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Öğe Effect of fiber set-up and density on mechanical behavior of robotic 3D-printed composites(Ice Publishing, 2022) İpekçi, Ahmet; Ekici, BulentThe further development of composite manufacturing methods is characterized by the progress of their mechanical properties which are widely used in many applications as automotive, aerospace, and marine industries. The automated composite production techniques are as follows: automatic tape layering, automatic fiber placement, and filament winding methods used in many industries. Photopolymerized composites and their additive manufacturing methods are promising with new advances in technology. This method for printing continuous fiber-reinforced plastic composite parts by a six-axis industrial robotic arm is based on fused deposition modeling technology. The objective of this work is to obtain a better understanding of the mechanical properties of robotic three-dimensional printed photopolymer resin continuous fiberglass-reinforced composites (CFGRCs) as a function of different printing speeds (10, 20 and 30mm/s), fiber densities (45, 55 and 65%), and fiber orientations (0, 0/90 and +/- 45 degrees). This work infers that mechanical properties are significantly affected by the fiber density and fiber orientation of CFGRC. With this method, approximately 300MPa tensile strength can be obtained and structurally preferred instead of ferrous materials in many areas.Öğe Experimental and Statistical Analysis of the Effect of Process Parameters on Mechanical Properties of 3D Printed Copper Reinforced Composite Samples(Chinese Soc Mechanical Engineers, 2022) Kam, Menderes; İpekçi, AhmetThe effects of 3D printing process parameters on mechanical properties of three-dimensional (3D) printing copper reinforced Polylactic acid (PLA) composite samples were analyzed as experimentally and statistically. In this context, tests were carried out with orthogonal array Taguchi method. Control factors were determined by using the Taguchi method for optimum mechanical properties. Two different filament materials (PLA and PLA+20% Copper Reinforced Composite), three different filling structures (Octogram spiral - Os, Archimedian cords - Ac, and 3D Honeycomb - Hc), and three different occupancy rates (10, 30, and 50%) were determined. The results showed that significant improvements in mechanical properties of PLA+20% copper reinforced composite samples were observed. According to the regression equations, optimum mechanical properties were found to be as 29.277MPa at tensile strength, 3.503% at percentage elongation, 3.458kJ/m(2) at izod impact values. Mechanical properties can be improved by using appropriate 3D printing process parameters. Occupancy rate and filling structure show a similar relationship for tensile strength and izod impact values. Hc filling structure can be selected for products which strength property is important. Os filling structure can be preferred for products when elongation and damping properties are required.Öğe Experimental investigation and optimization of machining parameters of deep cryogenically treated and tempered steels in electrical discharge machining process(Sage Publications Ltd, 2022) Kam, Menderes; İpekçi, Ahmet; Argun, KudbeddinElectrical Discharge Machining (EDM) is commonly used as non-traditional manufacturing methods for geometrically complex shaped or hardened materials that are extremely difficult-to-machine with traditional machining processes. In this experimental study, investigations were carried out on the machining of Conventional Heat Treated three different deep cryogenically treated and tempering processes (DCT&T) of AISI 4140 steels in EDM process. The process parameter such as discharge current (9, 16, 23, and 30 A), pulse on time (120, 180, 240, 300 mu s) and pulse off time (12, 18, 24, and 30 mu s) were investigated and the output responses like surface roughness, electrode wear ratio, material removal rate, and machining time were explored. Experiments were conducted using L-16 orthogonal array in EDM machining process. The data obtained from experiments were analyzed. As a result, determination of discharge current (30 Amps), pulse off time (12 to 18 mu s), pulse on time (180 to 240 mu s) and deep cryogenically treatment with 24 h and 48 h holding time as the optimum machining processing parameters for tempered steels to be subjected to DCT&T process. As a result of multi-criteria optimization, it is suitable for best surface quality and fast material removal rate.Öğe Experimental investigation of vibration damping capabilities of 3D printed metal/polymer composite sleeve bearings(Sage Publications Ltd, 2022) Kam, Menderes; Saruhan, Hamit; İpekçi, AhmetAdditive Manufacturing (AM) method enables to produce products easily, cheaply and quickly with more complex geometry compared to traditional production methods. In this context; Fused Deposition Modeling (FDM) is a widely used for AM method that requires a large number of process parameters. In this study, it is aimed to experimentally investigate the damping capabilities of the metal/polymer composite sleeve bearings printed using FDM. A total of 54 pieces (27 pairs) were printed from composite filaments such as nine pairs for each of PLA, PLA + 20% Bronze, and PLA + 20% Copper metal/polymer with different filling structures (Octogram spiral, Archimedian chords, and 3D Honey comb) and different occupancy rates (10, 30, and 50%), respectively. The experiments were carried out using the shaft-bearing system under the same operating conditions at a rotational speed of 900 revolution per minute (rpm), and vibration data was collected from the rotating shaft with proxy probes. Rotating shaft position is very important to determine journal position in bearing for understanding deterioration in the bearing. Bode and Orbit plots are used to detect the level of deterioration in the bearing. The value of bearing to shaft clearence can vary widely depending on application. Since the bearings were heavily loaded, they were compressed by radial load caused large clearence. The results showed that compressed bearing had significant influence on the stability of rotating shaft system and significant differences in damping capabilities of composite sleeve bearings with different filling structures and occupancy rate. Increasing occupancy rate decreases the vibration amplitude values in copper-reinforced sleeve bearing but increases in bronze-reinforced sleeve bearing. From the microstructure analysis, it has been observed that the vibration absorbation capability is better due to the more homogeneous distribution of the copper reinforced bearings than the bronze reinforced bearings. Also, vibration absorption capability of sleeve bearings with 3D Honeycomb filling structure is increased significantly proportion to the occupancy rate.Öğe Farklı Doldurma Şekillerinin Üç Boyutlu Yazıcılarda Üretilen Ürünlerin Mukavemetine Etkisi(2019) Kam, Menderes; Kam, Menderes; İpekçi, AhmetBu çalışmada, farklı doldurma şekillerinin Ergiyik Depolayarak Modelleme (Fused Deposition Modelling -FDM) yöntemi ile imal edilen ürünlerin mukavemetine etkisi deneysel olarak incelenmiştir. Çalışmada filamentmalzeme olarak PET-G (Polyethylene Terephthalate Glycol) kullanılmış ve farklı doldurma şekillerinde(Rectilinear, Grid, Triangular, Wiggle, Fast honeycomb, Full honeycomb), doluluk oranı (%30), işleme hızı(4200 mm/dak), nozul çapı (0,40 mm), nozul sıcaklığı (230 ºC), katman kalınlığı (0,20 mm) olmak üzere ISO527-2 standardına uygun ürünler imal edilmiştir. Bu numunelerin çekme mukavemetlerini incelemek için çekmetestleri gerçekleştirilmiş ve testlerden elde edilen sonuçlar karşılaştırılmıştır. Sonuçlar yazdırma şekillerinin ürünmukavemeti üzerinde önemli etkisi olduğunu göstermiştir. Rectilinear doldurma şeklinde imal edilen ürünlerdeelde edilen mukavemet değerleri diğer doldurma şekillerine göre yaklaşık % 15 daha yüksek çıkmıştır. Ayrıca,Full honeycomb doldurma şeklinin diğer doldurma şekillerine göre daha fazla uzama gösterdiği görülmüştür.Öğe FDM Yöntemi ile Üretilen Kovan Yatakların Titreşimi Sönümleme Kabiliyetlerinin Deneysel Analizi(2022) Kam, Menderes; Saruhan, Hamit; İpekçi, AhmetBu çalışmada, Ergiyik Depolayarak Modelleme (Fused Deposition Modelling - FDM) yöntemi ile üretilen kovan yatakların desteklediği milin titreşimlere karşı sönümleme kabiliyetleri deneysel olarak analiz edilmiştir. Çalışmada, PA12 (Nylon) filament malzeme kullanılarak farklı doldurma şekillerinde (Honeycomb, 3D Honeycomb, Gyroid, Hilbert curve, Archimed cords) ve doluluk oranlarında (% 10, 30 ve 50) toplam 30 adet kovan yatak üretilmiştir. Kovan yatakları analiz etmek için mil-yatak sisteminde aynı çalışma şartlarında 900 dev/dak mil dönme hızında deneysel çalışma gerçekleştirilmiş, kovan yatakların desteklerine bağlanan ivmeölçerler ile titreşim verileri toplanmıştır. Elde edilen sonuçlara göre, kovan yatakların titreşimi sönümleme kabiliyetlerinde önemli farklılıklar olduğu ve genel olarak doluluk oranları arttıkça titreşim genlik değerlerinin daha düşük olduğu görülmüştür .Öğe Investigation the Effect of 3d Printer System Vibrations on Surface Roughness of the Printed Products(2019) Kam, Menderes; Saruhan, Hamit; İpekçi, AhmetAdditive Manufacturing (AM), widely known as three-dimensional (3D) printing, is the process that a product isfabricated layer by layer in Cartesian coordinate system. Fused Deposition Modelling (FDM) is the most used AMprocess for functional rapid prototyping and products reduces the time and material involved in manufacturing. Thepurpose of this study is to investigate the effects of 3D printer system vibrations on the surface roughness offabricated products. Polyethyletherphthalate Glycol (PET-G) is used as material for fabrication. Six different fillingstructures - Rectilinear, Grid, Triangular, Wiggle, Fast Honeycomb, and Full Honeycomb - were used and for eachstructure two different top - two and three - layers implemented. A total of 12 samples specimens were fabricated.The results showed that using Full Honeycomb filling structure with three top layers is more suitable for surfaceroughness compare to the others filling structure used. It can be concluded that the vibration of 3D printer systemconsidering type of filling structure and number of top layers have a significant effect on surface quality of productÖğe INVESTIGATION THE EFFECTS OF 3D PRINTER SYSTEM VIBRATIONS ON MECHANICAL PROPERTIES OF THE PRINTED PRODUCTS(Yildiz Technical Univ, 2018) Kam, Menderes; Saruhan, Hamit; İpekçi, AhmetIn recent years, three-dimensional (3D) printing is attracting widespread interest due to functional rapid prototyping and products by reducing the time and material involved in process. Most of 3D printer users focus on mechanical properties of products neglecting vibration characteristics of printer system effects on products. The aim of this study is to investigate the effects of 3D printer system vibrations on mechanical properties of printed products. Fused Deposition Modeling (FDM) technology which is one of most used additive manufacturing process was used to print test samples and Polyethyletherphthalate Glycol (PET-G) was used as material for printing. Vibration measurements were taking for eighteen printed test samples. Vibrations data were measured from 3D printer movement in three axes (x, y, and z) by accelerometers. The processing parameters were selected as occupancy rate, filling structures orientation, and processing speed. The samples in rectilinear filling structure with occupancy rate of 50 % having different orientations (45 degrees by 45 degrees and 60 degrees by 30 degrees) and processing speeds (3600, 3900, and 4200 mm/min). Tensile test was used to test mechanical properties of test samples. The findings have shown that induced vibration has significant impact on mechanical properties which can be used to control the mechanical properties in terms of tensile stress and elongation of printed products during mass printing. Results showed that vibration amplitude values for orientations of 60 degrees by 30 degrees and processing speed 3600 mm/min are much lower compared to the other test samples. While tensile strength increases about % 5 when orientation is 45 degrees by 45 degrees with 3600 mm/min processing speed. From result obtained, it can be said that orientation of the product has a significant effect on the response of the printer system in terms of vibrations.Öğe Surface Roughness Performance of Cu Electrode on Hardened AISI 4140 Steels in EDM Process(Chinese Soc Mechanical Engineers, 2022) İpekçi, Ahmet; Kam, Menderes; Argun, KudbeddinElectrical Discharge Machining (EDM) is widely used unusual manufacturing methods due to the fact that requirement of cutting, brittle, hard and complex geometry. In this context, high-alloy and hardened steels used as mold material which is desired wearing resistance from the materials. The desired long-life criteria can also be achieved in many steel materials by cooling process. In this experimental study, surface roughness performance of Cu electrode in EDM process of hardened AISI 4140 steels was investigated. Discharge current, pulse duration, waiting period were determined as EDM processing parameters and two separate experiments were carried out on materials with different heat treatment processes. As a result of the experimental study, the surface roughness values were measured on machined workpiece surfaces and average surface roughness values were determined. It has been observed that the EDM processing parameters have variable effects on the surface roughness in heat treated workpieces. The results also show that EDM processing becomes more difficult and the surface quality decreases when AISI 4140 materials, which are cooled for a certain period of time, are subjected to tempering heat treatment.Öğe Taguchi optimization of fused deposition modeling process parameters on mechanical characteristics of PLA plus filament material(Sharif Univ Technology, 2022) Kam, Menderes; İpekçi, Ahmet; Şengül, O.This study attempts to investigate the effect of Fused Deposition Modeling (FDM) process parameters on mechanical characteristics with Taguchi optimization method. Three different FDM process parameters including filling structures (rectilinear, triangular, and full honeycomb), occupancy rates (10, 30, and 50%), and table orientation (0, 60, and -45 degrees) were specified as variable parameters for experiments. Other parameters kept fixed for each tensile and izod impact test samples were printed in line with the ISO 527-Type IV and ISO 180-Type I standards. The results found tensile strength and izod impact values to be directly proportional to the occupancy rate. The difference between the estimation model and the results of experiments did not exceed the maximum value of 1.8%. Thus, by using the equations derived from this optimization, printing parameters can be determined for the desired tensile strength and izod impact values. By improving the material properties using modified PLA+ filament material as observed in the results, it is possible to provide support for researchers, design engineers, and manufacturer to optimize raw-material usage and margin. (C) 2022 Sharif University of Technology. All rights reserved.
