http://bura.brunel.ac.uk/handle/2438/230 2013-05-25T12:48:32Z 2013-05-25T12:48:32Z Afsharizand, Behnood http://bura.brunel.ac.uk/handle/2438/7414 2013-05-03T09:38:18Z 2012-01-01T00:00:00Z

Title: Investigation on quantitative assessment of energy consumption and the associated sustainability performance of CNC milling machines Authors: Afsharizand, Behnood Abstract: The increasing trend of energy prices increment and more and tighter environmental legislation, has led to manufacturing industry and enterprises paying more attention to investigation of more prominent energy/resource efficient production methods, quantitative analysis on energy consumption in manufacturing systems and corresponding timely decision makings. This is further evidenced and supported by the development of latest ISO standards such as ISO 14000, ISO 20140, ISO/TC 39/SC 2, N1760 and ISO 14955 for this cause. Therefore, developing a comprehensive methodological approach for quantitative analysis of energy consumptions and the associated sustainability aspects of CNC machines and operations is the key driver for this research, albeit incorporating its implementation and application perspectives on shopfloor machining operations is the predominant goal as well. The research presented consists of two inter-related parts. The first part discusses the development of the systematic integrated ERWC approach used for the modelling and simulation tenacities in CNC machines and machining operations by taking account of energy consumption (E), resource utilization (R) and waste resulted in production (W), and collectively the resultant carbon footprint (C). The ERWC modelling and analysis is explored in details with support of the MATLAB-based simulations developed and relevant case carried out. The second part of the research is focused on evaluation of the methodological approach by design of a special testing workpiece and the well-designed CNC machining experiments. The experiments are carried out on the Bridgeport 3-axis CNC milling machine, so the maximum output power of the machine can be determined using the designed testing workpiece and appropriate testing procedures. In the experiments, the milling machine is opted with the clamped power logger for power data-acquisition. The results are used to further validate the model, approach and simulations developed. The contributions to knowledge are largely raised from developing the integrated ERWC modelling approach, innovative design of the testing workpiece, and their implementation perspectives on the 3-axis CNC milling machine, as supported with original research thoughts and exploration. Description: This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University.

2012-01-01T00:00:00Z Jiang, Jiangshan http://bura.brunel.ac.uk/handle/2438/7351 2013-04-15T10:37:23Z 2012-01-01T00:00:00Z

Title: Sustainable Manufacturing - A study of the business context and eco-efficiency practices in Chinese microelectronics firms Authors: Jiang, Jiangshan Abstract: Sustainable manufacturing is the implementation of sustainable standards in the Manufacture, Assembly, Disassembly and End-of-life (MADE) of the manufacturing process. The significance of environmental protection and sustainable development directly cause more and more organizations and firms to take sustainable criteria into account in their manufacturing and management systems. China is a developing country, with the largest population in the world and the greatest development pace over the last few decades. The rising awareness of environmental problems and the increasing needs of sustainable design are demanding particular sustainable standards research for China. This thesis aims to examine the sustainable design standards in China and make recommendations for a sustainable plan for the microelectronic industry based on research. Both quantitative and qualitative methods are used in this research. This research is based on a field survey in Beijing, Tianjin and Dongguan City of Guangdong. Interviews and questionnaire research methods are also included. This research found sustainable design standards in China are influenced by economic regime, public factors and environment protection concepts. The Government is short of feedback while firms and public have difficulty representing their own point of view –to build the communication and control system may be the first thing needed. Only 13.33% of the surveyed companies have official written sustainable design regulations. The significant economic, humanistic and political diversity of different areas in China require highly flexible and practical standards. Description: This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University.

2012-01-01T00:00:00Z Wang, C Au, YHJ http://bura.brunel.ac.uk/handle/2438/7224 2013-02-27T11:07:22Z 2012-01-01T00:00:00Z

Title: Comparative performance of squeeze film air journal bearings made of aluminium and copper Authors: Wang, C; Au, YHJ Abstract: Two tubular squeeze film journal bearings, made from Al 2024 T3 and Cu C101, were excited by driving the single-layer piezoelectric actuators at a 75-V AC with a 75-V DC offset. The input excitation frequencies were coincident with the 13th modal frequency, at 16.32 and 12.18 kHz for the respective Al and Cu bearings, in order to produce a ‘triangular’ modal shape. The paper also provided a CFX model, used to solve the Reynolds equation and the equation of motion, to explain the squeeze film effect of an oscillating plate with pressure end leakage. The dynamic characteristics of both bearings were studied in ANSYS and then validated by experiments with respect to their squeeze film thickness and load-carrying capacity. It was observed that whilst both bearings did levitate a load when excited at mode 13, the Al bearing showed a better floating performance than Cu bearing. This is due to the fact that the Al bearing had a higher modal frequency and a greater amplitude response than the Cu bearing. Description: This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. Copyright @ 2012 The Authors - The article can be accessed from the links below.

2012-01-01T00:00:00Z Wu, Tao http://bura.brunel.ac.uk/handle/2438/7211 2013-03-04T12:00:12Z 2012-01-01T00:00:00Z

Title: Tooling performance in micro milling: Modelling, simulation and experimental study Authors: Wu, Tao Abstract: With the continuing trend towards miniaturization, micro milling plays an increasingly important role in fabrication of freeform and high-accuracy micro parts or components directly and cost-effectively. The technology is in kinematics scaled down from the conventional milling, however, existing knowledge and experiences are limited and comprehensive studies on the micro tooling performance are essential and much needed particularly for the process planning and optimization. The cutting performance of micro tools is largely dependent on the dynamic performance of machine tools, tooling characteristics, work material properties and process conditions, and the latter three aspects will be focused in the study. The state of the art of micro milling technology with respect to the tooling performance has been critically reviewed, together with modelling work for performance prediction as well as metrology and instrumentation for the performance characterization. A novel 3D finite element method taking into account the geometry of a micro tool, including the tool diameter, rake angle, relief angle, cutting edge radius and helix angle, has been proposed for modelling and simulation of the micro milling process. Validation through well-designed micro milling trials demonstrates that the approach is capable of characterizing the milling process effectively. With the support of FEM simulation developed, the tooling geometrical effects, including those from helix angle, rake angle and cutting edge radius with influences on cutting forces, tool stresses, tool temperatures, milling chip formation and temperatures have been comprehensively studied and compared for potential micro tool design and optimization purposes. In an effort to prolong the tool life and enhance the tooling efficiency, DLC and NCD coatings have been deposited on micro end mills by PE-CVD and HF-CVD processes respectively. Corresponding cutting performance of these coated tools have been assessed and compared with those of WC micro tools in both dry and wet cutting conditions so as for better understanding of the coating influence on micro tools. Furthermore, the cutting characteristics of the DLC coated and uncoated tools have been analysed through verified plane-strain simulations. The effects of coating friction coefficient, coating thickness and UCT have been determined and evaluated by design of simulation method. Mechanical, chemical and physical properties of a work material have a direct influence on its micro-machinability. Five most common engineering materials including Al 6061-T6, C101, AISI 1045, 304 and P20, have been experimentally investigated and their micro milling behaviours in terms of the cutting forces, tool wear, surface roughness, and micro-burr formation have been compared and characterized. Feed rate, cutting speed and axial depth of cut constitute the complete set of process variables and they have significant effects on the tooling performance. Fundamental understanding of their influences is essential for production engineers to determine optimum cutting parameters so as to achieve the maximum extension of the tool life. 3D FE-based simulations have been carried out to predict the process variable effects on the cutting forces, tool stresses, tool temperatures as well as micro milling chip formation and temperatures. Furthermore, experimental approach has been adopted for the surface roughness characterization. Suggestions on selecting practical cutting variables have been provided in light of the results obtained. Conclusions with respect to the holistic investigation on the tooling performance in micro milling have been drawn based on the research objectives achieved. Recommendations for future work have been pointed out particularly for further future research in the research area. Description: This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.

2012-01-01T00:00:00Z