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Available. Open Access. Open Access
Article
Publication date: 17 October 2022

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…

1822

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.

Details

Rapid Prototyping Journal, vol. 28 no. 11
Type: Research Article
ISSN: 1355-2546

Keywords

Available. Open Access. Open Access
Article
Publication date: 25 February 2025

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…

0

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.

Details

Journal of Economics, Finance and Administrative Science, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2077-1886

Keywords

Available. Open Access. Open Access
Article
Publication date: 18 March 2021

Maximo Camacho and María Dolores Gadea

356

Abstract

Details

Applied Economic Analysis, vol. 29 no. 85
Type: Research Article
ISSN: 2632-7627

Available. Open Access. Open Access
Article
Publication date: 22 December 2022

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…

1054

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.

Details

Rapid Prototyping Journal, vol. 29 no. 11
Type: Research Article
ISSN: 1355-2546

Keywords

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