WEDM Manufacturing Method for Noncircular Gears, Using CAD/CAM Software

Noncircular gears are used in several technological applications in order to enhance the performance of different mechanical instruments (flow meters, bikes, internal combustion engines, etc.), in order to unify speed in assembly lines and in research. Noncircular gears are typically manufactured by shaving: milling each tooth or by generation. This requires controlling the geometric and kinematic variables in the process. In this research, a method to manufacture elliptical and oval gears using wire electro-discharge machining (WEDM) is presented. This is a continuous procedure, and its performance is not inferior to the previously mentioned methods. Mathematical models for manufacturing elliptical and oval gears are presented, simulations are carried out, and this method is implemented in a WEDM machine, obtaining two pairs of elliptical and oval gears. This method could be useful in the manufacturing of injection moulds or custom-made metallic gears. Finally, a discussion using bibliographic references is presented about the surface finish and the consequences of using WEDM in comparison to other shaving methods which do not involve a material phase change

Mass Optimization of Gears

The paper deals with the mass optimization of gear pairs. The proposed material science based selection strategy uses an extended version of Ashby model, where the minimum value of mass as function of material parameters and density can be calculated. Comparative analyses have proved that applying the method proposed, various gear materials can be classified and ranked. It could be concluded that case or induction hardened steels and titanium alloys with appropriate surface treatment are the best solutions for high quality gear materials. The presented relationships for material parameters and geometry of gears help empirical or heuristic selection of proper materials

Recent developments in sustainable manufacturing of gears: a review

Abstract: Environment awareness is of the utmost importance to all socially responsible manufacturers. To be competitive on a global scale manufacturing needs to be aligned with various strict environmental regulations. The manufacturing industry at large is striving to improve productivity and product quality while maintaining a clean and sustainable environment. This can only be achieved by adopting sustainable techniques of manufacturing which include minimizing the number of manufacturing steps by employing advanced and alternative methods, environment-friendly lubricants and lubrication techniques while machining, reducing wastage, active waste management and minimizing energy consumption etc. Gear manufacturing industries, the major service providers to all other industrial and manufacturing segments are also focusing on to implement the techniques targeting overall sustainability. Some of the recent developments to achieve sustainability in gear manufacturing can be summarized as reducing the use of mineral-based cutting fluids by employing alternative lubrication techniques i.e. minimum quantity lubrication (MQL) and dry machining, material saving, waste reduction, minimizing energy consumption and maintaining economic efficiency by reducing the number of gear manufacturing stages (eliminating the necessity of finishing processes) by utilizing advanced methods such as gear rolling and wire electric-discharge machining (WEDM), and finally increasing productivity by minimizing tool wear at high gear cutting speeds through the use of alternative tool materials and coatings. This paper reviews and amasses the current state of technology for sustainable manufacturing of gears and also recommends ways to improve the productivity and quality while simultaneously ensuring environmental sustainability

Predictive modelling and parametric optimization of minimum quantity lubrication assisted hobbing process

Abstract: This paper focuses on parametric analysis, modelling, and parametric optimization of minimum quantity lubrication assisted hobbing (MQLAH) using environment friendly lubricant for manufacturing superior quality spur gears. Influences of hob cutter speed, axial feed, lubricant flow rate, air pressure and nozzle angle on the deviations in total profile, total lead, total pitch and radial runout and flank surface roughness parameters were studied by conducting 46 experiments using Box-Behnken method of response surface methodology. Results revealed that effect of air pressure is negligible but other parameters have significant impact on the considered responses. Back propagation neural network (BPNN) model was developed to predict microgeometry deviations and flank surface roughness values of the MQLAH manufactured spur gears. The BPNN predicted results found to be very closely agreeing with the corresponding experimental results with mean square error as 0.0063. Real-coded genetic algorithm (RCGA) was used for parametric optimization of MQLAH process to simultaneous minimization of microgeometry deviations and flank surface roughness. Standardized values of the optimized parameters were used to conduct confirmation experiment whose results had very good closeness with RCGA computed and BPNN predicted values and produced spur gear of superior quality. This study proves MQLAH to be a potential sustainable replacement of conventional flood lubrication assisted hobbing for manufacturing cylindrical gears of better quality

Proceedings of the 4th International Conference on Innovations in Automation and Mechatronics Engineering (ICIAME2018)

The Mechatronics Department (Accredited by National Board of Accreditation, New Delhi, India) of the G H Patel College of Engineering and Technology, Gujarat, India arranged the 4th International Conference on Innovations in Automation and Mechatronics Engineering 2018, (ICIAME 2018) on 2-3 February 2018. The papers presented during the conference were based on Automation, Optimization, Computer Aided Design and Manufacturing, Nanotechnology, Solar Energy etc and are featured in this book

Tool Wear Characterisation and Parameter Optimisation in Micro-manufacturing Processes

Increases in demand for miniaturised static parts, actuators and devices has presented challenges in machining; requiring fast advancement in the field. This work examines two processes: Wire Electrical Discharge Machining (WEDM), and micro-milling. While very different processes, both of these have in common the fact that their behaviour and the phenomena seen differ from those seen in conventional subtractive machining. Capability of machine tools has increased to allow highly intricate parts to be produced, but there are significant challenges in achieving excellent surface finish, geometrical accuracy and tool life. WEDM is appropriate for cutting complex shapes without long set-up times, but cutting very thin workpieces represents difficulties in achieving stable machining, while the process results in a recast layer which can affect wear and transmission. This work focuses on investigating optimal parameters for machining micro-gears. This has traditionally been challenging because the limited area for spark generation between wire and workpiece leads to unstable machining, resulting in poor machining rate and surface finish. Investigations into significant machining parameters have taken place, followed by a feasibility study cutting brass gears of 0.3 mm thickness. The results indicate that the depth of the recast layer can be minimised while maintaining an acceptable Material Removal Rate (MRR), by considering gear geometry. This work suggests that WEDM is a valuable tool in prototyping miniature gears. Micro-milling allows small, accurate parts to be produced, but micro-tools wear quickly and unpredictably, therefore tool wear is difficult to measure. This results in a high rate of tool changes and reduced productivity. A protocol for measuring tool wear has been produced to allow a common method to be used across research institutes. This presents a method for analysing and reporting micro-mill tool wear which will allow transfer between research institutions and industry, to extend tool life and improving process efficiency. This protocol has then been used to investigate tool coatings on the micro scale, and compare the tribological processes seen on micro-tools to their macro counterparts. This work has resulted in extended tool life for industrial micro-mills and has been applied to industrial situations

Development of Sustainable Methodologies in Product Design, Manufacturing and Education

The influence of sustainability in product design and manufacturing processes can be considered from two different points of view: the design of sustainable products and the sustainable manufacturing of those products. Of course, a basic assumption for the aforementioned elements to be realized is the appropriate training and education for sustainability of the young designers and engineers. In this research, sustainability has been applied to many fields, including design, manufacturing and education acting as an umbrella which covers all the three elements and has as the main target to promote sustainability. In today’s world, in which a considerable number of contrasting signs reveal that our society is currently contributing to the planet’s collapse, a new kind of engineer is needed, an engineer who is fully aware of what is going on in society and who has the skills to deal with aspects of sustainability. According to the literature review on the state-of-the-art associated to the subject, in the current research were developed tools and methodologies for the promotion of sustainability aspects that are related to product design, manufacturing and education. Product DesignThe research work was based on a framework, which was built according to the direct communication between users and designers. There is a need for a cultural transformation, which can be focused on consumers and promote the needed behavioural change. Moreover there is a need for a cultural transformation on the role of designers and engineers to the product design process, with an aim to address sustainability as well as emerging priorities from societal to environmental challenges. New tools and methodologies were generated, in order to promote sustainability to the users/citizens bringing them inside to the product design process, giving them the opportunity to be a vital part of it. ManufacturingSustainable manufacturing faces new challenges for developing predictive models and optimization techniques in order to produce more products. The first part of the current is related to the drilling process and cutting tool technology. The creation of mathematical models focused on maximization of productivity and cost reduction by identifying crucial parameters and processes influencing manufacturing effectiveness. The second part of the current research is associated to the development of models used by CAD/ CAM that allow a rapid improvement and an efficient design and manufacture.EducationThe third aspect of the research is associated with the education related to sustainability. The engineering students should develop sustainability competences such as critical thinking, systemic thinking, obtaining values consistent with the sustainability paradigm, except of just taking a course on sustainability, focus on the technological role of sustainability. Focus on that the current research was based on sustainable characteristics such as a) remote control freeware applications, b) share of valuable resources, c) distance learning methodology and d) active participation of the students.<br /

Wireless capsule endoscope for targeted drug delivery

The diagnosis and treatment of pathologies of the gastrointestinal (GI) tract are performed routinely by gastroenterologists using endoscopes and colonoscopes, however the small intestinal tract is beyond the reach of these conventional systems. Attempts have been made to access the small intestines with wireless capsule endoscopes (WCE). These pill-sized cameras take pictures of the intestinal wall and then relay them back for evaluation. This practice enables the detection and diagnosis of pathologies of the GI tract such as Crohn's disease, small intestinal tumours such as lymphoma and small intestinal cancer. The problems with these systems are that they have limited diagnostic capabilities and they do not offer the ability to perform therapy to the affected areas leaving only the options of administering large quantities of drugs or surgical intervention. To address the issue of administering therapy in the small intestinal tract this thesis presents an active swallowable microrobotic platform which has novel functionality enabling the microrobot to treat pathologies through a targeted drug delivery system. This thesis first reviews the state-of-the-art in WCE through the evaluation of current and past literature. A review of current practises such as flexible sigmoidoscopy, virtual colonoscopy and wireless capsule endoscopy are presented. The following sections review the state-of-the-art in methods of resisting peristalsis, drug targeting systems and drug delivery. A review of actuators is presented, in the context of WCE, with a view to evaluate their acceptability in adding functionality to current WCEs. The thesis presents a novel biologically-inspired holding mechanism which overcomes the issue of resisting natural peristalsis in the GI tract. An analysis of the two components of peristaltic force, circumferential and longitudinal peristaltic contractions, are presented to ensure correct functionality of the holding mechanism. A detailed analysis of the motorised method employed to deploy the expanding mechanism is described and a 5:1 scale prototype is presented which characterises the gearbox and validates the holding mechanism. The functionality of WCE is further extended by the inclusion of a novel targeting mechanism capable of delivering a metered dose of medication to a target site of interest in the GI tract. A solution to the problem of positioning a needle within a 360 degree envelope, operating the needle and safely retracting the needle in the GI tract is discussed. A comprehensive analysis of the mechanism to manoeuvre the needle is presented and validation of the mechanism is demonstrated through the evaluation of scale prototypes. Finally a drug delivery system is presented which can expel a 1 ml dose of medication, stored onboard the capsule, into the subcutaneous tissue of the GI tract wall. An analysis of the force required to expel the medication in a set period of time is presented and the design and analysis of a variable pitch conical compression spring which will be used to deliver the medication is discussed. A thermo mechanical trigger mechanism is presented which will be employed to release the compressed conical spring. Experimental results using 1:1 scale prototype parts validate the performance of the mechanisms.Open Acces

Research & Technology 2005

This report selectively summarizes NASA Glenn Research Center's research and technology accomplishments for fiscal year 2005. It comprises 126 short articles submitted by the staff scientists and engineers. The report is organized into three major sections: Programs and Projects, Research and Technology, and Engineering and Technical Services. A table of contents and an author index have been developed to assist readers in finding articles of special interest. This report is not intended to be a comprehensive summary of all the research and technology work done over the past fiscal year. Most of the work is reported in Glenn-published technical reports, journal articles, and presentations prepared by Glenn staff and contractors. In addition, university grants have enabled faculty members and graduate students to engage in sponsored research that is reported at technical meetings or in journal articles. For each article in this report, a Glenn contact person has been identified, and where possible, a reference document is listed so that additional information can be easily obtained. The diversity of topics attests to the breadth of research and technology being pursued and to the skill mix of the staff that makes it possible. For more information, visit Glenn's Web site at http://www.nasa.gov/glenn/. This document is available online (http://www.grc.nasa.gov/WWW/RT/). For publicly available reports, visit the Glenn Technical Report Server (http://gltrs.grc.nasa.gov)

An investigation of machining induced residual stresses on Grade 4 and 5 titanium alloys

M.Ing. (Mechanical Engineering)Titanium and its alloys have the potential to serve as a strategic economic driver of the South African economy. The manufacture and use of high strength, lightweight materials such as titanium alloys have become of great importance in the aerospace and biomedical industries over the past few decades. The manufacturing costs of titanium alloy components however, are considered high due to the poor machinability of the material. Furthermore, as with all metals during machining, surface residual stresses are induced into the material. These are of particular interest in the aerospace industry as they can be either detrimental or beneficial to the performance and fatigue life of materials. The aim of this investigation is therefore to examine the effect that machining parameters have on the magnitude, sign and distribution of residual stresses induced in Grade 4 and 5 titanium alloys during high performance machining (turning). The effect of these machining parameters is investigated by residual stress measurements conducted with X-ray diffraction and grain structure analysis of the machined surfaces by optical microscopy. Results show that cutting speed and depth of cut have a significant effect on the residual stresses. At low cutting speeds, the surface residual stresses are largely compressive, becoming more tensile with an increase in cutting speed. An increase in depth of cut also introduces more compressive residual stresses into the material. The microstructural analysis of the alloys shows that grain deformation decreases with an increase in cutting speed and cutting depth