Browsing by Author "Kiliç,S.E."
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Conference Object Citation Count: 42D FE modelling of machining: A comparison of different approaches with experiments(2005) Bil,H.; Tekkaya,A.E.; Kiliç,S.E.[No abstract available]Conference Object Citation Count: 11An experimental study on surface quality of Al6061-T6 in ultrasonic vibration-assisted milling with minimum quantity lubrication(Elsevier B.V., 2022) Namlu, Ramazan Hakkı; Yilmaz,O.D.; Yılmaz, Okan Deniz; Lotfısadıgh, Bahram; Mechanical Engineering; Manufacturing EngineeringAl6061-T6 is frequently used in the automotive and aerospace industries, where milling is an essential process, due to its high strength-to-weight ratio. In order to achieve improved surface quality in milling, Ultrasonic Vibration-Assisted Milling (UVAM) has been introduced recently. Besides, Minimum Quantity Lubrication (MQL) is another advanced method to enhance the surface properties of the cutting by improving the coolant performance. However, the effects of simultaneous implementation of UVAM and MQL methods has not yet been studied sufficiently. This paper investigates the effects of applying UVAM in tandem with MQL in cutting of Al6061-T6. The results showed that surface quality enhanced with this combination. © 2022 The Authors.Conference Object Citation Count: 4Investigation of the effects of axial ultrasonic vibrations on chatter stability in milling with bull nose cutters(Elsevier B.V., 2023) Namlu, Ramazan Hakkı; Kiliç,Z.M.; Lorain,R.; Kiliç,S.E.; Mechanical EngineeringUltrasonic vibrations-assisted machining has positive effects on the chatter stability and surface integrity of the process. Radial vibration-assisted milling is effective but it needs an advanced control of vibration trajectory hence is not easy to implement. The aim of this paper is to investigate the effects of axial ultrasonic vibrations on stability through disturbing the chip regeneration. A simple way of predicting the stability increase is proposed using missed-cut effect that reduces the effective number of teeth in cut. The axial vibrations are shown to introduce radial runout such that a regular cutter will show the characteristics of a serrated tool. For a 2-tooth bull nose cutter, the proposed method was verified by milling of Ti-6Al-4V material. The results showed that the axial ultrasonic vibrations increased limit axial depth of cut by more than 40%. Therefore, applying axial vibrations would be a simple solution to improve chatter resistance in machining difficult-to-cut materials while avoiding the cost and complexity of serrated rounded edges. The attention on using axial ultrasonic vibrations in milling is increasing, hence further research on modelling the machining dynamics combined with the velocity effects will be needed following this study. © 2023 Elsevier B.V.. All rights reserved.Article Citation Count: 1Micro-WEDM of Ni55.8Ti shape memory superalloy: Experimental investigation and optimisation(Inderscience Publishers, 2021) Akar, Samet; Akar,S.; Seyedzavvar,M.; Kiliç,S.E.; Department of Mechanical EngineeringNickel-titanium superalloy has gained significant acceptance for engineering applications as orthotropic implants, orthodontic devices, automatic actuators, etc. Considering the unique properties of these alloys, such as high hardness, toughness, strain hardening, and development of straininduced martensite, micro-wire electro-discharge machining (μ-WEDM) process has been accepted as one of the main options for cutting intricate shapes of these alloys in micro-scale. This paper presents the results of a comprehensive study to address the material removal rate (MRR) and surface integrity of Ni55.8Ti shape memory superalloy (SMA) in the μ-WEDM process. The effects of discharge current, pulse on-time, pulse off-time, and servo voltage on the performance of this process, including MRR, white layer thickness, surface roughness, and micro-hardness of the machined surface, were investigated by multi-regression analysis using response surface methodology (RSM). The optimisation of input parameters based on the gradient and the swarm optimisation algorithms were also conducted to maximise the MRR and minimise the white layer thickness, surface roughness, and micro-hardness of the machined samples. © 2021 Inderscience Enterprises Ltd.. All rights reserved.Conference Object Citation Count: 0Multi-axial ultrasonic vibration-assisted machining of Inconel 718 using Al2O3-CuO hybrid nanofluid MQL(Elsevier B.V., 2024) Namlu, Ramazan Hakkı; Lotfi,B.; Lotfi, Bahram; Mechanical Engineering; Department of Mechanical EngineeringInconel 718 is a widely used superalloy in the aerospace industry, owing to its exceptional creep and corrosion resistance, as well as its ability to retain strength at elevated temperatures. However, its machinability presents challenges due to its low thermal conductivity and high work hardening rate during conventional machining, resulting in inadequate surface quality. To address this issue, a recent technique known as Ultrasonic Vibration-Assisted Machining (UVAM) has emerged. UVAM involves applying high-frequency, low-amplitude vibrations to the cutting tool or workpiece. Additionally, Minimum Quantity Lubrication (MQL) has been considered as an alternative cooling technique to enhance machining performance. Optimizing the performance of UVAM can be achieved by employing various vibration axes. Additionally, the effectiveness of MQL can be enhanced through the utilization of nanofluids. This study investigates the combined application of multi-axis UVAM and Al2O3-CuO added Hybrid Nanofluid MQL (HNMQL) during the milling of Inconel 718. The evaluation parameters include surface roughness, topography, burr formations, and cutting forces. The results demonstrate that the simultaneous use of multi-axis UVAM and HNMQL significantly improves the machining performance of Inconel 718. This combination leads to better surface quality and overall process efficiency, offering promising prospects for the aerospace industry and other applications involving difficult-to-cut materials. © 2024 The Authors. Published by Elsevier B.V.Conference Object Citation Count: 1Ontology based virtual enterprise system domain modeling(DEStech Publications Inc., 2014) Lotfi, Bahram; Ünver,H.Ö.; Dogdu,E.; Kiliç,S.E.; Department of Mechanical EngineeringA virtual enterprise (VE) is a product oriented temporary consortium which forms a collaboration platform to fulfil a specific common purpose (typically to create a product) by benefiting from various capabilities of multiple VE partner enterprises. VE lifecycle consists of 3 distinct phases including VE Formation, Operation and Dissolution. VE partner enterprises are selected from virtual breeding environment (VBE) based on specific criteria considering the new VE project specifications. In order to select the most appropriate partners for the forthcoming VE project, it is required to have comprehensive information regarding the VBE members, their current conditions, capabilities, capacities and their past performances. This database continuously changes and it is dynamic. Ontologies and the corresponding knowledge bases provide the best tools for modelling such complex domain knowledge and highly dynamic data requirements. Ontologies not only help model and capture complex domain knowledge, but also improve the sharing and reusability of data and knowledge providing a suitable environment for software agents and human communications. The VE system must be able to demonstrate what types of resources exist, where they are located, and how much resource capacity is available to be used by the consortium. In this paper a pilot Virtual Enterprise system model developed for OSTIM organized industrial park in Ankara will be presented in detail. The objective of this system model is to enable SMEs in the region to collaborate effectively in order to produce eco-friendly high value added products. © Copyright 2014 by DEStech Publications, Inc. All rights reserved.