Emerging Trends in Mechatronics

Mechatronics is a multidisciplinary branch of engineering combining mechanical, electrical and electronics, control and automation, and computer engineering fields. The main research task of mechatronics is design, control, and optimization of advanced devices, products, and hybrid systems utilizing the concepts found in all these fields. The purpose of this special issue is to help better understand how mechatronics will impact on the practice and research of developing advanced techniques to model, control, and optimize complex systems. The special issue presents recent advances in mechatronics and related technologies. The selected topics give an overview of the state of the art and present new research results and prospects for the future development of the interdisciplinary field of mechatronic systems

Integration of an electrical discharge machining module onto a reconfigurable machine tool

Electrical Discharge Machining (EDM) is a non-contact manufacturing process in which material is removed from a metal workpiece by high frequency electrical pulses produced between an electrode and the workpiece. EDM machines are usually stand-alone devices, and are quite expensive. The objective of this research was to integrate an EDM machine and an existing reconfigurable CNC machine tool, using a modular approach, to enable conventional milling and EDM to be conducted in a co-ordinated fashion on the same machine tool

Development of an electrochemical micromachining (μECM) machine

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.Electrochemical machining (ECM) and especially electrochemical micromachining (μECM) became an attractive area of research due to the fact that this process does not create any defective layer after machining and that there is a growing demand for better surface integrity on different micro applications such as microfluidics systems and stressfree drilled holes in the automotive and aerospace sectors. Electrochemical machining is considered as a non-conventional machining process based on the phenomenon of electrolysis. This process requires maintaining a small gap - the interelectrode gap (IEG) - between the anode (workpiece) and the cathode (tool-electrode) in order to achieve acceptable machining results (i.e. accuracy, high aspect ratio with appropriate material removal rate and efficiency). This work presents the design of a next generation μECM machine for the automotive, aerospace, medical and metrology sectors. It has 3 axes of motion (X, Y and Z) and a spindle allowing the tool-electrode to rotate during machining. The linear slides for each axis use air bearings with linear DC brushless motors and 2nmresolution encoders for ultra-precise motion. The control system is based on the Power PMAC motion controller from Delta Tau. The electrolyte tank is located at the rear of the machine and allows the electrolyte to be changed quickly. A pulse power supply unit (PSU) and a special control algorithm have been implemented. The pulse power supply provides not only ultra-short pulses (50ns), but also plus and minus biases as well as a polarity switching functionality. It fulfils the requirements of tool preparation with reversed ECM on the machine. Moreover, the PSU is equipped with an ultrafast over current protection which prevents the tool-electrode from being damaged in case of short-circuits. Two different process control algorithms were made: one is fuzzy logic based and the other is adapting the feed rate according to the position and time at which short-circuits were detected. The developed machine is capable of drilling micro holes in hard-to-machine materials but also machine micro-styli and micro-needles for the metrology (micro CMM) and medical sectors. This work also presents drilling trials performed with the machine with an orbiting tool. Machining experiments were also carried out using electrolytes made of a combination of HCl and NaNO aqueous solutions. The developed machine was used to fabricate micro tools out of 170μm WC-Co alloy shafts via micro electrochemical turning and drill deep holes via μECM in disks made of 18NiCr6 alloy. Results suggest that this process can be used for industrial applications for hard-to-machine materials. The author also suggests that the developed machine can be used to manufacture micro-probes and micro-tools for metrology and micro-manufacturing purposes.Brunel University European Commissio

Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Master of Science

thesisTechnological advancements have created a demand for ever more complex components with extremely small features, high aspect ratios, and tight tolerances. Components are also being made from harder materials, which are more difficult to produce with traditional machining methods. Electric discharge machining (EDM) offers a manufacturing method that addresses these issues. Micro electric discharge milling is a powerful method that rotates the electrode and enables the cutting of complex 3-D pockets with standard electrodes. In order to meet some of the challenges in the micro manufacturing industry, an micro electric discharge milling spindle has been designed. This design uses a standard industrial collet, is capable of loading a large variety of electrode sizes and shapes, and incorporates optimal dielectric flushing. The spindle design offers injection flushing through the electrode and side flushing for the use of solid electrodes. This spindle design also offers the unique feature of variable flushing pressure. The spindle varies the injection pressure automatically to maintain a constant flow rate of dielectric fluid through the electrode as the electrode becomes shorter. The spindle is also capable of automatically feeding and fixturing the electrode as it wears down. The addition of a C-axis gives the spindle the unique ability to rotationally orient the tool. When the C-axis ability of the spindle is used in conjunction with wire electric discharge grinding, the machine is given the ability to produce a large variety of electrode shapes with extremely high aspect ratios and small features. This spindle design offers an economical versatile and compact solution to micro-electric discharge milling and can be easily placed into a CNC machine platform for accurate creation of complex features. The electrode fixturing range, variable dielectric pressure, and C-axis capabilities of this design are unique to this design and are not offered on the current market

Development of localized electrochemical deposition process for the fabrication of on-machine micro-EDM electrode

Ph.DDOCTOR OF PHILOSOPH

Response surface methodology of Die-Sink-Electro-Discharge machined surfaces

The performance of most manufacturing processes depends on numerous parameters and their interactions. Most of the time, selection of an appropriate set of machining parameters is done based on experience, trial and error or both. Electro-discharge machining (EDM) process is complicated and random in nature. The large number of parameters and the inherent complexity of removal mechanism taking place in EDM make it even more difficult to select machining conditions for optimal performance. The objective of this study is to provide information on the relationships between the key input variables and resultant surface roughness and to develop a response model for surface roughness optimization utilizing factorial designs, direction of steepest descent method and response surface methodology (RSM). Experiments were setup and executed to understand the individual and combined impact of factors that included the following input variables: gap voltage, depth of penetration, electrode type, and average current and pulse duration. Six iterations were executed in the direction of steepest descent for minimization of surface roughness. Pulse duration and average current have been shown to have significant effect on surface roughness. Depth of penetration was found to be insignificant and was eliminated in the subsequent experiments. Graphite electrode gave better surface finish than copper electrode at given factor level combination. The results shows that graphite electrode can be used in finishing operation while achieving the unprecedented surface quality that was only attainable with copper electrode in such operations. The best surface roughness 0.96um Ra was achieved. Response surface model based on a central composite experimental design was established to give better idea about the relationship between significant parameters, their interactions and surface finish. A higher order model is developed that can relate process inputs to response. The results obtained may be used to recommend process setting to improve process robustness and to get the desired surface roughness

An investigation and analysis of Process Parameters for EDM Drilling machine using Taguchi method

Not availabl

Machining of silicon wafers with an abrasive water jet cutter

This thesis consists of a study of the effects of abrasive water jet cutting on brittle silicon substrates. In total, 26 different cuts were made in a single crystal silicon substrate with an abrasive water jet cutter under different conditions of water flow, water pressure, and abrasive flow rate. These cuts were analyzed for surface roughness, and microstructure. The roughness measurements were compared in order to determine the best possible cutting conditions. The cut with the best roughness of 0.000170 inches was obtained under cutting conditions of 30 KSI water pressure, 1 inch/minute cutting speed, and an abrasive flow rate of 56 grams/minute. Other trends in the data show the optimum cutting speed to be between 1 and 2 inches/ minute. The water pressure of 30 KSI achieved better results than the 50 KSI presures under similar cutting conditions . At both 50KSI and 30 KSI, low abrasive flow rates result in better roughness values

Effect of water on electrical properties of Refined, Bleached, and Deodorized Palm Oil (RBDPO) as electrical insulating material

This paper describes the properties of refined, bleached, deodorized palm oil (RBDPO) as having the potential to be used as insulating liquid. There are several important properties such as electrical breakdown, dielectric dissipation factor, specific gravity, flash point, viscosity and pour point of RBDPO that was measured and compared to commercial mineral oil which is largely in current use as insulating liquid in power transformers. Experimental results of the electrical properties revealed that the average breakdown voltage of the RBDPO sample, without the addition of water at room temperature, is 13.368 kV. The result also revealed that due to effect of water, the breakdown voltage is lower than that of commercial mineral oil (Hyrax). However, the flash point and the pour point of RBDPO is very high compared to mineral oil thus giving it advantageous possibility to be used safely as insulating liquid. The results showed that RBDPO is greatly influenced by water, causing the breakdown voltage to decrease and the dissipation factor to increase; this is attributable to the high amounts of dissolved water