Effect of chromium (cr) particle size and span-20 surfactant on Aisi d2 hardened steel using electrical discharge machining
Existing manufacturing industries are facing challenges from modern advanced materials such as composite, super alloys, and hardened steels, which are hard and difficult to machine and process. Since it is not suitable to use conventional machining of the hard material, non-conventional machining...
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| Format: | Thesis |
| Language: | English English English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/33/1/24p%20NOR%20AIN%20BT%20JAMIL%20HOSNI.pdf http://eprints.uthm.edu.my/33/2/NOR%20AIN%20BT%20JAMIL%20HOSNI%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/33/3/NOR%20AIN%20BT%20JAMIL%20HOSNI%20WATERMARK.pdf |
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| Summary: | Existing manufacturing industries are facing challenges from modern advanced
materials such as composite, super alloys, and hardened steels, which are hard and
difficult to machine and process. Since it is not suitable to use conventional machining
of the hard material, non-conventional machining such as electrical discharge machining
(EDM) is one of the ideal techniques in dealing with these materials. However, the
limitations of EDM will cause lower productivity and poor surface quality. Therefore,
Powder Mixed Electrical Discharge Machining (PMEDM) has emerged as one of the
advanced and innovative technique to eliminate the some of the disadvantages of EDM
method. The fine powder particles are added into the tank then the spark gap is filled up
with these additives particles. These electrically conductive powder particles reduce the
insulating strength of dielectric fluid and increase the spark gap distance between tool
electrode and workpiece, which due to this EDM process becomes more stable, thereby
improving the EDM efficiency and quality of the machined surface. This research
emphasizes the machining of AISI D2 hardened steel with EDM through adding both of
micro and nano chromium powder mixed and span-20 surfactant using copper tool
electrode. Then, machining productivity (i.e material removal rate (MRR), electrode
wear rate (EWR) and surface roughness (Ra) and surface characteristics were
investigated in terms of surface morphology, surface topography, recast layer thickness
(RL) and microhardness. It was indicated that the addition of micro-nano chromium
powder and span-20 surfactant to the dielectric notably enhanced the machining
efficiency and better surface quality. The highest improvement 35~46 % of MRR, 29~69
% of Ra and 42~54 % of RL were attained at combination of micro-nano chromium
powder and span-20 surfactant, respectively. There is no significant effect on EWR. For
this purpose, full factorial 32 design of experiments (DOE) was chosen which consists of
three levels of PMEDM parameters of chromium powder concentrations (Cp) and Span-
20 surfactant concentrations (Cs) for both micro and nano chromium powder. Response
Surface Methodology (RSM) was utilized for responses optimization and Central
Composite Design (CCD) was applied in designing the experiments to evaluate the
effects of PMEDM parameters to three responses, MRR, EWR and Ra. Thus, this is
clarify that the potential of addition of Cr powder and span-20 surfactant into dielectric
fluid ability to gives a notable potential to be utilized as one of innovative technique,
improving efficiency and better surface quality. |
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