|PAGE||ARTICLE ||3 || Grind-hardening of steel surfaces: a focused review
Abstract: Surface hardening of steel components using grinding-induced heat seems to be a cost-effective technique for production. This paper provides a review focusing on the research effort on grind-hardening in the author's Laboratory for Precision and Nano-processing Technologies. The discussion includes the mechanisms of heating and cooling, microstructural changes in workpiece materials, surface integrity generation and wear and fatigue behaviour of ground components
Keywords: grinding; surface hardening; phase transformation; compressed air; liquid nitrogen; residual stress; wear; fatigue; abrasive technology; steel surfaces; grind-hardening; heating; cooling; microstructure; surface integrity. link
|37 ||Characteristics of ductile mode chip formation in nanoscale cutting of brittle materials
Xiaoping Li, Minbo Cai, Kui Liu, Mustafizur Rahman
Abstract:A comprehensive study of the machining characteristics of nanoscale ductile mode cutting of brittle materials, covering the critical cutting conditions for the ductile mode of chip formation, cutting conditions for crack initiation in the chip formation zone, effect of the cutting edge radius, machined workpiece surface and subsurface damage, effect of ultrasonic vibration assistance, mechanism of nanoscale ductile mode chip formation, cutting forces, tool wear and dynamic hard particles in the chip formation zone. Systematic experiments for nanoscale cutting of a number of brittle materials, including tungsten carbide, silicon and glass, are conducted and Molecular Dynamics (MD) modelling and simulation for nanoscale cutting of monocrystalline silicon are carried out. The results are shown in detail in the paper.
Keywords: brittle materials; ductile mode; chip formation; nanomachining; molecular dynamics; machining characteristics; ultrasonic vibration; cutting edge effect; cutting forces; tool wear; dynamic hard particles; nanomanufacturing; abrasive technology; nanoscale cutting; crack initiation; modelling; simulation; monocrystalline silicon. link
|59 ||Application of ice-air jet blasting in treatment of sensitive surfaces
Krzysztof Kluz, Ernest S. Geski
Abstract:Application of water ice particles for precision cleaning was investigated experimentally. Several setups for ice particle generation and blasting were constructed. It was suggested that an efficient technology for formation of particles, in the range of 0.3–2.0 mm, involves ice crushing during water solidification. Freezing of water mist in a nitrogen bath constitutes the efficient technique to generate particles in the range of 15–25 microns. It was shown that ice-air jet containing larger particles is suitable for precision decontamination of metal, plastic, electronic and electromechanical parts, while the micron size particles are appropriate for processing of substrates in biomedical and food industries.
Keywords: ice blasting; sensitive surfaces; dermatology; abrasive technology; ice-air jet blasting; precision cleaning; ice particle generation; precision decontamination; substrate processing; metals; plastics; electronics; electromechanical parts; biomedical industry; food industry. link
|78 ||Grinding characteristics of engineering ceramics in high speed regime
Han Huang, Ling Yin
Abstract:Summarizes the high speed grinding characteristics of engineering ceramics. The performance in high speed grinding was compared with that of conventional speed grinding. Normal and tangential grinding forces and Acoustic Emission (AE) energy were measured to characterise the material removal characteristics of five polycrystalline ceramics. It was found that the microstructure and properties of the ceramic materials have significant influence on the removal and formation of their ground surfaces. Experimental results also demonstrated that grinding-induced vibration and coolant supply in high speed grinding of engineering ceramics are critical factors for achieving a satisfactory grinding performance.
Keywords: high speed grinding; engineering ceramics; grindability; microstructure; surface damage; abrasive technology; grinding forces; acoustic emission; material removal; polycrystalline ceramics; vibration; coolant supply; grinding performance. link
|94||Fabrication and evaluation for extremely thin Si wafer
Libo Zhou, Bahman Soltani Hosseini, Tatsuya Tsuruga, Jun Shimizu, Hiroshi Eda, Sumio Kamiya, Hisao Iwase, Yoshiaki Tashiro
Abstract:Grinding process on the Si wafer develops subsurface damage, which remarkably degrades deflective strength of the wafer and constitutes a barrier against producing a thin wafer for low-profile packaging. In this paper, the authors propose a new index for evaluation of the Degree of Subsurface Damage (DSD). Requiring no costly instrument, the new index is easily calculated via the external geometry of the ground wafer. With the new index, it is able to quantitatively evaluate the subsurface damage introduced by different processes (or wheel) and to estimate the minimally achievable thickness of the wafer by each process. Also, a novel fixed abrasive process of Chemo-Mechanical Grinding (CMG) has been proposed for stress relief. All results indicate that the subsurface damage after CMG is nearly zero.
Keywords: thin silicon wafers; subsurface damage index; residual stress; damaged layer depth; fixed abrasive process; abrasive technology; chemo-mechanical grinding; CMG. link
|106 ||Design and implementation of an intelligent grinding assistant system
Michael N. Morgan, Rui Cai, Andrea Guidotti, David R. Allanson, J.L. Moruzzi, W. Brain Rowe
Abstract:In modern competitive manufacturing industry, machining processes are expected to deliver products with high accuracy and assured surface integrity, using shorter cycle times with reduced operator intervention and increased flexibility. To meet such demands, the trend towards increased use of machine intelligence in machining systems and operations is clear and unlikely to be revised. This paper describes the structure, content and relations employed in a fully integrated intelligent grinding system for adaptive controlled cycle optimisation, thermal damage avoidance, dressing interval optimisation and data retention. This system, termed: 'Intelligent Grinding Assistant' (IGA©) is a unique, robust and versatile software system with embedded links and protocols for communication with the Computer Numerical Control (CNC) and instrumentation of a grinding machine. The IGA© was evaluated and implemented on a commercially available production machine and had its international launch in September 2005. The CNC, machine tool instrumentation, process monitoring and data analysis systems, Profibus link, and control strategies all constituted the IGA© system. Grinding performance was monitored and assessed in real time. An intelligent database was also developed to support the IGA© in the provision of optimised and/or safe starting cycle data to the operator/adaptive system and in the selective retention of data. Importantly, the IGA© has been designed and implemented in a way to ensure that an operator can readily use the system and achieve process improvement without recourse to extensive training.
Keywords: intelligent grinding; grinding assistant; artificial intelligence; adaptive control; thermal model; grinding kinematics; abrasive technology; optimisation; dressing interval; data retention; CNC grinding; machine tool instrumentation; process monitoring; data analysis. link
|136 ||Electrolytic conditioning of resin-metal-bonded diamond grinding wheels
Nobuhito Yoshihara, Mingxia Ma, Jiwang Yan, Tsunemoto Kuriyagawa
Abstract:Recently, high form accuracy and smooth surface are two important requirements in manufacturing of optical parts. It is quite difficult to meet these two demands at the same time. To achieve a high form accuracy, a grinding wheel must have a hard body. On the other hand, to achieve a good finish the surface of the grinding wheel must be soft. As a result, the grinding wheel is required to have such antithetical characteristics. To give a grinding wheel both of these characters, electrolytic conditioning is proposed in this paper. When this conditioning technique is used for dressing a resin-metal-bonded grinding wheel, only a thin layer on the grinding wheel surface will become soft, while the wheel body remains hard. Consequently, high form accuracy and smooth surfaces can be achieved using electrolytic conditioned grinding wheels.
Keywords: electrolytic conditioning; resin-metal bonded grinding wheels; precision grinding; optical parts; diamond grinding wheels; abrasive technology; grinding accuracy; smooth surfaces; surface roughness. link