Ismail Lazoglu

• Professor
• Director of Manufacturing and Automation Research Center at Koc University

Background and Objectives The cost and complexity associated with animal testing are significantly reduced by using mock circulatory loops prior. Novel mock circulatory loops allow us to test biomedical devices preclinically due to their flexibility, scalability, and cost‐effectiveness. The presented work describes the development of a hardware‐in‐...

Machining is a crucial process for the manufacturing of precision aerospace, automotive, and biomedical parts. Issues such as tool wear, chatter, and workpiece deformation affect the machined parts’ quality. Early detection of these issues is required to achieve the desired quality of precision machined parts. Traditionally, these process anomalies...

In recent years, sound quality (SQ) has become an increasingly important factor in the home appliance industry, enhancing the customer experience and comfort. Manufacturers that prioritize SQ in their designs can gain a competitive advantage in the market and increase customer satisfaction. The compressor is one of the main sources of noise in a re...

Eklemeli imalatın metaller için en çok kullanılan alt yöntemlerinden biri olan toz yatağı füzyon proseslerinin sağlamış oldukları avantajlarıyla birlikte ön plana çıkmaktadır. Toz yatağı füzyon proseslerinin temel ortak noktası lazer, elektron veya ısıl yazıcı kafası gibi bir ısı kaynağı kullanılarak, toz yatağı içerisinde üretilecek 3B parçanın ge...

Smart materials are ushering in the era of smart and adaptable products. Hydrogels are a distinct class of smart materials that can be 3D-printed to produce smart and active structures that can be used as sensors and actuators. The development and characterization of a 3D-printable and electrically conductive composite hydrogel, as well as its appl...

There is a critical demand for magnetorheological fluids (MRFs) with high particle loading, long-term stability, and high magneto-viscous properties to be used in industrial MRF devices. Bidisperse MRFs composed of highly magnetizable micron-sized carbonyl iron particles and poly(acrylic acid) coated superparamagnetic iron oxide nanoparticles (SPIO...

G-Lattices—a novel family of periodic lattice structures introduced by Armanfar and Gunpinar—demonstrate diverse mechanical properties owing to their generatively designed shapes. To effectively assess the properties of lattice structures, experimental tests and finite element analysis (FEA) are commonly used. However, the complex nature of these s...

One of the most crucial parts of a reciprocating compressor is the crankshaft, which conveys the motion of the rotor to the piston via the connecting rod. The effect of the gas, friction and inertial forces on the journal bearings not only creates the vibration but also initiates the mechanical losses. Since the design parameters of the crankshaft...

This article discusses a new approach to develop a machine learning model for the cooling profile prediction of plastic parts produced through injection molding to estimate the cooling time. Design parameters related to the cooling stage of injection molding, such as distance between the cooling channel and plastic part, pitch distance, channel dia...

Scapulothoracic arthrodesis is carried out by fixing the scapula to thoracic ribs which in turn allows the patient suffering from Facioscapulohumeral Muscular Dystrophy to carry out shoulder‐joint dependent activities of daily living. A biomechanical analysis of this procedure has not been conducted in the literature and, for the first time, this s...

Drying is a time-consuming and energy-intensive process linked to environmental thermodynamic properties. Conventional methods often use high temperatures for long durations, potentially harming textiles. This article introduces an innovative vacuum textile drying technique utilizing pressure pulsation. Experimental validation reveals that pulsed v...

A compressor (1) comprises: a casing (2); a body (3) which is disposed in the casing (2); a rotor which is disposed on the body (3) and a stator (4) which is disposed around the rotor so as to be concentric with the rotor; at least one connection member (5) which is disposed on the stator (4) and which enables the stator (4) to be placed into the c...

In object-oriented or acausal modelling, components of the model can be connected topologically, following the inherent structure of the physical system, and system equations can be formulated automatically. This technique allows individuals without a mathematics background to develop knowledge-based models and facilitates collaboration in multidis...

The study is aimed to develop a hip joint wear simulator using a modular design approach to help experimentally monitor and control critical wear parameters to validate in-silico wear models. The proper control and application of wear parameters such as the range of motion, and the applied force values while estimating the lost material due to wear...

Objective: This study aimed to introduce a method to extract the 3-dimensional spatial position of the femoral head implant from 2-dimensional fluoroscopic projections, allowing surgeons to assess fixation much more accurately and prevent cut-out complications in proximal femoral nailing. Methods: To define a safety region for the tip in the fem...

Background: While cardiovascular system and mechanical circulatory support devices are efficiently model the effect of disease and assistance, they can also lend valuable insights into clinical procedures. This study demonstrates the use of a CVS-VAD model for an invasive procedure; hemodynamic ramp testing, in-silico. Methods: The CVS model is...

Conformal cooling channels (CCCs) are employed to improve the cooling rate due to the equal distance from the mold surface. CCCs play a key role in mold injection productivity by enhancing heat transfer between the CCs and mold surface, which leads to shorter cooling time. As the cooling stage of the mold injection highly influences the quality and...

Background: Stress shielding is a detrimental phenomenon caused by the stiffness mismatch between metallic bone plates and bone tissue, which can hamper fracture healing. Additively manufactured plates can decrease plate stiffness and alleviate the stress shielding effect. Methods: Rectilinear lattice plates with varying cell sizes, wall thickne...

Background: Hand scrubbing is an absolute precaution to avoid surgical site infections. World Health Organization (WHO) recommends 4-min overall scrubbing (4MS) for surgical hand hygiene. However, we hypothesize that the more methodical 10-stroke counting technique (10SS) via locational partitioning of the arm is superior to WHO's superficial guid...

Distortion of machined monolithic thin-walled parts is a well-known issue and a perpetual concern in the aerospace industry. In this article, a novel analytical-FEM hybrid model for fast prediction of distortion of thin-walled parts is proposed. Moving cutting loads due to milling are calibrated and applied directly to the surface of the meshed mod...

Additive manufacturing has new revolutionary potential for carbon fiber‐reinforced polymers (CFRPs). Additive manufacturing of CFRPs combines the advantages of additive manufacturing such as customization, minimal wastage, low cost, fast prototyping and rapid manufacturing with high specific strength of carbon fiber. This article delivers a compreh...

Discharge tube is a critical component in a reciprocating compressor that carries the refrigerant. It also transmits vibrations from compressor body to housing, making the design of tube a complex engineering problem combining static, modal and flow behaviour. This study proposes a novel design algorithm for discharge tube, to decrease the dependen...

Tool flank wear monitoring can minimize machining downtime costs while increasing productivity and product quality. In some industrial applications, only a limited level of tool wear is allowed to attain necessary tolerances. It may become challenging to monitor a limited level of tool wear in the data collected from the machine due to the other co...

A hermetic reciprocating compressor is one of the most critical parts for the energy efficiency of a household refrigerator. Piston-cylinder contact in the hermetic compressor accounts for most of the energy loss. The tribological performance of the piston-cylinder pair can be enhanced by introducing micro-texturing on the piston surface. In this r...

Maximum vibration and maximum noise are generated during the transient startup and shut down operational phases of machines that demonstrate harmonic motion. Such vibrations and noise are especially undesired in household products. To abate such undesired effects associated with excessive body displacements and noise, a transient vibration and nois...

Although additive manufacturing is an attractive alternative for the manufacturing of complex ceramic geometries, the manufactured parts have low mechanical properties due to low solid loading, high porosity, and geometrical distortions. Introducing ductile metal particles into the brittle ceramic matrix is an effective technique to enhance the geo...

This paper presents a development of a system based on the photoelectric technique to measure the displacement of the reed valve in reciprocating type hermetic compressors. The motivation for that is mainly related to developing a cost-effective, non-invasive, and adaptable system to monitor valve dynamics in real-time. The proposed system is compr...

The fused Filament fabrication method gained its popularity in the additive manufacturing industry not only because of the low capital and manufacturing cost, but also due to its ease of production approach, availability, and mobility of the method. However, the quality of final parts and the mechanical properties are directly related to layer thic...

In vitro motion stimulation of the hip-joint prosthesis helps predict the critical parameters of the products more realistically than in silico investigations. For the joint prosthesis, Wear, the size of debris, fatigue life, and range of motion are some of the essential parameters to investigate. This study designs and develops a hip joint wear si...

Purpose The cut-out of the cephalomedullary nail is among the most common post-surgery complications for intertrochanteric fractures. As a risk predictor, a tip-apex distance (TAD) below 25 mm, observed from orthogonal fluoroscopic views, is recommended in the literature. This study aims to demonstrate that TAD < 25 mm is a mathematically insuffici...

Additive manufacturing (AM) is growing rapidly in the advanced industrial applications to reduce the cost and time of the manufacturing and assembly processes. The evolution of temperature during AM processes such as direct metal laser sintering (DMLS) has a considerable effect on residual stresses and thus undesired distortions in the parts. There...

Lubrication at low speeds is a general problem in the hermetic reciprocating compressors for household refrigerators. The aim of this article is to present a new method using a novel 3D printed unibody axial flow pump for the lubrication oil supply system of an inverter type hermetic reciprocating compressor used in household refrigerators during a...

Corneal collagen crosslinking (CXL) is a commonly used minimally invasive surgical technique to prevent the progression of corneal ectasias, such as keratoconus. Unfortunately, riboflavin/UV-A light-based CXL procedures have not been successfully applied to all patients, and result in frequent complications, such as corneal haze and endothelial dam...

The turning process used from ancient times to today’s modern turning centers is based on material removal. This article presents a new work to integrate additive manufacturing into the turning process and generate complex free-form additive turning part geometries. The conventional slicing method used in AM is the planar slicing method. In the pla...

Distortion of machined parts is a big concern for the aerospace industry. Every year huge amount of capital is lost due to distortions related scrap of components. Prediction and proper control of distortion is thus imperative to avoid huge losses in terms of money and time. Residual-stresses are known as a leading cause of the distortion of aerosp...

Temperature is a critical parameter in machining as it directly affects the cutting performance, part quality, residual stresses, distortion, tool life, etc. In this article, a novel analytical algorithm for fast temperature prediction in intermittent cutting processes like milling is proposed. For the first time, the temperature drop during the no...

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease, and ALS incidence is increasing worldwide. Patients with ALS have respiratory failure at the disease’s end stages, leading to death; thus, the lung is one of the most affected organs during disease progression. Tissue stiffness increases in various lung diseases because of...

The closed-cell metal foams are utilized in various industrial applications due to their impact and energy absorption capacity, noise cancelation, and lightweight properties. Additionally, the manufacturing methods of stochastic foams with blowing agents or inert gas injection are well known. However, the poor mechanical strength and high brittlene...

Additive manufacturing restructures the fabrication of custom medical implants and transforms the design, topology optimization, and material selection perspectives in biomechanical applications. Additionally, it facilitated the design and fabrication of patient-oriented hip implants. Selection of proper lattice type is critical in additive manufac...

In a typical machining process, workpiece and tool temperatures, tool wear, residual stresses, and part distortions are associated with cutting forces and torques. These forces and torques can be measured at the laboratory scale using sophisticated dynamometers. The use of these dynamometers is however impractical for mass production applications d...

Objective The present study aims to compare the thickness and the mechanical properties of the frontal, parietal, temporal, occipital human dura, autogenous grafts (facia lata, temporal fascia, galea aponeurotica), and artificial dura. Methods Sagittal and transverse dura samples were obtained from standard regions of the cranial dura from 30 auto...

Maneuvering a truck-trailer system while docking is extremely challenging. This article aims to alleviate this problem by presenting an enhanced path-following control framework for autonomous semi-trailer docking. In the proposed system, adaptive controllers that utilize gain scheduling are introduced for forward and reverse path-following tasks i...

Some undamped vibrations may cause undesirable behavior such as noise, overloads, excessive displacements, and early fatigue failures in the mechanical systems. Active vibration control is crucial for some of the mechanical systems such as washing machines. This article proposes a new vibration control strategy (VCS) for reduction of vibrations in...

Background: Inventory management or immediate availability of fracture plates can be problematic since for each surgical intervention a specific plate of varying size and functionality must be ordered. Modularization of the standard monolithic plate is proposed to address this issue. Methods: The effects of four different unit module design para...

Along with vast research on the additive manufacturing (AM) of polymeric and metallic materials, three-dimensional (3D) manufacturing of ceramic materials is now the modern trend. Among all the additive manufacturing techniques, Direct Ink Writing (DIW) permits the ease of design and rapid manufacturing of ceramic-based materials in complicated geo...

The typical domestic refrigerator employs a blind and periodic defrost strategy that leads to the clogging of the evaporator between the consecutive defrost cycles. The clogging of the evaporator causes a loss in performance which can be minimized using the demand defrost technique. The demand defrost systems proposed in the literature rely on the...

In this article, a sliding mode control of a magnetorheological fluid damper is presented for active damping of chatter in the boring process for the first time. A boring bar is integrated with an in-house developed magnetorheological fluid damper system. The variable gain super twisting sliding mode control algorithm is designed and implemented fo...

This paper presents a model for generating strut-based lattice structures using topology optimization and their efficient direct slicing. These structures exhibit better physical properties and can represent the partial densities at the macro-scale level, which often appear in designs based on topology optimization. The fabrication of such large me...

Background: AISI 316L stainless steel wire cerclage routinely used in sternotomy closure causes lateral cut-through damage and fracture, especially in cases of high-risk patients, which leads to post-operative complications. A biocompatible elastomer (Pellethane®) coating on the standard wire is proposed to mitigate the cut-through effect. Methods:...

One of the most challenging tasks for truck drivers is maneuvering the truck-trailer system in different parking scenarios. This article presents a novel path planning approach for truck-trailer parking, where a realistic and deterministic parking behavior model, Iterative Analytical Method (IAM), is proposed and combined with Closed-Loop Rapidly E...

In the design of rotary blood pumps, the optimization of design parameters plays an essential role in enhancing the hydrodynamic performance and hemocompatibility. This study investigates the influence of the volute tongue angle as a volute geometric parameter on the hemodynamic characteristics of a blood pump. A numerical investigation on five dif...

This article presents a spherical slicing method for additive manufacturing (AM) which is used to lay additive layers on a spherical surface, thus removing the stair stepping effect, increasing structural integrity and tensile strength. A toolpath is required to guide the extruder in the three-dimensional space and deposit the material in the desir...

Background To assess the success of proximal cephalomedullary nailing operations for treating trochanteric fractures, surgeons utilize 2D fluoroscopy to observe the relative positions of the femoral head and the implant. One distance-based risk parameter, observed from the AP and Lateral projections, is the Tip-Surface Distance(TSD) that dictates h...

Chatter is a limiting factor during boring of deep holes with long slender boring bars. In this article, a new magnetorheological (MR) damper is introduced to increase the stability of the boring process. The sponge-type configuration of the damper utilizes a minimal amount of MR fluid in the annulus around the boring bar. The MR fluid layer and th...

Despite good creep and fatigue durability, high resistance against chemicals and good surface finish, Polyoxymethylene (POM) has been sidelined in incremental sheet forming (ISF) literature due to its low formability at room temperature. This paper addresses the issue by deploying a cost-effective friction-induced heat at the tool-sheet interface....

The selectivity between electrically conductive and insulating regions within one additively manufactured part can open new domains for customized, smart, and active products. In this article, new electrically conductive polymer matrix composites (ePMC) were developed for additive manufacturing (AM) by loading an aqueous matrix of carboxymethyl cel...

Additive manufacturing (AM) of metal parts using the direct metal laser sintering (DMLS) process employs layer-wise melting of powder material to fabricate geometrically complex models. However, this option to build high-end metallic products comes with technical challenges, spreading along the overall process chain. Therefore, the powder bed fusio...

Accurate and fast prediction of cutting forces is important in high-performance cutting in the aerospace industry. Gamma titanium aluminide (γ-TiAl) is a material of choice for aerospace and automotive applications due to its superior thermo-mechanical properties. Nevertheless, it is a difficult to machine material. This article presents the predic...

A force sensor design utilizing a photo-interrupter is presented for measuring the static coefficient of friction (COF). The measurement of ice friction on polymer surfaces, a process that requires detecting forces in the sub-Newton range, is chosen for the study. The photo-interrupter is coupled with a specially designed sensitive flexure, with st...

The frosting is a phenomenon most detrimental to the efficiency of refrigeration systems. The accumulation of frost blocks the airflow, deteriorating the cooling capacity and the coefficient of performance. The commercially available refrigeration systems use a blind and periodic defrosting cycle without any quantification of frost, which leads to...

This article is a continuation of the preceding article and focuses on the performance evaluation of an oil-free linear compressor prototype. The article introduces performance analysis parameters for a linear compressor along with their analytical attributes. Initially, the kinetic and kinematic analysis at resonance excitation frequency is perfor...

This article presents a design of a high thrust density moving magnet linear actuator for linear refrigerator compressor. The shape of permanent magnet (PM) shows great effect on cost, fabrication and magnetic flux density generation in the actuator. Axially magnetised disk shaped PMs are low cost and convenient for fabrication. Moreover, axially m...

Background Superelastic Nitinol staples, utilized routinely in foot surgeries, are proposed to be used for sternal closure application in this study. It is hypothesized that the shape memory induced superelasticity will allow multiple staples placed along the sternum to promote fast and safe recovery by maintaining constant clamping pressure at the...

This article provides a detailed design and a CAD model of a new moving magnet linear compressor for the household refrigerator. A comprehensive electromechanical analytical model is provided to quantify the dynamic parameters necessary for the estimation of a compressor's performance. Additionally, the frequency response functions of the prototype...

The undesired accumulation of ice on aircraft wings, wind turbines, and evaporators results in aerodynamic and thermodynamic inefficiencies. This paper demonstrates the efficacy of heating elements additively manufactured from electrically conductive polymer composites. Virtuous to the flexibility and customizability offered by additive manufacturi...

Objectives: A continuous-flow centrifugal blood pump system has been recently developed as an implantable left ventricular assist device for patients with endstage heart failure. The objective of this study was to evaluate the initial in vivo performance of a newly developed left ventricular assist device (iHeart or Istanbul heart; Manufacturing a...

The purpose of this article is to introduce a nonplanar helical slicing method for additive manufacturing (AM) which forms a single continuous three-dimensional tool path and removes seam defects. In the proposed method, the geometry is initially sliced into planar slices. Afterwards, using two consecutive planar slices, direction vectors from the...

A novel Ti6Al4V adjustable locking plate (ALP) is designed to provide enhanced bone stability for segmental bone fractures and to allow precise positioning of disconnected segments. The design incorporates an adjustable rack and pinion mechanism to perform compression, distraction and segment transfer during plate fixation surgery. The aim of this...

Cutting forces and thermal loads in milling may cause distortion in machined parts. Especially in the aerospace industry, distortion of thin wall structural parts in milling is one of the major problems. This problem can lead to increasing production costs or even rejection of manufactured parts. This article presents a new finite element modeling...

Acclaimed for enabling the fabrication of complex parts, additive manufacturing is confined to established processing and planning methods that contribute impediments to its industrial adoption. The requirement of support structures and poor quality of produced surfaces are some of these impediments. Extension of the manufacturing method to accommo...

Background: Although columellar strut grafts (CSGs) are considered among the fundamental steps for providing nasal tip support, a downward rotation of the nasal tip in patients with strut grafts can still be encountered. Patient-related factors such as nasal skin thickness can allow the plastic surgeon to anticipate certain drawbacks that can be e...

This article presents a design of a novel moving magnet linear actuator (MMLA) for linear refrigerator compressor. A methodology to estimate the magnetic flux density as well as the magnetic force of MMLA is presented. Considering the simulation time of a 3D FEM software, a combination of 2D FEM with the analytical models makes this technique conve...

Aims: Impeller design has a significant impact on the overall performance of a blood pump. In this study, the effect of the blade curvature was investigated by performing in silico and in vitro studies on a recently developed centrifugal blood pump. Methods: A computational fluid dynamics study was performed for the flow rates of 3-5 L/min at 20...

Additive manufacturing can be enhanced through augmentation of additional axes of motion. This paper shows that such improvement allows support-less additive manufacturing of parts that will otherwise require support structures. By utilizing multi-axis additive manufacturing, model can be divided and sliced to avoid using support. The possibility o...

The use of composite materials in the aerospace and automotive industries have been increasing rapidly. The molds, also known as tools, used for laying the composites are generally made from metals which are manufactured by subtractive manufacturing. This is not only an expensive option but also results in long lead times. Additive manufacturing (A...

DESIGN AND DEVELOPMENT OF AN ADDITIVE MANUFACTURING SYSTEM FOR METAL PRINTING

Assembly process of a magnetically coupled integrated aortic-turbine venous assist device (iATVA) with ceramic bearings. The iATVA prototype supporting a single-ventricle circulation, in vitro demonstrated through an instrumented mock-up flow loop. Video available at: http://www.jtcvsonline.org/article/S0022-5223(18)30717-7/fulltext.

A compact triaxial dynamometer for detecting the cutting forces in machining is developed. Force measurements are performed using photo-interrupters. Structural parameters of a monolithic flexural component are chosen through parametric analysis for coupling the exerted forces with the optical sensors. A prototype of the dynamometer is manufactured...

Nowadays, additive manufacturing via topology optimization creates new opportunities for weight reductions in aerospace industry where high fly-to-buy ratio is desired. Selective laser sintering of advanced engineering materials like nickel super alloys are also expanding to reduce the cost and time of the manufacturing in aerospace industry. Eleva...

In this article, a new magneto rheological (MR) sponge damper is proposed for suppression of vibrations in a washing machine. The article presents design optimization of geometric parameters of MR sponge damper (MRSD) using the finite element analysis (FEA) and first order derivative techniques for a washing machine. The article explains the hyster...

Introduction Palliative repair of single ventricle defects involve a series of open-heart surgeries where a single-ventricle (Fontan) circulation is established. As the patient ages, this paradoxical circulation gradually fails, due to its high venous pressure levels. Reversal of the Fontan paradox requires an extra sub-pulmonic energy that can be...

The aim of this work was to analyze a shrouded impeller pediatric ventricular assist device (SIP-VAD). This device has distinctive design characteristics and parameter optimizations for minimization of recirculation flow and reduction in high-stress regions that cause blood damage. Computational Fluid Dynamics (CFD) simulations were performed to an...

This paper investigates a novel miniature-size resonant moving-magnet linear actuator designs to be used in miniature linear compressor applications. The miniature linear actuator has a slotless stator and a tubular topology. It utilizes moving magnets in which the magnets are lined up in the Halbach array structure. Finite-element and analytical a...

The main constraints in high performance machining of the titanium alloys are mostly due to the friction induced thermal issues. In thermal analysis, the friction coefficient is the critical parameter for estimating the heat generation at the tool-chip interface. This paper provides a direct approach for determining the friction coefficient from sl...

The Al7050 is the alloy of choice for the structural parts of major aircraft frames. Large sections are machined as a single unit. The production of distortion-free machined parts within the required dimensional accuracy is the limiting factor towards increasing productivity. In order to minimize the thermal loads in machining, friction analysis is...