Crack propagation in CBN insert in hybrid machining of RBSN ceramic

This research investigates the phenomenon that cryogenic cooling can significantly improve the cutting tool life and the workpiece quality in hybrid machining of advanced materials, such as Reaction Bonded Silicone Nitride (RBSN). Several finite element models are developed in order to analyze the temperature fields developed and the stress distributions in the Polycrystalline Cubic Boron Nitride (PCBN) cutting insert during a hybrid turning process. The analyses performed reveal that the hybrid machining with cryogenic cooling of the cutting tool leads to a decrease of stresses in the cutting insert, especially when micro-cracks are present in the insert exhibits. It is found that a decrease in cutting temperature from 1740°C to 597°C led to approximately 660 stress reduction at the tip of the micro-cracks on the flank face of the cutting tool, thus significantly reducing the wear rate of the cutting insert. The findings are consistent with previously published experimental data

Hybrid micro-machining processes : a review

Micro-machining has attracted great attention as micro-components/products such as micro-displays, micro-sensors, micro-batteries, etc. are becoming established in all major areas of our daily life and can already been found across the broad spectrum of application areas especially in sectors such as automotive, aerospace, photonics, renewable energy and medical instruments. These micro-components/products are usually made of multi-materials (may include hard-to-machine materials) and possess complex shaped micro-structures but demand sub-micron machining accuracy. A number of micro-machining processes is therefore, needed to deliver such components/products. The paper reviews recent development of hybrid micro-machining processes which involve integration of various micro-machining processes with the purpose of improving machinability, geometrical accuracy, tool life, surface integrity, machining rate and reducing the process forces. Hybrid micro-machining processes are classified in two major categories namely, assisted and combined hybrid micro-machining techniques. The machining capability, advantages and disadvantages of the state-of-the-art hybrid micro-machining processes are characterized and assessed. Some case studies on integration of hybrid micro-machining with other micro-machining and assisted techniques are also introduced. Possible future efforts and developments in the field of hybrid micro-machining processes are also discussed

Principles and Characteristics of Different EDM Processes in Machining Tool and Die Steels

Electric discharge machining (EDM) is one of the most efficient manufacturing technologies used in highly accurate processing of all electrically conductive materials irrespective of their mechanical properties. It is a non-contact thermal energy process applied to a wide range of applications, such as in the aerospace, automotive, tools, molds and dies, and surgical implements, especially for the hard-to-cut materials with simple or complex shapes and geometries. Applications to molds, tools, and dies are among the large-scale initial applications of this process. Machining these items is especially difficult as they are made of hard-to-machine materials, they have very complex shapes of high accuracy, and their surface characteristics are sensitive to machining conditions. The review of this kind with an emphasis on tool and die materials is extremely useful to relevant professions, practitioners, and researchers. This review provides an overview of the studies related to EDM with regard to selection of the process, material, and operating parameters, the effect on responses, various process variants, and new techniques adopted to enhance process performance. This paper reviews research studies on the EDM of different grades of tool steel materials. This article (i) pans out the reported literature in a modular manner with a focus on experimental and theoretical studies aimed at improving process performance, including material removal rate, surface quality, and tool wear rate, among others, (ii) examines evaluation models and techniques used to determine process conditions, and (iii) discusses the developments in EDM and outlines the trends for future research. The conclusion section of the article carves out precise highlights and gaps from each section, thus making the article easy to navigate and extremely useful to the related research communit

A review on conventional and nonconventional machining of SiC particle-reinforced aluminium matrix composites

AbstractAmong the various types of metal matrix composites, SiC particle-reinforced aluminum matrix composites (SiCp/Al) are finding increasing applications in many industrial fields such as aerospace, automotive, and electronics. However, SiCp/Al composites are considered as difficult-to-cut materials due to the hard ceramic reinforcement, which causes severe machinability degradation by increasing cutting tool wear, cutting force, etc. To improve the machinability of SiCp/Al composites, many techniques including conventional and nonconventional machining processes have been employed. The purpose of this study is to evaluate the machining performance of SiCp/Al composites using conventional machining, i.e., turning, milling, drilling, and grinding, and using nonconventional machining, namely electrical discharge machining (EDM), powder mixed EDM, wire EDM, electrochemical machining, and newly developed high-efficiency machining technologies, e.g., blasting erosion arc machining. This research not only presents an overview of the machining aspects of SiCp/Al composites using various processing technologies but also establishes optimization parameters as reference of industry applications

Tungsten Carbide

Tungsten Carbide - Processing and Applications, provides fundamental and practical information of tungsten carbide from powder processing to machining technologies for industry to explore more potential applications. Tungsten carbide has attracted great interest to both engineers and academics for the sake of its excellent properties such as hard and wear-resistance, high melting point and chemically inert. It has been applied in numerous important industries including aerospace, oil and gas, automotive, semiconductor and marine as mining and cutting tools, mould and die, wear parts, etc., which also has a promising future particularly due to enabling to resist high temperature and are extremely hard

Aplikasi android pembelajaran abjad Bahasa Jepun (JingoCat Apps)

Bahasa asing menjadi salah satu bahasa yang perlu dipelajari oleh pelajar Ijazah Sarjana Muda di Universiti Tun Hussein Onn Malaysia (UTHM). Pelajar yang mempelajari Bahasa Jepun sebagai satu kursus bahasa ketiga mempunyai masalah menguasai perbendaharaan kata (leksikal), struktur bahasa serta tatabahasa. Faktor masalah ini berlaku adalah disebabkan, perbendaharan kata (leksikal) yang asing bagi pelajar, menyebabkan sukar untuk dihafal dan diaplikasi dalam latihan sama ada latihan komunikasi atau latihan untuk membuat ayat (Noor Aizah Abas, 2009). Kajian ini bertujuan untuk membangunkan satu aplikasi android pembelajaran abjad bahasa jepun aras satu dan dua kepada pelajar UTHM khususnya dan umumnya boleh digunakan kepada mana-mana pengguna yang berminat. Aplikasi ini merupakan pembelajaran awal dalam mempelajari abjad Jepun di samping memudahkan pelajar untuk menguasai huruf Hiragana dan Katakana melalui aplikasi pembelajaran mudah alih berasaskan multimedia. Aplikasi android pembelajaran abjad jepun tahap 1 dan 2 (JingoCat Apps) mempunyai tiga menu utama iaitu Learn, Game dan Review di mana setiap menu mengandungi pembelajaran yang berbeza kandungan. Reka bentuk maklumat adalah berdasarkan Teori Kognitif, Teori Behaviorisme dan Teori Konstruktivisme. Model reka bentuk produk adalah berdasarkan Model Hannafin dan Peck (1988) terdiri daripada fasa Analisis, Reka Bentuk, Pembangunan dan Pengulangan dan Penilaian. Oleh itu, semua fasa akan mengandungi proses penilaian dan menyemak semula setiap fasa. Reka bentuk yang terlibat dalam pembangunan aplikasi JingoCat adalah informasi, interaksi dan antara muka. Metodologi kajian melibatkan temubual berstruktur untuk menilai kebolehfungsian aplikasi android yang dibangunkan. Penilaian terhadap pakar yang terdiri daripada empat orang pakar iaitu dua orang pakar dalam bidang Multimedia Kreatif dan dua orang pakar dalam bahasa asing (Bahasa Jepun). Hasil dapatan menunjukkan, keseluruhan pakar bersetuju bahawa reka bentuk informasi, interaksi dan antara muka memenuhi keperluan dan bersesuaian. Kesimpulannya, aplikasi pembelajaran abjad Jepun JingoCat menjadi satu Alat Bahan Bantu Mengajar (ABBM) dan mudah digunakan oleh semua pihak yang memerlukan

Modeling and simulation of surface generation in manufacturing

The paper describes the state-of-the-art in modeling and simulation of surface texture and topography generation at micro and nano dimensional scales. Three main classes of manufacturing processes used for the generation of engineering surfaces are considered: material removal processes, material conservative processes, and material additive processes. Types of modeling techniques for the simulation of surface generation are reviewed and discussed including analytical models, numerical multi-physics models, and data-driven methods. After presenting the application of those modeling techniques for the prediction of characteristics and geometry of surfaces generated by different manufacturing processes, their performance, implementation, and accuracy are discussed. Finally, a roadmap for the realization of a complete surface generation digital twin in manufacturing is outlined

Investigations on Machining Aspects of Inconel 718 During Wire Electro-Discharge Machining (WEDM): Experimental and Numerical Analysis

Wire electro- discharge machining (WEDM) is known as unique cutting in manufacturing industries, especially in the good tolerance with intricate shape geometry in die industry. In this study the workpiece has been chosen as Inconel 718. Inconel 718 super alloy is widely used in aerospace industries. This nickel based super alloy has excellent resistance to high temperature, mechanical and chemical degradations with toughness and work hardening characteristics materials. Due to these properties, the machinability studies of this material have been carried-out in this study. The machining of Inconel 718 using variation of wire electrode material (brass wire electrode and zinc coated brass wire) with diameter equal to 0.20mm has been carried out. The objective of this study is mainly to investigate the various WEDM process parameters and performance of wire electrodes materials on Inconel 718 with various types of cutting. The optimal process parameter setting for each of wire electrode material has been obtained for multi-objective response. The kerf width, Material Removal Rate (MRR) and surface finish, corner error, corner deviation and angular error are the responses which are function of process variables viz. pulse-on time, discharge current, wire speed, flushing pressure and taper angle. The non-linear regression analysis has been developed for relationship between the process parameter and process characteristics. The optimal parameters setting have been carried out using multi-objective nature-inspired meta-heuristic optimization algorithm such as Whale Optimization Algorithm (WOA) and Gray Wolf Optimizer (GWO). Lastly numerical model analysis has been carried out to determine MRR and residual stress using ANSYS software and MRR model validated with the experimental results. The overlapping approach has been adopted for solving the multi-spark problem and validate with the experimental results