edge (BUE). In this work, a review study is presented to discuss the research activities using the acoustic emission (AE) signals to monitor and control various machining processes. The discussed work does not only present an investigation of the AE signals, measured variables, and AE sensor setup during machining processes, but also shows several methods used for analyzing and processing the AE signals. The work focuses on studies, which employed AE in monitoring, and analyzing some specific characteristics such as chip formation and morphology, surface quality, and tool wear evolution for different machining operations and materials.

Application of acoustic emissions in machining processes: analysis and critical review

Abstract Metal matrix nanocomposites (MMNCs) become irreplaceable in tribology industries, due to their supreme mechanical properties and satisfactory tribological behavior. However, due to the dual complexity of MMNC systems and tribological process, the anti-friction and anti-wear mechanisms are unclear, and the subsequent tribological performance prediction and design of MMNCs are not easily possible: A critical up-to-date review is needed for MMNCs in tribology. This review systematically summarized the fabrication, manufacturing, and processing techniques for high-quality MMNC bulk and surface coating materials in tribology. Then, important factors determining the tribological performance (mainly anti-friction evaluation by the coefficient of friction (CoF) and anti-wear assessment with wear rate) in MMNCs have been investigated thoroughly, and the correlations have been analyzed to reveal their potential coupling/synergetic roles of tuning tribological behavior of MMNCs. Most importantly, this review combined the classical metal/alloy friction and wear theories and adapted them to give a (semi-)quantitative description of the detailed mechanisms of improved anti-friction and anti-wear performance in MMNCs. To guarantee the universal applications of these mechanisms, their links with the analyzed influencing factors (e.g., loading forces) and characteristic features like tribo-film have been clarified. This approach forms a solid basis for understanding, predicting, and engineering MMNCs’ tribological behavior, instead of pure phenomenology and experimental observation. Later, the pathway to achieve a broader application for MMNCs in tribo-related fields like smart materials, biomedical devices, energy storage, and electronics has been concisely discussed, with the focus on the potential development of modeling, experimental, and theoretical techniques in MMNCs’ tribological processes. In general, this review tries to elucidate the complex tribo-performances of MMNCs in a fundamentally universal yet straightforward way, and the discussion and summary in this review for the tribological performance in MMNCs could become a useful supplementary to and an insightful guidance for the current MMNC tribology study, research, and engineering innovations. 

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Metal matrix nanocomposites in tribology: Manufacturing, performance, and mechanisms

Understanding and designing metal matrix nanocomposites with high electrical conductivity: a review

The major difficulty faced in a machining process is predicting the failure of cutting tools and analyzing the stipulated time for tool replacement. The former and latter can be achieved t...

Tool condition monitoring in the milling process with vegetable based cutting fluids using vibration signatures

Rationale At present, clinicians aiming to support patients through the challenges after critical care have limited evidence to base interventions. Objectives Evaluate a multicentre integrated health and social care intervention for critical care survivors. A process evaluation assessed factors influencing the programme implementation. Methods This study evaluated the impact of the Intensive Care Syndrome: Promoting Independence and Return to Employment (InS:PIRE) programme. We compared patients who attended this programme with a usual care cohort from the same time period across nine hospital sites in Scotland. The primary outcome was health-related quality of life (HRQoL) measured via the EuroQol 5-dimension 5-level instrument, at 12 months post hospital discharge. Secondary outcome measures included self-efficacy, depression, anxiety and pain. Results 137 patients who received the InS:PIRE intervention completed outcome measures at 12 months. In the usual care cohort, 115 patients completed the measures. The two cohorts had similar baseline demographics. After adjustment, there was a significant absolute increase in HRQoL in the intervention cohort in relation to the usual care cohort (0.12, 95% CI 0.04 to 0.20, p=0.01). Patients in the InS:PIRE cohort also reported self-efficacy scores that were 7.7% higher (2.32 points higher, 95% CI 0.32 to 4.31, p=0.02), fewer symptoms of depression (OR 0.38, 95% CI 0.19 to 0.76, p=0.01) and similar symptoms of anxiety (OR 0.58, 95% CI 0.30 to 1.13, p=0.11). There was no significant difference in overall pain experience. Key facilitators for implementation were: integration with inpatient care, organisational engagement, flexibility to service inclusion; key barriers were: funding, staff availability and venue availability. Conclusions This multicentre evaluation of a health and social care programme designed for survivors of critical illness appears to show benefit at 12 months following hospital discharge.

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Evaluation of a health and social care programme to improve outcomes following critical illness: a multicentre study

Wear of a cutting tool in a machining operation is highly undesirable because it severely degrades the quality of machined surfaces and causes undesirable and unpredictable changes in the work geometry. From a process automation point of view, it is therefore necessary that an intelligent sensing system be devised to detect the progress of tool wear during cutting operations so that worn tools can be identified and replaced in time. As a ‘non – destructive’ sensing methodology, Acoustic Emission (AE) based techniques offer some advantages over force or power based tool monitoring techniques because of the close relationship between the generation of the emission signal and the fracture or wear phenomenon in machining. The generation of the AE signals directly in the cutting zone makes them very sensitive to changes in the cutting process. Acoustic Emission Techniques (AET) is a relatively recent entry into the field of Non – Destructive Evaluation (NDE) which has particularly shown very high potential for material characterization and damage assessment in conventional as well as non-conventional processes. This method has also been widely used in the field of metal cutting to detect process changes like tool wear etc. In this research work the results obtained from the analysis of Acoustic Emission sensor employs to predict flank wear in turning of C45 steel of 250 BHN hardness using Polycrystalline diamond (PCD) insert. The correlation between the tool wear and AE parameters is analyzed using the experimental study conducted in 5 H.P all geared lathe.

Study of flank wear in single point cutting tool using acoustic emission sensor techniques

The current manufacturing trend mainly involves automation precisely to offer better productivity and improved quality. In this context, on-line monitoring of tools becomes essential. Acoustic emission is the most recognized technique used for condition monitoring of machine tools. Grinding is a material removal and surface generation process employed to shape and finish components made of metals and other materials. The research work deals with machining of CUMITUFF WR-90 alumina ceramics by employing two different grinding wheels made of aluminum oxide and silicon carbide under varying depth of cut. Surface roughness of the machined component and wear of both grinding wheels were analyzed using acoustic emission technique. For a constant depth, the quality of machining has been improved for the material grinded using silicon carbide wheel, which is inferred from low surface roughness value compared to material grinded using aluminum oxide wheel.

Acoustic emission testing of surface roughness and wear caused by grinding of ceramic materials

Finite element analysis and modeling of fractured femur bone

Among the nontraditional machining process, electrical discharge machining (EDM) is one of the significant processes for machining complicated and complex shapes. An experimental investigation was made with the help of electrical discharge machine on Inconel 718 using brass electrode tool to study the vibration behavior in the titanium carbide nanoparticles mixed dielectric fluid environment. Titanium carbide nanoparticles mixed with dielectric fluid possess a high strength, have good electrical and thermal properties and require lesser machining time than pure dielectric fluid. In this experiment, the central composite second order rotatable design and response surface methodology were used to develop an experimental model. Based on the developed models, analyses on machining characteristics of titanium carbide nanoparticles mixed EDM have been carried out. The current, pulse on time and pulse off time were considered as input process parameters and the output process parameters such as material...

S. Sundaram

Papers

Evaluation of a health and social care programme to improve outcomes following critical illness: a multicentre study

Study of flank wear in single point cutting tool using acoustic emission sensor techniques

Acoustic emission testing of surface roughness and wear caused by grinding of ceramic materials

Finite element analysis and modeling of fractured femur bone

Effect of machining characteristics of nano-TiC mixed dielectric fluids on Inconel 718 in the EDM process