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Article
Publication date: 7 July 2020

Fusheng Dai, Haiou Zhang and Runsheng Li

The study aims to fabricate large metal components with overhangs built on cylindrical or conical surfaces with a high dimensional precision. It proposes methods to address the…

546

Abstract

Purpose

The study aims to fabricate large metal components with overhangs built on cylindrical or conical surfaces with a high dimensional precision. It proposes methods to address the problems of generating tool-paths on cylindrical or conical surfaces simply and precisely, and planning the welding process on these developable surfaces.

Design/methodology/approach

The paper presents the algorithm of tool-paths planning on conical surfaces using a parametric slicing equation and a spatial mapping method and deduces the algorithm of five-axis transformation by addressing the rotating question of two sequential points. The welding process is investigated with a regression fitting model on a flat surface, and experimented on a conical surface, which can be flattened onto a flat surface.

Findings

The paper provides slicing and path-mapping expressions for cylindrical and conical surfaces and a curvature-speed-width (CSW) model for wire and arc additive manufacturing to improve the surface appearances. The path-planning method and CSW model can be applied in the five-axis fabrication of the prototype of an underwater thruster. The CSW model has a confidence coefficient of 98.02% and root mean squared error of 0.2777 mm. The reverse measuring of the finished blades shows the residual deformation: an average positive deformation of about 0.5546 mm on one side of the blades and an average negative deformation of about −0.4718 mm on the other side.

Research limitations/implications

Because of the chosen research approach, the research results may lack generalizability for the fabrication based on arbitrary surfaces.

Originality/value

This paper presented an integrated slicing, tool-path planning and welding process planning method for five-axis wire and arc additive manufacturing.

Details

Rapid Prototyping Journal, vol. 26 no. 8
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 December 2001

V.T. Rajan, Vijay Srinivasan and Konstantinos A. Tarabanis

Many engineering and scientific problems require the filling of a two‐dimensional region with scan lines of finite width. The number of contiguous scan line segments required for…

1463

Abstract

Many engineering and scientific problems require the filling of a two‐dimensional region with scan lines of finite width. The number of contiguous scan line segments required for the filling depends on the direction used for scanning. When the cost of the filling operation increases with the number of scan line segments, as is the case in numerically controlled machining, layered fabrication and computer graphics applications, then it is desirable to select a direction that minimizes this number. In this paper we provide a method for efficiently computing such an optimal direction when the region to be filled is bounded by straight‐line segments and/or circular arcs.

Details

Rapid Prototyping Journal, vol. 7 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 22 August 2017

Jikai Liu and Huangchao Yu

Structural performance of additively manufactured parts is deposition path-dependent because of the induced material anisotropy. Hence, this paper aims to contribute a novel idea…

1325

Abstract

Purpose

Structural performance of additively manufactured parts is deposition path-dependent because of the induced material anisotropy. Hence, this paper aims to contribute a novel idea of concurrently performing the deposition path planning and the structural topology optimization for additively manufactured parts.

Design/methodology/approach

The concurrent process is performed under a unified level set framework that: the deposition paths are calculated by extracting the iso-value level set contours, and the induced anisotropic material properties are accounted for by the level set topology optimization algorithm. In addition, the fixed-geometry deposition path optimization problem is studied. It is challenging because updating the zero-value level set contour cannot effectively achieve the global orientation control. To fix this problem, a level set-based multi-step method is proposed, and it is proved to be effective.

Findings

The proposed concurrent design method has been successfully applied to designing additively manufactured parts. The majority of the planned deposition paths well match the principle stress direction, which, to the largest extent, enhances the structural performance. For the fixed geometry problems, fast and smooth convergences have been observed.

Originality/value

The concurrent deposition path planning and structural topology optimization method is, for the first time, developed and effectively implemented. The fixed-geometry deposition path optimization problem is solved through a novel level set-based multi-step method.

Details

Rapid Prototyping Journal, vol. 23 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 8 August 2024

Yogesh Patil, Ashik Kumar Patel, Gopal Dnyanba Gote, Yash G. Mittal, Avinash Kumar Mehta, Sahil Devendra Singh, K.P. Karunakaran and Milind Akarte

This study aims to improve the acceleration in the additive manufacturing (AM) process. AM tools, such as extrusion heads, jets, electric arcs, lasers and electron beams (EB)…

156

Abstract

Purpose

This study aims to improve the acceleration in the additive manufacturing (AM) process. AM tools, such as extrusion heads, jets, electric arcs, lasers and electron beams (EB), experience negligible forces. However, their speeds are limited by the positioning systems. In addition, a thin tool must travel several kilometers in tiny motions with several turns while realizing the AM part. Hence, acceleration is a more significant limiting factor than the velocity or precision for all except EB.

Design/methodology/approach

The sawtooth (ST) scanning strategy presented in this paper minimizes the time by combining three motion features: zigzag scan, 45º or 135º rotation for successive layers in G00 to avoid the CNC interpolation, and modifying these movements along 45º or 135º into sawtooth to halve the turns.

Findings

Sawtooth effectiveness is tested using an in-house developed Sand AM (SaAM) apparatus based on the laser–powder bed fusion AM technique. For a simple rectangle layer, the sawtooth achieved a path length reduction of 0.19%–1.49% and reduced the overall time by 3.508–4.889 times, proving that sawtooth uses increased acceleration more effectively than the other three scans. The complex layer study reduced calculated time by 69.80%–139.96% and manufacturing time by 47.35%–86.85%. Sawtooth samples also exhibited less dimensional variation (0.88%) than zigzag 45° (12.94%) along the build direction.

Research limitations/implications

Sawtooth is limited to flying optics AM process.

Originality/value

Development of scanning strategy for flying optics AM process to reduce the warpage by improving the acceleration.

Details

Rapid Prototyping Journal, vol. 30 no. 8
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 May 1960

Most of the major research projects to be carried out by Aslib in accordance with its programme will necessarily take the best part of a year to complete, and some of them longer…

11

Abstract

Most of the major research projects to be carried out by Aslib in accordance with its programme will necessarily take the best part of a year to complete, and some of them longer. In the interval between the start of work on a project and the final publication of results, members, particularly when they have themselves co‐operated directly in an investigation by providing data, may well wish to know what progress is being made. For this reason brief notes about current research work will be published in Aslib Proceedings at intervals. They may include reports on minor ad hoc investigations the results of which are not to be fully reported elsewhere.

Details

Aslib Proceedings, vol. 12 no. 5
Type: Research Article
ISSN: 0001-253X

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Article
Publication date: 8 February 2019

Blaoui Mohammed Mossaab, Mokhtar Zemri and Mustapha Arab

The purpose of this paper is to evaluate the effects of medium carbon steel microstructure on the tensile strength and fatigue crack growth (FCG) behavior.

135

Abstract

Purpose

The purpose of this paper is to evaluate the effects of medium carbon steel microstructure on the tensile strength and fatigue crack growth (FCG) behavior.

Design/methodology/approach

To achieve this aim, four different heat treatment methods (normalizing, quenching, tempering at 300°C and tempering at 600°C) were considered. Microstructural evolution was investigated by scanning electron microscopy. FCG rate tests were conducted on the resultant microstructures with compact tension specimens at room temperature by a standard testing method.

Findings

The results show that the normalized microstructure had the largest number of cycles to failure, indicating a high fatigue resistance, followed by the as received, tempered at 600°C, tempered at 300°C and quenched microstructure.

Originality/value

The paper shows the influence of the microstructure on the fatigue-propagation behavior with the definition of the Paris parameters of each heat treatment condition.

Details

International Journal of Structural Integrity, vol. 10 no. 1
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 4 February 2022

Janos Plocher, Jean-Baptiste Wioland and Ajit Singh Panesar

Fibre-reinforced additive manufacturing (FRAM) with short and continuous fibres yields light and stiff parts and thus increasing industry acceptance. High material anisotropy and…

543

Abstract

Purpose

Fibre-reinforced additive manufacturing (FRAM) with short and continuous fibres yields light and stiff parts and thus increasing industry acceptance. High material anisotropy and specific manufacturing constraints shift the focus towards design for AM (DfAM), particularly on toolpath strategies. Assessing the design-property-processing relations of infill patterns is fundamental to establishing design guidelines for FRAM.

Design/methodology/approach

Subject to the DfAM factors performance, economy and manufacturability, the efficacy of two conventional infill patterns (grid and concentric) was compared with two custom strategies derived from the medial axis transformation (MAT) and guided by the principal stresses (MPS). The recorded stiffness and strength, the required CPU and print time, and the degree of path undulation and effective fibre utilisation (minimum printable fibre length) associated with each pattern, served as assessment indices for different case studies. Moreover, the influence of material anisotropy was examined, and a stiffness-alignment index was introduced to predict a pattern’s performance.

Findings

The highest stiffnesses and strengths were recorded for the MPS infill, emphasising the need for tailoring print paths rather than using fixed patterns. In contrast to the grid infill, the concentric infill offered short print times and reasonable utilisation of continuous fibres. The MAT-based infill yielded an excellent compromise between the three DfAM factors and experimentally resulted in the best performance.

Originality/value

This constitutes the first comprehensive investigation into infill patterns under DfAM consideration for FRAM, facilitating design and processing choices.

Details

Rapid Prototyping Journal, vol. 28 no. 7
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 13 February 2025

Mao Shi

We identify several theoretical shortcomings in the derivative formulas for rational Bézier curves and propose a new formula for the derivatives.

5

Abstract

Purpose

We identify several theoretical shortcomings in the derivative formulas for rational Bézier curves and propose a new formula for the derivatives.

Design/methodology/approach

Dependence on control points gives a new recursive approach to the derivation of rational Bézier curves.

Findings

We present the new derivation formula for rational Bézier curves that overcomes this drawback and show that the kth degree derivative of a nth degree rational Bézier curve can be written in terms of a (2kn)th degree rational Bézier curve.

Originality/value

This paper leads to a further complete understanding of the derivatives of rational Bézier curves.

Details

Engineering Computations, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 December 2001

Konstantinos A. Tarabanis

Presents algorithms for determining the paths employed by the Proteus rapid prototyping system when building three‐dimensional parts. Proteus is a fused deposition modeling system…

924

Abstract

Presents algorithms for determining the paths employed by the Proteus rapid prototyping system when building three‐dimensional parts. Proteus is a fused deposition modeling system that extrudes a thermoplastic in beads through a nozzle. Determines within each layer of the layered manufacturing process, the material deposition paths as well as the regions where local structures are required to support these paths. Computes the paths with the goal of reducing the amount of supports needed to build the physical prototype of the part by taking advantage of the two novel manufacturing techniques of shelving and bridging that had been developed previously. The path planning algorithms presented are designed to utilize the above techniques and address the variety of conditions that appear in practice allowing the Proteus system to “build in air”.

Details

Rapid Prototyping Journal, vol. 7 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 1 September 1996

Rida T. Farouki and Thomas König

Looks at how layered fabrication processes typically entail extensive computations and large memory requirements in the reduction of three‐dimensional part descriptions to…

600

Abstract

Looks at how layered fabrication processes typically entail extensive computations and large memory requirements in the reduction of three‐dimensional part descriptions to area‐filling paths that cover the interior of each of a sequence of planar slices. Notes that the polyhedral “STL” representation exacerbates this problem by necessitating large input data volumes to describe curved surface models at acceptable levels of accuracy. Develops a geometrical modelling system that captures and processes analytic slice representations, based on models bounded by the natural quadric surface. Finds that empirical results from this system on representative parts systematically yield improvements of between one and two orders of magnitude in efficiency, accuracy and data volume over an equivalent processing of the STL model. Furthermore, discovers that the analytic form is significantly more reliable, since it is not subject to the geometrical or topological defects frequently encountered in STL files generated by commercial CAD systems.

Details

Rapid Prototyping Journal, vol. 2 no. 3
Type: Research Article
ISSN: 1355-2546

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