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This paper presents a review of recent advances in modeling and simulation of conventional metal machining processes, which continue to dominate a significant part of all machining processes, and in recent years, the need for predictive models for machining processes has grown in importance in the digital manufacturing age. Significant advances have been made in modeling the mechanics of cutting in conventional machining, driven by industrial need and enabled by rapid advances in computational power. The paper surveys the state-of-the-art in analytical and numerical modeling of conventional metal machining processes with a focus on their ability to predict useful performance attributes including chip geometry, forces, temperatures, tool wear, residual stress, and microstructure. Also included in the review is a discussion of the industrial use of modeling and simulation tools for conventional machining. Additionally, the practical applicability, implementation benefits, and methodological limitations of conventional machining process modeling have been examined. The paper concludes with a summary of future research directions in modeling and simulation of conventional metal machining processes. [ABSTRACT FROM AUTHOR]

Understanding and simulating the evolution of fracture in cellulose-based paper materials is vital for many eco-sustainable applications of packaging solutions. In this work, we conduct an integrated experimental-statistical mechanics analysis to elucidate how the microstructural mechanisms govern the fracture behavior of paper. We employ in-situ tensile tests combined with confocal microscopy to observe and analyze key microstructural phenomena, such as fibers' activation and recruitment, and progressive tensile failure of unnotched paper samples under uniaxal loading. The developed stochastic mechanics critical cross-section model to treat the cellulose fiber network is able to decouple the stochastic morphological parameters from the constitutive model of the fibers. Notably, it robustly predicts the anisotropic properties of paper materials in the machine direction (MD) and cross-machine direction (CD) as a direct consequence of the different statistical distribution of fibers' orientation, for the same fiber constitutive model. The proposed approach is finally employed to get an insight into the role of the main morphological parameters, local/non-local fibers' strain redistribution, and finite elasticity of fibers on the whole mechanical behavior of paper. [Display omitted] • Stochastic network model of a cellulose fiber network. • Mechanical simulation of paper material till fibers' failure. • In-situ micro-mechanical testing of paper. • The model decouples the effect of fibers' morphology from their constitutive law. [ABSTRACT FROM AUTHOR]

A manufacturing process is a unique combination of 4 Ms viz. manpower, methods, machines and materials in developing a product. Process capability indices have been used to provide quantitative measures of process potential and performances. High quality production assures advantages like cost saving, scrap reduction or remanufacturing, higher yield and increased customer satisfaction and market share. Process capability Indices like Cp, Cpk, Cpm and Cpmk are commonly used in industry to assess the ability of a process to meet specification limits on quality characteristics of interest. In modern manufacturing when product designs are complicated and consumers' requirements are changeable rapidly, multiple characteristics must be assessed simultaneously to improve product's quality and also to consider the correlation effects among different quality characteristics. The objective of this paper is to identify the critical variables of the whole process of paper manufacturing and to conduct process capability analysis (univariate and multivariate) to measure performance in a multistage manufacturing process by understanding the concepts, and methodologies of quality engineering techniques. The paper manufacturing has various stages namely pulping, screening, cleaning, deinking, refining, pressing, steam drying, bleaching, steam drying and size press. The results show that multivariate capability indices, MCpk for Cobb and RCT (CD), BF anf Paper Ash, significantly correlated, are 0.17 and 0.40 respectively. [ABSTRACT FROM AUTHOR]

Abstract The presence of machining-induced white layer in the near-surface of critical aeroengine alloys has a detrimental effect on the lifetime of a component. Present techniques for identifying and characterizing white layer, such as optical microscopy and hardness testing, whilst effective, are destructive, costly and time-consuming. Non-destructive testing methods may, therefore, offer improvements to the process of white layer detection. This paper discusses the formation mechanisms and the defining physical properties of machining-induced white layers before offering a comprehensive review of the current state-of-the-art in both destructive and non-destructive testing methods for detecting this anomalous surface feature. [ABSTRACT FROM AUTHOR]

In the current scenario, cutting tool industries use the powder material tungsten carbide of 60-80 microns grain size to produce cutting inserts. There are a lot of scopes to improve the properties of cutting tool materials to enhance their ability to machine challenging materials like heat resistant super alloys (HRSA). Reducing the grain size of cutting tool material powder to nano level may help to increase the strength, substrate hardness, Fracture toughness, and thermal conductivity of the cutting insert. This review studies different strategies used to develop nano powders for the cutting tool application. We observed that most of the studies focused on the latest powders used in cutting tool industries like tungsten carbide, boron carbide powders which are reduced as nano powders, pressed, and sintered with different techniques like hot isostatic pressing (HIP), Spark plasma sintering. Finally, the current research gaps and the future challenges in understanding the development of nano powders for cutting tool applications are critically discussed, providing an interpretation of the possible directions for scientific development in this field. [ABSTRACT FROM AUTHOR]

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In this paper the cutting stock problem minimizing saw cycles is considered. In this context where objects can be cut simultaneously the trade-off between raw material and machine utilization costs is of major interest. Different processing times for each cutting pattern are considered, according to the number of items on it, different from previous works of the literature. The optimization aims to minimize both machine utilization costs due to the saw cycles and raw material usage costs. An integer mathematical formulation is proposed, and a solution method based on a column generation procedure is used. Computational tests were performed to assess the impact on costs for illustrative and real industry instances. A set of instances were also randomly generated to analyse the behaviour of the outcome of the problem in face of different technical parameters. [ABSTRACT FROM AUTHOR]

The price of electrocardiograph (ECG) machine on the market is very high. Currently, the technology used is still very complicated and ineffective, and the ECG machine cannot be connected to other devices. A new development of a low-cost ECG machine with a customized design was needed to integrate the machine with other devices. Therefore, the purpose of this study is to develop a low-cost ECG machine which can be connected to other devices and equipped with sensitivity and paper speed setting. So that portable ECG machines can be produced and used at small clinics in the society. In this study, the main controller of the 12 channels ECG machines was supported by ATMEGA16 microcontroller, that is available on the market at low prices. The main part of the ECG amplifier is built using a high common mode rejection ratio (CMRR) instrumentation amplifier (AD620) and a bandpass filter which the cutoff frequency for highpass filter and lowpass filter are 0.05 Hz and 100 Hz, respectively. In order to complement the previous study, some features were introduced such as selectivity and motor speed option. In this study, 10 participants are involved for data acquisition, and an ECG phantom was used to calibrate the machine. The performance of the ECG machine was evaluated using standard measurement namely relative percentage error (% error) and uncertainty (UA). The result shows that %error from all of the feature is less than 2% and the UA is 0.0 which shows that the ECG machine is feasible for diagnostic purposes. [ABSTRACT FROM AUTHOR]