Material removal rate and surface roughness in electrical discharge machining of alumina /
Alumina (Al2O3), a non-conductive ceramic material can meet the needs of demand in many engineering applications. Especially in the application of biomedical field it is used due to its excellent physical and chemical properties. But due to high hardness and brittleness, Al2O3 cannot be machined by...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur :
Kulliyyah of Engineering, International Islamic University Malaysia,
2015
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| Subjects: | |
| Online Access: | http://studentrepo.iium.edu.my/handle/123456789/4968 |
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| Summary: | Alumina (Al2O3), a non-conductive ceramic material can meet the needs of demand in many engineering applications. Especially in the application of biomedical field it is used due to its excellent physical and chemical properties. But due to high hardness and brittleness, Al2O3 cannot be machined by conventional machining process. Electrical discharge machining (EDM) is a suitable process for machining conductive materials. EDM has been applied recently for structuring non-conductive Al2O3 ceramic with assisting electrode (AE) technique. However, the effect of parameters on the outputs in EDM of Al2O3 is not well studied. Therefore, in this research, models are developed for material removal rate (MRR), average surface roughness (Ra) and root mean square surface roughness (Rq) in EDM of Al2O3. These models are developed by an experimental study correlating three process parameters peak current (Ip), pulse-on time (Ton) and gap voltage (U). EDM of Al2O3 is conducted with copper (Cu) tool electrode and adhesive Cu foil as AE in kerosene dielectric fluid according to response surface methodology (RSM). The parametric investigation using design of experiment is done with central composite design (CCD). A quadratic model for MRR and two factor interaction models for both Ra and Rq are obtained. After developing the empirical models for the output responses with the three process parameters, multiple response optimization is done for maximum MRR and minimum Ra and Rq by using desirability function. The optimum values for MRR, Ra and Rq are found to be 0.078 mm3/min, 2.58 µm and 3.70 µm respectively at 1.1 A peak current, 6.0 µs pulse-on time and 14 V gap voltage. Confirmation experiments are done to validate and measure the accuracy of the models. The average percentage errors are found to be 7.2% for MRR, 5.5% for Ra and 6.9% for Rq. The errors are within the limit of prediction accuracy. The developed models can be used in selecting parameters for desired outputs in machining of precision parts and components from Al2O3 ceramic material. |
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| Physical Description: | xvii, 101 leaves : ill. ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 93-97). |