Experimental investigation for the optimization of the WEDM process parameters to obtain the minimum surface roughness of the Al 7075 aluminium alloy employed with a zinc-coated wire using RSM and GA
Eksperimentalna raziskava optimizacije procesnih parametrov žične erozije s cinkom oplaščene Cu žice za zagotovitev minimalne površinske hrapavosti Al zlitine 7075 z uporabo postopkov RSM in GA

J. Shanthi, M. Raman, T. Ramasamy
2019 Materiali in Tehnologije  
Wire Electrical Discharge Machining (WEDM) is widely used for machining conductive materials of intricate, complex and challenging shapes in the field of aerospace, die and mould making, automobile industries and the medical field. Proper selection of the WEDM process parameters can give good responses. Out of the various process responses, to achieve the minimum surface roughness is very difficult, due to arcing by the electrical discharge. The present investigation has been made to optimize
more » ... e process parameters of WEDM during machining the Al 7075 aluminium alloy with zinc-coated copper wire using the Response Surface Methodology (RSM). Four input process parameters of WEDM, i.e., Pulse On Time, Pulse Off Time, Wire Feed and Wire Tension, were chosen as the process variables to study the process performance and to obtain the minimum surface roughness. An analysis of variance (ANOVA) was carried out to study the effect of the process parameters on the surface roughness and a mathematical model was developed. The model has been verified and checked for adequacy. The best fit surface roughness (Ra) value predicted is 1.048 μm for a Pulse On (TON) value of 120 μsec, a Pulse Off (TOFF) value of 58 μsec, a Wire Feed (WF) of 3 m/min and a Wire Tension (WT) value of 9 gm. Furthermore, it is observed that with an increase in the pulse-on time the Surface Roughness also increases, and an increase in the pulse-off time and the wire tension, the Surface Roughness decreases. Wire Feed does not influence much on the Surface Roughness. @i~na erozija (WEDM; angl.: Wire Electrical Discharge Machining) se pogosto uporablja za obdelavo in rezanje kompleksno oblikovanih izdelkov, modelov in orodij iz prevodnih materialov v letalski, orodjarski, modelarski in avtomobilski industriji ter v zdravstvu. Pri tem postopku je zelo pomembna izbira ustreznih procesnih parametrov WEDM. Doseganje minimalne povr{inske hrapavosti reza je zelo zahtevno zaradi nastajajo~ega talilnega obloka med razelektrevanjem. Avtorji so optimizirali procesne parametre WEDM, ki uporablja s cinkom opla{~eno bakreno'ico med mehansko obdelavo Al zlitine 7075 z uporabo metodologije odgovora povr{ine (RSM, angl.: Response Surface Methodology). Izbrali so {tiri vhodne procesne parametre WEDM, in sicer:~as vklopa (TON) in izklopa (TOFF) elektri~nega impulza, hitrost dovajanja'ice WF in napetost'ice WT kot spremenljivke za {tudij vpliva procesa na zagotovitev minimalne hrapavosti. Z analizo variance (ANOVA) so raziskovali vpliv procesnih parametrov na povr{insko hrapavost in na njeni osnovi razvili matemati~ni model. Model so verificirali in preizkusili njegovo ustreznost. Najbolj{e ujemanje vrednosti za povr{insko hrapavost (Ra) je bilo 1,048 μm pri TON vrednosti 120 μsec, TOFF vrednosti 58 μsec, hitrosti dovajanja'ice WF 3 m/min ter napetosti'ice WT 9 mN/m. Avtorji ugotavljajo, da se je z nadaljnjim podalj{evanjem~asa TON pove~evala povr{inska hrapavost. S podalj{evanjem~asa TOFF in pove~evanjem napetosti'ice pa se je povr{inska hrapavost zmanj{evala. Hitrost dovajanja'ice ni pomembno vplivala na povr{insko hrapavost.
doi:10.17222/mit.2018.166 fatcat:amuc67npkza73hl7e635dbsbwe