bluuebunny/crossref_metadata_2025 huggingface dataset:
The importance of the technical specification of works for the ships repair processes in the maritime shipyards
Authors: Manea M G , Zăgan R , Manea E
Published: October 2021

The technical specification purpose is to include the ship maintenance and improvement works needed to be carried out onboard in a repair shipyard, so that after these works performing to allow for the classification society certification, thus confirming the ship satisfactory technical condition and the relevant requirements of the classification rules were applied, thus confirming the applied management maintenance also. The technical specification has a very important role for the evaluations, done by the shipyard in preparing price and time quotation and the owner / manager, done for the comparison analyzing based on the evidence that the maintenance and improvement workflows performing on board the ship in a shipyard for works depend on the technical specification quality of preparation, which means that had to provide the necessary information in relation to the volume and type of works needed to be carried to the ship hull and structures, machinery, equipment, plants and systems supported by the necessary technical information plans approved by the classification society and the works sheets documentation referring to the followings: work location / equipment thereof number of pieces; types of the works required to be performed on location / equipment; works estimated required to be undertaken on location / equipment. The advantage of a quality technical specification is the limitation of the possibility of ordering additional works during the execution of works for maintenance, upkeeping and improvements on board the shipyard, the costs of the shipyard and the ship being thus maintained at the estimated budgets. The paper purpose is to highlight the advantages of a good quality technical specifications which consists of limiting the possible means of developing additional orders during the execution of maintenance and improvement works on board, thus the shipyard and ship costs being possible to be kept within the original estimated budget margins.
Behavior of Arboblend V2 Nature under AWJ machining
Authors: Marguta D , Herghelegiu E , Tampu C , Mazurchevici S-N , Nedelcu D
Published: October 2021

The harmful effects on the environment caused by the overexploitation of fossil resources and their industrial processing have attracted the attention of researchers worldwide. Their interest is not only in the use of biodegradable materials based on renewable natural resources but also in the use of manufacturing and processing technologies that minimize as much as possible the negative footprint left on the natural ecosystem. In the present paper, the thermoplastic material processed using abrasive water jet cutting technology (AWJ) is Arboblend V2 Nature. Thus, both the processed material and the technology closely follow the interests of the researchers. The study aims to obtain surfaces with higher quality than other synthetic polymers by appropriate variation of process parameters (abrasive material flow, traverse speed and pressure). Two methods for determining the roughness were used, one in accordance with the standard and one adopted by the authors in order to render more accurately the surface roughness value. Other output parameters observed were: the amount of material removed, the width of the machined surface, the deviation from the perpendicularity and the inclination angle of the machined surface. The output parameters result confirms the possibility of using the parts obtained by AWJ in engineering applications and not only because the shape deviations fall within the limitations imposed at the industrial level.
Expanded glass spheres applications for low thermal transfer
Authors: Mocanita O , Chicet D , Istrate B , Raileanu L , Munteanu C
Published: October 2021

This study addresses the possibility of using expanded glass to obtain elements with low thermal transfer and stable from a geometric point of view when exposed to high temperatures, which may later be part of a fire-resistant multi-layer element. For this purpose, three types of recipes were designed and produced, which are composed of expanded foam glass spheres bounded with polymeric resin. Subsequently, 3 sets of each sample were subjected to baking: T1 (heating to 700°C, maintaining for 3 hours, oven cooling); T2 (heating to 600 ° C, maintaining for 3 hours, oven cooling); T3 (heating to 600° C, oven cooling). The 4 sets of samples (1 set in initial state and 3 sets of heat treated samples) were exposed for 1 hour at direct flame. It was found that the samples maintained their structural integrity and all three types of material ensure a temperature difference between the side exposed to temperature and the unexposed side higher than 200°C (considered satisfactory according to SREN 1363-1 / 2001).
Path finding and guidance algorithms for autonomous mobile robots in a tree structure network
Authors: Nanu S , Belgiu G , Dan A-M , Berdich A , Anistoroaei A
Published: October 2021

Considering an autonomous mobile robot that has to navigate indoor and outdoor from a certain point towards another certain point in a tree structure, the paper is giving a solution for finding the path and navigation. The mathematical model is proposed for a number nDP of departure/destination points (DP), a number nIP of intersection points (IP) and connections between them in a tree structure. Based on mathematical model, the problems solved and presented in this paper are i) to find a path from any departure point to any destination point, ii) to generate an algorithm for guidance of an autonomous robot to follow the path. Both algorithms were tested on Matlab Simulink® environment. An implementation of algorithms in a pseudocode is presented. The algorithms were adapted to be implemented on a microcontroller based board. The advantage of algorithms and implementation is simplicity. The outcome is less memory consumption and increased computing and execution speed.
Race car mirror cover production focused on reducing air drag
Authors: Nowak A , Baier A , Kołodziej A , Żur P
Published: October 2021

The paper presents a mirror cover manufacturing process, focused on geometry optimization by reducing air drag for Silesian Greenpower electric car. Silesian Greenpower is a student’s interfaculty project, of which aim is to design, build, and race an electric vehicle. Each car is equipped with the same motor and batteries. Target is to finish as many laps as possible during a set amount of time. Major development takes place in aerodynamics to decrease movement resistance. In the presented development process, computer-aided design software was used to create part concepts and then aerodynamics simulation was carried out to determine quality of each design. The influence of chosen geometric parameters was analysed and discussed in the article. The final concept was manufactured using 3D-printing technology with ABS - acrylonitrile butadiene styrene, because of good mechanical properties but also availability and relatively low cost. 3D˗printed elements were verified experimentally using smoke stream generator.
Application of digital twins in specific manufacturing processes
Authors: Olender-Skóra M
Published: October 2021

Following the requirements of the modern economic environment is a challenge for entrepreneurs. The more, that there is an increasing need to manufacture product for individual customers, the so-called customization approach. As a result, the production is individualized, so that the repeatability of products and stocks is low. This forces companies to apply specific organizational development strategies such as Lean and Agile. It also forces an increase in flexibility of the implementation of individual production tasks of enterprises. Increased production flexibility, at the same time, influences a greater number of decisions made, data generation and the use of enterprise resources. For this purpose, entrepreneurs use various simulations approaches, including applications for simulation of complex production processes, but nowadays they are increasingly leaning towards the so-called digital twins. The article presents the possibility of using a digital twin and the necessary data required to make such a twin in order to reflect the actual activities carried out in production.
Effect of Ti and C alloyants on the microstructure of laser cladded cobalt-chromium coatings
Authors: Poloczek T , Janicki D , Górka J , Kotarska A
Published: October 2021

The article presents the results of Ti and C additives on the microstructure of the Metcoclad 6 coating. Effect of chemical composition with optimal laser cladding parameters has been studied in the terms of modification of the carbide morphology. The experiments were carried out on TruDisk 3302 Yb:YAG disk, equipped with a disc powder feeder. As a deposited material Metcoclad 6 powder produced in inert gas-atomization process was used. To assess the impact of alloying elements on microstructure, SEM observations and EDS analysis were carried out. Vickers microhardness tests were provided on the cross-section of coatings on Wilson Wolpert 401 MVD device. It has been stated that addition of titanium changes the morphology of carbides from lamellar eutectic carbides to isolated primary TiC while addition of Ti and graphite allowed to maintain the structure typical for pure Stellite 6 alloy, but additional formation of primary carbides were observed.
Non-Destructive Determination of the Elastic and Acoustic Properties of Resonant Wood Used in the Manufacture of Violins
Authors: Stanciu M D , Gliga V G , Georgescu SV , Savin A , Dobrescu G
Published: October 2021

The aim of the paper was to determine the acoustic characteristics (speed of sound propagation in wood) and elastic (modulus of elasticity) on the three directions of wood, using non-destructive methods. The samples studied were cubic in shape from spruce and maple wood species, resonant and common. To determine the Young’s modulus and shear modules as well as the Poisson’s ratios, the expression of the propagation of Lamb waves generated and received using US translators with Hertzian contact with fr = 100kHz was used. The experimental data obtained show that mainly the velocities in radial and tangential direction are about one third of the longitudinal velocity, with the radial velocity higher than the tangential one. The radial velocity can be up to almost 14% higher than the tangential velocity. The applicability of this study consists in establishing the acoustic quality of the resonant wood from the Romanian area, used in the manufacture of our violins from the country.
Numerical Modal Analysis of Kinked Bars –Triangle Case of Study
Authors: Stanciu M D , Trandafir M , Dron G , Munteanu M V , Bucur V
Published: October 2021

The paper deals with numerical modal analysis of a kinked bars similar with an open triangle, with different sizes, angles and diameters of bar. Using SIMCENTER software, the first step was to design the geometry of each type of structure, then discretization of model in finite elements and assigning properties of material (in this case, Al alloy). The results in terms of eigenvalues and eigenmodes of each structure revealed that the angles of kinked bars influenced the value of natural frequency: with increase the tip angle from 30° to 60° and 90°, the eigenvalue decreased in ratio of 1:1.39:1.611. Also, the length of each side of the kinked bar influences the modal response of the structure: increasing the length from 200 mm to 450 mm, leads to decreases of eigenvalue of almost 5.6 times. The applicability of this study is linked to percussion instruments used in musical orchestra and also to explain the energy transfer and acoustic effect of different types of triangle instruments.
Dimensional measuring of parts as function of temperature variation and FEM study
Authors: Stanciu F , Nitoi D , Chivu O , Tăpȃrdea A
Published: October 2021

The components of astructure can be made in many different areas by many suppliers, before being brought together as a single final. Measuring geometry and geometric dimensions of a structure is an essential process in establishing product quality. Dimensional measurement is often affected by several human or physical factors, of which temperature is an essential factor in introducing deviations. Often the expected results are out of specification due to temperature variation. Paper aims to present the effects due to temperature variations in dimensional measurement as well as way to solve problems. One of the problems in the measurement process is the lack of repeatability in measuring tolerated dimensions. The study presents measurements in the conditions of volumetric thermal expansion of AMCs and measured parts, which are directly influenced by temperature. The need to verify the accuracy of measurements and control of equipment is an important step for quality departments in this industry because the quality of production is based on the target of “zero defects” so the need to know about the condition of equipment is extremely important. In specific cases in addition to the normal calibration which is according to international standard ISO 10360-2: 2009 as a mandatory application, the same standard determines the need to perform re-verification tests according to user specifications, looking for deviations that should not occurs in systematic errors. Also, the international standard ISO 17025: 2005 which defines the general requirements for testing and calibration components of laboratories, in point 5.5.10 of the technical requirements it is said that intermediate checks are necessary to maintain confidence in the calibration status of equipment, these checks having to be done according to a specific procedure. Three techniques for assessing measurement uncertainty are presented in ISO 15530-; they can be used alone or in combinations. The first of these is known as sensitivity analysis and is described in the ISO Guide for Expressing Uncertainty in Measurement. Modeling and simulation can help evaluate the size of a part as a function of temperature. The article presents in the second part this method which offers values very close to the experimental ones and which may in the future simulate the values of the measurements where the experimental part is difficult to be done.
Analysis of the turning efficiency of the Cu-Ni 70/30 ASTM B122 alloy under minimum quantity of lubricant conditions
Authors: García E , Miguel V , Martínez A , Manjabacas M C , Coello J
Published: October 2021

Traditional flood lubrication on machining processes involves a severe environmental risk due to the high quantity of contaminant that is deposited on the atmosphere. For this reason, the search of more sustainable lubrication methods is necessary. This paper analyses the minimum quantity of lubricant (MQL) procedure on the turning of copper-nickel ASTM B122 alloy in terms of cutting forces and surface integrity in comparison to dry cutting, using two different cutting oils: a synthetic vegetable oil and a synthetic mineral one. The aim is to find out the lower limit of cutting oil flow rate needed to improve the cutting condition. The results show that MQL conditions improve the efficiency of the turning process of this alloy, being effective in cutting force reduction and limiting the surface adhesions and defects. Besides, vegetable oil performance is better than mineral one. It has been found that flow rate needed depends on the depth of cut.
Turning process with ceramic inserts of ADI cast material, surface analysis
Authors: Fernández A , González H , Fernández P , Calleja A , Urbikain G , López De Lacalle L N
Published: October 2021

Austempered ductile iron castings (ADI) are widely used due to their main characteristics, high resistance to fatigue, impacts, high strength and wear resistance, among others. These mechanical properties of ADI are achieved performing a heat treatment to produce an ausferrite microstructure, leading ADI to be considered to reduce the weight of industrial components and satisfy the most demanding mechanical requirements. The main challenge derived from these heat-treatments is the low machinability. Therefore, a precise control of the microstructure after turning is essential to optimize the cutting process. In this paper, some tests were performed using ceramic tools for dry turning of ADI castings. Based on previous works, cutting parameters are defined to perform an integrity analysis of the obtained surface: microstructure, residual stresses and microhardness were analysed.
Deep hole finishing of Inconel 718 SLMed features by endmilling and reaming
Authors: Pérez J D , Fernandez P , Del Olmo A , López De Lacalle L N
Published: October 2021

Additive manufacturing by selective laser melting (SLM) allows significant flexibility in obtaining components with complex morphologies, which usually require finishing to correct the geometric distortions and roughness inherent in the process. This paper investigated surface quality by milling and reaming deep holes into ducts obtained by SLM technology. For this purpose, tools with different characteristics were tested, with a reaming stage necessary to obtain roughness levels of less than one μm. Dimensional distortions in SLMed ducts led to substantial variability in axial cutting forces. The helix angle of the endmill had a significant influence on the axial cutting force and roughness.
Design, manufacturing and validation of chip breakers in ceramic inserts for the machining of aeronautic nickel-based superalloys Inconel® 718
Authors: Fernández P , Villarón I , Pereira O , Amigo F J , Ukar E , López De Lacalle L N
Published: October 2021

In a world were reducing manufacturing times of components is primordial, achieving not only increased cutting tool life but also the capacity to machine faster is a great advance in the technique. Furthermore, sectors, such as the aeronautic engine one, work with very low machinability materials as heat-resistant superalloys. The nature of these kinds of alloys prevents machining from high cutting speeds. There is only one way to do it by using ceramic tools that are harder than the traditional cemented carbide tools, but much more fragile, with a shorter tool life and too expensive. This work involves the design, the manufacturing and the validation of a chipbreaker in an alumina reinforced with whiskers of SiC turning insert for the machining of these heat-resistant superalloys (Inconel® 718), so used in sectors like the aeronautic. In view of the lack of chipbreakers in ceramic turning inserts, something unthinkable in nowadays-cemented carbide inserts, this works is intended to open a gate to a new generation of cutting tools.
Study and analysis of the wiredrawing of CuZn37 wires via numerical simulations and slab method
Authors: Rodríguez O , Santana G A , Del Rey J C , Guerrero G
Published: October 2021

Improving efficiency and productivity of industrial manufacturing activities is crucial in today’s global economy and the advanced engineering methods they have proven to be an effective solution to better understand the operation of the processes. The technological problem in wiredrawing is conditioned by multiple factors such as drawing die geometry, tribological system, process speed and the state of the metal to be drawn, among others. A wire rod of CuZn37 alloy brass with Ø8 mm is obtained by continuous casting process from electrolytic materials. The structural state of the initial wire rod and the draft sequence conditions the deformations and residual stresses accumulated in its cross section, affecting the sequential process and final quality. The present work proposes a complete analytical-numerical study aided to the better understanding of the problem for the design of a process proposal for an adequate continuous wiredrawing sequence for the production of Ø2 mm brass wire. An industrial sequence without intermediate annealing was evaluated by the analytical-numerical procedure allowing to better understand the technological problems involved. This methodology has allowed to check that it is not possible to achieve such a high degree of reduction ratio above of r=0.70÷0.75, without applying intermediate annealing heat treatment.
The effect of different epoxidised vegetable oils on injection-moulded starch based thermoplastic polymer filled with almond shell powder
Authors: Ibáñez A , Ferrándiz S , Martínez A
Published: October 2021

This article is focused on the development and characterization of biodegradable and eco-friendly biocomposites, based on starch thermoplastic polymer (TPS) filled with 20 wt% almond shell powder (ASP). Three epoxidised vegetable oils (EVOs) were added at 5, 10 and 20 parts per hundred resin (phr) of TPS/ASP biocomposite, as additive, to study the effect in the properties of injected biodegradable parts: epoxidised soybean oil (ESBO), epoxidised linseed oil (ELO) and epoxidised corn oil (ECO). The biocomposites are prepared in a twin-screw extruder and characterized in terms of their mechanical (tensile and Charpy impact tests) and thermal properties (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). In addition, disintegration tests were evaluated. Results showed the addition of EVOs successfully reduced the stiffness and brittleness produced by the incorporation of almond shell, whereas thermal stability increased. The addition of EVOs had a stabilising effect on the disintegration of the biocomposites. The most optimal performance was attained for biocomposites with ELO or ESBO between 10-20 phr.
Ball Burnishing effects on hardness and residual stresses in UDIMET 720 pieces
Authors: Rue J , Velazquez E , Marques J , Llumà J , Jerez R , Travieso J A
Published: October 2021

Ball burnishing can be used to increase superficial hardness in treated materials. The aim of this paper is to study its influence over a nickel-based superalloy, UDIMET 720. To do this, the specimens where burnished and their hardness is analyzed, before and after the process, in the micro and nanometric scales. To corroborate findings, residual stresses are measured by the X-ray diffraction technique. This process has been found to be able to increase superficial hardness values up to 31% in the superalloy. Results also show that the hardness differential between the micro and nanometric scale is around 13%. An increase in compressive stress has been measured after the procedure, which can help explain this increase in hardness.
A methodology for the study of Friction Stir Welded butt joints applied to unweldable aerospace aluminium alloys
Authors: Del Sol I , Piñero D , Caballero J , Astarita A , Salguero J
Published: October 2021

Weight reduction is a constant improvement point for the aerospace sector. The joining of difficult to weld materials such as 2xxx and 7xxx aluminium series alloys has attracted the attention to Friction Stir Welding (FSW) in this field. This solid state welding process has already been presented as an environmentally friendly alternative for riveted joints and conventional welding operation in the automobile sector. Unfortunately, its application on the aeronautical sector is not completely studied at the moment and concerns about its quality and in-service behaviour have delayed its implementation. This paper stablished a methodology to study the effect of the welding parameter and applied it to a structural aluminium AA2024-T3, covering the design of the testing bench, the tool, the process monitoring and the analysis of the quality and main mechanical properties of the joint. The results showed the impact of the welding parameters on the quality of the joint. The burr and the roughness were optimised for 850 rpm and the forces were reduced up to 30% for this rotational speed. Similarly, the mechanical properties were reduced by up to 61.5% and 45% compared to the base material for the UTS and microhardness respectively.
Ontological modelling of welding processes
Authors: Solano L
Published: October 2021

In this work, an ontological model for welding processes is proposed and the need to manage the information and knowledge associated with such complex discipline is justified. First, an overview of the meaning and use of the models for this purpose and the concept of interoperability applied to the information contained in the welding standards is given. Next, an approach to the concept of ontology is made, the ontology applications for engineering, basic functionalities of ontologies and the way in which they are implemented. The work concludes showing some entities of the proposed ontology, focusing on the definition and classification of welding processes and knowledge inference based on the information contained in the ontology.
Study of the tribological performance of Ti6Al4V textured with pyramidal dimples by electro discharge machining
Authors: Salguero J , Piñero D , Del Sol I , Vazquez J M
Published: October 2021

Surface texturing has demonstrated to be a useful technique for improving the tribological performance of surfaces in contact. In particular, in this research it has been applied to the Ti6Al4V titanium alloy, with poor tribological behaviour, by creating different texturing densities with pyramidal geometries. Additionally, these geometries have been obtained through sinking electro-discharge machining processes, scarcely addressed in the scientific literature. In dry sliding conditions, the results obtained show an improvement of about 65% in the coefficient of friction, while in lubricated contact, the improvement in the lubricant retention capacity results in the formation of an abrasive paste formed by the lubricant and the wear debris, which worsens tribological behaviour.
Mechanical and electrical properties of additively manufactured copper
Authors: Rodriguez J , Vicente J I , Ezeiza J C , Zuriarrain A , Arrazola P J , Badiola X , Dominguez E , Soler D
Published: October 2021

Additive Manufacturing (AM) has become the new paradigm of design and production strategies. While structural and functional materials are the most implemented ones, it is also possible to manufacture parts using precious metals, being copper one of the most interesting. Among AM technologies, the novel Atomic Diffusion Additive Manufacturing (ADAM) has recently included this material between available ones. ADAM is free from thermal and energetic issues caused by high reflectivity and conductivity of copper which other AM encounter. Therefore, it could be a great alternative to manufacture pure copper. In this work ADAM was used to fabricate pure copper specimens in order to measure electrical and mechanical properties. The influence of a machining post processes in strength and ductility is also discussed. Results are compared with wrought C1 1000 copper and published results of other AM technologies. Despite the newness of ADAM, significant improvement in surface roughness and comparable results in other properties was observed. However, further research shall be done to optimize the manufacturing parameters in order to increase the relative density value, as it was found to be significantly lower than in other AM technologies.
Study of corrosion resistance in Ti 6Al 4V additive manufactured parts
Authors: Ruiz J E , Arrizubieta J I , Vega J M , Ostolaza M , Lamikiz A
Published: October 2021

Laser Directed Energy Deposition is an additive manufacturing process widely extended in industry, whose development is not free of challenges. The gaseous domain in which the process takes place, plays a major role in the resulting quality of the components, even bigger when the process involves a highly reactive materials like Ti 6Al 4V. Titanium alloys are extensively employed due to a combination of mechanical and chemical properties, being one of them their good corrosion resistance. The present work aims to provide an analysis of this corrosion resistance for LMD manufactured parts in comparison with raw material. For this purpose, a manufacturing methodology is described, using a local protective atmosphere to create the specimens, and a methodology for corrosion testing is presented. Results show similar corrosion resistance values for both raw and additively manufactured materials, therefore reinforcing the feasibility of manufacturing titanium parts by means of L-DED additive process.
Influence of printing conditions in Binder Jetting on the resin infiltration post-processing
Authors: Martínez S , Giganto S , Castro M A , Fernández A I , Barreiro J
Published: October 2021

The goal of this work is to study the influence of 3D Binder Jetting process in order to identify the best processing conditions for the resin infiltration post-process. In particular, a dimensional study is carried out to select the most suitable conditions for infiltration in terms of part location in the building bed. Also, the influence of infiltration time on dimensional changes of the processed parts is analysed. The results of this study let us conclude and verify the importance of part location on the bed, especially when it will be exposed to infiltration pros-processing. A good choice can improve the final result by shortening the infiltration times, and therefore time and cost of production.
Design for FDM of flexible tooling for manufacturing aeronautical components by incremental sheet forming
Authors: Flores G , Palomo D , Martínez A J , Borrego M , López J A , Morales D , Centeno G , Vallellano C
Published: October 2021

Nowadays, industrial production is required to reduce industrialization times and development costs for new products while maintaining high quality standards. In this context, the development of new flexible manufacturing technologies has gained relevance in the last few years. The use of Fused Deposition Modelling (FDM) additive technique has been recently proposed in different industrial sectors for manufacturing rapid tooling (dies) to be used in conventional sheet metal stamping or stretching processes with a significant decrease in costs and time savings. On the other hand, Incremental Sheet Forming (ISF) technology is characterized by an enhanced formability of the parts thus manufactured as well as for the need of a small number of tooling, reducing costs compared to conventional processes such as hydroforming or stamping. In particular, its simplest variant, Single-Point Incremental Forming (SPIF) requires the use of backing plates, which do not require tight tolerances as their only function is to collaborate in the deformation process acting as a support point. Furthermore, the strength requirements are also not a limitation since the forces involved in SPIF are very small given the local nature of the deformation. In this context, the main objective of this work is the design of a modular tooling system, manufactured using the FDM additive technique, that allows the flexible manufacturing of different aeronautical components by SPIF.
Influence of product variety on work allocation and server distribution of flexible manufacturing lines
Authors: Arteaga A , Calvo R
Published: October 2021

Mass customization involves medium volume production of a high variety of products where flexible manufacturing systems can cope with it. The work allocation problem of assigning the work content of each workstation in a manufacturing line is formulated as the design problem of capacity allocation across the line by looking for the throughput maximization and/or simultaneous work-in-process containment or minimization. The bowl phenomenon refers to the distribution shape of work across the workstations in unpaced flow line (asynchronous flow) with buffers, experimentally observed and conjectured back in the 1960’s, but with theoretical roots not successfully established up today. The increasing value of flexible capability for mass customization makes worthy the research of the phenomenon in the presence of product variety, beyond the classical model of balanced dedicated flow lines. The three problems of workload, buffer, and server allocation are closely related, and they have been previously studied in queuing networks with metaheuristics. This paper faces the effect of product variety (service time variability) impact on the performance of the flow line, researching the bowl effect through experimental analysis. The results show a main influence of the coefficient of variation of the service times with the secondary effect of the buffer size.
An approach to Reverse Engineering Methodology for Part Reconstruction with Additive Manufacturing
Authors: López J , Vila C
Published: October 2021

In diverse sectors such as aerospace, transport or energy, equipment is several decades old. Due to their extended lifespan, technical and manufacturing documentation might be inaccessible or inexistent. Manufacturing process problems, wear occurring during a part life cycle, or even the unavailability of digital data (redesign of obsolete parts produced in pre-digital era, legal restriction, or trade secrecy) are some examples to outline the lack of reliable 3D data for manufacturing purposes. The manufacturing and subsequent replacement of these components can turn into a significant problem. Lack of knowledge about system’s functioning, unknown operating conditions and limited technical information hamper the design development and manufacturing of these components. Classical Reverse Engineering (RE) approaches are commonly used to facilitate the understanding of a system’s functioning and ease the design recovery to create a more accurate and suitable model for engineered components. Combining these approaches with modern digitalisation technologies and new customized fabrication techniques, such additive manufacturing, can help to reconstruct obsolete, old or legacy components lacking manufacturing data. This paper contributes with a structured method aimed to design for additive manufacturing.
Selecting software filter settings for evaluating periodic and aperiodic surface roughness
Authors: Kubátová D , Kaufnerová A
Published: October 2021

A lot of properties depend on the quality of the surface, such as efficiency, reliability, functional properties, external appearance, and, last but not least, the cost of the entire production process. And if there is an inaccurate assessment during evaluating the integrity of the surface, especially for assessing roughness, this can lead to fatal problems in the actual use of the inspected part in practice. In order to meet all the requirements of the evaluation of the surface structure, it is necessary to keep up with the times and always have control of new possibilities and knowledge from the fields of measuring and evaluating the integrity of the surface, and being able to implement this knowledge into real conditions of use.

In the area described in this article, the selection of software filters, this is not always the case. The main reason is low awareness and the great complexity of choosing a suitable combination of possible procedures and techniques for setting software filters.

Therefore, a comprehensive methodology for the selection of software filters for both periodic surfaces and subsequently for aperiodic surfaces was created and is described in this article. Its coherence and graphical simplicity are prerequisites for quick understanding and easy implementation of the methodology in common practice.

The methodology for the selection of the software filter has 4 steps for periodic surfaces and 5 for aperiodic surfaces, which help the user of the profilometer, whether contact or contactless, to correctly set the device. Furthermore, the methodology should ensure that two people measure the same, or at least in the order of hundredths of the same results (values), which currently is not quite the case.
Influence of different wavelet filtering reconstruction techniques applied to bidimensional surface texture characterization
Authors: Villena C , Pazos D , Andrés E M , Sanz A
Published: October 2021

This article develops a preliminary study of the wavelet filtering application in surface finishing, extracting two-dimensional information from the surface microgeometry in a profile. First, the key elements to be considered in the analysis are described, starting with the surface finishing process of measurement. Then, the fundamentals of wavelet-based filtering and the traditional filtration procedure is shown. This procedure eliminates the values of the detail coefficients obtained in the filtering process before the reconstruction of the signal. Other alternatives of filtration, based on the shrinkage wavelet methodology, are also considered. Next, the features of the surface finish characteristic signals are highlighted, and the alternatives considered are applied on three different profiles generated from the result of a Brinell hardness test. Finally, the main conclusions drawn from the study are presented.
Novel system for the automatization of photogrammetric data capture for metrological tasks: application to study of gears
Authors: Rodríguez M , Rodríguez P
Published: October 2021

This paper presents a novel methodology for the macro-photogrammetric reconstruction of gears for metrological and maintenance purposes. The process presented includes the automation of close-range photogrammetric data acquisition using a referenced platform supported by measures gathered using an Articulated Coordinate Measure Machine and the subsequent Structure for Motion processing that allows the generation of dense 3D point cloud models with metrical scale and photorealistic colour texture of the gears. On these models, it is possible to directly take measurements, extract different profiles that can be exported in 2D formats and apply advanced processes that allow the computation of roughness and curvature parameters to evaluate the wear and possible defects or pathologies.
Evaluation of the influence of post-processing on the optical inspection accuracy of additively manufactured parts
Authors: Giganto S , Martínez S , Barreiro J , Cuesta E
Published: October 2021

Optical measurement systems are important techniques for rapid inspecting additively manufactured parts by techniques such as selective laser melting (SLM). Depending on their application, SLM parts require post-processes such as sandblasting or heat treatment, commonly applied in order to improve their surface finish or mechanical properties, respectively. These post-processes modify the parts surface characteristics, and therefore the suitability for optical inspection. This work evaluates the influence of these SLM post-processes on optical inspection. For this, a test part, manufactured in 17-4PH stainless steel using a 3DSystems ProX100 machine, was optically measured using a structured light scanner and compared to the values obtained from contact measurements (reference values). Both optical and contact measurements were performed under three conditions: as-built, post sandblasting, and post sandblasting and subsequent heat treatment. The analysis results show that applying the sandblasting post-processing provides a surface finish to the SLM parts suitable for optical inspection. This post-process allows precise inspection of this type of parts, reaching values close to those obtained by contact. Likewise, it is concluded that the used structured blue-light scanner is suitable for inspecting SLM parts.
Feasibility analysis of using machinable glass ceramics to manufacture non-contact measurement approach metrological artefacts
Authors: Zapico P , Alvarez B J , Meana V , Telenti A , Cuesta E
Published: October 2021

Rather than measurement contact methods, non-contact ones are more desirable in case of on-machine and in-process measurement due to their great accessibility and high acquisition rates. Nevertheless, it is well known that these methods commonly present different issues related to the surface properties of the digitized material and other external factors. Thus, an important characterization work must be carried out by exposing each non-contact technique to different conditions. For this characterization work, the use of metrological gage artefacts is mandatory. These artefacts must be made of materials on which non-contact methods will work properly. Therefore, the analysis of new materials is still an important issue nowadays. Among the current possible materials, those that can be easily formed in typical artefact geometries stand out, while maintaining the required properties such as low thermal expansion, high hardness, etc. In this work the feasibility of a machinable glass ceramic named Macor® to produce a metrological artefact to be used with a non-contact digitizing sensor is analysed. Once stated the benefits of this material and proposed some machining conditions, an artefact is manufactured and digitized with a non-contact laser triangulation sensor, comparing its results regarding to a widely used metrological reference system.
Reference standard for the uncertainty estimation of X–ray Computed Tomography measurements of complex macro-and micro-geometries
Authors: Albajez J A , Nuño S , Díaz L C , Gallardo D , Yagüe J A , Jiménez R , Torralba M
Published: October 2021

Traditionally, measuring both macro and micro geometries with a single device has been challenging in metrology. Coordinate Measuring Machines (CMM) are common devices for the inspection of large features, while optical microscopes can achieve resolutions in the order of micrometers in small areas. X-Ray Computed Tomography (XCT) has become a solution not only to characterize both micro and macro geometries, but also to inspect internal features without destroying the sample. In this field, various reference standards have been developed in order to verify the capabilities of XCT systems, these artefacts include geometrical features or profiles for roughness inspection. This paper shows the design and develompent of a reference standard for XCT test which includes internal and external geometrical features and profiles for macro and micro geometrical inspection. The model is manufactured by additive manufacturing (AM), easing the process of fabrication of the artefact and allowing to test the capabilities of this technology to produce reference standards.
Determining the required cleanliness level using synthetic test contamination
Authors: Brag P , Piotter V , Plewa K , Umbach S , Herzfeldt M
Published: October 2021

As electrification in the automotive industry progresses, the demand is rising for test particles with specific properties. More and more new applications are also being developed, such as processes for validating cleaning steps, contamination tracking or determining cleanliness limits. This article describes how test particles can be reproducibly manufactured in all three dimensions by micro milling. In addition, it explains how the dimensional accuracy of these free-form surfaces can be analyzed with computer tomography.
Risk-based inspection planning for hydrogen technologies: review of currents standards and suggestions for modification
Authors: Ustolin F , Wan D , Alvaro A , Paltrinieri N
Published: October 2021

The research addressing loss of integrity (LOI) for hydrogen containment technologies requires a multidisciplinary perspective. However, lack of collaboration between materials and process safety engineers is reflected in the theory addressing the LOI phenomena. Even though the potential degrading mechanisms related to hydrogen-metals interaction are being extensively studied, they are not explicitly considered by standards and recommended practices in relation to plant inspection planning. This inevitably introduces additional uncertainties while planning for inspections and predictive maintenance and leads to the necessity to address and consider generic mechanisms of material degradation within the framework of LOI development prediction. A review of the available standards and recommended practices for inspection planning is here conducted to identify how metal-hydrogen interactions are currently considered in terms of degradation mechanisms. Focus is given to risk-based approaches, which include the assessment of potential accident scenarios as consequence of LOI. In particular, the association of metal-hydrogen mechanisms with damage factors influencing the predicted LOI frequency is studied to understand their impact both on the risk and the inspection typology. Appropriate knowledge of material degradation mechanisms for hydrogen containment is of paramount importance as it allows not only for a correct design of the equipment of interest, but also for a suitable inspection and maintenance planning so to guarantee its integrity through an effective and informed risk-based approach. A few modifications to the current standards are suggested as a result of this work.
A device to reduce positioning errors due to the machine tool compliance
Authors: Noriega A , Campa F J
Published: October 2021

One of the main problems that large machine tool designers must face is the onset of deflection and vibration due to the forces involved during the process: the own weight of the elements of the machine, the cutting forces and the inertial forces. The last ones are especially relevant in the case of large and heavy machine tools with cantilever elements as rams or columns. To counteract these forces, the present work proposes the use of an inertial device, based on the rotation of two eccentric mases around the same axis. Hence, a simplified dynamic model of a column is first developed, and tested during a standard face milling operation. Then, the dynamic model of the device is also developed, and a Computed Torque Control is proposed to govern the action of the device. The simulations show that the use of this device has the potential to reduce drastically the effect of the inertial forces and even the lower frequency components of the cutting forces.
Contact Image Sensor integration in Fused Filament Fabrication machines for layer inspection
Authors: Peña F , Rico J C , Valiño G , Fernández P , Meana V , Zapico P
Published: October 2021

One of the limiting factors for industrial application of additive manufacturing (AM) is the lack of geometrical accuracy of manufactured parts. To improve precision, non-contact sensors should be integrated into AM machines, capable of performing in-situ inspection of the part and being able to detect and compensate for the actual geometrical errors. A non-contact digitizing system is proposed in this work for the inspection of the deposited material layers, based on a Contact Image Sensor (CIS) extracted from a commercial flatbed paper scanner. In order to integrate this sensor in an AM machine, a methodology was developed that includes the sensor operation analysis, the design of the necessary hardware and software to be externally controlled and the subsequent processing of the captured images. Results prove that the CIS sensor can be integrated in any device external to the original scanner.
Finite element modelling and evaluation of mechanical properties of wood-PLA parts manufactured through Fused Filament Fabrication
Authors: Durlan J , Adrover B , Zandi M D , Lluma J , Jerez R , Travieso J A
Published: October 2021

Fused Filament Fabrication (FFF) is one of the most common additive manufacturing (AM) technologies that has arisen interesting from industry in a wide range of applications. In this paper, the mechanical properties of FFF 3D printed wood-PLA (Timberfill®) parts are investigated both experimentally and computationally to predict the mechanical characteristics of this material. Firstly, experimental tensile test is carried out to achieve the properties of the material. Secondly, the obtained parameters (Young’s modulus, Poisson’s ratio and yielding stress) will be use as input data in the ANSYS software to simulate a 4-point bending test. Finally, in order to validate the obtained model, the simulation results are compared to an experimental flexural test results indicating the correspondence between them. The main result of this work is an appropriate model to predict the behaviour of a 3D-printed piece formed by an internal structure with certain characteristics suitable for the manufacturing process and surrounded by a skin, which is subjected to certain external load.