bluuebunny/crossref_metadata_2025 huggingface dataset:
The efficiency of electric power supply with the transmission of peak loads to distributed generation
Authors: Yu Brostilova T , Ageev V A , Golobokov S V , Sotnikov M V
Published: October 2021

A model of a radial power supply system in MatLAB was compiled to perform the research. The transformer substation is represented by a step-down transformer, the load of the substations in the form of a resistance. Electricity is transmitted to the substations along three power transmission lines. The power center is represented by an ideal source. A reserve source of limited power is connected to the remote substation. We made calculations of the voltage drop in the lines, voltage at the inputs of substations and electricity losses for transit. The study of the radial power supply system was performed in the daytime maximum mode; the minimum load mode was performed at night and in the peak load mode. As a result of modeling the operating modes, the indicators of the classical radial power supply scheme were compared with the indicators of the system when the local generation facilities were switched on during the working shift or during peak hours. Connection of reserve sources allows reducing voltage fluctuations along the line and reducing power losses for transit.
Numerical simulation of processes in the latent-heat thermal energy storage tank
Authors: Faizullin R O , Zakharova V Y , Baranenko A V
Published: October 2021

This paper has proposed a computer model for numerical calculations of heat flows in regular rhombic packed bed of capsules with phase change material. The mathematical model of heat transfer in a capsule is based on finding a zero-dimensional solution to the Stefan problem, considering the influence of convective flows arising in the liquid phase. To take into account the heat transfer due to the convective component in the liquid phase in the capsule, the effective thermal conductivity coefficient is calculated. An experimental dependence has been applied to describe the heat exchange conditions of the coolant and the capsule wall. The calculation is reduced to finding the temperature of the coolant t after passing one layer of packed bed. The resulting temperature is the input parameter for calculating the next layer. This operation is repeated until the calculation is made for all layers of packed bed. The numerical calculation has been performed in the mathematical software Scilab. According to the proposed model, the results of calculating the temperature of the coolant after passing the storage device correlate well with the experimental data for a thermal energy storage device with spherical capsules filled with paraffin.
Thermophysical analysis of heat-insulated glued laminated profiled timber for wooden houses
Authors: Tsvetkov N A , Kozlobrodov A N , Boldyryev S , Romanenko S V , Nemova T N , Tsvetkov D N
Published: October 2021

The paper presents the thermophysical analysis of two types of the wall system made of heat-insulated glued laminated timbers with connectors comprised of water-resisting multilayer plywood. The paper describes a novel timber configuration, which reduces the weight of one square meter area by 55% compared with an ordinary timber having a cross-section of 0.21 m × 0.21 m and saves not less than 60% of wood. The latter is highly relevant because forests remove carbon dioxide emissions from the atmosphere; reducing the use of wood in construction is of great importance for ecology. The ANSYS finite element program is used for calculating temperature fields and heat fluxes. It is found that one connector affects not more than 0.2 m of the exterior wall length in relation to the temperature and heat flux fields, whereas the heat loss increase is not over 0.44%.
Use of chelators and hydrofluoric acid for the improvement of well productivity
Authors: Khai Le Viet , Veliev M M , Sh Mukhametshin V , Veliev E M , Tyncherov K T , Andreev A V
Published: October 2021

The paper presents the results of microscopic analysis of the content of elements on the surface of clay samples after treatment with an acidic mixture of HV:HF. The analysis showed that as a result of the dissolution of clay and quartz, quartz dissolves faster, the Si/Al ratio on the sample surface decreased, which indicated the formation of a protective film of aluminum phosphate silicate. The studies of the ability of chemical reagents to dissolve clay by the method of weight loss showed that in the HV:HF system, the dissolution rate of clays is much lower due to the formation of a coating layer. The stage of the increase in the rate of dissolution occurs when a part of this layer is dissolved. The studies of the ability of the HV:HF chemical reagent system to dissolve silicon showed that the amount of dissolved silicon varied linearly with the exposure time and the rate of silicon dissolution was proportional to the HF concentration in the system. The dissolution rate of silicon in the HV:HF system is much higher than in the HCl:HF system at the same HF concentration. This is a significant advantage of the proposed system of chemical reagents HV: HF in comparison with the traditional HCl:HF system. HV: HF system dissolves calcium carbonate much more efficiently than traditional hydrochloric or acetic acid systems.
Aspects regarding the behaviour and comfort of reusable wool protective masks in the context of the COVID 19 pandemic
Authors: Dochia M , Kaminszky R , Fogorasi M S , Bucevschi A , Barbu I , Popa A , Nicolaescu C
Published: October 2021

In the current context of involvement in the fight against COVID 19 wearing protective masks are strictly necessary to limit the spread of the virus SARS-CoV2. Since the appearance of this virus, solutions have been sought to cover the needs of masks for the population and also to improve their wearing comfort compared to nonwoven fabric (TNT) masks. These masks are made of chemical fibres and it is recommended to be worn for a maximum of 4-8 hours and then they must be discarded. In this study, two types of masks from wool and silk blended knitted fabrics were manufactured and analysed. The masks were initially subjected to manual ironing sterilization and disinfection. Subsequently, several analyses were performed: specific mass, density, abrasion and pilling resistance, colourfastness to crocking, colour fastness to accelerated laundering, air permeability, bacterial filtration efficiency and breathability. The analysed masks can be washed and disinfected at home and are reusable. This aspect offers a strong sense of safety for the user, but also has beneficial effects on environmental protection. Even so, they do not correspond to bacterial filtration efficiency. Eventually, the comfort perception of about 300 volunteers was also taken into consideration.
Study of the functional parameters of main engine turbocharger for a tanker ship
Authors: Faităr C , Jugănaru D , Buzbuchi N , Stan L-C , Poenaru V
Published: October 2021

To correctly understand the requirements of a system, we must first study its schematics. In the case of energy systems, they require a detailed diagram of energy performance. Heat losses can be classified into high-temperature losses, medium-temperature and low-temperature losses. On board ships with low-speed propulsion engines, heat recovery systems operate in the range of 100-400 °C. Many residual energy recovery systems from internal combustion engines are under development: for example the MAN WHR development program for Tier III technologies. In this paper, I will treat both theoretical calculation elements and real elements of the operation of the turbocharging system, for the main reference engine. I chose to treat this system because it is a main subassembly for the engine, in terms of operation and thus its efficiency. In the theoretical calculation, I will start from the initial calculation data and I will expose the geometric and functional parameters of the turbocharger. The exhaust gases up to a temperature of 650 °C passes continuously through the turbine and heat its components, without its system of contraction cooling. In particular, the shaft bearing must withstand high operating temperatures without ever breaking the lubrication device. On the compressor side, the air is heated to over 200 °C. High temperatures lead to extreme thermal loads of the material in many locations. Speeds are extremely high: METxxSE turbochargers, as in figure 1, run at speeds between 10000 and 35000 rpm, depending on size. In this respect, the tangential speeds of 560 m / s and even more are reached at the compressor turbine, which rises to 1.7 times the speed of sound or 2000 km / h. The efficiency of the operation of the turbocharger system related to the main propulsion engine depends on the internal processes that take place in its operation, and also on the environmental conditions. In this way, the direction of processing on the installation is dictated by the engine load, taking into account the extreme situations, corresponding to the operation of the ship in special conditions (overload, tropical temperature, arctic temperature etc.).
Analysis of precipitates in heat treated thermo-mechanically processed steel with a high yield strength
Authors: Górka J , Poloczek T , Kotarska A , Jamrozik W
Published: October 2021

The aim of this study was to analyse the precipitates and determine their impact on the structure of thermomechanically processed high strength S700MC steel. The tested samples were subjected to a heating process at temperatures from 100°C up to 1300°C with a 100°C step. The chemical composition analysis in the micro-areas of the samples, thin-film tests and quantitative measurements of carbonitride precipitates were performed. In order to describe the grain size, a method of calculating the number of grains cut through the measuring line was used. In order to determine the effect of heat treatment on strength and plastic properties, Charpy V-notch, Vickers hardness and static tensile tests were carried out. The study showed that S700MC steel is characterized by a non-equivalent, fine-grained bainitic-ferritic structure. The test showed a significant impact of heat treatment on the strength and plastic properties of S700MC steel.
High-pressure water jet cutting of S235JR steel alloy. Influence of process parameters on dimensional accuracy
Authors: Grigoraș CC , Chiriță B , Brabie G , Zichil V , Herghelegiu E , Tâmpu C , Ciubotariu VA
Published: October 2021

This paper aims to determine the influence that water jet cutting parameters have on dimensional accuracy. The input parameters of this study were the workpiece material, that was made from 19 mm thick S235JR steel alloy plate, using a medium to high cutting pressure (2000, 2500, and 3000 bar), with a variable standoff distance (1, 2, and 3 mm) and a programmed quality of the cut from Q1 to Q5. A statistical interpretation of the results was conducted, and the experimental plan was obtained using the Response Surface Method. The samples were analysed for entrance and exit width of cut and kerf angle. A total number of 45 samples were measured, and the results were interpreted using an ANOVA analysis for statistical significance (p-value) and fit statistics (R2). The results have shown what values are optimum for the input parameters to obtain precision cutting quickly.
Finite element modelling of a plan polymeric composite product under impact and thermal conditions
Authors: Ion S M , Nitoi D , Chivu O , Opran C G
Published: October 2021

Polymeric composites products are undeniable trends today, especially in the most innovative fields and with a permanent degree of novelty. The specialized literature presents a very wide range of their applications in the avant-garde fields such as the aerospace field and that of the automotive industry. Paper presents the results of research on modelling and impact simulation of these types of products besides a transient temperature analyse using the finite element method. Starting from the experimental part through which a flat composite product is made, the authors research its behaviour on impact and at the same time try to make a mathematical model by the finite element method. This comes to complete the experimental research by providing information on the mechanical stress that occur during experimental testing. The properties of the materials both those used in the realization of the experimental product and in the simulation are those offered by the manufacturers. The input data used in the finite element simulation tries to provide an image as close as possible to the probable behaviour of the product in case of car crash. Considering obtained results, large-scale industrial application is envisaged for automotive polymeric composite parts leading to the increase of the safety of the traffic participants in optimal vehicle manufacturing conditions.
Design of production systems using computer modelling of human-robot interaction
Authors: Kampa A , Gołda G , Konysz D
Published: October 2021

Designing a production system is a complex process that requires many factors to be taken into account, including the interaction between a human and a machine. The industrial robot is a specific type of a handling machine, which can work similarly to a human, and can be used in different areas in a factory. Therefore, there is a need to consider all important human and robotic factors early in the manufacturing process and industrial system design. Especially the computer simulation of the production processes with the use of Discrete Event Simulation method, carried out for the needs of a new project, allows us to already include the process flow at the industry system planning stage, before real implementation. The purpose of this work is developing a framework of a digital twin of a manufacturing system. An example of a newly designed manufacturing system for the production of elements from the automotive industry is presented, as well as simulation models developed in the FlexSim program, which enables predefined parametrized objects for humans and robots. An area requiring improvement was defined, and the possible effects of these actions on the overall process were reengineered, considering the parameters of availability, performance, quality, and failure rate that make up the OFE (Overall Factory Effectiveness) metric. The information obtained during the simulation allowed us to define the location of the bottleneck in the process, and thus determine what to focus on during the implementation of the manufacturing line. In the future, the models will be expanded in perspective of using the digital twin in Industry 4.0.
An Analysis of the Thermal Simulation of Parts Processed by Cutting, with Different Geometries
Authors: Olaru I , Olaru C
Published: October 2021

In practice, different cutting processes are encountered, each process having different characteristics. Due to the existing friction forces between the workpiece and the cutting tool, a significant amount of heat is generated. This amount of heat can be determined by experimental measurements. With the help of the SolidWorks program, the geometric element that must be studied can be made, so that later it can be studied from the point of view of the thermal behaviors following the processing. We will take into account the different critical areas that may occur and that may materialize through areas where the final surface is not compliant. This paper aims to study the way in which the temperature is propagated in the workpiece, so that the phenomenon can be understood and determined how this excessive heat can be removed from the cutting area.
Structural strength evaluation of a 3000 dwt river-barge, under oblique quasi-static design waves
Authors: Perijoc D S , Domnisoru L , Angheluta C M
Published: October 2021

The present study consists of the 3D-FEM global structural analysis of a typical open-top, double-hull, 3000 DWT inland navigation barge, having 90 m in length. The 3D-FEM model developed to perform the evaluation idealizes the barge structure with high accuracy, average element size being in the range of 50-75 mm. Two loading cases were analyzed, consisting of the ballast and full loading conditions. For the equilibrium floating condition in calm water and oblique design waves, an eigen iterative scheme has been used to generate the input parameters for the 3D-FEM analyzed cases. The push-barge finite element model has been subjected to oblique quasi-static design waves, headings ranging from 0 to 75 degrees. Wave heights considered in the analysis range from 0 to 1.2 m, step 0.3 m, corresponding to the Danube navigation conditions and freeboard limit imposed by the classification societies for inland navigation vessels. Numerical results following the FE analysis have been assessed by the yielding stress ratio, von Mises criterion, and the maximum deformation, thus indicating the structural areas that need to be improved in the design process.
Optimisation of the production process in manufacturing a smart equipment for precision agriculture
Authors: Roşu M M , Cotfas P A , Iliescu M
Published: October 2021

The paper presents the optimizing process of a production system that it is intended for manufacturing process of a customized smart equipment. The initial variant (already in use) of this equipment dose no longer fit the requirements for precision agriculture so, new concept and, further, prototype development are to be done. The objective is to have smart innovative equipment suitable for digging furrows with controllable depth and geometric shape, not to mention its ability to determine soil’s moisture. The depth and geometric shape of the trench section are important elements in preparing the soil for irrigation as they ensure controlled slope for water runoff. Humidity is important for establishing and controlling the irrigation norm. Once the new equipment prototype is manufactured, tested and validated, it will be produced in series. For this it is necessary planning, programming and optimization of the production process so that to obtain a competitive product on the market through quality and price. Also, the transition from single production to series production involves great adaptability of the production process using self-optimization, self-configuration and self-diagnosis procedures, which are able to support and assist the human operator in the complex process of handling workpieces in the process.
Noninvasive evaluation of elastic properties for magnesium-calcium biodegradable alloys
Authors: Savin A , Steigmann R , Craus M L , Stanciu M D , Istrate B , Munteanu C
Published: October 2021

Bone injuries can be fixed and stabilized using degradable implants from magnesium - calcium alloys. Mg and Ca being natural elements in human body, they are easiest to be absorbed without causing toxicity problems. The aim of the paper is to present the effect of Gd and Mn addition in 0.5wt.% in order to improve elastic properties of Mg-Ca0.5-[E]x (E = Mn or Gd) and possibility to be used as biodegradable materials. The addition of Mn / Gd in the binary MgCa alloy modify the structural properties of the alloy (analyzed as elastic properties, respectively crystallographic structure). The measurements and the results calculus were carried out using the ultrasound methods and the Resonant Ultrasound Spectroscopy.
Influence of the ball screw stiffness on the positioning accuracy of the CNC machine tools
Authors: Stoica A , Stan G
Published: October 2021

This work is researching the ball screw stiffness influence on the positioning accuracy of the feed kinematic linkage of a CNC machine tool fitted with an indirect type measuring system for positioning the moving element. Because the machine tool is equipped with an indirect measuring system, backlashes and elastic deformations in the kinematic linkage cannot be offset by the position loop, consequently these are directly affecting the positioning accuracy. In this context, methods are used for diminishing their influence as well as compensation methods with a view to improve the positioning accuracy. Ways to preloading the ball screws and bearings of the ball screw are presented as well, by focussing on the optimisation, through calculations, of the preloading force value. An important component, analysed in this work, consists of the research of the ball screw–nut stiffness that depends on the strategy being used on the axial bearing of the two ends of the ball screw. The experimental tests have been performed at idle running on the CNC milling machine (CPFH 500), fitted with three controlled axes (X, Y and Z). Based on the experimental results, it may be noticed that, once increased the ball screw stiffness, within the limits stated by the ball screw supplier, the positioning accuracy will increase as well.
Thermal influence on the positioning accuracy of the CNC machine tool rotary tables
Authors: Tanase I , Stan G
Published: October 2021

This work analyses the perturbing thermal sources and design solutions to avoiding the thermal effects. The analysis is focused, as main factors of the thermal dilatation, on the rotary tables, the guiding systems, the radial one and, especially, the axial one (that takes over the weight of both table and work piece), as well as on the positioning of the driving servomotor that is a thermal source in the vicinity of the rotary table. The new solutions presented in this work refer to the rotary tables with direct measuring whose number of indexing positions is 360000 that means a minimum increment of 0.0001degrees. It is to be mentioned that this structure allows the kinematic linkage of the rotary table to take part to machining. If the rotary table provides positioning only, the table will have a clamping system that confers a high stiffness, needed for heavy duty cutting. The experimental trials have been carried out on a machining centre of the Micro-production workshop of the University in Bacau. The size of the rotary table is 630x630 mm. Repeated trials have been performed for determining the positioning accuracy through the modification of the thermal conditions of the worm-wormed gear mechanism. The results have proven an enhancement of the positioning accuracy of approximately 7%.
Laser welding of 4330V steel with a micro-additive of vanadium
Authors: Żuk M , Stano S
Published: October 2021

This article presents the results of a test of laser welding of high-strength low-alloy steel with a micro-additive of vanadium. Steel 4330V is a delivery material after heat treatment. Welded joint was made by laser welding using a TruDisk 12002 disc laser. As a result of welding, a joint was formed which was subjected to visual and penetration tests from the face side, as well as macro and microscopic tests. Impact tests were carried out at reduced temperature in the weld and in the heat affected zone (HAZ). The resulting joint was also subjected to the Vickers hardness test, bend test and the tensile strength test. This research show how the low-alloy high-strength material behaves during welding without processing before and after welding. In results after welding show incomplete penetration from the root side. No cracks on the weld face. In HAZ hardness was of 520HV0.5and tensile strength of joint was on level1077MPa.
Changes in Structure and Corrosion Resistance of Cryogenically Treated WC-Co Cemented Carbides
Authors: Bricín D , Průcha V , Jansa Z , Kříž A
Published: October 2021

The aim of this study was to evaluate changes in the corrosion resistance and microstructure of deeply cryogenic treated (DCT) cemented carbides (CC). Changes in corrosion resistance were determined by potentiodynamic testing in artificial mine water. Microstructural changes were characterized using X-ray diffraction analysis. Four sorts of WC-Co cemented carbides with different WC grain sizes and volume fractions of cobalt binder were used for the experiment. Specimens were divided into two groups. The first group of specimens was deeply cryogenic treated (DCT) at -186°C in dry liquid nitrogen vapor. The second group of specimens was tempered at 450°C. The results of the experiments show that DCT increased the amount of ε-Co in all the types of CC compared to the tempered group of specimens. This microstructural change and a change in the micro-stresses in the surfaces of the specimens contributed to increasing the corrosion resistance of CC after DCT.
Study of particle size and position on debris evacuation during Wire EDM operations
Authors: Izquierdo B , Wang J , Sánchez J A , Ayesta I
Published: October 2021

Wire Electrical Discharge Machining (WEDM) is a well-known non-conventional machining process for those applications that require both good finishing and tight tolerances. One of the main problems that occur during EDM operations is wire breakage, which leads to stops in the machining process and lowers process productivity. Recent findings have revealed that discharge accumulations near the same spot of the wire are the main cause for wire breakage. If this discharge accumulation is not stopped, the wire finally breaks. In the present work CFD simulations have been effectively used to simulate dielectric flow and particle movement. The effect of particle size and position, together with the effect of high and low pressure flushing conditions have been analyzed. The studied variables have a clear effect on debris evacuation, and it can be concluded that particle size and position, together with nozzle position affect process stability and wire breakage. This work can help to develop new WEDM strategies that consider the relation between mentioned variables and wire breakage.
Preliminary study of abrasive water jet texturing on low thickness UNS A92024 alloy sheets
Authors: Bañon F , Sambruno A , Gómez A , Mayuet P F
Published: October 2021

Texturing and surface modification operations are a line of research of great interest nowadays. The requirement to establish a process that can generate a constant and homogeneous roughness as a previous step to joining operations, application of paint or mechanical tests is a current challenge. Technologies such as shot blasting or laser texturing have achieved great results in terms of roughness and surface activation. Nevertheless, there is an alternative technology that is achieving great interest. Abrasive water jet texturing takes advantage of the combination of the impact of abrasive particles and water at high speed with the controlled displacement of the jet to generate a surface with a controlled roughness. Thus, in comparison with other technologies, abrasive waterjet texturing can achieve higher roughness values and a constant texturing area as a function of the overlap established between the passes. In this work, a preliminary study is proposed in order to establish a direct relationship between the parameters governing the technology and the roughness generated in a low thickness UNS A92024 alloy. Defectology associated to the process, as well as the combination of texturing parameters have been determined.
3D printing of spare parts: experimental study using non-standardized tests of the maximum supported torque
Authors: Cerro A , Molero E , González R , Romero P E
Published: October 2021

Industry 4.0 is scanning the spare parts of your machines and printing them directly when they are needed. This reduces storage space and shortens downtimes associated with corrective maintenance. In this work, we study which printing factors are the most important in spare parts that are going to be subjected to torque and have been manufactured by fused deposition modelling. For this purpose, an L16 design of experiments with three factors and two levels has been carried out. The factors studied were: number of shells, infill pattern and infill density. Following this design of experiments, cylindrical specimens with hexagonal heads were manufactured. These specimens were subjected to a non-standardized torsion test. From the experimental results, using the Taguchi method and the analysis of variance, it was found that the factors that most influence the maximum torque reached by the parts are the number of shells and the infill density. As a practical application of the work, the spare part for a water heater selector has been manufactured, using 5 shells and a density of 80 %.
Tensile properties of elastomer process through FFF for biomedical applications
Authors: Adrover B , Lluma J , Jerez R , Travieso J A
Published: October 2021

3D printing technology, specifically the fused filament fabrication technique (FFF), is growing in both, industrial and private sector. Due to the large number of possible applications for parts built through this technique, the need to study new materials increases. This paper aims to characterize a thermoplastic elastomer material, TPE 96A. TPE is a flexible material that, among others, can have applications in the field of biomedicine thanks to its flexibility and strength. In order to study the material, two controlled printing parameters (layer height and fill density) are related with its mechanical properties defining the responses obtained in a tensile test. A factorial design of experiments is applied to optimize the process. The specimens are manufactured according to the ASTM D638 standard. Finally, the results will be analyzed by means of an analysis of variance test (ANOVA). Results show that the highest Young’s modulus achieved experimentally is 129 MPa if a combination of 75% of fill density and a 0.2 mm layer height is used for manufacturing the samples.
Presentation of a concrete additive manufacturing extruder with online rheology modification capabilities
Authors: Poudelet L , Castellví A , Calvo L , Cardona R , Uceda R , Fenollosa F
Published: October 2021

To date, Additive Manufacturing (AM), a driving technology for the Industry 4.0 paradigm, is a growing technology field but has not reached relevant impact in the construction sector. The reason exposed in this article is the fact that current capabilities in terms of control of the setting reaction of concrete in real time are limited. Experimentation with a state-of-the-art concrete AM print-head has evidenced that the full stabilization of concrete’s chemical reactions is complex and involves phenomena that are not yet fully understood. Addressing this problem and the development of a fully automatic closed loop control would allow a great step forward in the capabilities of concrete additive manufacturing. So, as a first step, valuable information from thermal and pressure sensors were collected along the printing process, and their variations associated with the control of actuators (mixers and pumps) have been noted. A path for full real-time automatic control can be foreseen, and will guide future research and developments.
The commissioning of a hybrid multi-material 3D printer
Authors: Castellví A , Poudelet L , Tejo A , Calvo L , Uceda R , Lustig P , Minguella J , Buj I , Fenollosa F , Krauel L , Valls A , Ayats M
Published: October 2021

Additive Manufacturing (AM) has rapidly become an important technology in both research and industry. This development has allowed the evolution of 3D printers which are able to print complex geometries at low costs and faster than traditional methods. Despite this, most of these printers are either only for using one material or one technology. This limits a lot its use in different sectors such as aeronautics, automotive or health, because multi-material prototypes are needed. For example, surgeons need surgical planning prototypes for preoperative planning. These 3D printed prototypes have mainly been manufactured using just one technology. As a result, the prototypes have some main limitations: (1) do not actually mimic the anatomical structures of the human body, (2) high costs specially for Material Jetting and Powder Bed Fusion AM technologies. Therefore, the aim of present manuscript is the design, development, and commissioning of a hybrid multi-material 3D printer.
Lean Safety - assessment of the impact of 5S and Visual Management on safety
Authors: Sá J C , Manuel V , Silva F J G , Santos G , Ferreira L P , Pereira T , Carvalho M
Published: October 2021

This study was developed in a furniture company and aimed to implement some Lean tools, such as 5S and Visual Management to reduce waste, by improving the production process. To carry out this analysis an observation plan was used, having the Spaghetti diagram as a reference as well as the value-added analysis of the operations. The implementation of 5S’s allowed the improvement of the visual management and the organization through a reorganization of the layout, as well as normalization of the production process. With this, a reduction of 40% was achieved in terms of waste related to activities that did not add value to the product, such as unnecessary movements, waiting times and even movement of materials, having achieved a level of productivity of 74% and 87% in the finishing and joinery sections, respectively. In addition to improvements in the production process, the impact of the measures at the safety level (lean safety) was assessed. For this purpose, a questionnaire was prepared to assess the opinion of the employees, in which 40% considered that the implementation of the tools provided a greater motivation to develop their work activities safely.
Evaluation of mechanical properties of FDM components reinforced with fibre
Authors: Rodríguez P , Zapico P , Robles P E , Soto A , Barreiro J
Published: October 2021

This research analyses the influence of different parameters of the Fused Deposition Modelling process with continuous carbon fibre reinforcement upon tensile strength of manufactured parts. For that, the appropriate behaviour of specimens designed according to ISO 527 standard was verified, in a preliminary test. Hereafter, a full factorial Design of Experiment was proposed with five parameters and two levels. After manufacturing and testing the specimens, a regression including all possible interactions of the parameters was performed with their tensile results. This model was optimized, considering the terms with the highest statistical significance (p-value less than 0.05), so that a simplified model of 14 terms with an r-squared of 97.5% was obtained. Thanks to this research the tensile response of a printed part as a function of the chosen manufacturing parameters can be predicted in advance.
Robust metrological characterization of circular profiles
Authors: Greco L , Caja J , Maresca P
Published: October 2021

Outliers are likely to corrupt data acquired by optical profiles and ignoring them can badly affect the output of the analysis. The occurrence of very few outliers can completely invalidate the fitting process and uncertainty evaluations. Outliers are unexpected values that often mask each other being not detectable by any pre-screening of the data. Therefore, there is the need to adopt a proper robust approach to fit circular profiles data and identify data inadequacies. Here, it is suggested to resort to impartial trimming to fit the centre and the radius of a circle. The optimization problem is based on a subset of the data after discarding that fraction of points with the largest distance from the fitted centre. Trimmed observation are likely to be outliers. The methodology is illustrated through both synthetic and real data.
Merging complex information in high speed broaching operations in order to obtain a robust machining process
Authors: Del Olmo A , Martínez de Pissón G , Sastoque L , Fernández A , Calleja A , López De Lacalle L N
Published: October 2021

Current machine-tool users require more unattended machine centres due to the high competition in the global market of manufacturing. As a result, the control and monitoring systems became of utmost importance to detect the different events that could happen during the machining process. For example, broaching process is critical for firtree machining in turbine and automotive components. Tight tolerances and high productivity are the two main requirements for this kind of operation; therefore, it is essential to capture any anomaly during the process, that could damage the piece. This work proposes an alternative way of monitoring broaching process, based on machine internal signals, instead of the use of expensive force sensors for cutting force measurement. This paper presents an indirect monitoring procedure and its application in AISI 1045 high-speed broaching. The results showed the correlation between cutting force and servomotor power consumption, is as a good parameter in the monitoring process of vertical high-speed broaching forces, capable of capture even changes in the cutting forces range of 500N.
Design of a machine to rectify ceramic tiles for laboratory tests
Authors: Serrano J , Abellán J V , Bruscas G M
Published: October 2021

The tile rectification process, also called squaring, consists of machining the edges of the tile to make them straight, parallel two by two and perpendicular to the other two in addition to controlling the size of the tile (calibrating). The current industrial lines are based on multiple heads (abrasive wheels) where the characterization of the process in terms of product quality and power consumption is hard to be conducted. In this work we present a laboratory machine equipped with a single grinding wheel to be used for testing and simulating the working conditions of a conventional rectification tile. The specifications of the machine that are required and the analysis of the different functional systems designed (clamping and motion, cutting, cooling, structure/enclosure, and electrical/control system) is reported. This machine may lead researchers to characterize the rectification process and propose actions for improving the efficiency and the sustainability of the industrial process.
Machine-dynamics monitoring for L-DED operations
Authors: Arrizubieta J I , Ruiz J E , Ostolaza M , Ukar E , Lamikiz A
Published: October 2021

Laser Directed Energy Deposition is an Additive Manufacturing technology that enables repairing or coating high-added-value components. The obtained results depend on the process parameters, but also on the machine dynamics, e.g. the capability of the machine to follow the programmed trajectory at a constant velocity. In the present research work, the response of a laser machine and a FAGOR 8070 CNC control at different situations is analysed. Special attention is paid to the trajectory smoothing command of the control. The machine acceleration is found to affect the initial and final accelerations, but not the velocity reduction in the direction change. On the contrary, the value of the chordal error influences the machine deceleration in the direction change corner, whereas its influence is almost negligible in the initial and final accelerations.
Numerical investigation of deposition strategies on the residual stress and geometrical deviation in Laser Metal Deposition
Authors: Ghasempour M , Afonso D , Torcato R
Published: October 2021

In the current study, effect of deposition strategy on the residual stress, geometrical deviation, area change, and temperature distribution has been investigated. To do so, four different strategies namely continuous, two direction raster, inside-out contouring, outside-in contouring with the same process parameters were used. To run simulation, Simufact software was used and both powder and substrate were considered as deformable part with SS316. Having run the simulation, the most important results are as follows: maximum and minimum residual stress occurred by using continuous and outside-in contouring, respectively. The maximum and minimum total displacement (total geometrical deviation) occurred by applying inside-out contouring and outside-in contouring, respectively.
Development of Machine Learning prediction models for their integration in a Digital Twin for a tapered roller bearing production line
Authors: Domínguez J , Esteban A , Romeo J A , Cebrián F , Domingo S Santo , Aguilar J J
Published: October 2021

The aim of this work is to develop the prediction models that are integrated in a digital twin for a tapered roller bearing multi-stage production line. The manufacturing process consists of rings machining and component assembly processes, including intense quality control. This work proposes the use of machine learning techniques for a 4-step strategy which consists of: a data analysis, the development of one prediction model for the manufacture of the double outer ring, one model for the two inners rings, and finally their integration in the digital twin. The strategy is validated with real data. Several regression techniques are tested and the selected model is the exponential regression due to its better performance when compared with other algorithms. Once incorporated in the digital twin, the developed models can predict the process behaviour under potential changes so determining the optimum operating conditions can be fairly facilitated; as well as predict the final bearing setting under different machining conditions.
Modular and flexible Automation Middleware based on LabVIEW and OPC UA
Authors: Künzel A , Puchta A , Gönnheimer P , Fleischer J
Published: October 2021

The increasing automation level of processes in production systems leads to new technical challenges, especially in the implementation and maintenance of software architectures. New requirements arise regarding the interface between Programmable Logic Controllers (PLC), robots, Human Machine Interfaces (HMI) and superordinate information systems (e.g. ERP). Industry 4.0 demands, among other things, an increase in flexibility, adaptability and transparency to achieve vertical and horizontal interoperability and a continuous integration. The innovative automation middleware is capable of replacing the heterogeneous interface landscape, which currently exists in many companies and institutions. The basic idea is the implementation of a modular and standardized middleware. Due to relevant characteristics, such as dataflow orientation and graphical programming interface, using LabVIEW as a programming language turned out to be the most suitable solution. The system deploys OPC Unified Architecture (OPC UA) to connect all required components across multiple enterprise levels. Moreover, the software solution controls the workflow and collects process data for further analysis. In contrast to software products available on the market, which usually come along with manufacturer dependencies, the established middleware based on the combination LabVIEW and OPC UA is transparent, extensible and independent.
Development of a modular kit to improve DFA learning
Authors: Serrano J , Benavent S , Bruscas G M , Abellán J V , Rosado P , Romero F
Published: October 2021

DFA (Design for assembly) is an important part of the contents included in some of the manufacturing courses taught at Jaume I University. DFA is a tool to analyse and improve product design from an assembly point of view. Although DFA contents had been covered using different teaching activities (theoretical, problem and laboratory sessions), the results in students’ assessment revealed that the expected learning outcomes were not being achieved. In particular, results were especially unsatisfactory in the practical application of DFA. Students misunderstood concepts such as “handling” and “insertion” operations, and failed at identifying assembly problems related to thickness or alignment among others. A learning by doing approach has been proved to improve students’ learning and engagement, as they take an active role and have the opportunity of doing things themselves. In a previous work, a specific modular and reconfigurable kit to improve DFA learning by experimentation was designed. Based on this work, this paper presents the analysis of the results obtained in two different courses where the modular kit has been used by students in a new seminar session.
Digital skills mentoring for online teaching and evaluation in the Industrial Engineering Faculty of the University of Málaga
Authors: Lozano M M , Martín S , Herrera M , Cano M J , Sevilla L
Published: October 2021

COVID-19 pandemic has forced the usual face-to-face educative activities to change to e-learning processes. When the faculty has the necessary knowledge on digital skills this obligatory step becomes easier. Videoconferences, as synchronous communication tool and Learning Management Systems (LSM) allow to carry out the e-learning actuations. The University of Málaga has required to adapt its educative activities to e-learning processes due to the pandemic. To facilitate this change, a digital skill mentoring actuation has been implemented in all faculties of the University of Málaga. The digital skill actuations have been related with evaluation processes and with communication systems to development the teaching classes. In this work, the experience in the Faculty of Industrial Engineering of the University of Malaga, is exposed. The results obtained show that the previous LSM used by the University of Malaga facilitated the change to the e-learning process in the Faculty of Industrial Engineering.
Creation of a virtual museum as a learning tool in the teaching of the Manufacturing Engineering subject
Authors: Martín M J , Martín F , Cano M J
Published: October 2021

Teaching subjects such as Manufacturing Engineering requires the use of effective teaching tools, which help students in their learning process. While the traditional transmission model can be effective when teaching concepts and theoretical contents, others activities are essential to allow students to participate, act or reflect, thus developing skills and competences, such as communication, teamwork, and creativity. This paper presents a learning tool based on the creation of a virtual museum related to the Manufacturing Engineering field, which is included as a coursework in the teaching program of the subject “Manufacturing Engineering”. This subject is taught at the second year of different degrees at the Industrial Engineering School of the University of Malaga and a percentage of its final grade comes from this activity. The museum is materialized through the posters whose format is similar to those presented at conferences and whose content may be referred to three topics (object, process or biography). Once the students are given the necessary instructions, each project is selected by a work group and its development is supervised in the next two sessions by the lecturer. In the final stage, each group gives the presentation about their work. The analysis of the students’ grades obtained from both this activity and the whole subject makes it possible to quantify the impact of this type of activities on the student learning and achievement. Eventually, best posters will be part of the department collection, being accessible to students in subsequent years.