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Article
Publication date: 9 November 2018

Antonio Armillotta

The purpose of this paper is to propose a method for simulating the profile of part edges as a result of the FDM process. Deviations from nominal edge shape are predicted as a…

323

Abstract

Purpose

The purpose of this paper is to propose a method for simulating the profile of part edges as a result of the FDM process. Deviations from nominal edge shape are predicted as a function of the layer thickness and three characteristic angles depending on part geometry and build orientation.

Design/methodology/approach

Typical patterns of edge profiles were observed on sample FDM parts and interpreted as the effects of possible toolpath generation strategies. An algorithm was developed to generate edge profiles consistent with the patterns expected for any combination of input variables.

Findings

Experimental tests confirmed that the simulation procedure can correctly predict basic geometric properties of edge profiles such as frequency, amplitude and shape of periodic asperities.

Research limitations/implications

The algorithm takes into account only a subset of the error causes recognized in previous studies. Additional causes could be integrated in the simulation to improve the estimation of geometric errors.

Practical implications

Edge simulation may help avoid process choices that result in aesthetic and functional defects on FDM parts.

Originality/value

Compared to the statistical estimation of geometric errors, graphical simulation allows a more detailed characterization of edge quality and a better diagnosis of error causes.

Details

Rapid Prototyping Journal, vol. 25 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 20 June 2017

Antonio Armillotta, Stefano Bianchi, Marco Cavallaro and Stefania Minnella

This paper aims to provide an experimental evaluation of geometric errors on the edges of parts manufactured by the fused deposition modeling (FDM) process.

328

Abstract

Purpose

This paper aims to provide an experimental evaluation of geometric errors on the edges of parts manufactured by the fused deposition modeling (FDM) process.

Design/methodology/approach

An experimental plan was conducted by building parts in ABS thermoplastic resin on a commercially available machine with given combinations of the three geometric variables (inclination, included and incidence angle) defined in the first part of the paper. Edges on built parts were inspected on a two-dimensional non-contact profilometer to measure position and form errors.

Findings

The analysis of measurement results revealed that the edge-related variables have significant influences on the geometric errors. The interpretation of error variations with respect to the different angles confirmed the actual occurrence of the previously discussed error causes. As an additional result, quantitative predictions of the errors were provided as a function of angle values.

Research limitations/implications

The experimental results refer to fixed process settings (material, FDM machine, layer thickness, build parameters, scan strategies).

Originality/value

The two-part paper is apparently the first to have studied the edges of additively manufactured parts with respect to geometric accuracy, a widely studied topic for surface features.

Details

Rapid Prototyping Journal, vol. 23 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

Available. Open Access. Open Access
Article
Publication date: 14 January 2020

Antonio Armillotta

This paper aims to investigate the feasibility of adding macro-textures to triangle meshes for additive manufacturing (AM) focusing on possible time and quality issues in both…

670

Abstract

Purpose

This paper aims to investigate the feasibility of adding macro-textures to triangle meshes for additive manufacturing (AM) focusing on possible time and quality issues in both software processing and part fabrication.

Design/methodology/approach

A demonstrative software tool was developed to apply user-selected textures to existing meshes. The computational procedure is a three-dimensional extension of the solid texturing method used in computer graphics. The tool was tested for speed and quality of results, considering also the pre- and post-processing operations required. Some textured meshes were printed by different processes to test build speed and quality.

Findings

The tool can handle models with realistic complexity in acceptable computation times. Parts are built without difficulties or extra-costs achieving a good aesthetic yield of the texture.

Research limitations/implications

The tool cannot reproduce sample patterns but requires the development of a generation algorithm for different type of textures. Mesh processing operations may take a long time when very fine textures are added to large parts.

Practical implications

Direct texturing can help obtain parts with aesthetic or functional textures without the need for surface post-treatments, which can be especially difficult and expensive for plastic parts.

Originality/value

The proposed method improves the uniformity and consistency of textures compared to existing approaches, and can support future systematic studies on the detail resolution of AM processes.

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Article
Publication date: 17 October 2017

Antonio Armillotta and Marco Cavallaro

The purpose of this paper is to discuss the problem of the geometric accuracy of edges in parts manufactured by the Fused Deposition Modeling process, as a preliminary step for an…

376

Abstract

Purpose

The purpose of this paper is to discuss the problem of the geometric accuracy of edges in parts manufactured by the Fused Deposition Modeling process, as a preliminary step for an experimental investigation.

Methodology/approach

Three geometric variables (inclination, included and incidence angles) were defined for an edge. The influence of each variable on the geometric errors was explained with reference to specific causes related to physical phenomena and process constraints.

Findings

Occurrence conditions for all causes were determined and visualized in a process map, which was also developed into a software procedure for the diagnosis of quality issues on digital models of the parts.

Research limitations/implications

The process map was developed by only empirical considerations and does not allow to predict the amount of geometric errors. In the second part of the paper, experimental tests will help to extend and validate the prediction criteria.

Practical implications

As demonstrated by an example, the results allow to predict the occurrence of visible defects on the edges of a part before manufacturing it with a given build orientation.

Originality/value

In literature, the geometric accuracy of additively manufactured parts is only related to surface features. The paper shows that the quality of edges depends on additional variables and causes to be carefully controlled by process choices.

Details

Rapid Prototyping Journal, vol. 23 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 1 January 2006

Antonio Armillotta

Test the detail resolution of fused deposition modeling (FDM) in the direct manufacture of rapid prototypes with textured surfaces.

4791

Abstract

Purpose

Test the detail resolution of fused deposition modeling (FDM) in the direct manufacture of rapid prototypes with textured surfaces.

Design/methodology/approach

A benchmark part carrying regular surface patterns with different feature sizes and aspect ratios has been manufactured on a FDM system with different build orientations. Layered parts have been inspected to detect the occurrence of quality defects on textured surfaces.

Findings

The experiments reveal the ability of currently available FDM systems to enhance prototype surfaces with form details on a millimeter scale. Results assist in identifying conditions which need to be satisfied in order to successfully reproduce generic texture geometries.

Research limitations/implications

Although the testing method can be applied to any layered manufacturing technique, results are limited to a specific process, and may be influenced by technical improvements of commercial fabrication systems.

Practical implications

A first contribution is given to a full feasibility assessment of direct texturing, which potentially appears as more responsive and cost‐effective solution than current post‐finishing practices.

Originality/value

The paper proposes a systematic approach to the manufacture of textured parts by rapid prototyping techniques. The analysis of surface appearance in the presence of small‐scale form details adds a novel aspect to current approaches to performance benchmarking, which typically focus on form errors and roughness of plain surfaces.

Details

Rapid Prototyping Journal, vol. 12 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 1 April 2014

Antonio Armillotta

This paper aims to present a method for the tolerance analysis of mechanical assemblies that is suitable to nonlinear problems where explicit functional equations are difficult or…

248

Abstract

Purpose

This paper aims to present a method for the tolerance analysis of mechanical assemblies that is suitable to nonlinear problems where explicit functional equations are difficult or even impossible to write down. Such cases are usually modelled by linearised tolerance chains, whose coefficients (or sensitivities) are calculated from assembly data.

Design/methodology/approach

The method is based on the free-body diagrams of force analysis, which are shown to be related to the sensitivities of linearised functional equations. Such an analogy allows the conversion of a tolerance chain into a corresponding static problem, which can be solved by common algebraic or graphical procedures.

Findings

The static analogy leads to a correct treatment of tolerance chains, as the analysis of several examples has confirmed by comparison to alternative methods.

Research limitations/implications

Currently, the method has only been tested on two-dimensional chains of linear dimensions for assemblies with nonredundant kinematic constraints among parts.

Practical implications

The proposed method lends itself to ready application by using simple operations with minimal software assistance. This could make it complementary to current methods for calculating sensitivities, which are mathematically complex and require software implementation for deployment in industrial practice.

Originality/value

Analogy with force analysis, which has not been previously highlighted in the literature, is a potentially interesting concept that could be extended to a wider range of tolerancing problems.

Details

Assembly Automation, vol. 34 no. 2
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 18 January 2016

Sunpreet Singh and Rupinder Singh

This paper aims to review the industrial and biomedical applications of state-of-the-art fused deposition modelling (FDM)-assisted investment casting (FDMAIC). Brief literature…

1344

Abstract

Purpose

This paper aims to review the industrial and biomedical applications of state-of-the-art fused deposition modelling (FDM)-assisted investment casting (FDMAIC). Brief literature survey of methodologies, ideas, techniques and approaches used by various researchers is highlighted and use of hybrid feedstock filament-based pattern to produce metal matrix composite is duly discussed.

Design/methodology/approach

Pattern replica required for investment casting (IC) of biomedical implant, machine parts, dentistry and other industrial components can be directly produced by using FDM process is presented. Relevant studies and examples explaining the suitability of FDMAIC for various applications are also presented.

Findings

Researches to optimize the conventional IC with FDM solutions and develop new hybrid feedstock filament of FDM done by researchers worldwide are also discussed. The review highlights the benefit of FDMAIC to surgeons, engineers and manufacturing organizations.

Research limitations/implications

The research related to this survey is limited to the suitability and applicability of FDMAIC.

Originality/value

This review presents the information regarding potential IC application, which facilitates the society, engineers and manufacturing organizations by providing variety of components for assisting FDM. The information reported in this paper will serve doctors, researchers, organizations and academicians to explore the new options in the field of FDMAIC.

Details

Rapid Prototyping Journal, vol. 22 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 27 September 2021

Michele Ciotti, Giampaolo Campana and Mattia Mele

This paper aims to present a survey concerning the accuracy of thermoplastic polymeric parts fabricated by additive manufacturing (AM). Based on the scientific literature, the aim…

407

Abstract

Purpose

This paper aims to present a survey concerning the accuracy of thermoplastic polymeric parts fabricated by additive manufacturing (AM). Based on the scientific literature, the aim is to provide an updated map of trends and gaps in this relevant research field. Several technologies and investigation methods are examined, thus giving an overview and analysis of the growing body of research.

Design/methodology/approach

Permutations of keywords, which concern materials, technologies and the accuracy of thermoplastic polymeric parts fabricated by AM, are used for a systematic search in peer-review databases. The selected articles are screened and ranked to identify those that are more relevant. A bibliometric analysis is performed based on investigated materials and applied technologies of published papers. Finally, each paper is categorised and discussed by considering the implemented research methods.

Findings

The interest in the accuracy of additively manufactured thermoplastics is increasing. The principal sources of inaccuracies are those shrinkages occurring during part solidification. The analysis of the research methods shows a predominance of empirical approaches. Due to the experimental context, those achievements have consequently limited applicability. Analytical and numerical models, which generally require huge computational costs when applied to complex products, are also numerous and are investigated in detail. Several articles deal with artificial intelligence tools and are gaining more and more attention.

Originality/value

The cross-technology survey on the accuracy issue highlights the common critical aspects of thermoplastics transformed by AM. An updated map of the recent research literature is achieved. The analysis shows the advantages and limitations of different research methods in this field, providing an overview of research trends and gaps.

Details

Rapid Prototyping Journal, vol. 28 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 12 March 2018

Anand M.B. and Vinodh S.

The purpose of this study is to rank additive manufacturing (AM) processes for microfabrication using integrated fuzzy analytic hierarchy process (AHP)-technique for order of…

510

Abstract

Purpose

The purpose of this study is to rank additive manufacturing (AM) processes for microfabrication using integrated fuzzy analytic hierarchy process (AHP)-technique for order of preference by similarity to ideal solution (TOPSIS).

Design/methodology/approach

AM technology selection is formulated as multi-criteria decision-making (MCDM) problem and ranking is obtained using fuzzy AHP-TOPSIS. Five candidate processes considered are laser-induced forward transfer (LIFT), microstereolithography, micro-selective laser sintering (micro-SLS), inkjet, micro 3D printing.

Findings

Criteria weights are obtained using fuzzy AHP, and ranking is obtained using fuzzy TOPSIS. The top ranked criteria include material compatibility, geometrical complexity and minimum feature size. The ranking sequence is LIFT > microstereolithography > micro-SLS > inkjet > micro-3D printing.

Research limitations/implications

In the present study, ten criteria and five alternatives are used. In future, additional criteria and alternatives could be considered in line with technological advancements.

Practical implications

The generated ranking enabled the selection of appropriate AM process for microfabrication.

Originality/value

The application of hybrid MCDM approach for ranking AM processes for microfabrication is the contribution of the study.

Details

Rapid Prototyping Journal, vol. 24 no. 2
Type: Research Article
ISSN: 1355-2546

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