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Article
Publication date: 18 April 2017

Marco Montani, Ali Gökhan Demir, Ehsan Mostaed, Maurizio Vedani and Barbara Previtali

This paper aims to investigate the processability by selective laser melting (SLM) of materials of potential interest for innovative biodegradable implants, pure Fe and pure Zn…

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Abstract

Purpose

This paper aims to investigate the processability by selective laser melting (SLM) of materials of potential interest for innovative biodegradable implants, pure Fe and pure Zn. The processability of these materials is evaluated with a more established counterpart in permanent implants, stainless steel. In particular, the processing conditions were studied to reduce porosity due to incomplete fusion of the powder.

Design/methodology/approach

In the first phase of the experiments, SLM of AISI 316L was studied through design of experiments method. The study was used to identify the significant parameters in the experimental range and estimate the fluence ranges for pure Fe and pure Zn using the lumped heat capacity model. In the second phase, SLM of pure Fe and pure Zn were studied using estimated fluence ranges. In the final phase, best conditions were characterized for mechanical properties.

Findings

The results showed that complete melting of AISI 316L and pure Fe could be readily achieved, whereas laser melting generated a foam-like porous structure in Zn samples. The mechanical properties of laser melt implant materials were compared to as-cast and rolled counterparts. Laser melted AISI 316L showed superior mechanical performance compared to as-cast and rolled material, whereas Fe showed mechanical performance similar to rolled mild steel. Despite 12 per cent apparent porosity, laser melted Zn exhibited superior mechanical properties compared to as-cast and wrought material because of reduced grain size.

Originality/value

The paper provides key processing knowledge on the SLM processability of new biodegradable metals, namely, pure Fe, which has been studied sparingly, and pure Zn, on which no previous work is available. The results prefigure the production of new biodegradable metallic implants with superior mechanical properties compared to their polymeric counterparts and with improved degradation rates compared to magnesium alloys, the reference material for biodegradable metals.

Details

Rapid Prototyping Journal, vol. 23 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 9 April 2018

Marco Anilli, Ali Gökhan Demir and Barbara Previtali

The purpose of this paper is to demonstrate the use of selective laser melting for producing single and double chamber laser cutting nozzles. The main aim is to assess a whole…

612

Abstract

Purpose

The purpose of this paper is to demonstrate the use of selective laser melting for producing single and double chamber laser cutting nozzles. The main aim is to assess a whole production chain composed of an additive manufacturing (AM) and consecutive finishing processes together. Beyond the metrological and flow-related characterization of the produced nozzles, functional analysis on the use of the produced nozzles are carried out through laser cutting experiments.

Design/methodology/approach

SLM experiments were carried out to determine the correct compensation factor to achieve a desired nozzle diameter on steel with known processibility by SLM and using standard nozzle geometries for comparative purposes. The produced nozzles are finished through electrochemical machining (ECM) and abrasive flow machining (AFM). The performance of nozzles produced via additive manufacturing (AM) are compared to conventional ones on an industrial laser cutting system through cutting experiments with a 6 kW fibre laser. The produced nozzles are characterized in terms of pressure drop and flow dynamics through Schlieren imaging.

Findings

The manufacturing chain was regulated to achieve 1 mm diameter nozzles after consecutive post processing. The average surface roughness could be lowered by approximately 80 per cent. The SLM produced single chamber nozzles would perform similarly to conventional nozzles during the laser cutting of 1 mm mild steel with nitrogen. The double chamber nozzles could provide complete cuts with oxygen on 5 mm-thick mild steel only after post-processing. Post-processing operations proved to decrease the pressure drop of the nozzles. Schlieren images showed jet constriction at the nozzle outlet on the as-built nozzles.

Originality/value

In this work, the use of an additive manufacturing process is assessed together with suitable finishing and functional analysis of the related application to provide a complete production and evaluation chain. The results show how the finishing processes should be allocated in an AM-based production chain in a broader vision. In particular, the results confirm the functionality for designing more complex nozzle geometries for laser cutting, exploiting the flexibility of SLM process.

Details

Rapid Prototyping Journal, vol. 24 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 16 November 2012

B. Valsecchi, B. Previtali and E. Gariboldi

The present work aims at developing the laser cladding technology by means of an active fiber laser source applicable for hardfacing of martensitic steel turbine blades. It also…

352

Abstract

Purpose

The present work aims at developing the laser cladding technology by means of an active fiber laser source applicable for hardfacing of martensitic steel turbine blades. It also aims to investigate two process parameter conditions to reproduce two different heat inputs, in order to highlight the effect of the thermal input on the thermal alteration and dilution of the substrate material and clad layer.

Design/methodology/approach

The experimentation was performed initially at a sample level, reproducing the material and thickness of the blade leading edge, then on an industrial real component. Cladding process parameters were experimentally selected and two different process parameter conditions, at different specific energy, were determined. The microstructural and geometrical features of the clad samples were analyzed both by optical microscopy and scanning electron microscopy, in this latter case combining the information supplied by different probes, among which the EDX microanalysis to obtain chemical profiles. Hardness distribution was also evaluated by means of Vickers hardness tester.

Findings

All the two investigated conditions were suitable for laser cladding of the blade leading edge, since a crack and pore free clad layer with a strong metallurgical bond to the substrate was obtained. The experimented two different heat inputs affected the extension of the HAZ as well the chemical and geometrical dilution. The clad integrity was preserved in both cases. The condition at higher specific energy was chosen to clad the turbine blade. The high specific energy condition was preferred because the iron dilution in the clad layer was inferior.

Research limitations/implications

Further research is needed to correlate the chemical dilution and the thermal alteration introduced by the laser cladding process on such a kind of substrate at different process parameter conditions to the wear and corrosion resistance of the turbine blade.

Practical implications

Laser cladding process with an innovative active fiber laser source of the leading edge of a steam turbine blade was developed. Progress achieved in laser cladding technology development is of practical value for manufacture of turbine blades, made of martensitic steels.

Social implications

The paper investigates the effect of different energy input on the laser cladding of steam turbine blades, mainly used in coal, gas and nuclear plants to produce electricity by heating water to create steam. The laser cladding process is an effective technology to increase the steam blades toughness and resistance to creep, stress and corrosion. This increase in the turbine blade properties contributes to extend the life of such a critical components, decreasing cost and time of substitution and ensuring better service conditions.

Originality/value

The most original aspect of the paper is related to the focus on the difference between the chemical and the geometrical dilution, being the first one mainly related to the corrosion and wear resistance of the clad layer, while the later mainly regards the clad layer adhesion to the substrate. More in general the paper presents one of the first experiments accomplished while making use of the active fiber laser source.

Details

International Journal of Structural Integrity, vol. 3 no. 4
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 1 August 2019

Martina Dal Molin and Ezio Previtali

The purpose of this paper is to estimate and assess the impact of public procurement activities of an Italian basic research center (the National Institute for Nuclear Physics…

329

Abstract

Purpose

The purpose of this paper is to estimate and assess the impact of public procurement activities of an Italian basic research center (the National Institute for Nuclear Physics [INFN]) on supplier companies.

Design/methodology/approach

Starting from the exploratory nature of this research, a single case study research strategy has been applied. The impact of basic research public procurement has been estimated using survey data on 168 INFN supplier companies. Supplier companies have been surveyed on six different categories of company outcomes, namely, sales volume, learning and innovation, relationship with the market, alliances and network and social impact.

Findings

Results of the analysis reported that the activity of INFN public procurement generates a positive impact on supplier companies on different dimensions, especially related to learning and innovative outcome and economic impact and market penetration outcome.

Social implications

Policy implications can be derived from the current study. In particular, to support the policymakers in the effort of assessing the impact of basic research public procurement, this study, first highlights the impact dimensions on supplier companies, and second, it provides empirical evidence of public procurement as a viable tool to foster companies’ innovation.

Originality/value

This research explores a relevant but understudied topic that has recently attracted the attention of policymakers. In fact, although public procurement have been recognized as a tool to foster companies’ innovation, empirical evidence is still scant, particularly in the case of basic research.

Details

Journal of Public Procurement, vol. 19 no. 3
Type: Research Article
ISSN: 1535-0118

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Article
Publication date: 4 August 2023

Nunzia Carbonara, Barbara Scozzi and Roberta Pellegrino

This paper aims to provide an easy-to-use yet powerful tool to assess the organizational readiness to adopt effective Smart Working (SW). In light of this main objective, based on…

456

Abstract

Purpose

This paper aims to provide an easy-to-use yet powerful tool to assess the organizational readiness to adopt effective Smart Working (SW). In light of this main objective, based on the current state of research, the study develops a maturity model to assess the SW organizational readiness (SWOR). The SWOR maturity model consists of three dimensions, each of them further detailed into two sub-dimensions. A tool was developed to make use of the model.

Design/methodology/approach

The SWOR maturity model was converted into a Web-based questionnaire that includes 54 questions based on 44 items to operationalize the model sub-dimensions. The questionnaire was used in a survey conducted at the Local Health Authority (ASL) of the province of Bari (Italy).

Findings

Several implications derive from the present study. From a managerial perspective, the SWOR maturity model supports companies in the as-is analysis of processes, technologies and human resources, which are the enablers of an effective SW, and in the development of a roadmap to achieve a desired “to-be” situation.

Originality/value

Despite recent studies on SW have identified the key drivers that affect the success of SW implementation, there is a lack of models and tools that help companies become aware of the actions and investments to be taken to move towards an effective SW adoption. Even the analysis of the literature on maturity models reveals a gap in the research related to the assessment of SW organizational readiness. The present paper tries to overcome these limitations.

Details

Journal of Workplace Learning, vol. 35 no. 6
Type: Research Article
ISSN: 1366-5626

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Article
Publication date: 20 June 2024

Yong Huang, Xiangfeng He, Zhiguang Lian and Zhirong Yang

This study explores the deep integration of digital technology and cultural heritage to promote the preservation and inheritance of cultural heritage. Focusing on Digital Cultural…

181

Abstract

Purpose

This study explores the deep integration of digital technology and cultural heritage to promote the preservation and inheritance of cultural heritage. Focusing on Digital Cultural Heritage (DCH), this research investigates its key role in activating theoretical research and practical applications in cultural heritage.

Design/methodology/approach

This study conducted an extensive bibliometric analysis utilizing VOSviewer and Bibliometrix visualization software to meticulously examine DCH research. Insights were gleaned from a dataset comprising 2,997 DCH-related publications harvested from the Web of Science database.

Findings

The bibliometric analysis reveals several notable findings: driven by active contributions from Italy, China, Spain, and the USA, the number of DCH publications shows a linear upward trend. Consiglio Nazionale delle Ricerche in Italy emerges as a prominent institution, while the Journal of Cultural Heritage stands out as the most influential journal in the DCH field. Scholars such as Remondino, Guidi, Barazzetti, and Carrozzino have significantly impacted DCH research. Furthermore, an in-depth analysis of keyword co-occurrence networks elucidates six major research trajectories in the DCH field, covering various aspects from cultural heritage digitization to digital humanities.

Practical implications

The study emphasizes the value of global knowledge exchange, interdisciplinary collaboration, innovative technology applications, and digital content provision practices in advancing DCH research.

Originality/value

By delving into the multifaceted landscape of DCH research, this study brings forth original insights into the escalating trends, pivotal contributors, and burgeoning research directions.

Details

Library Hi Tech, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0737-8831

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