Papers by Mohammad Rafighi
Materials Today: Proceedings
This study examined the machinability of GG25 gray cast iron with carbide inserts in the CNC mill... more This study examined the machinability of GG25 gray cast iron with carbide inserts in the CNC milling process. Cutting parameters were selected as feed rate, cutting speed, and depth of cut, while response variables were chosen as surface roughness, force, and power. The experimental design was made using Taguchi L27 full factorial array. The utilization of response surface methodology and analysis of variance was employed to assess the outcomes. Furthermore, ballbar tests were conducted to optimize the performance of the CNC milling machine without the necessity of chip removal, thereby enhancing the overall efficiency of the machining process. According to the study's findings, surface roughness was measured in the range of 1.29–4.27 µm, cutting force was determined in the range of 14–262 N, and power was calculated from 1116 to 4115 W. Based on the results, the feed rate and depth of cut had the most influence on the output characteristics. The effect of feed rate on the surface roughness, cutting force, and power is 82.37 %, 18.68 %, and 27.24 %, respectively. The impact of cutting depth on the Ra, Force, and Power is 11.15 %, 68.82 %, and 49.34 %, respectively. The experimental data show that power and force increase as the feed rate, depth of cut, and cutting speed rise, while feed rate is the only dominant factor on the surface roughness. The obtained regression equations show that the output parameters could be predicted with at least 91 % accuracy. Based on the response optimizer, the optimum cutting parameters for machining the GG25 gray cast iron with carbide insert are calculated as Vc: 300 m/min, f: 2000 mm/min, and a: 0.1 mm.
Sustainability
This study investigates the performance comparison of machining of UNS S32750 super-duplex stainl... more This study investigates the performance comparison of machining of UNS S32750 super-duplex stainless steel under single- and double-nozzle pulse mode minimum quantity lubrication (MQL) conditions. The pulse mode MQL system delivers lubricant pulses at specific intervals. The Taguchi L9 design, with three factors and their three levels, was taken to perform the CNC turning experiments under both single-nozzle and double-nozzle MQL cooling environments. The surface roughness (Ra), tool-flank wear (VB), tool-flank temperature (Tf), power consumption (Pc), and material removal rate (MRR) are evaluated and compared as performance indicators. In comparison to single-nozzle MQL, the responses of Ra, VB, Tf, and Pc were found to be decreased by 11.16%, 21.24%, 7.07%, and 3.16% under double-nozzle conditions, respectively, whereas MRR was found to be 18.37% higher under double-nozzle conditions. The MQL pulse time was found to be an important variable that affects Ra, VB, Tf, and MRR signifi...
Canadian Metallurgical Quarterly, Mar 31, 2022
Aluminium-silicon carbide reinforced metal matrix (Al/SiC-MMC) composite materials has tremendous... more Aluminium-silicon carbide reinforced metal matrix (Al/SiC-MMC) composite materials has tremendous application in automobile, aerospace and other industries due to their excellent properties. The machining of these materials are needed to obtain a near-nett shape. In the present work, an attempt has been made to model the surface roughness in machining of Al/SiC-MMC composites through Response Surface Methodology (RSM). Three factors central composite design is employed for carrying out this work. Analysis of variance is used for checking the validity of the model. Optimum machining condition for minimising the surface roughness is determined using desirability function approach. The influences of different parameters in machining Al/SiC particulate composite have been analysed in detail.
Politeknik dergisi, Mar 15, 2022
❖ 1.2367 sıcak iş takım çeliğinin sert tornalanmaı / Hard turning of 1.2367 hot work tool steel ❖... more ❖ 1.2367 sıcak iş takım çeliğinin sert tornalanmaı / Hard turning of 1.2367 hot work tool steel ❖ Taguchi yöntemi kullanarak deney tasarımı / Employing Taguchi method for the design of experiment ❖ ANOVA ile en etkili parametrenin belirlenmesi / Determining the most effective parameter by ANOVA ❖ Kesme parametrelerinin optimizasyonu / Optimization of cutting parameters
Sustainability, Mar 10, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Bu çalışmanın amacı, yürüme engelliler için destekleyici bir cihazın tasarımı ve üretimidir. Düny... more Bu çalışmanın amacı, yürüme engelliler için destekleyici bir cihazın tasarımı ve üretimidir. Dünyada birçok insan felç ya da başka hastalıklardan dolayı yürüme engellidir. Yürüme engelliler için dünyada birçok destekleyici cihaz üretilmiştir ve her bir cihaz birbirinden farklıdır. Cihazlar içerisinde en yaygın olarak tekerlekli sandalyeler kullanılmaktadır. Bu projenin diğer projelerden en önemli farkı tekerleksiz olmasıdır. Bu nedenle bu cihaz engelliler için daha yararlı olacaktır. Projenin yapım aşamasında yürüme engelli bir vatandaştan yararlanıp ve onun hareket sırasında hangi tür sorunlarla karşılaştığı belirlenmiş ve çalışma ona göre şekillendirilmiştir. Cihazın en önemli kısmı bir insanın yürümesini simüle yapan kısmıdır. Örneğin: Kalça, bacak, diz, topuk gibi kısımların hareketleri simüle edilmiştir. Bu cihaz bel kısmından engelliye bağlanmış ve insanın yere tutunmasını sağlayan iskelet görevini görmüştür. Cihaz yürüme engellinin ayaklarına paralel olarak dış taraftan kemer...
Politeknik Dergisi, 2022
Bu çalışmada 1.2367 sertleştirilmiş (55 HRC) sıcak takım çeliğinin tornalanmasında farklı kesme p... more Bu çalışmada 1.2367 sertleştirilmiş (55 HRC) sıcak takım çeliğinin tornalanmasında farklı kesme parametrelerinin yüzey pürüzlülüğü (Ra) ve kesme kuvvetleri üzerindeki etkisi incelenmiştir. Bu deneysel çalışmada, deney tasarımı Taguchi metodu kullanılarak yapılmış ve kesme parametreleri olarak sabit talaş derinliği, üç farklı kesme hızı ve üç farklı ilerleme miktarı seçilmiştir. Kesme parametrelerinin yüzey pürüzlülüğü ve kesme kuvvetleri üzerindeki etkisi varyans analizi (ANOVA) yapılarak değerlendirilmiştir. Sonuçlara göre ilerleme hızındaki artışa bağlı olarak yüzey pürüzlülüğü değerinin arttığı görülmüştür. Kesme hızının ise yüzey pürüzlülük değeri üzerinde belirli bir etkisi görülmemiştir. Radyal kuvvet (Fx), teğetsel kuvvet (Fy) ve ilerleme kuvveti (Fz) üzerinde ise, en etkili parametrenin ilerleme hızı olduğu görülmüştür.
Metals
This experimental study presents the machinability comparison of TiCN-Al2O3-TiN, TiAlN-TiN, and T... more This experimental study presents the machinability comparison of TiCN-Al2O3-TiN, TiAlN-TiN, and TiAlSiN coated carbide inserts in hard turning AISI 4340 steel. The primary purpose of this research is to determine the most appropriate cutting inserts in turning hardened AISI 4340 (30–40 HRC) steel considering surface roughness (Ra), cutting sound (Cs), power consumption (P), radial force (Fx), tangential force (Fy), and feed force (Fz). To fulfill this objective, the turning experiments for each tool were executed based on the Taguchi L9 design. The comparative assessment of cutting tools revealed that the TiAlSiN coated tool exhibited superior performance compared to other tools. Machining with the TiCN-Al2O3-TiN coated tool showed 32.05% greater roughness than with the TiAlN-TiN coated tool, and 68.80% higher surface roughness than the TiAlSiN coated tool. The main novelty of this research is considering the cutting sound and power consumption as responses to select the most suitab...
Sustainability
Advances in developed and developing countries are more attributable to growth in industrial acti... more Advances in developed and developing countries are more attributable to growth in industrial activities that directly impact increasing energy demand. Energy availability has been inconsistent globally, necessitating energy storage (ES) for use as per requirement. Various energy storage technologies (ESTs) are available in mechanical, electrochemical, electrical, chemical, and thermal forms to fulfil the energy demand of a user as and when required. The factors responsible for making a commercially viable energy storage product are further being researched for an eco-friendly and optimal solution to store energy for a longer duration. Researchers are employing different strategies to evaluate the energy efficiency of storage technologies. This paper uses the VIKOR technique to analyze ESTs while assigning objective weights with the entropy weights method based on identified energy performance indicators and ranking them according to their commercialization viability. The method help...
Coatings
Dry hard-turning is a vital manufacturing method for machining hardened steel due to its low cost... more Dry hard-turning is a vital manufacturing method for machining hardened steel due to its low cost, high machining efficiency, and green environmental protection. This study aims to analyze the effect of various machining parameters on cutting forces and surface roughness by employing RSM and ANOVA. In addition, multi-objective optimization (Grey Relation Analysis: GRA) is performed to determine the optimum machining parameters. Dry hard-turning tests were carried out on AISI 4140 steel (50 HRC) using coated carbide and CBN inserts with different nose radii. The results show that the cutting force components are greatly affected by the cutting depth and cutting speed for both cutting inserts. As the level of cutting depth and cutting speed rise, the cutting forces also increase. However, the feed rate was the main factor in surface roughness. A low feed rate and high cutting speed lead to good surface quality. According to the results, CBN inserts exhibited better performance compare...
Lubricants, Jan 30, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
DergiPark (Istanbul University), Mar 1, 2017
Talaş kaldırma sürecinde, izlenmeyen takım aşınması parça bozukluğunu ve hurda sayısını artırmakl... more Talaş kaldırma sürecinde, izlenmeyen takım aşınması parça bozukluğunu ve hurda sayısını artırmakla beraber, aynı zamanda takımın kırılmasına ve pahalı CNC takım tezgâhlarında yüksek hasarlara sebep olmaktadır. Aşınma oranına dayalı, takıma verilmesi gereken takım aşınma telafi değerlerinin doğru tespiti, takımda oluşan aşınmanın iş parçasının boyutlarında ve yüzey kalitesinde kabul edilemez bir sınıra geleceği anın bilinmesi ve kırılma olmadan önce yeni bir takımla değiştirilmesi için talaş kaldırma sürecini izleyen bir otomasyon takip sistemi gereklilik olmuştur. Bu çalışmada, talaşlı imalatta bir otomasyon sistemi kurmak ve yan yüzey takım aşınma miktarını anlık tahmin etmek için kuvvet ve titreşim algılayıcıları kullanılarak bir bulanık mantık sistemi tasarlanmıştır. Sistemin kurulması için, talaş kaldırma parametreleri, kesme kuvveti ve titreşim değişkenleri girdi olarak ve takım aşınma miktarı çıktı olarak bulanık mantık sistemine verilmiş. Taguchi metodu kullanılarak deney tasarımı yapılmıştır. Ölçülen ve tahmin edilen sonuçlar, takım aşınmasının tespiti için, bulanık mantık metodunun güvenilir olduğunu göstermiştir.
DergiPark (Istanbul University), Jan 30, 2017
Bu çalışmada, takım durumunun izlemesi için son yıllarda yapılan çalışmalar incelenmiş ve talaş k... more Bu çalışmada, takım durumunun izlemesi için son yıllarda yapılan çalışmalar incelenmiş ve talaş kaldırma işlemlerinin izlenmesinde etki sağlayan parametreler tartışılmıştır. Son yıllardaki çalışmalar göz önüne alınarak, takım durumunun izlenmesi için etkili değişkenler, sinyal işleme metotları, veri seçilmesi ve izleme sınırlıkları tartışılarak tüm avantajları ve dezavantajları incelenmiştir. Ayrıca bu makalede takım izleme modelinin genelliğinin geliştirilmesi için kullanılan ve en çok tanınan deney tasarım metotlarından bahsedilmiştir. Son olarak, takım durumunun tahmini için kullanılan tüm karar destek sistemleri bahsedilerek gerekli karşılaştırmalar yapılmıştır. Buna ek olarak, en güvenilir karar destek sistemleri açık bir şekilde anlatılmış ve farklı deney tasarımı prosedürüne uygun olan yöntemler bahsedilmiştir.
Surface Review and Letters
Ti–6Al–4V ELI alloy is one of the most familiar materials for orthopedic implants, aeronautical p... more Ti–6Al–4V ELI alloy is one of the most familiar materials for orthopedic implants, aeronautical parts, marine components, oil and gas production equipment, and cryogenic vessel applications. Therefore, its appropriate quality of finishing is highly essential for these applications. But the characteristics like lower modulus of elasticity, lesser thermal conductivity, and high chemical sensitivity placed it in the categories of difficult-to-cut metal alloys. Also, tooling cost is one of the prime issues in the machining of this alloy. Therefore, this research is more inclined to use a low-budget uncoated carbide tool in turning the Ti–6Al–4V ELI alloy. Also, the selection of suitable levels of machining parameters is highly indispensable to get the appropriate surface finish with a low tooling cost. So, the [Formula: see text] experimental design is utilized to check the performances of the uncoated carbide tool in the turning tests. The performance indexes like surface roughness (Ra...
Surface Review and Letters
In this work, initially, the raw AISI 52100 bearing steel was heat-treated to obtain 40 HRC and 4... more In this work, initially, the raw AISI 52100 bearing steel was heat-treated to obtain 40 HRC and 45 HRC workpiece hardness. Further, dry hard turning tests were carried out to study the impact of workpiece hardness ([Formula: see text]), cutting speed ([Formula: see text]), feed ([Formula: see text]), and depth of cut ([Formula: see text]) on cutting force (Fy), surface roughness (Ra), and sound intensity (SI). An economically viable PVD-coated carbide turning tool was implemented for the experiments. The Taguchi L[Formula: see text] (2–3 mixed level) design of experiments was employed to establish the experimental plan in order to save the experimental time, energy, and cost of manufacturing. The results disclosed that the feed has the prevailing consequence on surface roughness with a 96.3% contribution, while it also significantly affects the cutting force with a contribution of 13.8%. The contribution of cutting speed and workpiece hardness on the cutting force was reported as 48...
Artikülatör; diş hekimliğinde alt (mandibular) ve üst (maksiler) çenelerin birbirine göre konumun... more Artikülatör; diş hekimliğinde alt (mandibular) ve üst (maksiler) çenelerin birbirine göre konumunu belirlemek için kullanılan manuel ve mekanik bir cihazdır. Bu cihaz, alt veya üst çeneye ait şekil, yapı ve uyum bozukluklarının düzeltilmesinde fonksiyonel bir özelliğe sahiptir. Ayrıca, hareketli ve sabit protez restorasyonları, ortodontik apareylerin yapımı ve ortognatik cerrahi vakaların tedavisinde de kullanılmaktadır. Ortognatik cerrahide alt veya üst çenenin kafa kaidesine göre konumu değiştirilir. Böylece, ortognatik cerrahi yapılacak hastalarda, önce alt ve üst çenenin ölçüsü alınır ve çene modelleri kapanış mumu ile tespit edilir, sonra bu modeller alçı yardımıyla artikülatöre sabitlenir. Bu yöntemin uygulanışında hekim, çenelere ameliyat sırasında yaptırılmasını düşünülen hareketlere sefalometrik teknikleri (röntgen yöntemleri vs.) kullanarak karar vermektedir. Artikülatöre alınmış olan çeneler, alçılı bölümden kesilerek serbestleştirmekte, planlanan hareketler yaptırılmakta...
Materials Testing
Recently, many applications have used austempered ductile iron due to its high hardness, strength... more Recently, many applications have used austempered ductile iron due to its high hardness, strength, toughness, and wear resistance. These superior properties make austempered ductile iron an alternative material to forged steels. However, machining of austempered ductile iron is challenging because of its high hardness and strength. In this study, machining operations were performed on the alloyed ductile iron workpiece to investigate the machinability of the material prior to the austempering process. This experimental study was carried out on EN 1.7131 alloy steel and alloyed ductile iron using single point carbide inserts under dry cutting conditions. A constant feed of 0.1 mm × rev-1, constant depth of cut of 1 mm, and variable cutting speeds were selected as input parameters, whereas tool life is considered as a response parameter. The tool life tests were accomplished considering flank wear as tool life criterion according to ISO 3685. The results of this study indicated that a...
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2022
Titanium alloys are widely used in various industries such as aerospace, petrochemical, marine, a... more Titanium alloys are widely used in various industries such as aerospace, petrochemical, marine, and biomedical due to their high corrosion resistance, high strength, good heat resistance, and lightweight. However, the low thermal conductivity of titanium alloys makes their machinability poor compared to steel alloys. Therefore, it is of great importance to evaluate the machinability of titanium alloys. This experimental study presents the effects of machining parameters on the machinability factors such as surface roughness, power consumption, cutting sound, and machining force in dry turning of Ti-6Al-4V titanium alloy using CBN inserts. Sound emission is a substantial factor for the operator’s safety during the turning process. High cutting sound is generated due to removing a large amount of material from the workpiece using different cutting tools. Since there are not many studies related to the cutting sound in machining processes, the attempt was made to investigate the effect...
Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering
Hardened AISI 4140 steel is widely used in automotive industries due to its high strength, high h... more Hardened AISI 4140 steel is widely used in automotive industries due to its high strength, high hardness, and good formability. It can be subjected to cryogenic treatments to increase wear resistance, increase the toughness and decrease the residual stress. Although many studies have been performed related to the machinability of AISI 4140 steel, the number of studies that considered four responses simultaneously are limited. In this study, the effects of cutting speeds, feed rates, and depths of cut on the vibration, motor current, machining noise, and surface roughness were investigated in turning hardened AISI 4140 steel using coated carbide insert under dry cutting conditions. Besides, the attempt was made to predict surface roughness based on machining noise, motor current, and chuck vibration during the turning process. Analysis of variance and response surface methods were carried out to analyze the experimental results and the prediction models were developed. The machining ...
Surface Review and Letters
Cryogenic treatments have been applied to enhance both wear and abrasion resistance for the cutti... more Cryogenic treatments have been applied to enhance both wear and abrasion resistance for the cutting inserts. Therefore, many investigations focused on the shallow and deep cryogenic treatments in terms of their performance on the machinability criteria. This paper presents a detailed analysis on machinability investigation of cryogenically treated hardened 4140 steel (55 HRC), and sustainability assessment in hard machining on finishing mode carried out at dry cutting regime. A series of machining trials have been performed under varied cutting conditions (feed, depth of cut and speed) following the L9 orthogonal array design experimental layout for analysis of various responses along with cost estimation in hard turning. Moreover, the machining parameters are optimized and mathematically formulated for the minimization of various responses using a multi-objective optimization method. Finally, considering the motivational idea of “Go green–Think green–Act green”, a unique novel appr...
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Papers by Mohammad Rafighi