Angelos P. Markopoulos

National Technical University of Athens | NTUA · Department of Manufacturing Technology

The paper presents the state regarding practices in teaching at partner universities of the EDURES project and current approaches supporting research-based education. It also presents the needs of various groups of stakeholders formulated on the basis of survey results. Moreover, the paper proposes tools and strategies which are useful if research...

The spread of bacteria through contaminated surfaces is a major issue in healthcare, food industry, and other economic sectors. The widespread use of antibiotics is not a sustainable solution in the long term due to the development of antibiotic resistance. Therefore, surfaces with antibacterial properties have the potential to be a disruptive appr...

Additive manufacturing is considered an important alternative way for the fabrication of high quality polymer parts for various applications. Especially, Acrylonitrile styrene acrylate (ASA) is a promising thermoplastic polymer, exhibiting favorable mechanical properties and is also resistant to environmental conditions and various chemical substan...

Additive manufacturing is considered an important alternative way for the fabrication of high quality polymer parts for various applications. Especially, Acrylonitrile styrene acrylate (ASA) is a promising thermoplastic polymer, exhibiting favorable mechanical properties and is also resistant to environmental conditions and various chemical substan...

Nowadays, lasers are used in a wide variety of manufacturing processes, such as cutting, sintering and welding. The evolution of laser technologies has led to the creation of ultrashort pulsed lasers, with a pulse duration below 10 ps, which have the ability, on the contrary with the conventional lasers, to stimulate separately the electrons and th...

Additive manufacturing (AM) is now considered a reasonable alternative for fabricating polymer parts with sufficient strength, dimensional accuracy and surface quality, able to be used in demanding engineering applications. Selective Laser Sintering (SLS) is one of the most popular AM techniques for polymers able to produce complex geometries with...

Laser engraving process is widely used for various industrial applications, such as the creation of small and complex geometries with ultra-high precision. As surface topography can affect the functionality of produced surfaces in various ways, it is required to carry out comprehensive experimental work in order to correlate the laser engraving pro...

The paper presents selected case studies in the area of research and teaching activities focused on technical assemblies. The aim of the work is to discuss the current trends in assembly-related research activities in partner universities of the EDURES project and to present teaching methodology related to the research. Due to the great importance...

Electrical Discharge Machining (EDM) is an established non-conventional process, which is particularly efficient for the processing of hard-to-cut materials, in order to obtain high dimensional accuracy and surface integrity. However, in order to determine the appropriate parameters for machining novel materials, it is necessary to investigate the...

Non-conventional machining processes offer various advantages, including the capability of processing hard-to-cut materials with a reasonable cost and sufficient productivity. However, depending on the application, different machining strategies need to be employed, in order to increase the flexibility of the process and produce parts with a better...

Electrical Discharge Machining (EDM) is an established non-conventional process, which is particularly efficient for the processing of hard-to-cut materials, in order to obtain high dimensional accuracy and surface integrity. However, in order to determine the appropriate parameters for machining novel materials, it is necessary to investigate the...

The results of static and dynamic 3D modeling of the cutting process with a blade tool made of synthetic polycrystalline diamonds (PCD) are presented. Theoretical studies using the DEFORM-3D and COSMOSWorks software packages made it possible to study the influence of the bond's properties, the presence of metal phase inclusions in the structure of...

This article deals with electrical discharge machining (EDM) of an alnico alloy, focusing on how key process parameters affect the surface finish. The experiments were conducted using a BP93L EDM machine. The Box–Behnken design was employed to study the effects of three factors, i.e., spark current, pulse-on time, and pulse-off time, each at three...

The capabilities of the milling process stem from the appropriate regulation of its parameters, the adoption of efficient milling strategies and the use of cooling methods, especially during machining of hard-to-cut materials. In the present work, the effect of kinematic parameters and cooling methods during trochoidal end milling of Incoloy 800 is...

During Abrasive Waterjet (AWJ) machining of hard-to-cut materials, apart from other important process parameters, the properties of the abrasive material can also considerably influence its outcome. In this research, the efficiency of silicon carbide as an abrasive on the geometrical characteristics of the kerf is investigated. Slots were machined...

The grinding of superhard materials poses an important challenge to manufacturing industry, due to the increased wear and the high possibility of fracture of both the wheel and workpiece material. Various strategies have been proposed for effective grinding of these materials, but further research is still required, especially in cases in which the...

As a non-conventional machining technology, EDM is used extensively in modern industry, particularly in machining difficult-to-cut materials. CALMAX is a chromium-molybdenum-vanadium tool steel with exceptional toughness, ductility, and wear resistance that has a wide range of applications. Despite the fact that EDM is routinely used in CALMAX mach...

In the present study, a pre-heating process was employed on Ti–6Al–4V alloy to overcome the machining difficulties in milling and the influence of the pre-heating on surface roughness, vibration, power consumption, and cutting tool wear was investigated. The experiments were conducted based on a Taguchi L18 orthogonal array at room temperature, hot...

Abrasive processes are essential to the manufacturing field, due to their capability of rendering high-quality surfaces with minimum effect on workpiece integrity. As it is especially difficult to perform sufficient experimental work, numerical studies can be successfully employed to evaluate techniques for the improvement of the efficiency of nano...

As additive manufacturing machines price is decreasing, while, at the same time, the expertise in the relevant field is rising, it is essential to test and evaluate the low-budget machines that are available for commercial use. Whilst low-budget machines are widely utilized for rapid prototyping and experimentation, they are not capable of producin...

Welding is considered the most versatile joining method, with extensive applicability in every modern industrial field. Especially, laser welding technology is widely utilized due to its numerous advantages, and its capability to process a variety of different materials. Among the several process parameters that impact the welding results, the abso...

Selective Laser Melting (SLM) consists one of the most widely used 3D printing methods, capable of producing metallic parts of high density and quality. During SLM, complex physical mechanisms and phenomena are taking place, affecting the overall process, thus, extensive relevant research is conducted in the recent years. Along with the experimenta...

Electrical Discharge Machining is a thermo-electrical non-conventional machining process, which is widely used in machining difficult-to-cut materials in complex shapes and geometries, regardless their mechanical properties. Aluminum series 7 alloys are the strongest wrought aluminum alloy with extensive utilization in numerous modern applications....

Electrical Discharge Machining (EDM) is a non-traditional cutting technology that is extensively utilized in contemporary industry, particularly for machining difficult-to-cut materials. EDM may be used to create complicated forms and geometries with great dimensional precision. Titanium alloys are widely used in high-end applications owing to thei...

Abrasive Waterjet (AWJ) machining is considered an excellent alternative to conventional machining processes due to its superb machining characteristics. More specifically, Abrasive Waterjet drilling is nowadays a promising non-conventional process for obtaining high quality holes. In the present study, drilling experiments based on Taguchi L9 orth...

Electrical discharge machining (EDM) is a non-conventional machining process, which is mostly used for machining of difficult-to-cut materials. These materials are often used in engineering applications that require improved surface properties; thus, surface modification is desirable in these cases. In the recent past, it has been observed that EDM...

Electrical Discharge Machining (EDM) is a non-conventional machining process in which the material removal occurs by utilizing thermoelectric energy. EDM's inherent properties render it a feasible method in machining hard-to-cut materials, like tool steels. The current study presents an experimental study regarding the machining of Calmax, a chrom...

Processing of hard-to-cut materials is always challenging, justifying the need of the adoption of efficient non-conventional cutting processes, such as Abrasive Waterjet (AWJ) cutting. In the present study, an experimental work on AWJ cutting of a titanium alloy is performed and analysis of the results is conducted in two steps; after the correlati...

Abrasive Waterjet Machining (AWJM) is considered a viable alternative to conventional machining processes, due to its capability of rendering even complex features on parts with high productivity. However, it is currently also important for manufacturing processes to comply with the various aspects of sustainability, by putting emphasis on the envi...

Circular Economy (CE) and the potential of reusing and recycling the products after the end of their life, becomes imperative for environmental, economic and social reasons. Especially during the 4th Industrial Revolution that is taking place nowadays, an increasing number of out-of-date equipment has to be replaced, which constitutes a chance and...

The notion of function has been a key element in most of the design methodologies. Its definition has been controversial within the research community, with issues arising when methodologies rely solely on one universal strict definition. Axiomatic design relies on functional decomposition, which has as a perquisite the correct definition of the ma...

3D printing is a process that has become widely used in recent years, allowing the production of parts with relatively complicated shapes from metallic and non-metallic materials. In some cases, it is challenging to evaluate the ability of 3D printers to make fine details of parts. For such an assessment, the printing of samples showing intersectio...

Electrical discharge machining (EDM) is a non-conventional machining process, extensively applicable in the modern industry. Owing the non-contact nature of the process, any electrical conductive material can be machined in high quality, regardless its mechanical properties. Titanium alloys are commonly machined by EDM, as difficulties related with...

Machining of hard-to-cut materials with conventional processes is still considered as a challenge, as the special properties of these materials often lead to rapid tool wear and reduced surface integrity. For that reason, it is preferable to combine conventional machining processes with other technologies in order to overcome the problems of machin...

The rotational motion of the medium granules under the influence of an impeller installed in the bottom of a cylindrical reservoir is considered. The dependencies of the circulation velocity of the abrasive granules, as well as the dependence of the pressure in the circulation flow of the granules on the radius of the vibrating machine cylindrical...

Electrical discharge machining is one of the most important non-conventional machining processes for removing material from electrically conductive materials by the use of controlled electric discharges. EDM is a non-contact machining process, therefore, is free from mechanical stresses. This paper investigates the machining Al7075-T6 alloy by EDM...

In this paper, the dependences of the tangential component of the velocity of movement of the medium granules, inside the oscillating reservoir, on its radius and oscillation period are obtained. For the analysis, the circulatory motion of working medium granules under the influence of a rotating impeller and the dynamics of a pseudo-gas from abras...

Additive Manufacturing concentrates the attention, not only of the research and academic community, but of the industry as well. Selective Laser Melting (SLM) and Selective Laser Sintering (SLS) are among the broadest employed methods in AM, since they can treat almost all types of materials. Along with the extensive experimental research that is c...

Electrical Discharge Machining (EDM) is a non-conventional machining process, widely utilized in the modern industrial environment, especially in applications that involve the manufacturing of complex shapes and geometries, along with high dimensional accuracy. Conceptually EDM is a simple process, which is based on the erosion that accompanies the...

Titanium alloys, due to their unique properties, are utilized in numerous modern high-end applications. Electrical Discharge Machining (EDM) is a non-conventional machining process, commonly used in machining of hard-to-cut materials. The current paper, presents an experimental study regarding the machining of Titanium Grade2 with EDM, coupled with...

Improvement in the manufacturing process on the basis of lean production is considered. Specifically , attention focuses on value stream maps (VSM), the Kanban system, just-in-time (JIT) production, single-minute exchange of dies (SMED), and the five-step (5S) system, as applied to the production of special purpose clocks. Current and future value...

Surface quality has always been an important goal in the manufacturing industry, as it is not only related to the achievement of appropriate geometrical tolerances but also plays an important role in the tribological behavior of the surface as well as its resistance to fatigue and corrosion. Usually, in order to achieve sufficiently high surface qu...

Abstract. Aluminium honeycombs are well-known anisotropic structures which are commonly used as energy absorber units. In the past decades, several researchers have focused on developing finite element models credible enough to predict the crash behaviour of honeycomb structures. A number of modelling methodologies have been developed and validated...

Electro-discharge machining (EDM) is mostly used for machining difficult-to-cut materials which are difficult to machine by conventional machining processes. In recent years, EDM is also used for surface modification. This work aims to investigate the phenomenon of surface modification of tool steel Calmax (Uddeholm) by EDM process using Cu-ZrO2 po...

Electrical Discharge Machining (EDM) is a non-conventional machining process, in which, the material removal occurs by repetitive sparks. By utilizing EDM, conductive materials can be machined in complex shapes and geometries, with high dimensional accuracy, regardless of their mechanical properties. Titanium alloys, due to their unique inherent pr...

The modern, highly competitive industrial environment demands machining and production processes that result in exceptional quality and precision [...]

As modern industry advances, the demand for more time and cost effective machining is rising. In order to achieve high levels of standard during machining it is necessary to employ sophisticated techniques for precise prediction of various important parameters that relate to the machining processes. Such technique is the implementation of finite el...

A three-dimensional, thermal-structural finite element model, originally developed for the study of laser–solid interactions and the generation and propagation of surface acoustic waves in the macroscopic level, was downscaled for the investigation of the surface roughness influence on pulsed laser–solid interactions. The dimensions of the computat...

Electrical Discharge Machining (EDM) consists of a non-conventional machining process, which is widely used in modern industry, and especially in machining hard-to-cut materials. By employing EDM, complex shapes and geometries can be produced, with high dimensional accuracy. Titanium alloys, due to their unique inherent properties, are extensively...

The use of ultrasonic vibrations during grinding can lead to favorable results, such as easier processing of difficult-to-cut materials, improved surface quality, reduced workpiece damage and cutting forces. In order to investigate the efficiency of this technique to nanometric grinding, simulations are essential to be initially conducted. Thus, in...

Abrasive waterjet cutting is a well-established non-conventional technique for the processing of difficult-to-cut material and rendering of various complex geometries with high accuracy. However, as in every machining process, it is also required that high efficiency and productivity are achieved. For that reason, in the present study, the effect o...

In this study, the development of a 3D Finite Element (FE) model for the turning of AISI-D3 with ceramic tooling is presented, with respect to four levels of cutting speed, feed, and depth of cut. The Taguchi method was employed in order to create the orthogonal array according to the variables involved in the study, reducing this way the number of...

The hardened tool steel AISI O1 has increased strength, hardness, and wear resistance, which affects the complexity of the machining process. AISI O1 has also been classified as difficult to cut material hence optimum cutting parameters are required for the sustainable machining of the alloy. In this work, the effect of feed peer tooth (f z), cutti...

Selective laser melting (SLM) has emerged as one of the leading additive manufacturing (AM) processes for the fabrication of complex metallic components, due to its capability to achieve high quality at acceptable times. However, due to the complexity of physical phenomena occurring during SLM, such as heat transfer and phase transformations, laser...