Jesús Miguel Chacón, Javier Sánchez-Reyes, Javier Vallejo and Pedro José Núñez
Non-uniform rational B-splines (NURBSs) are the de facto standard for representing objects in computer-aided design (CAD). The purpose of this paper is to discuss how to stick to…
Abstract
Purpose
Non-uniform rational B-splines (NURBSs) are the de facto standard for representing objects in computer-aided design (CAD). The purpose of this paper is to discuss how to stick to this standard in all phases of the additive manufacturing (AM) workflow, from the CAD object to the final G-code, bypassing unnecessary polygonal approximations.
Design/methodology/approach
The authors use a commercial CAD system (Rhino3D along with its programming environment Grasshopper) for direct slicing of the model, offset generation and trimming. Circular arcs are represented as quadratic NURBSs and free-form geometry as quadratic or cubic polynomial B-splines. Therefore, circular arcs are directly expressible as G2/G3 G-code commands, whereas free-form paths are rewritten as a succession of cubic Bézier curves, thereby admitting exact translation into G5 commands, available in firmware for AM controllers, such as Marlin.
Findings
Experimental results of this paper confirm a considerable improvement in quality over the standard AM workflow, consisting of an initial polygonization of the object (e.g. via standard tessellation language), slicing this polygonal approximation, offsetting the polygonal sections and, finally, generating G-code made up of polyline trajectories (G1 commands).
Originality/value
A streamlined AM workflow is obtained, with a seamless transfer from the initial CAD description to the final G-code. By adhering to the NURBS standard at all steps, the authors avoid multiple representations and associated errors resulting from approximations.
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Cristina Calvo-Porral, Sergio Rivaroli and Javier Orosa-González
Celebrity endorsement is one of the most popular marketing communication tools that have been used by beverage companies to influence consumers’ behaviour, but little is known…
Abstract
Purpose
Celebrity endorsement is one of the most popular marketing communication tools that have been used by beverage companies to influence consumers’ behaviour, but little is known about the extent this communication strategy can be impactful and benefit alcoholic beverages like beer and wine. In this context, this study aims to examine whether and how social media celebrity endorsement influences consumers’ beer and wine purchase behaviour. Further, this study examines what are the characteristics of the celebrities that exert greater influence on beer and wine purchase behaviour.
Design/methodology/approach
Based on the source credibility and source attractiveness theoretical models, and on the match-up theory, a model of consumer purchase behaviour was proposed. Online celebrity endorsement was categorised as promoting either beer or wine, as well as beer and wine brands. Then, this model is empirically analysed through multiple group structural equation modelling on two samples of consumers who read online celebrity’s recommendations in Spain (beer = 280; wine = 277).
Findings
Findings indicate that celebrity’s recommendations exert a different influence pattern on consumer purchase behaviour depending on the product category: congruence is the most relevant variable in beer endorsement, whereas expertise is the most influencing factor in wine celebrity recommendations. Therefore, beer celebrity endorsers should be congruent with the product, whereas wine endorsers should be perceived as experts.
Originality/value
This study extends the literature on celebrity endorsement providing an empirical examination of the social media celebrity characteristics that influence consumer purchase behaviour of beer and wine, reporting interesting differences between these two alcoholic beverages.
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Francisco Javier Saavedra-Macías, Samuel Arias-Sánchez and Ana Rodríguez-Gómez
Carlos Torres Carbonell, Gastón Silverio Milanesi, Fernando Tohmé, Patricia Chimeno and Javier Ignacio García Fronti
This paper analyzes the application of real options to livestock production. It evaluates the strategic flexibility in determining the optimal selling time for livestock…
Abstract
Purpose
This paper analyzes the application of real options to livestock production. It evaluates the strategic flexibility in determining the optimal selling time for livestock, considering the technological and market risks involved in its production.
Design/methodology/approach
Based on a data sample of 300 records collected over the past 15 years, a biophysical-economic model was developed and simulated using an iterative stochastic procedure.
Findings
The alternatives that provide the highest profit growth are identified by quantifying their risk parameters and yielding strategies for enhancing the value of livestock companies.
Originality/value
This research aims to understand how to improve decision-making in companies managing biological assets under conditions of risk and uncertainty, using the case of livestock systems in Argentina as a basis. This case can be easily adapted to similar cases in other countries.
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Carolina Bermudo Gamboa, Sergio Martín Béjar, Francisco Javier Trujillo Vilches and Lorenzo Sevilla Hurtado
The purpose of this study is to cover the influence of selected printing parameters at a macro and micro-geometrical level, focusing on the dimensions, geometry and surface of…
Abstract
Purpose
The purpose of this study is to cover the influence of selected printing parameters at a macro and micro-geometrical level, focusing on the dimensions, geometry and surface of printed parts with short carbon fibers reinforced PLA. For this case study, a hollow cylindrical shape is considered, aiming to cover the gap detected in previous works analyzed.
Design/methodology/approach
Nowadays, additive manufacturing plays a very important role in the manufacturing industry, as can be seen through its numerous research and applications that can be found. Within the engineering industry, geometrical tolerances are essential for the functionality of the parts and their assembly, but the variability in three-dimensional (3D) printing makes dimensional control a difficult task. Constant development in 3D printing allows, more and more, printed parts with controlled and narrowed geometrical deviations and tolerances. So, it is essential to continue narrowing the studies to achieve the optimal printed parts, optimizing the manufacturing process as well.
Findings
Results present the relation between the selected printing parameters and the resulting printed part, showing the main deviations and the eligible values to achieve a better tolerance control. Also, from these results obtained, we present a parametric model that relates the geometrical deviations considered in this study with the printing parameters. It can provide an overview of the piece before printing it and so, adjusting the printing parameters and reducing time and number of printings to achieve a good part.
Originality/value
The main contribution is the study of the geometry selected under a 3D printing process, which is important because it considers parts that are created to fit together and need to comply with the required tolerances. Also, we consider that the parametric model can be a suitable approach to selecting the optimal printing parameters before printing.