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Hard turning is a turning process in which work pieces whose hardness ranges between 50and 70 HRC are machined by using single point cutting tools which have high hardness andwear resistance. The hard turning exhibits a uni ue behavior! which is di""erent thanconventiona turning operations. The application o" hard turning technology can be improved

by utili#ing advanced optimi#ation algorithms! which helps manu"acturers to make educated

decisions in the presence o" multiple ob$ectives that need to be satis"ied %&!'(. )igni"icantadvances have been seen in cutting tools and machine tools in recent years. Cutting

parameters may be speci"ied according to hardness o" materials and roughness o" the sur"aceo" a work piece. The advantages in machining materials with higher hardness are decreasingmachining costs! saving time! improving sur"ace uality! and eliminating o" de"ormities in

parts caused by temperature %*!+(.

,slan et al. %+(conducted an optimi#ation study by machining a hardened ,-)- +&+0 grade/* HRC steel on a lathe by using ,l'1* 2 TiC3 coated ceramic inserts. They determined

that ,l'1*4base ceramics are re uired "or cutting tools in machining hard steels during wear resistance and high hardness. They ensured optimi#ation in their experimental studies byusing the Taguchi method. The experimental parameters chosen were three di""erent cuttingspeeds! "eed rates and depths o" cut. 6lank wear 6 and sur"ace roughness were chosen ascriteria "or per"ormance. The obtained results were analy#ed by using variance analysis

,31 , . ,s a result! it was seen that the 6 value decreased as the cutting speed and thedepth o" cut increased8 however! it "irst decreased and then increased as the "eed rateincreased. 1n the other hand! the sur"ace roughness decreased as the cutting speed increased.-n contrast sur"ace roughness increased when the "eed rate increased.

9cun and ,slantas: %5( investigated the e""ects o" the cutting parameters on sur"aceroughness in hard turning. They examined machining per"ormance with respect to tool wear and sur"ace roughness in machining hardened ,-)- 5'&00 grade bearing steels with coatedcarbide cuttingtools. ;our di""erent cutting speeds! three di""erent "eedrates and two di""erentdepths o" cut were used during their experimental studies. ,s a result! they observed thatcarbide cutting tools were not suitable "or the hard turning process! especially at high cutting

parametric values.

(used the Taguchi method "or determining optimum cutting parameters.They machined )+5C steel work piece with carbide cutting tools. The cutting parameterschosen were cutting speed! "eed rate and depth o" cut. Taguchi?s signal@ noise ratio andvariance analysis were used to determine the e""ect o" the cutting parameters on tool li"e andsur"ace roughness. They obtained optimum cutting parameters as a result o" their studies.

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Ahang and Chen %B(experimented to optimi#e the sur"ace uality in a C3C drilling operationusing Taguchi design. The control "actors in their study were "eed rate! spindle speed! peck rate and tool type! while the noise "actors simulated were machine shop vibration and the

presence or absence o" magnetism in the work piece material. Through statistical analysis o" response variables and signal4to4noise ratios! the determined signi"icant "actors were the

spindle speed! tool type and peck rate! and the optimal combination o" cutting parameterswere selected. They veri"ied that the selected optimal combination through Taguchi designachieved the desired sur"ace roughness.

6hattacharya et al. %&0(investigated the e""ects o" cutting parameters on "inish and power consumption by employing Taguchi techni ues. Their results showed a signi"icant e""ect o" cutting speed on the sur"ace roughness and power consumption! while the other parametersdid not substantially a""ect the responses. There"ore! optimal cutting parameters wereobtained.

opac et al. %&&(considered cutting speed! cutting tool materials! "eed rate and depth o" cut ascutting parameters in machining C&5 D+ steel on a lathe. They used the Taguchi orthogonalarray o" E&/ '5 ! which has two levels and a degree o" "reedom o" &* in the experimentaldesign. The uality determinant o" FFthe smaller the better?? was used in calculating thesignal@noise ratio. -t was observed that the control parameter having the highest e""ect onsur"ace roughness is the cutting speed! and better sur"ace roughness values were obtained athigher cutting speeds.

):ahin %&'(compared the tool li"e o" C63 and ceramic inserts in turning hard steels usingthe Taguchi method. The e""ects o" cutting parameters on tool li"e were determined by usingorthogonal array! signal@noise ratio and variance analysis. He chose cutting speed! "eed rateand tool hardness as cutting parameters. ,s a result! it was concluded that the e""ects o" cutting speed! tool hardness and "eed rate on tool li"e were +&./*G! *'./>G and '5.''G!respectively.

,bu4)inna et al. %&*(investigated the e""ect o" the loading "rame sti""ness on the deadweight"orce machine@ loadcell interaction. -n order to per"orm the "inite element analysis e""iciently!they utili#ed the Taguchi techni ue! as this typically reduces the total re uired simulations.The validity o" the "inite element analysis was con"irmed through experiments.

The Taguchi method "or "inding out the optimal value o" sur"ace roughness under optimumcutting condition in turning )C ++0 alloy steel was applied by Thami#hmanii et al. %&+(.

They detected that the causes o" poor sur"ace "inish were machine tool vibrations and toolchattering whose e""ects were ignored "or analysis. The authors concluded that depth o" cutwas the only signi"icant "actor which contributed to the sur"ace roughness.

ilickap %&5(investigated the use o" the Taguchi method and the Response )ur"aceethodologies R) "or minimi#ing the burr height and the sur"ace roughness in drilling

,l47075. The Taguchi method! a power"ul tool to optimi#e design uality! was used to "indoptimal cutting parameters. The optimi#ation results showed that the combination o" lowcutting speed! low "eed rate and high point angle were necessary to minimi#e burr height. The

best results o" the sur"ace roughness were obtained at lower cutting speed and "eed rates andat higher point angles.

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