Papers by Author: Joaquim de Ciurana

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Authors: L. Serenó, J. Delgado, Joaquim de Ciurana
Abstract: The development of open Additive Manufacturing (AM) technologies, such as the Fab@Home system, has emerged as a freeform approach capable of producing complex three-dimensional objects with a broad variety of materials. The main objective of this work is to analyze and optimize the manufacturing capacity of this system when producing 3D edible objects. A new heated syringe deposition tool was developed and several process parameters were optimized to adapt this technology to consumers needs. The results revealed in this study show the potential of this system to produce customized edible objects without qualified personnel knowledge, therefore saving manufacturing costs compared to traditional technologies.
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Authors: Guillem Quintana, Maria Luisa García-Romeu, Joaquim de Ciurana
Abstract: The current requirements for an efficient dimensional inspection of manufactured parts have lead to development of different in process and on-machine measurement (OMM) techniques. Touch trigger probes (TTP) are the most common technologies utilized, inspired on contact probes used on coordinate measuring machines (CMMs). The on-machine accuracy of TTPs depends upon precision of the tool-machine control as well as upon the procedure for TTP presetting. Taking this into account, a different OMM technique is considered in this work, which consists on a laser micrometer (LM) that is commonly used for in-process measurement of continuous products. The behaviour of TTP and LM is analysed and discussed in terms of repeatability and reproducibility. Results obtained by both techniques are compared each other by measuring a cylindrical workpiece and by checking the results with those obtained on a CMM.
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Authors: Daniel Teixidor, I. Ferrer, Joaquim de Ciurana
Abstract: This paper reports the characterization of laser machining (milling) process to manufacture micro-channels in order to understand the incidence of process parameters on the final features. Selection of process operational parameters is highly critical for successful laser micromachining. A set of designed experiments is carried out in a pulsed Nd:YAG laser system using AISI H13 hardened tool steel as work material. Several micro-channels have been manufactured as micro-mold cavities varying different process parameter. Results are obtained by evaluating the dimensions and the surface finish of the micro-channel. The dimensions and shape of the micro-channels produced with laser-micro-milling process exhibit variations. In general the use of low scanning speeds increases the quality of the feature in both surface finishing and dimensional.
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Authors: Guillem Quintana, Joaquim de Ciurana, Daniel Teixidor, I. Ferrer
Abstract: In milling operations, cutting edge impacts due to the interaction between the cutter and the workpiece excite vibrations. It is possible to distinguish between free, forced and self-excited vibrations. Chatter is a self-excited vibration that can occur in machining processes, and is considered to be a common limitation of productivity and quality. Stability lobes diagrams (SLDs) show the frontier between chatter-free milling operations, i.e. stable dominated by forced vibrations, and operations with chatter, i.e. unstable. These diagrams are usually obtained from impact hammer testing. However, this method requires trained personnel with advanced knowledge and it is not easily applied in engineering studies or operator training. This paper presents an experimental method that allows engineering students and operators-in-training to observe the chatter phenomenon and to distinguish between forced and chatter vibrations and identify process stability diagrams.
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Authors: Daniel Teixidor, Guillem Quintana, Joaquim de Ciurana
Abstract: Surface roughness influences the performance of a finished part. In machining operations, the surface roughness generated is influenced by an enormous set of factors. In ball end milling operations, the geometric characteristics of the cut clearly affect the surface crests generated. This paper presents an experimental methodology that permits engineering students to identify and analyze the surface roughness. The methodology is applicable to training courses and surface texture generation as well.
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Authors: Marc Sabater, Maria Luisa García-Romeu, Joaquim de Ciurana
Abstract: The aim of this paper is to present the results of the first step of a defined methodology for the neural network tool development. That first step is to studying the variables that have influence on extrusion process, especially in those that affect billet temperature and extrusion speed. In order to determine those parameters, a preliminary analysis was conducted with experimental data from real industry. Then, a multiple regression analysis was carried out to define which parameters will be the inputs of the neural network prediction tool.
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