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Article
Publication date: 3 August 2023

Abdul Wahab Hashmi, Harlal Singh Mali, Anoj Meena, Shadab Ahmad and Yebing Tian

Three-dimensional (3D) printed parts usually have poor surface quality due to layer manufacturing’s “stair casing/stair-stepping”. So post-processing is typically needed to…

Abstract

Purpose

Three-dimensional (3D) printed parts usually have poor surface quality due to layer manufacturing’s “stair casing/stair-stepping”. So post-processing is typically needed to enhance its capabilities to be used in closed tolerance applications. This study aims to examine abrasive flow finishing for 3D printed polylactic acid (PLA) parts.

Design/methodology/approach

A new eco-friendly abrasive flow machining media (EFAFM) was developed, using paper pulp as a base material, waste vegetable oil as a liquid synthesizer and natural additives such as glycine to finish 3D printed parts. Characterization of the media was conducted through thermogravimetric analysis and Fourier transform infrared spectroscopy. PLA crescent prism parts were produced via fused deposition modelling (FDM) and finished using AFM, with experiments designed using central composite design (CCD). The impact of process parameters, including media viscosity, extrusion pressure, layer thickness and finishing time, on percentage improvement in surface roughness (%ΔRa) and material removal rate were analysed. Artificial neural network (ANN) and improved grey wolf optimizer (IGWO) were used for data modelling and optimization, respectively.

Findings

The abrasive media developed was effective for finishing FDM printed parts using AFM, with SEM images and 3D surface profile showing a significant improvement in surface topography. Optimal solutions were obtained using the ANN-IGWO approach. EFAFM was found to be a promising method for improving finishing quality on FDM 3D printed parts.

Research limitations/implications

The present study is focused on finishing FDM printed crescent prism parts using AFM. Future research may be done on more complex shapes and could explore the impact of different materials, such as thermoplastics and composites for different applications. Also, implication of other techniques, such as chemical vapour smoothing, mechanical polishing may be explored.

Practical implications

In the biomedical field, the use of 3D printing has revolutionized the way in which medical devices, implants and prosthetics are designed and manufactured. The biodegradable and biocompatible properties of PLA make it an ideal material for use in biomedical applications, such as the fabrication of surgical guides, dental models and tissue engineering scaffolds. The ability to finish PLA 3D printed parts using AFM can improve their biocompatibility, making them more suitable for use in the human body. The improved surface quality of 3D printed parts can also facilitate their sterilization, which is critical in the biomedical field.

Social implications

The use of eco-friendly abrasive flow finishing for 3D printed parts can have a positive impact on the environment by reducing waste and promoting sustainable manufacturing practices. Additionally, it can improve the quality and functionality of 3D printed products, leading to better performance and longer lifespans. This can have broader economic and societal benefits.

Originality/value

This AFM media constituents are paper pulp, waste vegetable oil, silicon carbide as abrasive and the mixture of “Aloe Barbadensis Mill” – “Cyamopsis Tetragonoloba” powder and glycine. This media was then used to finish 3D printed PLA crescent prism parts. The study also used an IGWO to optimize experimental data that had been modelled using an ANN.

Details

Rapid Prototyping Journal, vol. 29 no. 10
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 7 September 2022

Abdul Wahab Hashmi, Harlal Singh Mali and Anoj Meena

The purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However, the…

Abstract

Purpose

The purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However, the products manufactured using AM usually suffer from defects like roughness or uneven surfaces. This paper discusses the various surface quality improvement techniques, including how to reduce surface defects, surface roughness and dimensional accuracy of AM parts.

Design/methodology/approach

There are many different types of popular AM methods. Unfortunately, these AM methods are susceptible to different kinds of surface defects in the product. As a result, pre- and postprocessing efforts and control of various AM process parameters are needed to improve the surface quality and reduce surface roughness.

Findings

In this paper, the various surface quality improvement methods are categorized based on the type of materials, working principles of AM and types of finishing processes. They have been divided into chemical, thermal, mechanical and hybrid-based categories.

Research limitations/implications

The review has evaluated the possibility of various surface finishing methods for enhancing the surface quality of AM parts. It has also discussed the research perspective of these methods for surface finishing of AM parts at micro- to nanolevel surface roughness and better dimensional accuracy.

Originality/value

This paper represents a comprehensive review of surface quality improvement methods for both metals and polymer-based AM parts.

Graphical abstract of surface quality improvement methods

Details

Rapid Prototyping Journal, vol. 29 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 6 November 2023

Huda Abdullah, Norshafadzila Mohammad Naim, Kok Seng Shum, Aidil Abdul Hamid, Mohd Hafiz Dzarfan Othman, Vidhya Selvanathan, Wing Fen Yap and Seri Mastura Mustaza

Regular monitoring of bacteria, especially Escherichia coli, in wastewater is crucial to ensure the maintenance of public health. Amperometric detection proves to be a fast…

Abstract

Purpose

Regular monitoring of bacteria, especially Escherichia coli, in wastewater is crucial to ensure the maintenance of public health. Amperometric detection proves to be a fast, sensitive and economically viable solution for E. coli enumeration. This paper reported a prototype amperometric sensor based on PANI-ZnO-NiO nanocomposite thin films prepared by sol–gel method and irradiated with gamma ray. The purpose of this study is to investigate the sensor performance of PANI-ZnO-NiO nanocomposite thin films to detect E. coli in water.

Design/methodology/approach

The films were varied with different compositions of ZnO and NiO by using the formula PANI-(ZnO)1-x-(NiO)x, with x = 0.2, 0.4, 0.6 and 0.8. PANI-ZnO-NiO nanocomposite thin films were characterized by using X-ray diffraction (XRD) and atomic force microscopy (AFM) to study the crystallinity and surface morphology of the films. The sensor performance was conducted using the current–voltage (I-V) measurement by testing the films in clean water and E. coli solution.

Findings

XRD diffractograms show the peaks of ZnO (1 0 0) and NiO (1 0 2). AFM analysis shows the surface roughness, and the grain size of PANI-ZnO-NiO thin films decreases when the concentration ratios of NiO increased. I-V curves show the difference in current flow, where the current in E. coli solution is higher than the clean water.

Originality/value

PANI-(ZnO)1-x-(NiO)x nanocomposite thin film with the highest concentration of ZnO performed the highest sensitivity among the other concentrations, which can be used to indicate the presence of E. coli bacteria in water.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 27 October 2023

Quang Khai Nguyen

This study aims to investigate the effect of the presence of women in top executive positions on financial reporting quality (FRQ) and the role of external audit in enhancing the…

Abstract

Purpose

This study aims to investigate the effect of the presence of women in top executive positions on financial reporting quality (FRQ) and the role of external audit in enhancing the role of women in top executive positions.

Design/methodology/approach

This study uses a sample of 644 Vietnamese-listed firms from 2010 to 2020 and applies fixed-effect and dynamic system generalized method of moments techniques for empirical models to test the related hypotheses.

Findings

First, this study found a U-shaped relationship between women on the board and FRQ as well as women on the audit committee and FRQ. Second, female CEOs are positively associated with FRQ in small firms but there is no evidence of this in large firms. Third, a female chief accountant can enhance FRQ. Finally, external audit quality can reduce the negative effect of women on the board and the audit committee on FRQ and increase the positive impact of female chief accountants on FRQ.

Practical implications

The results support all risk-averse, ethical sensitivity and glass ceiling hypotheses in different contexts. This study provides important implications for firms to enhance FRQ by nominating women in a majority of top executive positions and simultaneously using high-quality external audit services.

Originality/value

The impact of women in top executive positions on controlling FRQ in different contexts is an original contribution to gender in management literature.

Details

Journal of Accounting in Emerging Economies, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2042-1168

Keywords

Article
Publication date: 5 June 2023

Yidong Zhang

The purpose of this paper is to study the electronic transport performance of Ag-ZnO film under dark and UV light conditions.

Abstract

Purpose

The purpose of this paper is to study the electronic transport performance of Ag-ZnO film under dark and UV light conditions.

Design/methodology/approach

Ag-doped ZnO thin films were prepared on fluorine thin oxide (FTO) substrates by sol-gel method. The crystal structure of ZnO and Ag-ZnO powders was tested by X-ray diffraction with Cu Kα radiation. The absorption spectra of ZnO and Ag-ZnO films were recorded by a UV–visible spectrophotometer. The micro electrical transport performance of Ag-ZnO thin films in dark and light state was investigated by photoassisted conductive atomic force microscope (PC-AFM).

Findings

The results show that the dark reverse current of Ag-ZnO films does not increase, but the reverse current increases significantly under illumination, indicating that the response of Ag-ZnO films to light is greatly improved, owing to the formation of Ohmic contact.

Originality/value

To the best of the author’s knowledge, the micro electrical transport performance of Ag-ZnO thin films in dark and light state was firstly investigated by PC-AFM.

Details

Microelectronics International, vol. 41 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 19 February 2024

Bassem Assfour, Bassam Abdallah, Hour Krajian, Mahmoud Kakhia, Karam Masloub and Walaa Zetoune

The purpose of this study is to investigate the structural, surface roughness and corrosion properties of the zirconium oxide thin films deposited onto SS304 substrates using the…

Abstract

Purpose

The purpose of this study is to investigate the structural, surface roughness and corrosion properties of the zirconium oxide thin films deposited onto SS304 substrates using the direct current (DC) magnetron sputtering technique.

Design/methodology/approach

DC sputtering at different powers – 80, 100 and 120 W – was used to deposit ZrO2 thin films onto different substrates (Si/SS304) without annealing of the substrate. Atomic force microscope (AFM), energy-dispersive X-ray spectroscopy (EDS), Tafel extrapolation and contact angle techniques were applied to investigate the surface roughness, chemical compositions, corrosion behavior and hydrophobicity of these films.

Findings

Results showed that the thickness of the deposited film increased with power increase, while the corrosion current decreased with power increase. AFM images indicated that the surface roughness decreased with an increase in DC power. EDS analysis showed that the thin film has a stoichiometric ZrO2 (Zr:O 1:2) composition with basic uniformity. Water contact angle measurements indicated that the hydrophobicity of the synthesized films decreased with an increase in surface roughness.

Originality/value

DC magnetron sputtering technique is infrequently used to deposition thin films. The obtained thin films showed good hydrophobic and anticorrosion properties. Finally, results are compared with other deposition techniques.

Details

World Journal of Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 25 August 2023

Xin Zhou, Wenbin Zhou, Yang Zheng Zhang, Meng-Ran Li, Haijing Sun and Jie Sun

This paper aims to study the corrosion inhibition behavior of imidazopyridine and its three derivatives on brass.

Abstract

Purpose

This paper aims to study the corrosion inhibition behavior of imidazopyridine and its three derivatives on brass.

Design/methodology/approach

The authors performed weight loss experiments, electrochemical experiments including the polarization curve and electrochemical impedance spectrum, corrosion morphology observation using scanning electron microscope (SEM) and atomic force microscope (AFM) and surface composition analysis via X-ray photoelectron spectroscopy (XPS) to analyze the corrosion inhibition behavior of imidazopyridine and its three derivatives on brass by using quantum chemical calculation (Gaussian 09), molecular dynamics simulation (M-S) and Langmuir adsorption isotherm.

Findings

According to the results, imidazole-pyridine and its derivatives were found to be modest or moderately mixed corrosion inhibitors; moreover, they were spontaneously adsorbed on the metal surface in a single-layer, mixed adsorption mode.

Originality/value

The corrosion inhibition properties of pyrazolo-[1,2-a]pyridine and its derivatives on brass in sulfuric acid solution were analyzed through weight loss and electrochemical experiments. Moreover, SEM and AFM were simultaneously used to observe the corrosion appearance. Furthermore, XPS was used to analyze the surface. Then, Gaussian 09 and M-S were combined along with the Langmuir adsorption isotherm to investigate the corrosion inhibition mechanism of imidazole-[1,2-a]pyridine and its derivatives.

Details

Anti-Corrosion Methods and Materials, vol. 70 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 25 October 2022

Carlos A. Gonzalez Lugo, Dylan Scott Caputo, Michael J. Hutchinson, Kamran Fouladi and Babak Eslami

The purpose of this study is to design and develop an environmentally controlled enclosure for commercial three-dimensional (3D) printers.

Abstract

Purpose

The purpose of this study is to design and develop an environmentally controlled enclosure for commercial three-dimensional (3D) printers.

Design/methodology/approach

Computational fluid dynamics (CFD) simulations and experimental testing investigated various designs for environmentally controlled enclosures. CFD simulations provided the necessary information to select the optimal and feasible design, whereas experimental testing validated the CFD simulation results. An environmentally controlled environment allowed test samples to be printed at several relative humidity (RH) settings (20% RH, 50% RH and 80% RH). The test samples were characterized at both the macro and micro scales. The macroscale characterization was conducted using the static tensile testing procedure, while the microscale polymer material properties were determined using atomic force microscopy.

Findings

An environmentally controlled enclosure was designed and built to produce airflow in the print region with an average RH uniformity of over 0.70. Three batches of ASTM D638 standard test samples were printed at 20% RH (low RH), 50% RH (mid RH) and 80% RH (high RH). Macroscale characterization showed that the samples printed at lower humidity had statistically significantly higher tangent modulus, ultimate tensile strength and rupture strength. atomic force microscopy studies have also verified these results at the microscale and nanoscale. These studies also showed that a high humidity environment interacts with melted polylactic acid, causing additional surface roughness that reduces the strength of 3D-printed parts.

Originality/value

There is a need for stronger and higher-quality 3D-printed parts in the additive manufacturing (AM) market. This study fulfills that need by designing and developing an environmentally controlled add-on enclosure for the AM market.

Details

Rapid Prototyping Journal, vol. 29 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 7 September 2023

Vali Dalouji and Nasim Rahimi

In this paper, it can be seen from AFM images of the as-deposited ZnO and CZO films, and the particle size and shape are not clear, while by increasing annealing temperature, they…

Abstract

Purpose

In this paper, it can be seen from AFM images of the as-deposited ZnO and CZO films, and the particle size and shape are not clear, while by increasing annealing temperature, they become distinguishable. By increasing temperature to 600°C, ZnO and CZO, CAZO and aluminum-doped zinc oxide (AZO) films particles became almost spherical. Due to high content of Cu in CZO target, and of Al in AZO target which was 5% weight ratio, doping plays a great role in the subject. Therefore, the annealing processing strongly affect the size and the shape of nanoparticles.

Design/methodology/approach

In this paper, the authors tried to study, in detail, nobel optical characterizations of ZnO films doped by transition metals in different annealing temperature. The authors found that the values of skin depth, optical density, electron–phonon interaction, steepness parameter, band tail width, direct and indirect carriers transitions and the dissipation factor, free carriers density and roughness of films affect the optical properties, especially the optical absorptions of ZnO films doped by transition metals. Also these properties were affected by annealing temperatures. The authors also found that topography characterizations strongly were affected by these parameters.

Findings

The CZO films have maximum value of coordination number ß, with considering NC = 4, Za = 2, Ne = 8. The CZO films annealed at 500 °C have maximum value of optical density. The as-deposited CAZO films have maximum value of steepness parameters in about of 0.13 eV. The as-deposited AZO films have maximum value of dispersion energy Ed in about of 5.75 eV. Optical gap and disordering energy plots of films can be fitted by linear relationships Eg = 0.49 + 0.2 EU and Eg = 0.52 + 0.5 EU, respectively.

Originality/value

With considering Nc = 4, Za = 2, Ne = 8 for ZnO films, coordination number ß has maximum value of 0.198. CZO nanocomposites films annealed at 500°C have maximum value of optical density. Different linear fitting of ln (α) for films were obtained as y = Ax + B where 5<A < 17 and 5<B < 12. As-deposited CAZO nanocomposites films have minimum value of electron phonon interaction in about of 4.91 eV. Optical gap and disordering energy plots can be fitted by linear relationships Eg = 0.49 + 0.2 EU and Eg = 0.52 + 0.5 EU for as-deposited films and films annealed at 500°C, respectively. Steepness parameters of as-deposited CAZO nanocomposites films have maximum value of 0.13 eV. Dispersion energy Ed for as-deposited AZO nanocomposites films has maximum value of 5.75 eV.

Details

Soldering & Surface Mount Technology, vol. 35 no. 5
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 7 September 2023

Liangbin Chen, Lihong Zhao and Keren Ding

This paper aims to improve the permeability and antifouling of polysulfone (PSF) ultrafiltration membranes, the PSF matrix was modified by incorporating sulfonated polysulfone…

Abstract

Purpose

This paper aims to improve the permeability and antifouling of polysulfone (PSF) ultrafiltration membranes, the PSF matrix was modified by incorporating sulfonated polysulfone (SPSF).

Design/methodology/approach

Systematic investigations were conducted on the synergistic effects of a pore-forming agent, coagulation bath temperature and SPSF doping in the casting solution on blended ultrafiltration membranes. The chemical composition of the membranes was analyzed using Fourier transform infrared spectroscopy. The morphology and surface roughness of the membranes were characterized using scanning electron microscopy and atomic force microscopy. The hydrophilicity of the membrane surface was analyzed using a contact angle meter. The permeability and antifouling properties of the blended membranes were also investigated through filtration experiments.

Findings

The results indicated that the blended ultrafiltration membranes demonstrated an optimal overall performance when PVP-K30 content was 5.0 Wt.%, coagulation bath temperature was 30°C and SPSF content was 2.4 Wt.%. In comparison to a pure PSF ultrafiltration membrane, there was a significant increase in pure water flux (390.7 L·m−2·h−1) by 2.2 times, while bovine serum albumin retention slightly decreased to 93.8%. In addition, the flux recovery rate improved by 2.1 times (71.4%) compared to that of the original PSF ultrafiltration membrane.

Practical implications

The method provided a simple and practical solution for improving the antifouling and permeability of PSF ultrafiltration membranes.

Originality/value

SPSF was anticipated to serve as an excellent modification additive for the preparation of ultrafiltration membranes with superior properties.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

Keywords

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