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Öğe A comparative study on the microstructure, mechanical properties, wear and corrosion behaviors of SS 316 austenitic stainless steels manufactured by casting and WAAM technologies(Elsevier, 2023) Gürol, Uğur; Kocaman, Engin; Dilibal, Savaş; Koçak, MustafaReplacing the traditional casting method with wire arc additive manufacturing (WAAM) to produce complex shaped parts will lead to using cost-effective technology even for challenging engineering applications depending on their geometry and number of the parts to be produced. This work performed a comparative study on the stainless steel 316 parts manufactured by WAAM and sand casting to reveal the microstructural, mechanical, wear, and corrosion behaviors. The WAAM components were manufactured using three different cooling dwell times and compared in terms of microstructures with the as-cast and heat-treated cast parts to reveal the properties of the WAAM parts. It was concluded that WAAM is a viable engineering alternative to the casting technology. Results showed that the WAAM and cast parts revealed similar microstructures, including delta ferrite and austenite phases, but the cast parts had a coarser grain and lower amount of delta ferrite due to slower cooling during the solidification. The yield and tensile strength of WAAM parts showed an increasing trend with the increase in dwell time, and on average, their yield strength was similar to 1.5 times higher than in cast parts due to the smaller grains and more elevated delta-ferrite content resulting from rapid cooling. Furthermore, the greatest wear resistance was obtained in the cast parts after solution annealing heat treatment followed by water quenching. In contrast the highest corrosion resistance was obtained from WAAM parts produced using a dwell time of 120 sec. In conclusion, WAAM technology can be an excellent alternative to casting technology for producing stainless-steel parts with optimized process parameters.Öğe A novel design on polymeric material recycling technology(Eduem - Editora da Universidade Estadual de Maringa, 2021) Tanrıver, Kürşat; Dilibal, Savaş; Şahin, Haydar; Kentli, AykutThe necessity for recycling of wastes has increased nowadays and there are various solutions according to the types of wastes which are presented accordingly. By observing these solutions, the recycling system from the waste collection and separation system of the long-term disappearing of polymer waste to the additive manufacturing design stage has been indicated. Waste collection and separation systems have been reviewed and systems to be used effectively in the systematic way have been exemplified. Among four different separating systems which are with rotating, rail and fixed containers, fixed container four-sorting waste separation systems were chosen and developed as a mechatronic system design. The mechatronic system design is very prominent in order to create efficient and economical mechanisms in fixed-container four-sorting waste separation collection system (FCWS) applications. In addition, physical mechatronic system design (MSD), mechanical design, material selection, electrical electronic design sub-heading and cost analysis were made. In this study, the necessity and importance of the waste separation plants are revealed.Öğe Additively manufactured continuous processing reactor system for producing liquid-based pharmaceutical substances(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Khabiyev, Alibek; Dilibal, Savaş; Mussulmanbekova, Assel; Kanapiya, Magzhan; Kerimkulov, DaniyarIn this study, an AM-based continuous processing reactor system was designed, manufactured, and assembled on a laboratory scale for the generation of pharmaceutical substances with an improved process control. The developed AM-based (additively manufactured) continuous pharmaceutical reactor system for the synthesis of metronidazole derivatives aimed to optimize both the physical and the chemical processes with time savings. Using AM, we were able to build reactor subcomponents with complex designs and precise dimensions, which facilitated the precise control of the reaction parameters and reduced the amount of chemicals required compared to macroscale reactors. The assembly of the whole reactor system consisted of main reactor bodies, mixers, valves, heat exchangers, electrical motors, and a microcontroller system. The assembled reactor system revealed a continuous flow of reagents and ensured uniform mixing and reaction conditions, thereby increasing the process efficiency and product quality. Five metronidazole derivatives were synthesized via two continuous processes, involving metronidazole reduction and its subsequent reactions with terephthalic aldehyde and anthracen-9(10H)-one to form Schiff bases. The optimal conditions were determined as follows: compound A (72% yield, 120 min, 55 °C), compounds B and C (63% and 68% yield, respectively, 8 h, 65 °C), and compounds D and E (74% and 85% yield, respectively, 8 h, 45 °C).Öğe Additively manufactured custom soft gripper with embedded soft force sensors for an industrial robot(Korean Society for Precision Engineering, 2021) Dilibal, Savaş; Şahin, Haydar; Danquah, Josiah Owusu; Emon, Md Omar Faruk; Choi, Jae-WonSoft robotic grippers are required for power grasping of objects without inducing damage. Additive manufacturing can be used to produce custom-made grippers for industrial robots, in which soft joints and links are additively manufactured. In this study, a monoblock soft robotic gripper having three geometrically gradient fingers with soft sensors was designed and additively manufactured for the power grasping of spherical objects. The monoblock structure design reduces the number of components to be assembled for the soft gripper, and the gripper is designed with a single cavity to enable bending by the application of pneumatic pressure, which is required for the desired actuation. Finite element analysis (FEA) using a hyperelastic material model was performed to simulate the actuation. A material extrusion process using a thermoplastic polyurethane (TPU) was used to manufacture the designed gripper. Soft sensors were produced by a screen printing process that uses a flexible material and ionic liquids. The grasping capability of the manufactured gripper was experimentally evaluated by changing the pneumatic pressure (0-0.7 MPa) of the cavity. Experimental results show that the proposed monoblock gripper with integrated soft sensors successfully performed real-time grasp detection for power grasping.Öğe Anthropomorphic finger antagonistically actuated by SMA plates(IOP Publishing Ltd, 2015) Engeberg, Erik D.; Dilibal, Savaş; Vatani, Morteza; Choi, Jae-Won; Lavery, JohnMost robotic applications that contain shape memory alloy (SMA) actuators use the SMA in a linear or spring shape. In contrast, a novel robotic finger was designed in this paper using SMA plates that were thermomechanically trained to take the shape of a flexed human finger when Joule heated. This flexor actuator was placed in parallel with an extensor actuator that was designed to straighten when Joule heated. Thus, alternately heating and cooling the flexor and extensor actuators caused the finger to flex and extend. Three different NiTi based SMA plates were evaluated for their ability to apply forces to a rigid and compliant object. The best of these three SMAs was able to apply a maximum fingertip force of 9.01N on average. A 3D CAD model of a human finger was used to create a solid model for the mold of the finger covering skin. Using a 3D printer, inner and outer molds were fabricated to house the actuators and a position sensor, which were assembled using a multi-stage casting process. Next, a nonlinear antagonistic controller was developed using an outer position control loop with two inner MOSFET current control loops. Sine and square wave tracking experiments demonstrated minimal errors within the operational bounds of the finger. The ability of the finger to recover from unexpected disturbances was also shown along with the frequency response up to 7 rad s(-1). The closed loop bandwidth of the system was 6.4 rad s(-1) when operated intermittently and 1.8 rad s(-1) when operated continuously.Öğe Characterization of a low-alloy steel component produced with wire arc additive manufacturing process using metal-cored wire(Walter de Gruyter GmbH, 2022) Gürol, Uğur; Dilibal, Savaş; Turgut, Batuhan; Koçak, MustafaIn this study, a low-alloy steel component was manufactured using specially produced E70C-6M class of metal-cored welding wire according to AWS A5.18 standard for the WAAM process. The manufactured low-alloy steel component was first subjected to radiographic examination to detect any weld defect. Uniaxial tensile tests were conducted for the bottom, middle and upper regions. The micro-hardness tests were performed parallel to the deposition direction. The results show that microstructures varied from base metal to the face region of the WAAM component, including the bottom, middle and top sections. The bottom region showed lamellar structures; the middle and upper region presented equiaxed ferrite structure with a small amount of grain boundary pearlites and the face region displayed a mix of equiaxed and lamellar structures of ferrites. The yield and ultimate tensile strengths of the top, middle, and bottom regions exhibited similar results varying between 370 MPa and 490 MPa, respectively. In contrast, the top region showed an elongation value about 15% higher than other regions. Moreover, the yield and ultimate tensile strength for WAAM-produced component were found to be 14% and 24% lower than the multiple-pass all-weld metal of E70C-6M class of metal-cored wire.Öğe Characterization of energy dissipative cushions made of Ni-Ti shape memory alloy(IOP Publishing Ltd , 2022) Güllü, Ahmet; Danquah, Josiah Owusu; Dilibal, SavaşEarthquake-resistant design of structures requires dissipating seismic energy by deformations of structural members or additional fuse elements. Owing to its easy-to-produce, plug-and-play, high equivalent damping ratio, and large displacement capacity characteristics, energy dissipative steel cushions (SCs) were found to be an efficient candidate for this purpose. However, similar to other conventional metallic dampers, residual displacement after a strong shaking is the most notable drawback of the SCs. In this work, cushions produced from Ni-Ti shape memory alloy (SMA) are evaluated numerically by experimentally verified finite element models to assess their impact on the performance of earthquake-resistant structures. Furthermore, a reinforced concrete testing frame is retrofitted with energy dissipative steel and Ni-Ti cushions. Performance of the frames (e.g. dissipated energy by the cushions, hysteretic energy to input energy ratio, maximum drift, and residual drift) with different types of cushions are evaluated by nonlinear response history analyses. The numerical results showed that the SCs are effective to reduce peak responses, while Ni-Ti cushions are more favorable to reduce residual drifts and deformations. Hence, a hybrid system, employing the steel and SMA cushions together, is proposed to reach optimal seismic performance.Öğe Characterization of Ni-Ti alloy powders for use in additive manufacturing(Pleiades Publishing Inc, 2018) Altuğ Pedük, Gözde Sultan; Dilibal, Savaş; Harrysson, Ola; Özbek, Sunullah; West, HarveyAdditive manufacturing (AM) offers a fully integrated fabrication solution within many engineering applications. Particularly, it provides attractive processing alternatives for nickel-titanium (Ni-Ti) alloys to overcome traditional manufacturing challenges through layer by layer approach. Among powder-based additive manufacturing processes, the laser beam melting (LBM) and the electron beam melting (EBM) are two promising manufacturing methods for Ni-Ti shape memory alloys. In these methods, the physical characteristics of the powder used as raw material in the process have a significant effect on the powder transformation, deposition, and powder-beam interaction. Thus, the final manufactured material properties are highly affected by the properties of the powder particles. In this study, the Ni - Ti powder characteristics are investigated in terms of particle size, density, distribution and chemical properties using EDS, OM, and SEM analyses in order to determine their compatibility in the EBM process. The solidification microstructure, and after built microstructure are also examined for the gas atomized Ni-Ti powders.Öğe Comparison of the mechanical properties and drilling performance of the AISI 316 parts produced with casting, LPBF and WAAM(Springer Science and Business Media Deutschland GmbH, 2024) Kocaman, Engin; Köklü, Uğur; Morkavuk, Sezer; Coşkun, Mert; Koçar, Oğuz; Dilibal, Savaş; Gürol, UğurAISI 316 stainless steel parts are widely utilized in many industrial fields with a vast scope of applications. These steel parts, which are used in many fields, can be produced using different production methods, but the mechanical properties of the parts produced with different processes may be different, and the machinability characteristics will also be different. In this study, the drilling machinability characteristics of AISI 316 stainless steel parts manufactured via cast, LPBF and WAAM methods were experimentally investigated and compared considering thrust force generation, burr analysis and chip morphology. In order to clarify the differences in machinability behavior among the tested samples, the corresponding microstructure, microhardness and mechanical strength (yield strength, UTS and elongation) were also examined in detail. The experimental results showed the manufacturing method, and particularly cooling rate, significantly affecting the microstructure, mechanical response and further machinability characteristics; besides, due to higher cutting forces generation, the machinability of the parts produced by additive manufacturing methods (LPBF and WAAM) is more difficult compared to the parts produced by conventional manufacturing methods (cast and cast-HT).Öğe Compliant underwater manipulator with integrated tactile sensor for nonlinear force feedback control of an SMA actuation system(Elsevier Science Sa, 2020) Lin, Maohua; Vatani, Morteza; Choi, Jae-Won; Dilibal, Savaş; Engeberg, Erik D.Design, sensing, and control of underwater gripping systems remain challenges for soft robotic manip-ulators. Our study investigates these critical issues by designing a shape memory alloy (SMA) actuation system for a soft robotic finger with a directly 3D-printed stretchable skin-like tactile sensor. SMA actuators were thermomechanically trained to assume a curved finger-like shape when Joule heated, and the flexible multi-layered tactile sensor was directly 3D-printed onto the surface of the fingertip. A nonlinear controller was developed to enable precise fingertip force control using feedback from the compliant tactile sensor. Underwater experiments were conducted using closed-loop force feedback from the directly 3D-printed tactile sensor with the SMA actuators, showing satisfactory force tracking ability. Furthermore, a 3D finite element model was developed to more deeply understand the shape memory thermal-fluidic-structural multi-physics simulation of the manipulator underwater. An application for human control via electromyogram (EMG) signals also demonstrated an intuitive way for a person to operate the submerged robotic finger. Together, these results suggested that the soft robotic finger could be used to carefully manipulate fragile objects underwater.Öğe Development of bioinspired robotic pectoral fin structure using radial scissor mechanism(Institute of Electrical and Electronics Engineers Inc., 2021) Sapmaz, Ali Rıza; Dilibal, Savaş; Özbaran, Can; Gerçek, MertIn this study, the flapping pectoral fin structure of the manta ray has been mimicked with radial scissor mechanisms. The flapping behavior for swimming is configured via generative design using two different scissor mechanisms. The bioinspired four-cell and six-cell robotic fin structures are designed, analyzed and additively manufactured for comparison purpose. Experimental and numerical analysis are conducted to unveil the displacement, and stress distribution parameters for both structures. A comparison is made between the experimental and numerical analysis results.Öğe Development of hybrid actuator system for recovery of the model rockets(Institute of Electrical and Electronics Engineers Inc., 2024) İpek, Gülhas; Dalkıran, Atılay; Dilibal, SavaşModel rockets are the advanced mechatronic systems established through the design, manufacturing, and integration of the model-scale mechatronic sub-systems for a rocket mechanism capable of operating at low altitudes. The safe recovery and reusability of model rockets are prominent tasks to address. Various actuator systems are used in model rockets to solve the safe recovery problem by safely releasing and recovering the payloads that they carry at specific altitudes, allowing the rockets to be recovered. Traditionally, model rockets have employed recovery units powered by gunpowder. This research aims to design a novel hybrid actuator system integrating mechanical components with pressurized gas and servo motor components as an alternative to traditional gunpowder systems to enhance reliability and safety. The objective is to develop a prototype of a hybrid recovery actuator system using CO2 tubes and servo motors. The principle behind the designed recovery system relies on the release of CO2 gas, which facilitates the separation of the rocket motor body from the main body. This principle is based on the mechanism within the designed actuator system, which functions by releasing the potential energy stored in compressed springs. Servo motors triggered by signals from the rocket's flight computer release the springs, allowing the CO2 gas to escape. The released gas separates the rocket bodies, ensuring a safe descent. Within the scope of this research, the efficiency and effectiveness of the CO2 based hybrid recovery actuator system are evaluated through the production of a prototype. The experimental results unveiled that the development of the CO2 based hybrid recovery actuator system enables safe and successful recovery of model rockets. To achieve the timely release of the CO2 gas in the recovery system, the required pressure is determined via experimental studies for the separation of rocket bodies, ensuring a safe descent.Öğe Development of IoMT device for mobile eye examination via cloud-based teleophthalmology(IEEE, 2020) Dilibal, Çınay; Hacımustafaoğlu, Ali Murat; Dilibal, SavaşA periodic visit of an ophthalmologist is crucial for monitoring the eye health regularly. However, the periodic visit to the ophthalmologist may become difficult to handle in the cases of the patient's visual status varies; personal location is far away from the hospital or special cases; such as COVID-19 pandemic. In this study, a novel ophthalmologist-and-patient-in-the-loop telemedicine platform is built to remotely examine the corneal surface of the eye. An internet-of-medical-things (IoMT)-based biomedical device is developed with ophthalmologist dashboard and patient interface. The developed biomedical device, Mobile XMI, is validated by testing in the ophthalmologist-and-patient-in-the-loop telemedicine system. The preliminary results showed that the cloud-based teleophthalmology architecture provides a potential tool for the early detection and diagnosis of the corneal related symptoms and diseases. Additionally, the developed medical platform facilitates the remote eye examination of the patients with disability or patients who locate far away from the ophthalmologist or hospital.Öğe DEVELOPMENT OF MULTI-MATERIAL COMPONENTS VIA ROBOTIC WIRE ARC ADDITIVE MANUFACTURING(2021) Kızılcalıoğlu, Gaye; Turgut, Batuhan; Güleçyüz, Nurten; Dilibal, Savaş; Koçak, MustafaAdditive manufacturing technologies are applied in different industrial fields. It is possible to produce 3D parts in complex form at a lower cost with faster production capability using additive manufacturing compared to traditional subtractive manufacturing. Robotic welding-based wire arc additive manufacturing (WAAM) is a novel additive manufacturing technology which offers various solutions. Many products can be produced through the additive manufacturing in the fields of defense, aerospace, and automotive industries. In this study, multi-material metallic parts were produced by depositing ferritic ER 70 S-6 and stainless steel ER316L welding wires using robotic WAAM technology. Detailed microstructural analysis and hardness tests were conducted on the manufactured samples including interfaces between two different materials. Characterization of Fe-austenite weld interfaces has shown the presence of hard phases due to migration of hardening elements. The microhardness examination revealed that the highest hardness values are recorded at the bimetallic interface due to Fe and C migration through the interface layer.Öğe EFFECT OF WIRE ELECTRICAL DISCHARGE MACHINING ON THE SURFACE OF EBM-ADDITIVE MANUFACTURED NITI ALLOYS(2021) Peduk, Gozde Sultan Altug; Dilibal, Savaş; Gürol, UğurNickel-titanium (NiTi) shape memory alloys are used in varied engineering products, such as biomedical device and mechatronic actuator applications. The conventional machining technology are utilized in the limited fields due to their effects on the hardness and brittleness of the machined alloys. However, the wire electrical discharge machining (WEDM) technology is one of the most preferred post-processing tool to obtain a surface with high quality. The electrical current and voltage values with pulse on and pulse off time are the crucial parameters for WEDM. These parameters should be optimized before wire electrical discharge machining process. Electron beam melting (EBM)-based additive manufacturing of the nickel-titanium powders provides obtaining bulk NiTi shape memory alloys using high energy electron beams. In this study, the application of WEDM which is used as a post-processing tool is evaluated for the EBM-based additive manufactured NiTi samples. Additionally, the scanning electron microscopy results of the wire electrical discharge machined NiTi samples are carefully investigated.Öğe Elastomerik malzemelerin katmanlı imalatında temel parametrelerin analizi(Kerim Çetinkaya, 2018) Elbaba, Ömer; Sezer, Samet; Şahin, Haydar; Dilibal, SavaşKatmanlı imalat teknolojisindeki gelişmeler mekatronik, robotik, havacılık ve biyomedikal ürünler gibi birçok farklı uygulamanın üretim yapılmasına olanak sağlamaktadır. Bu uygulamalardaki istenen parametrelerden biri de esnek mekanik özelliklere sahip olunmasıdır. Geleneksel döküm teknolojisi kullanılarak yapılan üretimle karşılaştırıldığında katmanlı imalat tekniği birçok açıdan daha kolay son ürüne erişilebilen bir tekniktir. Bu çalışmada, esnek ürün elde edilmesi için katmanlı imalat teknolojisinde malzeme seçimi ve imalat parametreleri ile ilgili gerekli ön şartlar araştırılmıştır. Çekme dayanımı, sertlik, elastisite modülü gibi mekanik özellikler dikkate alınarak, kullanılacak uygulama gereksinimlerine göre polimerik malzeme seçimi yapılması gerektiği tespit edilmiştir. Ergiyik yığma (FDM) tekniği kullanılarak esnek polimerik filament ile imalat parametreleri belirlenmiştir.Öğe Experimental and numerical analysis for improving the suction capacity of the manufactured water jet ejectors(Jve Int Ltd, 2022) Ayna, Tuncer; Dilibal, SavaşWater jet ejectors are the silent pumping fluid devices which doesn't have any rotating parts in functional industrial applications. The dimensionless geometrical parameters effects ejector suction capacity. In this study, it is found that optimum design intervals have been determined by using the Response Surface Method (RSM). Design ranges determined in the dimensionless study have been used in the improvement of the suction capacity of an existing ejector. The suction capacity of the existing ejector is investigated via numerical and experimental analysis. Two new water jet ejector designs (D1 and D2) are built to improve the suction capacity of the initial water jet ejector (D0). The generated design parameters have been analyzed by using SolidWorks flow analysis and optimization software. The suction capacity of the ejector has been determined through the iterative numerical analysis for the selected geometrical parameters under the applied design conditions. The effect of design parameters on the suction capacity of the water jet ejectors is unveiled through numerical and experimental analysis. The established designs were produced as two novel bronze water jet ejectors. The suction capacities of the produced bronze water jet ejectors have been investigated experimentally. The numerical results have been validated using the experimental results. It is achieved that the suction capacity of the manufactured water jet ejector with the improved design (D2) is suddenly increased from 52.05 m3/h to 103.4 m3/h.Öğe Experimental and numerical analysis on the bending response of the geometrically gradient soft robotics actuator(Polish Academy of Sciences, Institute of Fundamental Technological Research, 2018) Dilibal, Savaş; Şahin, Haydar; Çelik, YahyaIN THIS STUDY, THREE DIFFERENT SOFT PNEUMATIC ACTUATORS (SPA) are designed and directly fabricated through additive manufacturing using thermoplastic polyurethane (TPU) filaments. The equal total inner volume size is used in the three varied designs to compare their effect on the bending response. A material model is selected and implemented according to the uniaxial tensile test parameters. The experimental results obtained from three different soft pneumatic actuators are compared with numerical model results. Especially, the experimentally measured bending forces are compared with the numerical model counterparts. The highest continuous bending deformation is determined among the three different soft pneumatic actuators. Additionally, a new integrated design and manufacturing approach is presented aiming to maximize the potential bending capability of the actuator through additive manufacturing.Öğe Experimental investigation of wire arc additively manufactured inconel 625 superalloy(Springer India, 2023) Gürol, Uğur; Tümer, Mustafa; Dilibal, SavaşThe aim of the present study was to reveal how the microstructure and mechanical properties of Inconel 625 superalloy produced via wire arc additive manufacturing (WAAM) changed in relation to deposition direction. Results showed that the microstructure mainly consists of columnar dendrites including some intermetallic and carbides constituents, which are Laves and NbC phases. The hardness values showed heterogeneous distribution from bottom to top and mainly change between 275 +/- 15 to 298 +/- 16 HV5 except for the initial area reaching 318 +/- 14 HV5. The tensile test results revealed that the stress-strain responses of the samples change depending on the extracted direction. The lowest elongation was obtained at the transverse top and bottom regions with 33.5 +/- 1.5% and 35 +/- 6% while the highest elongation was obtained at the angular top and bottom with 48.5 +/- 6.7% and 55.5 +/- 2%. The results confirmed the more pronounced difference with sample direction, indicating anisotropy in ductility.Öğe Experimental investigation on the EBM-based additively manufactured prismatic nickel–titanium SMA components(Pleiades Publishing Inc, 2021) Altuğ Pedük, Gözde Sultan; Dilibal, Savaş; Harrysson, Ola; Özbek, SunullahAdditive manufacturing (AM) of the nickel-titanium (NiTi) shape memory alloys (SMA) have provided novel component solutions with a variety of design configurations in the industry. Electron beam melting (EBM) is a trending metal additive manufacturing process for industrial applications in the field of biomedical and aerospace engineering. In this study, experimental investigations were conducted to reveal the effect of processing conditions on the microstructure and hardness properties of EBM-fabricated nickel-titanium components. Furthermore, detailed microstructural characterizations were performed with a scanning electron microscope, EDS, and XRD for unveiling of the microscopic structure and phase analysis during the layer by layer solidification. The experimental results were systematically evaluated for the powder and the bulk prismatic components, respectively.
