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  • [ X ]
    Öğe
    EVALUATION OF THE EFFECTS OF CUTTING PARAMETERS ON THE SURFACE ROUGHNESS DURING THE TURNING OF HADFIELD STEEL WITH RESPONSE SURFACE METHODOLOGY
    (2014) Ekici, Ergün; Uzun, Gültekin; Kıvak, Turgay
    Hadfield çeliği (X120Mn12) sahip olduğu mükemmel aşınma direncinden dolayı mühendislik uygulamalarında yaygın olarak kullanılmaktadır. Bu çalışmada Hadfield çeliğinin tornalanmasında kesme parametrelerinin yüzey pürüzlülüğü üzerindeki etkileri araştırılmıştır. Deneyler 80, 110, 140 m/dak kesme hızı, 0.2, 0.3, 0.4 mm/dev ilerleme ve 0.2, 0.4, 0.6 mm kesme derinliğinde kaplamalı karbür takımlar kullanılarak gerçekleştirilmiştir. Halfield çeliğinin işlenebilirliğinin değerlendirilmesinde yanıt yüzey yöntemi (RSM) kullanılarak bir model oluşturulmuştur. Kesme parametrelerinin yüzey pürüzlülüğü üzerindeki etkilerinin belirlenmesinde merkezi tümleşik tasarım (CCD) ve varyans analizi (ANOVA) kullanılmıştır. Deneysel çalışma sonrasında oluşturulan modelle, yüzey pürüzlülüğü üzerinde kesme parametrelerinden ilerlemenin % 90,28 katkı oranı ile en etkili parametre olduğu ortaya konulmuştur. İlerlemenin artmasıyla yüzey pürüzlülüğünün arttığı görülmüştür. Yüzey pürüzlülüğü üzerinde etki bakımından ilerlemeyi % 3,12 katkı oranı ile kesme hızı, % 1,7 katkı oranı ile de kesme derinliği takip etmiştir.
  • [ X ]
    Öğe
    Evaluation of the effects of drilling parameters, tool geometry and core material thickness on thrust force and delamination in the drilling of sandwich composites
    (World Scientific Publishing, 2021) Ekici, Ergün; Uzun, Gültekin; Altaş, Sedat
    This study examined the effects of drilling parameters, tool geometry, and core material thickness (CMT) on thrust force and the delamination factor in the drilling of sandwich composites. Aluminum honeycomb (10 and 15mm in thickness) was used as the core material, with carbon fiber-reinforced polymer (CFRP) as the top and bottom surfaces. In the drilling experiments, three different cutting speeds (60, 78 and 100 m/min) and two different feed rates (0.05 and 0.075 mm/rev) were used. Drills having a diameter of 6.35 mm and three different geometries (candlestick drills, twist drills and dagger drills) were used in the experiments. At the end of the experiments, thrust force was seen to increase with increased feed rate and CMT. Increased cutting speed generally decreased the thrust forces and the minimum thrust force was achieved with the 10 mm thick core material, 0.05 mm/rev feed rate and 100m/min cutting speed using the dagger drill. The delamination factor at the entrance area was very low when drilling the sandwich composites and there was no significant difference based on drilling parameters, tool geometry, or CMT. Tool geometry was the main effective factor on exit delamination, and the highest delamination occurred with the use of the candlestick drill. Although increased feed rate increased delamination with all tools, with the dagger drill, increased cutting speed led to a severe increase. Delamination, tearing, and uncut fiber formation were observed when images of the exit areas of the drilled holes were examined.
  • Küçük Resim
    Öğe
    Multi-Objective Optimization of Process Parameters for Drilling Fiber- Metal Laminate Using a Hybrid GRA-PCA Approach
    (Belgrade University, 2021) Ekici, Ergün; Motorcu, Ali Rıza; Uzun, Gültekin
    This study investigated the effects of drilling parameters and cutting tool coating conditions on the thrust force, surface roughness, and delamination factor in the drilling of fiber-reinforced carbon reinforced aluminum laminate (CARALL) composite, a commercial type of fibermetal laminate. Gray relational analysis (GRA) was used as a multiobjective optimization method to determine optimum processing parameters and principal component analysis (PCA) was used to determine the weights. According to the findings of this experimental study, the most effective control factors for the thrust force, surface roughnes, and delamination factor were the feed rate, tool coating conditioncutting speed interaction, and tool coating condition, with 93.87%, 66.504%, and 29.137% contribution rates, respectively. From the results of the GRA-PCA analysis, the optimum levels of the control factors were determined as 110 m/min cutting speed, 0.1 mm/rev feed rate, and the uncoated tool.