Surface and porous recast layer analysis in µ-EDM of MWCNT-Al2O3 composites. Issue 5 (4th April 2019)

• Record Type: Journal Article
• Authors: Singh, Meinam Annebushan; Rajbongshi, Sanjib Kr; Sarma, Deba Kumar; Hanzel, Ondrej; Sedláček, Jaroslav; Šajgalík, Pavol
• Is Part Of: Materials and manufacturing processes. Volume 34:Issue 5(2019)
• Page Start: 567
• Page End: 579
• Publication Date: 2019-04-04
• Subjects: µ-EDM -- MWCNT -- alumina -- porous -- recast -- layer -- spalling -- MRR; Manufacturing processes -- Periodicals; Materials -- Periodicals; Manufactured Materials; 670.5
• DOI: 10.1080/10426914.2019.1566617
• Languages: English
• ISSNs: 1042-6914

Abstract

ABSTRACT: Machining of ceramic materials has been a major challenge owing to high hardness and brittleness. The reinforcement of a conducting filler allows permissible machining in electrical discharge machining (EDM) process. The current effort analyses the impact of multi-walled carbon nanotubes (MWCNT) of concentrations of 2.5 and 5 vol. %, as conducting filler towards machinability of alumina composites in µ-EDM process. The influence of tool materials and its rotation are closely analyzed. A successful machining process is observed in both the two composites, with a higher material removal rate (MRR) in 5 vol. % MWCNTs. When the tool starts to rotate at 750 rpm, an increment of around 60–65% is observed in MRR for both the two composites. Similarly, the surface roughness (Ra ) decreases by a factor of 20−25%. The brass tool is observed to yield better machining capabilities due to the frequent initiation of sparks. A highly porous machined surface is observed in both the two composites. This scenario depicts the spalling effect as more dominant than melting-evaporation effect. The extent of porous recast layer on the drilled edges is found to reduce with increasing the speed of tool rotation.