Table of contents

The 11^thInternational Conference of Advanced Manufacturing Technologies, ICAMaT 2020, was organized by the Manufacturing Engineering Department (TCM) from University POLITEHNICA of Bucharest, Romania, Faculty of Industrial Engineering and Robotics, on 29^thof October 2020, with the remarkable participation of experts from Algeria, Austria, Republic of Moldova, Russia, Serbia and Ukraine. The organizers were happy to welcome participants from 21 academic and research institutions - which include 15 universities, four research centers and two companies.

The first ICAMaT Conference was held in 1999 under the acronym CITAF (derived from the abbreviation in Romanian) at the initiative of the Manufacturing Engineering Department (TCM) and had a national character. The following Conference sessions were held almost every two years and attracted increasingly more specialists.

List of title Scientific Committee, Reviewers are available in this Pdf.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

• Type of peer review: Single-blind

• Conference submission management system: Easy Chair

https://easychair.org/my/conference?conf=icamat20200#

• Number of submissions received: 44

• Number of submissions sent for review: 36

• Number of submissions accepted: 30

• Acceptance Rate (Number of Submissions Accepted / Number of Submissions Received X 100): 68.2 %

• Average number of reviews per paper: 2

• Total number of reviewers involved: 24

• Any additional info on review process:

• Contact person for queries: Tom SAVU (tom.savu@upb.ro)

The paper analyzes the effect of the vertical track irregularities upon the vibrations in a two-axle bogie. The method in use implies the bogie modelling and the measurement of the vibrations in wheelsets generated by the track vertical irregularities. The behaviour of vibrations in the bogie is evaluated via the results derived from applications of numerical simulation developed on the basis of the bogie model, where the inputs are the accelerations measured in the two wheelsets. The vibration features in the bogie are pointed out at according to the spectra of accelerations in the bogie frame, to the standard deviation values of accelerations and to the maximum values of the accelerations calculated against the two wheelsets.

Piezoelectric elements can produce a high displacement resolution with high force outputs but exhibits large hysteresis nonlinearities. An efficient way to compensate for nonlinearities is using a closed loop control technique. Another limitation for many applications is their relatively short displacement ranges. One method to avoid the above-mentioned shortcoming is to integrate a piezoelectric element with a mechanical displacement amplifier based on a compliant mechanism. This paper presents the design and closed-loop control of such a piezoelectric actuator. Using the integrated strain gauge sensors, a PI controller was designed and tested.

The issue of qualitative centering of the casing in wells with complex trajectory is considered. When choosing an effective centralizer, two competing requirements are simultaneously assigned to its mechanical properties. The centralizer must have sufficiently low stiffness in order to provide the descent of the casing into wellbore. At the same time, the centralizer must have high stiffness in order to provide proper clearance gap for high-quality cementing of the annular space. Several new designs of rod centralizers are proposed in the paper. Their main feature is that they are equipped with an additional thrust ring, which allows one to change the mechanical characteristics of the centralizer at high contact loadings. The boundary-value problems for the differential equations of mechanics of the arc rods with boundary conditions in the form of inequalities are formulated and solved. Analytical relations between the clamping force and mutual approach of the casing and the well wall, which characterize the radial stiffness of the centralizer equipped with axial thrust, are determined. It is established that the described designs of the centralizers have essentially nonlinear characteristics that contribute to the efficient centering of the casing. At vertical and slightly deviated from the vertical intervals of the wellbore, the centralizer behaves as soft and does not interfere with the descent of the string; at intervals with large curvature of the wellbore the stiffness of the centralizer increases due to the axial thrusts.

In the recent years, the scientific community's attention has gradually started to focus in finding solutions for pollution control and replacement of non-biodegradable products with natural products. In this matter, composite materials with natural fibres are increasingly interesting for different research studies. The present work regards a flax fibre-epoxy resin composite material, which the response is studied under tensile tests until break and repeated loading/unloading cycles. An independent variable under study has been material fibre direction of 0°, 90° and ± 45°, for both types of tests. Samples were extracted from thermo-compression fabricated plates with dimensions following the ASTM D 3039 standard. The experimental setup included an MTS C45 105 Universal Testing Machine, with variable load cells, an extensometer, as well as digital image correlation equipment. The devices allowed the determination of stressstrain curves as well as material constants and Poison ratio. Results show, for the 90° and ± 45° typical responses for composites with these fibre directions, but a particular evolution, bilinear for the 0°.

Railway transport systems play a very important role in the future of transport. They offer sustainable solutions that reduce carbon emissions (environmental requirements) and allow more mobility with better energy efficiency, and they generate advantageous economic benefits in the long term. But the interaction between the wheel and the rail is always very difficult to approach. There are a large number of studies in the literature on this problem. However, there is still no comprehensive approach. On this work we propose to study numerical modelling of contact between wheel-rail systems by using fuzzy logic. For this purpose, the experimental collection data reported in literature are used to predict the resonance noise during wheel-rail contact in rail transport. We found a good agreement between the elaborated model and the results of the literature.

The rapid variation of the wheel and rail profile influences, on one hand, the grip-pseudo-slip - wear characteristics, and on the other hand, the dynamic behavior of the vehicle, because the pseudo-slip forces are significantly influenced by the contact area and pressures from within this area. It must be borne in mind that, in most cases, the rail-road has deviations from the geometric dimensions, which must not affect traffic safety and the demands of the running gear and the track must be within the permissible limits. Railway switches ensure discontinuities on the railway causing high dynamic loads. In operation, the rail-way devices must ensure three basic requirements: safety against derailment, stability while on the move and passenger comfort. In this context the paper presents aspects of the multipoint wheel-rail-way switch contact using the Contact software. Considering the influence of sliding speeds on the contact phenomena at the intersection of the wheel with the running path, the paper presents an analysis of the kinematic behavior of the axle while passing over a point rail.

The paper presents a mathematical model and the design details to manufacture a prototype of a smart orthosis for posture correction while sitting on a chair at your office or at home. The global geometry for developing the mathematical model was obtained by direct measuring a human 3D model, developed by scanning one of the authors' body and 3D printing it. Based on the mathematical model, the detailed design for the entire product was performed in accordance with the product architecture. The stages of detailed design for the critical systems within the final assembly are also presented in the paper. The posture correction orthosis must be customized for each user, thus, once the design for the critical components has been validated, a parametric design has been generated to facilitate the manufacturing process. The technical solutions are generated and analysed for a vertebral element of the orthosis, representing the critical component of the product. The vertebral element is subject to mechanical stresses, so that a finite element analysis was performed. The geometry of the component and its material were validated by using FEA on the CAD model of the vertebral element. The further work will include research regarding the changes needed for transforming the orthosis into a medical device for spinal column illnesses.

Many industrial processes, such as chemical process and pharmaceuticals, use aggressive acidic and caustic solution which may result in an early failure of the components of plant. The various corrosion processes in harsh environments could be uniform corrosion, localized corrosion, galvanic corrosion, etc. In order to extend the life of components, a proper material selection is necessary. This direction is intended to address the behaviour of materials due to exposure in harsh environments. The main objective is to develop new vitreous coatings for different kind of materials as metals or glasses in order to protect them against acid attack. SiO₂-ZnO materials were prepared by chemical route in order to be used as protective coatings. The SiO₂-ZnO materials were investigated by infrared spectroscopy and differential thermal analysis in order to determine their structure and thermal characteristics. SEM and EDS measurements were performed to investigate their structure and morphology. The chemical resistance tests in acid media (HCl and HF) were followed based on STAS and ISO standards and the extraction solutions were tested by ICP-MS in order to identify elements lost during tests. Mechanical tests were performed.

Antireflection coatings have been widely used to increase the absorption of solar collectors and to reduce surface reflection. Many techniques have been explored to prepare thin coatings, such as sputtering, chemical etching, chemical vapour deposition, and sol-gel method. SiO₂-ZnO coatings were prepared on the surface of glass substrates via the sol-gel dip-coating process. The structural, morphological and optical properties of the coatings were characterized. The vitreous structure was identified by infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Morphology of materials was observed by scanning electron microscopy (SEM). The reflectance spectra were investigated and the optical performance of the structure was determined.

The process of micro-cutting with abrasive grain - complicated tribological phenomenon. The removal of the chip-shaped material from the surface of the semi-finished product is accompanied by elastic and plastic deformations of the surface, with heat releases and phase changes. One of the features of the grinding process and other types of abrasive processing, is that the removal of the chip especially takes place with negative front angles. According to [1] the average value of the front cutting angle values is within the limits -(46.6... 56.9). To the geometric parameters of the distant layer that characterizes the cutting process can be attributed: the thickness and width of the cut and the shrinkage of the chip. A series of scientific and manual works on cutting materials can be objected to the fact that in the process of deformation at cutting which is characterized by the coefficient of shrinkage of the chip a physical-mechanical influence has the characteristic of the processed material, the value of advance, depth of cutting and other parameters.

Nitriding is the most common and effective surface hardening method. Such chemical-thermal treatment is capable of increasing surface hardness, contact endurance, wear and seizure resistance, as well as heat resistance and corrosion resistance of a wide range of machine parts. This process of surface hardening has found its application in many branches of modern mechanical engineering. The operational requirements for the parts led to the need to replace high-temperature methods of chemical-thermal treatment (carburizing, high-temperature nitrocarburizing, etc.) for hardening processes at lower temperatures (500-650° C), namely nitriding. This replacement was facilitated by the latest technological developments in the field of various nitriding methods. The scientific developments obtained to date make it possible to gradually eliminate such disadvantages of nitriding as a significant duration of the process, increased fragility of the surface layer, insufficient values of contact endurance, and labor intensity of the process [1, 2].

On the basis of finite element analysis (FEA), geometric differences in the shaping during hot upsetting of cylindrical billets with a height-to-diameter ratio of 1.0 and 2.0 made of C45 (1.0503) steel and copper (Cu-ETP) between pointed convex conical dies with a cone slant angle of 12.5°, 15.0° and 17.5° are considered. The stroke velocity of the upper die is 0.5 m/s; process temperature (t) and accepted surface friction coefficient (|μ): for steel - t = 1100 °C, μ = 0.32, for copper - t = 850 °C, μ = 0.34. An equation is obtained for the relation between values of reduction in height ratio and engineering strain on height of workpiece during upsetting between conical dies, taking into account the initial billet dimensions and unevenness of forming due to the geometry of tool. The presence of qualitative and quantitative differences in shaping along the height of upset steel and copper billets was revealed, i.e. influence on unevenness of forming the rheological properties of materials under process conditions. It is advisable to use the results obtained to design and improve of technological processes of open die and closed die forging with preforming of billets.

The paper presents the research of plastic expansion of a pipe workpiece by punches of various configurations. It is shown that interest in this process is caused by the development of oil production, where there is a need to increase the diameter of well pipes, the automobile industry, where the protection of the driver and passengers in case of accidents comes first. Here, stable plastic deformation plays an important role as a good absorber of kinetic energy, etc. Data on the problems of expanding pipe ends are given, where special attention is paid to the destruction of the end in the form of localization of deformations and appearance of a longitudinal crack. To eliminate this phenomen onvarious technological methods are used. Here the influence of the design and shape of the punch on the localization of deformations along the thickness of the workpiece is researched. Several spatial outlines of the tool are proposed to create an effective reloading of the pipe workpiece in the deformation zone. Based on numerical modeling, the distribution of stresses according to Mises, the displacement of the end of the semi-finished product and logarithmic deformations in the radial direction is shown for each standard size of the punch. Comparative results reveal an increase in the thickness of the workpiece in the dangerous section for all presented punches. The comparison was carried out with a reference tool that has a straight generatrix of a tapered surface. The best results are shown by a punch with an enlarged generatrix at the end of the working stroke. Attention is focused on conducting further research in order to study the possibility of overcritical deformation by the proposed tool.

The article has grounded the necessity to develop an empirical power dependence of cutting modes influence on part surface roughness obtained during thread grinding. The calculations were carried out for grinding of parts made of steel and hard alloy. There have been developed a relation of part material properties, grinding wheel options, lubricating and cooling liquid (constant for concrete conditions of thread grinding), depth of cutting (thickness of a grinded layer per path), revolutions of a part and a wheel, longitudinal feed refer to obtained roughness. It has been stated that components of the grinding mode contribute in roughness values in different way, in particular they are arranged in the ascending order as follows: grinding depth, rotation speed, and detail's diameter.

One of the steps in designing a modular jig or fixture assembly is that of selecting the appropriate components. Among these components, those forming the jig's body must be chosen for closing the dimensional chains between the other locating, clamping, or indexing components. The methodology starts by defining the components' virtual connectors, specifying the rules for establishing their coordinates systems, and then is defining the rules to be followed for aligning and assembling two adjacent components. Different cases are described and only some of them are detailed, for clarity reasons. The algorithm is looking to determine a series of components from which the first is in a fixed position, related to other locating or clamping jig's component. A hierarchical tree is generated, using available components, having in each node a component which is assembled with a previous one using the above-mentioned connectors. Interference criteria is checked for selecting possible solutions only. A stop criterion related to the number of components in a branch is used, Solutions from the different branches are compared using the distances to an end component.

Minimizing machining time is an objective that must be taken into account when choosing the cutting tool. The diameter of the cutting tool is one of the parameters which greatly influences the machining time of different geometric shapes, especially pockets. In this study, a methodology for optimizing the choice of milling cutting tools for machining triangular pockets was proposed. An analytical model expressing the length of cutting tool paths has been optimized using sequential quadratic programming. the study carried out in this work leads to the conclusion that the spiral contour strategy makes it possible to have a minimum length for the machining of triangular shaped pockets.

The lack of comprehending and control of the micro-hardness of the machined surface is an important obstacle to the use of the milling process. In order to optimize the machining process by milling, this work has focused on the problem of micro-hardness changing of machined surfaces by milling, which has been the subject of several scientific works. A fuzzy inference model was developed to study the influence of cutting conditions (cutting speed, feed per tooth and depth of cut) on the micro-hardness of machined surfaces by milling. The predicted values, obtained by fuzzy model, are compatible with the experimental values, with an average error percentage of 0.63%.

Nowadays, several technological problems were raised by industrial beneficiaries regarding spiral and pipe heat exchangers repairs and thus studies were done in this regard. X2CrNiMo17-12-2, austenitic stainless steel pipes were considered for the experiments on which artificial defects, simulating functioning defects, were done. In order to perform the repair activities on the designed defects, WIG welding process was used and an experimental stand was created. This paper presents some of the difficulties that can occur during the repair by welding of pipes and the defects identified using destructive and non-destructive testing on the probes and samples created for the experimental study scope. Significant conclusions can be drawn; up to a distance of about 100 - 150 mm from the access end, the repair has a good appearance with no serious imperfections.

Among other problems to be solved, the design of a technological process of machining by cutting a part involves establishing the dimensions that can be achieved in the pre-final machining of the same surface of the part. There are distinct ways to calculate the so-called intermediate dimensions and, in particular, to define the dimensions for adjusting the position of the cutting tool tip before starting the actual machining process. The paper analyzes some such ways of establishing the intermediate dimensions, highlighting the conditions under which they can be applied, their advantages and limitations of use. Subsequently, the double-entry matrix method was applied to identify one or more methods with wider possibilities of use. It was concluded that the method of tolerance chart and respectively a method that takes into account a statistical processing of the results accumulated over time are methods likely to lead to an efficient solving the problem of determining the intermediate dimensions.

Artificial intelligence systems are usefully tools for estimation of different parameters for industrial and non-industrial applications. In this paper is presented a fuzzy logic application for surface roughness prediction for two material type for a CAM milling process. A minimum number of measurements have been made on a specific material (Al 6061) and were used for prediction of a roughness of another material (Al 7075). The link parameters between these materials, used in Fuzzy logic system, is the Rockwell hardness. In this way many correction parameters of cutting regime can be calculated in a short time with minimum resource (less experiments and tests needed).

When referring to product design assessment, even with a standard evaluation format, the perspective from which the criteria are approached differs strongly from one market category to another, this having a direct impact on the accuracy of the method. In order to achieve an objective assessment, the product must relate to a frame of reference in accordance with the product's destination, taking into account the user specifications and the actual experience of use. This paper represents the study of correlations between the market segment, product features and context and their degree of interdependence. Thus, analysing the relations between sections, the representative influence formulas for each considered feature were deduced, highlighting the extent to which the user's typology and context relate to the product features.

The rapid evolution of science and technology has forced the processes and systems of production, training and learning to adapt to innovation and the digital era of industrial technology. In the case of production processes and systems, innovation and digitalization refer to the transformation of production units into smart factories. In the case of training and learning processes and systems, innovation and digitalization lead to the creation of learning factories. Thus, this process involves the use of modern methods and techniques to develop innovative training, learning and production processes and systems. This paper is an analysis of recent studies and seeks to briefly present the evolution of industrial production processes and systems and Industry 4.0 but also the concept of learning factory. The paper also presents a review of the main methods and techniques used in innovative industrial training, learning and production processes and systems. Finally, some conclusions related to the use of these methods and techniques are summarized.

In the last period, logistics knew a strong technological evolution that has changed the way it operates and determined its transformation into innovative logistics, especially in the case of internal logistics. Innovation in internal logistics processes and systems consists in the use of different Industry 4.0 and digitization technologies. So, it is necessary to use modern methods and techniques to support the transformation of internal logistics processes and systems into innovative ones. This paper presents an analysis of recent studies, briefly presenting the evolution of the concept of logistics, the concepts of process and logistics system and Industry 4.0. Also, the most common methods and techniques used in the realization of innovative internal logistics systems are presented and some conclusions are presented regarding their use.

The new design of petal space antenna is considered in the paper. Various versions of solid petal-type mirrors have been considered and investigated in a number of articles and space projects. The classical scheme of petal type deployable space reflector was proposed and developed by Dornier Corporation within FIRST space project and was used in the Radioastron project to create a 10-meter antenna of space radio telescope. However, the classical petal mirror design has two significant drawbacks. Firstly, in the open state, the petals are cantilevered on the central mirror, what leads to low rigidity of the structure in open state. Secondly, in the classical design, the accuracy of the reflecting surface of the open mirror strongly depends on small errors in the operation of the deployment system. To overcome these drawbacks a new design of petal type mirror and a new system for precise opening of the mirror were proposed and studied. To test a new technical solution, a physical model of a deployable reflector was developed. The model contains a central mirror, a set of petals, hinges, locks and actuators for opening the mirror. 3D printing technology, CNC (computer numerical control) milling, plastic injection molding and carbon fiber technologies have been tested for central mirror and petals of the model fabrication. The results of computer and physical simulation are presented in the paper.

Engineering design problems involving a set of continuous, discrete and integer design variables and complex, non-convex objective functions and linear and non-linear constraints represent optimization problems with considerable complexity which are not trivial to solve. In recent years a number of optimization methods, particularly meta-heuristic optimization algorithms, were highlighted as effective optimization tools to deal with this type of engineering design problems. Despite certain advantages, their stochastic nature may be insufficient in dealing with various kinds of variables, constraints and objective functions. This paper discusses the application of developed software solution for solving engineering design optimization problems which is based on deterministic approach, i.e. the use of exhaustive iterative search algorithm. The use of the developed software solution is validated using four standard engineering design problems reported in the referential literature. In all case studies, the determined optimization solutions are equally good or better than those reported from other researchers using algorithms representative of the state-of-the-art in the area.

It is advisable to implement the use of key indicators by each company as a support for its continuous performant activity. Massive potential for optimisation can be found in the whole production industry. A scientific survey study has been designed and addressed to a number of companies from production industry in Europe. In the framework of this survey, the paper industry, as part of production industry, has been more profoundly analysed, in order to find the level of understanding and use of the key performance indicators and KPI systems, as an example. Based on the elements revealed by this analysis, a KPIs - Model for processes, production, financials, quality, supply chain, human resources and innovation is developed. This KPIs - Model can be a basis for the development of further KPIs - Models by any interested company, based on its specific conditions.