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Article
Publication date: 11 February 2020

Vito Ricotta, Robert Ian Campbell, Tommaso Ingrassia and Vincenzo Nigrelli

The purpose of this paper is to implement a new process aimed at the design and production of orthopaedic devices fully manufacturable by additive manufacturing (AM). In…

Abstract

Purpose

The purpose of this paper is to implement a new process aimed at the design and production of orthopaedic devices fully manufacturable by additive manufacturing (AM). In this context, the use of generative algorithms for parametric modelling of additively manufactured textiles (AMTs) also has been investigated, and new modelling solutions have been proposed.

Design/methodology/approach

A new method for the design of customised elbow orthoses has been implemented. In particular, to better customise the elbow orthosis, a generative algorithm for parametric modelling and creation of a flexible structure, typical of an AMT, has been developed.

Findings

To test the developed modelling algorithm, a case study based on the design and production of an elbow orthosis made by selective laser sintering was investigated. The obtained results have demonstrated that the implemented algorithm overcomes many drawbacks typical of the traditional computer aided design (CAD) modelling approaches. The parametric CAD model of the orthosis obtained through the new approach is characterised by a flexible structure with no deformations or mismatches and has been effectively used to produce the prototype through AM technologies.

Originality/value

The obtained results present innovative elements of originality in the CAD modelling sector, which can contribute to solving problems related to modelling for AM in different application fields.

Details

Rapid Prototyping Journal, vol. 26 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

Content available
Article
Publication date: 8 December 2020

Maximilian Kunovjanek and Christian Wankmüller

The COVID-19 pandemic caused global supply disruptions and shortages that resulted in countries battling over desperately needed (medical) supplies. In this mayhem…

Abstract

Purpose

The COVID-19 pandemic caused global supply disruptions and shortages that resulted in countries battling over desperately needed (medical) supplies. In this mayhem, additive manufacturing (AM) provided relief to the strained healthcare systems and manufacturing environments by offering an alternative way to rapidly produce desired products. This study sheds light on how AM was used globally in response to the COVID-19 pandemic.

Design/methodology/approach

The study undertakes a systematic and content-centric review of 289 additively manufactured products made in response to the COVID-19 pandemic. Additionally, quantitative frequency-based text mining and various descriptive analyses were applied that support the investigation of the subject under regard.

Findings

Results show that AM was primarily used in the medical domain for the production of standard medical items, such as personal protective equipment (PPE) but also for non-obvious and new applications (e.g. swab simulator, rapid diagnostic kits, etc.). Also, certain paradigm shifts were observed, as the effective move to mass production and the mitigation of problems related to certification and standardization emerged as prominent management prospects. Nevertheless, various obstacles arose and remained in the path of lasting AM success, especially with respect to print quality, raw material supply and technological versatility.

Originality/value

Due to the actuality of the topic under investigation, no comparable study has so far been conducted. The systematic review provides a conclusive and precise foundation for further analysis and subsequent discussions. Additionally, no comparable study mapping such a wide array of different AM products exists today.

Details

Journal of Manufacturing Technology Management, vol. 32 no. 9
Type: Research Article
ISSN: 1741-038X

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Article
Publication date: 28 January 2020

Sathies T., Senthil P. and Anoop M.S.

Fabrication of customized products in low volume through conventional manufacturing incurs a high cost, longer processing time and huge material waste. Hence, the concept…

Abstract

Purpose

Fabrication of customized products in low volume through conventional manufacturing incurs a high cost, longer processing time and huge material waste. Hence, the concept of additive manufacturing (AM) comes into existence and fused deposition modelling (FDM), is at the forefront of researches related to polymer-based additive manufacturing. The purpose of this paper is to summarize the research works carried on the applications of FDM.

Design/methodology/approach

In the present paper, an extensive review has been performed related to major application areas (such as a sensor, shielding, scaffolding, drug delivery devices, microfluidic devices, rapid tooling, four-dimensional printing, automotive and aerospace, prosthetics and orthosis, fashion and architecture) where FDM has been tested. Finally, a roadmap for future research work in the FDM application has been discussed. As an example for future research scope, a case study on the usage of FDM printed ABS-carbon black composite for solvent sensing is demonstrated.

Findings

The printability of composite filament through FDM enhanced its application range. Sensors developed using FDM incurs a low cost and produces a result comparable to those conventional techniques. EMI shielding manufactured by FDM is light and non-oxidative. Biodegradable and biocompatible scaffolds of complex shapes are possible to manufacture by FDM. Further, FDM enables the fabrication of on-demand and customized prosthetics and orthosis. Tooling time and cost involved in the manufacturing of low volume customized products are reduced by FDM based rapid tooling technique. Results of the solvent sensing case study indicate that three-dimensional printed conductive polymer composites can sense different solvents. The sensors with a lower thickness (0.6 mm) exhibit better sensitivity.

Originality/value

This paper outlines the capabilities of FDM and provides information to the user about the different applications possible with FDM.

Details

Rapid Prototyping Journal, vol. 26 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 23 October 2020

Wilco M.H. Verbeeten, Miriam Lorenzo-Bañuelos, Rubén Saiz-Ortiz and Rodrigo González

The purpose of the present paper is to quantify and analyze the strain-rate dependence of the yield stress for both unfilled acrylonitrile-butadiene-styrene (ABS) and…

Abstract

Purpose

The purpose of the present paper is to quantify and analyze the strain-rate dependence of the yield stress for both unfilled acrylonitrile-butadiene-styrene (ABS) and short carbon fiber-reinforced ABS (CF-ABS) materials, fabricated via material extrusion additive manufacturing (ME-AM). Two distinct and opposite infill orientation angles were used to attain anisotropy effects.

Design/methodology/approach

Tensile test samples were printed with two different infill orientation angles. Uniaxial tensile tests were performed at five different constant linear strain rates. Apparent densities were measured to compensate for the voided structure. Scanning electron microscope fractography images were analyzed. An Eyring-type flow rule was evaluated for predicting the strain-rate-dependent yield stress.

Findings

Anisotropy was detected not only for the yield stresses but also for its strain-rate dependence. The short carbon fiber-filled material exhibited higher anisotropy than neat ABS material using the same ME-AM processing parameters. It seems that fiber and molecular orientation influence the strain-rate dependence. The Eyring-type flow rule can adequately describe the yield kinetics of ME-AM components, showing thermorheologically simple behavior.

Originality/value

A polymer’s viscoelastic behavior is paramount to be able to predict a component’s ultimate failure behavior. The results in this manuscript are important initial findings that can help to further develop predictive numerical tools for ME-AM technology. This is especially relevant because of the inherent anisotropy that ME-AM polymer components show. Furthermore, short carbon fiber-filled ABS enhanced anisotropy effects during ME-AM, which have not been measured previously.

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Article
Publication date: 26 April 2013

Mercedes Gumbau‐Albert and Joaquin Maudos

Using the EU‐KLEMS database for 12 countries and 16 industries, the purpose of this paper is to analyze the differences in technological capital intensity (R&D capital…

Abstract

Purpose

Using the EU‐KLEMS database for 12 countries and 16 industries, the purpose of this paper is to analyze the differences in technological capital intensity (R&D capital stock as a percentage of GVA) between industries and the evolution of inequalities between the EU‐11 and the USA, as well as between EU countries.

Design/methodology/approach

The authors use shift‐share analysis and a Theil inequality index to break down these inequalities and to quantify the importance of either a country or a specialization effect.

Findings

Results from the shift‐share analysis show that there was a technological gap in favor of the USA until the mid‐1990s linked to the greater accumulation of technological capital in most of the productive sectors considered, this being the main reason for the differences in technological innovation between the USA and the EU‐11. However, since 1995 a change in productive specialization has occurred, with a significant drop in the weight of lower technology‐intensive industries in the EU‐11 economy, as well as a significant drop in the weight of some medium technology‐intensive industries in the USA, accounting for the reduction in the technological gap between the EU and the USA. Results from the Theil index show that the differences in the productive structure of European countries explain most of their differences in technological capital intensity.

Originality/value

The study discusses the issue from the standpoint of the distribution of technological innovation across industries. The variable analyzed and constructed is R&D capital stock and not R&D expenditures. It applies a methodology (shift‐share analysis and Theil index) not commonly used to analyze technological innovation inequalities.

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Article
Publication date: 11 September 2019

Swapnil Vyavahare, Soham Teraiya, Deepak Panghal and Shailendra Kumar

Fused deposition modelling (FDM) is the most economical additive manufacturing technique. The purpose of this paper is to describe a detailed review of this technique…

Abstract

Purpose

Fused deposition modelling (FDM) is the most economical additive manufacturing technique. The purpose of this paper is to describe a detailed review of this technique. Total 211 research papers published during the past 26 years, that is, from the year 1994 to 2019 are critically reviewed. Based on the literature review, research gaps are identified and the scope for future work is discussed.

Design/methodology/approach

Literature review in the domain of FDM is categorized into five sections – (i) process parameter optimization, (ii) environmental factors affecting the quality of printed parts, (iii) post-production finishing techniques to improve quality of parts, (iv) numerical simulation of process and (iv) recent advances in FDM. Summary of major research work in FDM is presented in tabular form.

Findings

Based on literature review, research gaps are identified and scope of future work in FDM along with roadmap is discussed.

Research limitations/implications

In the present paper, literature related to chemical, electric and magnetic properties of FDM parts made up of various filament feedstock materials is not reviewed.

Originality/value

This is a comprehensive literature review in the domain of FDM focused on identifying the direction for future work to enhance the acceptability of FDM printed parts in industries.

Details

Rapid Prototyping Journal, vol. 26 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 3 April 2017

Eujin Pei, Giselle Hsiang Loh, David Harrison, Henrique de Amorim Almeida, Mario Domingo Monzón Verona and Rubén Paz

The purpose of this paper is to extend existing knowledge of 4D printing, in line with Khoo et al. (2015) who defined the production of 4D printing using a single…

Abstract

Purpose

The purpose of this paper is to extend existing knowledge of 4D printing, in line with Khoo et al. (2015) who defined the production of 4D printing using a single material, and 4D printing of multiple materials. It is proposed that 4D printing can be achieved through the use of functionally graded materials (FGMs) that involve gradational mixing of materials and are produced using an additive manufacturing (AM) technique to achieve a single component.

Design/methodology/approach

The latest state-of-the-art literature was extensively reviewed, covering aspects of materials, processes, computer-aided design (CAD), applications and made recommendations for future work.

Findings

This paper clarifies that functionally graded additive manufacturing (FGAM) is defined as a single AM process that includes the gradational mixing of materials to fabricate freeform geometries with variable properties within one component. The paper also covers aspects of materials, processes, CAD, applications and makes recommendations for future work.

Research limitations/implications

This paper examines the relationship between FGAM and 4D printing and defines FGAM as a single AM process involving gradational mixing of materials to fabricate freeform geometries with variable properties within one component. FGAM requires better computational tools for modelling, simulation and fabrication because current CAD systems are incapable of supporting the FGAM workflow.

Practical implications

It is also identified that other factors, such as strength, type of materials, etc., must be taken into account when selecting an appropriate process for FGAM. More research needs to be conducted on improving the performance of FGAM processes through extensive characterisation of FGMs to generate a comprehensive database and to develop a predictive model for proper process control. It is expected that future work will focus on both material characterisation as well as seamless FGAM control processes.

Originality/value

This paper examines the relationship between FGAM and 4D printing and defines FGAM as a single AM process that includes gradational mixing of materials to fabricate freeform geometries with variable properties within one component.

Details

Assembly Automation, vol. 37 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 28 August 2019

Niknam Momenzadeh, Hadi Miyanaji, Daniel Allen Porter and Thomas Austin Berfield

This study aims to investigate the material extrusion additive manufacturing (MEAM) deposition parameters for creating viable 3-D printed polyvinylidene fluoride (PVDF…

Abstract

Purpose

This study aims to investigate the material extrusion additive manufacturing (MEAM) deposition parameters for creating viable 3-D printed polyvinylidene fluoride (PVDF) structures with a balanced mix of mechanical and electrical properties.

Design/methodology/approach

Different combinations of deposition conditions are tested, and the influence of these parameters on the final dimensional accuracy, semi-crystalline phase microstructure and effective mechanical strength of MEAM homopolymer PVDF printed parts is experimentally assessed. Considering printed part integrity, appearance, print time and dimensional accuracy, MEAM parameters for PVDF are suggested.

Findings

A range of viable printing parameters for MEAM fabricated PVDF Kynar 740 objects of different heights and in-plane length dimensions was determined. For PVDF structures printed under the suggested conditions, the mechanical response and the microstructure development related to Piezoelectric response are reported.

Originality/value

This research first reports on a range of parameters that have been confirmed to facilitate effective MEAM printing of 3-D PVDF objects, presents effects of the individual parameters and gives the mechanical and microstructure properties of PVDF structures fabricated under the suggested deposition conditions.

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Book part
Publication date: 4 March 2015

György Simon

The study deals with key questions of Serbia’s economic development, including the regularities of transforming self-managed socialism to a standard capitalist system. It…

Abstract

The study deals with key questions of Serbia’s economic development, including the regularities of transforming self-managed socialism to a standard capitalist system. It is based on the concept of endogenous growth and the general theory of market transition. In the empirical part of investigation, the main directions of economic development and transition in Serbia are analysed. Crucial issues of economic policy are also considered with a particular emphasis on the latest phase of transition. Concerning the problems of economic efficiency, an attempt is made to quantify the various types of technical progress and determine their contribution to its overall rate. The macroeconomic role of external factors is quantitatively shown through a globalisation effect related to inflows of FDI. The author believes that the Serbian economy, despite all its problems and difficulties, in principle has the potential necessary for finding adequate answers to the challenges of ‘neo-transition’. Of these challenges, he regards as most serious Serbia’s ability to comply with the standards of accession to the European Union, which, among others, requires closer regional cooperation.

Details

Neo-Transitional Economics
Type: Book
ISBN: 978-1-78441-681-2

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Article
Publication date: 2 February 2021

Ali Alperen Bakır, Resul Atik and Sezer Özerinç

This paper aims to provide an overview of the recent findings of the mechanical properties of parts manufactured by fused deposition modeling (FDM). FDM has become a…

Abstract

Purpose

This paper aims to provide an overview of the recent findings of the mechanical properties of parts manufactured by fused deposition modeling (FDM). FDM has become a widely used technique for the manufacturing of thermoplastic parts. The mechanical performance of these parts under service conditions is difficult to predict due to the large number of process parameters involved. The review summarizes the current knowledge about the process-property relationships for FDM-based three-dimensional printing.

Design/methodology/approach

The review first discusses the effect of material selection, including pure thermoplastics and polymer-matrix composites. Second, process parameters such as nozzle temperature, raster orientation and infill ratio are discussed. Mechanisms that these parameters affect the specimen morphology are explained, and the effect of each parameter on the strength of printed parts are systematically presented.

Findings

Mechanical properties of FDM-produced parts strongly depend on process parameters and are usually lower than injection-molded counterparts. There is a need to understand the effect of each parameter and any synergistic effects involved better.

Practical implications

Through the optimization of process parameters, FDM has the potential to produce parts with strength values matching those produced by conventional methods. Further work in the field will make the FDM process more suitable for the manufacturing of load-bearing components.

Originality/value

This paper presents a critical assessment of the current knowledge about the mechanical properties of FDM-produced parts and suggests future research directions.

Details

Rapid Prototyping Journal, vol. 27 no. 3
Type: Research Article
ISSN: 1355-2546

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