Application of innovative software to the subject Project I of the Degree in Engineering in Industrial Technologies (GETI)

In this work the results about the use of innovative software in the subject Project I is presented. The subject is given in the Degree in Engineering in Industrial Technologies (GETI) in the School of Industrial Engineering of Barcelona (ETSEIB) of Universitat Politècnica de Catalunya (UPC). In Project I, small groups of 12 students or less are defined, with the purpose of developing a collaborative project along one semester. The project discussed in this work was prepared by two different departments: Mechanical Engineering and Statistics and Operative Investigation. It deals with the measurement of shaft diameters with a micrometre, in order to evaluate the measuring system employed. Traditionally, many activities of the subject were recorded in handwritten reports. The present academic year, within the frame of the project EQUIPA’T (equip yourself), innovative software was applied to the subject. As for the methodology, first the teachers attended a training course. Then, the application of innovative software to the subject was planned. Finally, it was implemented. Google forms was used in the first and last classes to gather information to prepare subgroups of students and to evaluate the subject respectively, Edpuzzle was employed to add questions to videos about two lessons of the manufacturing area: metrology and turning, and Trello was used to manage the design of a 3D printed support by different teams of students. In subsequent years, the application of new software is expectedPeer ReviewedPostprint (published version

Roughness evolution of previously milled samples along a polishing test

In the present work results about roughness evolution along a polishing operation with corundum disks of size Norton 400 are presented. Hardened steel and hardened stainless steel samples were previously subjected to ball-end milling or side milling with cylindrical tool at different cutting conditions. Roughness height parameters Ra and Rt, as well as parameters related to the Abbott-Firestone curve such as Rk, Rpk, and Rvk, and shape parameters such as Rsk and Rku were studied. It is usually considered that a polishing operation is complete when Ra does not decrease significantly with more polishing time. In the present paper, an alternative method for determining the end of a polishing test is presented. Roughness is measured both in the longitudinal and in the transversal direction with respect to cutting marks, and it is assumed that the polishing operation is finished when longitudinal values equal transversal values, provided that from that moment on roughness values do not decrease significantly. Moreover, it is recommended to measure parameter Rvk in addition to or even instead of Ra, in order to obtain information about the presence of valleys from the previous milling operation.Postprint (author's final draft

Application of innovative software to the subject Project I of the Degree in Engineering in Industrial Technologies (GETI)

In this work the results about the use of innovative software in the subject Project I is presented. The subject is given in the Degree in Engineering in Industrial Technologies (GETI) in the School of Industrial Engineering of Barcelona (ETSEIB) of Universitat Politècnica de Catalunya (UPC). In Project I, small groups of 12 students or less are defined, with the purpose of developing a collaborative project along one semester. The project discussed in this work was prepared by two different departments: Mechanical Engineering and Statistics and Operative Investigation. It deals with the measurement of shaft diameters with a micrometre, in order to evaluate the measuring system employed. Traditionally, many activities of the subject were recorded in handwritten reports. The present academic year, within the frame of the project EQUIPA’T (equip yourself), innovative software was applied to the subject. As for the methodology, first the teachers attended a training course. Then, the application of innovative software to the subject was planned. Finally, it was implemented. Google forms was used in the first and last classes to gather information to prepare subgroups of students and to evaluate the subject respectively, Edpuzzle was employed to add questions to videos about two lessons of the manufacturing area: metrology and turning, and Trello was used to manage the design of a 3D printed support by different teams of students. In subsequent years, the application of new software is expected

Influence of Print Orientation on Surface Roughness in Fused Deposition Modeling (FDM) Processes

In the present paper, we address the influence of print orientation angle on surface roughnessobtained in lateral walls in fused deposition modelling (FDM) processes. A geometrical model isdefined that considers the shape of the filaments after deposition, in order to define a theoreticalroughness profile, for a certain print orientation angle. Different angles were considered between 5¿and 85¿. Simulated arithmetical mean height of the roughness profile, Ra values, were calculated fromthe simulated profiles. The Ra simulated results were compared to the experimental results, whichwere carried out with cylindrical PLA (polylactic acid) samples. The simulated Ra values were similarto the experimental values, except for high angles above 80¿, where experimental roughness decreasedwhile simulated roughness was still high. Low print orientation angles show regular profiles withrounded peaks and sharp values. At a print orientation angle of 85¿, the shape of the profile changeswith respect to lower angles, showing a gap between adjacent peaks. At 90¿, both simulated andexperimental roughness values would be close to zero, because the measurement direction is parallelto the layer orientation. Other roughness parameters were also measured: maximum height ofprofile, Rz, kurtosis, Rku, skewness, Rsk, and mean width of the profile elements, Rsm. At high printorientation angles, Rz decreases, Rku shifts to positive, Rsk slightly increases, and Rsk decreases,showing the change in the shape of the roughness profiles.Postprint (published version

Multi-Objective Optimization of Material Removal Rate and Tool Wear in Rough Honing Processes

This study focuses on obtaining regression models for material removal rate and tool wear in rough honing processes. For this purpose, experimental tests were carried out according to a central composite design of experiments. Five different parameters were varied: grain size or particle size of abrasive, density of abrasive or abrasive concentration, pressure of the stones against the cylinder internal surface, tangential speed (in this case, corresponding to the rotation speed of the cylinder), and linear speed of the honing head. In addition, multi-objective optimization was carried out with the aim of maximizing the material removal rate and minimizing tool wear. The results show that, within the range studied, the material removal rate depends mainly on tangential speed, followed by grain size and pressure. Tool wear is directly influenced by density of abrasive, followed by pressure, tangential speed, and grain size. According to the multi-objective optimization, if the two responses are given the same importance, it is recommended that high grain size, high density, high tangential speed, and low pressure be selected. Linear speed has less influence on both responses studied. If the material removal rate is considered to be more preponderant than tool wear, then the same values should be considered, except for high pressure. If tool wear is preponderant, then lower grain size of 128 (ISO 6106) should be selected, and lower tangential speed of approximately 166 min-1. The other variables, density and pressure, would not change significantly from the first situation.Peer ReviewedPostprint (published version

Neural network modelling of Abbott-Firestone roughness parameters in honing processes

In present study, three roughness parameters defined in the Abbott-Firestone or bearing area curve, Rk, Rpk and Rvk, were modelled for rough honing processes by means of artificial neural networks (ANN). Input variables were grain size and density of abrasive, pressure of abrasive stones on the workpiece's surface, tangential or rotation speed of the workpiece and linear speed of the honing head. Two strategies were considered, either use of one network for modelling the three parameters at the same time or use of three networks, one for each parameter. Overall best neural network consists of three networks, one for each roughness parameter, with one hidden layer having 25, nine and five neurons for Rk, Rpk and Rvk respectively. However, use of one network for the three roughness parameters would allow addressing an indirect model. In this case, best solution corresponds to two hidden layers having 26 and 11 neurons.Peer ReviewedPostprint (author's final draft

3D Printing of Bioinert Oxide Ceramics for Medical Applications

Three-dimensionally printed metals and polymers have been widely used and studied in medical applications, yet ceramics also require attention. Ceramics are versatile materials thanks to their excellent properties including high mechanical properties and hardness, good thermal and chemical behavior, and appropriate, electrical, and magnetic properties, as well as good biocompati- bility. Manufacturing complex ceramic structures employing conventional methods, such as ceramic injection molding, die pressing or machining is extremely challenging. Thus, 3D printing breaks in as an appropriate solution for complex shapes. Amongst the different ceramics, bioinert ceramics appear to be promising because of their physical properties, which, for example, are similar to those of a replaced tissue, with minimal toxic response. In this way, this review focuses on the different medical applications that can be achieved by 3D printing of bioinert ceramics, as well as on the latest advances in the 3D printing of bioinert ceramics. Moreover, an in-depth comparison of the different AM technologies used in ceramics is presented to help choose the appropriate methods depending on the part geometry.Peer ReviewedPostprint (published version

Decision Support Models for the Selection of Production Strategies in the Paradigm of Digital Manufacturing, Based on Technologies, Costs and Productivity Levels

Digital manufacturing has opened a new window in the way to approach the manufacture of parts. The possible switch from manufacturing and holding physical stock to manoeuvring with a fully-digital one is promising but still has not been undertaken‑or only in a small proportion‑by the majority of the manufacturing companies. What are the cost and productivity frontiers that halt the transformation taking place so far? When does it make sense, in terms of production volume and costs, to undertake this transformation? What level of savings could be achieved and what investments would be favourable? The base line of the present chapter is to depict quantitative tools to address the potential impact of endeavouring digital transformation in manufacturing environments, considering costing and production variables, as well as technological decision-making parameters. Keeping the modelling of the demand very basic, some exploration on the degree of postponement of the production is discussed. Also, decision support systems (DSSs) for manufacturing selection are reviewed. Finally, a case study serves to apply the mathematical framework presented and to quantify the results in a realistic industrial case. Using this case, the chapter outlines and describes how to apply artificial intelligence (AI) techniques to implement the DSSs

Implementation of intelligent manufacturing algorithms in agile architectures for production: world models for systems incorporating binary and continuous variables

Agile Manufacturing, Intelligent systems, AlgorithmsBuilding in previous works of the authors, the present paper focuses on the extension of the Algorithms described for the specific case study of binary systems (systems in which each variable can take one out of two values), to cases that also incorporate continuous variables (those which can take any continuous value within a range). This extension of the Algorithms makes possible the incorporation of new possibilities and functionalities for the treatment of the information received by the sensors of the manufacturing systems and in particular reduce the number of variables in which to monitor the states and costs of execution. The Construction of World Models based on this logical theory -that incorporates the knowledge derived from the results of a set of experiments conducted by the system utilizing a set of different algorithms- is applicable to a wide range of production systems topologies, which is also visited in the present work.Postprint (published version

Comparative study about dimensional accuracy and surface finish of constant-breadth cams manufactured by FFF and CNC Milling

In this work, the design, manufacture and measurement process of constant-breadth cams is presented. The motion law of the cam was designed by means of Bézier curves and the corresponding design desmodromic constraints. The cams were manufactured in two different materials employing two different processes: PLA cams with fused filament fabrication (FFF) and aluminium cams with computer numerical control (CNC) milling. The main aim of this work is to compare both types of cams regarding dimensional accuracy and surface finish, in order to evaluate if it would be possible to temporally replace a metallic cam with a plastic one during the repair of the first one. Dimensions were measured with micrometres and surface roughness with a contact roughness meter. The results show that, in diametral dimensions, similar dimensional error values were obtained for both the 3D-printed and the machined cams. However, in longitudinal dimensions, whose direction is perpendicular to the 3D-printed layers, the 3D-printed cams showed higher dimensional error than the machined ones. The average roughness Ra in the 3D-printed cams was 20 times higher than in the milled cams. According to the results, it would be recommended to temporally replace metallic cams with plastic ones in applications of low-power transmission. Given that in the literature little information is available about the measurement of 3D-printed desmodromic cams, this work will contribute to the study and analysis of this kind of 3D printed mechanism.Peer ReviewedPostprint (published version