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Article
Publication date: 4 October 2011

Ruidong Xie, Dichen Li and Shuaijun Chao

This paper seeks to describe the development of an inexpensive stereolithography (SL) system with high power ultraviolet light‐emitting diode (UV‐LED) curing light source…

Abstract

Purpose

This paper seeks to describe the development of an inexpensive stereolithography (SL) system with high power ultraviolet light‐emitting diode (UV‐LED) curing light source. The advantages of UV‐LED light source will be investigated and the results presented.

Design/methodology/approach

The working principle of the UV‐LED light‐based SL system (LED‐SL) and its characteristics were explicated; the effect of beam divergence angle on the shape of a single cured line was analyzed; and the effects of the shapes of single cured lines shone by different light sources on the fabrication accuracy were compared.

Findings

LED‐SL has significantly higher part fabrication efficiency and accuracy than UV lamplight‐based prototyping systems. Furthermore, the UV‐LED energy consumption is much lower than laser and UV lamp sources, which conforms to the requirement of Green Manufacturing.

Research limitations/implications

In increasing the scanning speed, the vibration of the focusing lens set has an obvious effect on the scanning accuracy; therefore, further research is needed.

Originality/value

This research verified the feasibility of adopting high power UV‐LED as the light source for a rapid prototyping system and enhanced the versatility of conventional UV‐SL technology.

Details

Rapid Prototyping Journal, vol. 17 no. 6
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 24 June 2019

Ahmad Fairuz Omar, Wan Long Chiong, Wei Yee Tan and Jia Wen Wong

This paper aims to propose an area under the curve model to represent ultraviolet (UV) exposure doses on EBT3 films (in mJ/cm2). The model was developed on a cross-section…

Abstract

Purpose

This paper aims to propose an area under the curve model to represent ultraviolet (UV) exposure doses on EBT3 films (in mJ/cm2). The model was developed on a cross-section of the exposed films using visible absorbance method. Ultraviolet–A light emitting diodes (UVA–LEDs) with 20° and 60° half angle with distinctive peak emission wavelengths between 365 to 405 nm are used in this experiment. No similar experimental setup or findings have been reported thus far, though the various application of EBT3 for the measurement of solar UV (A + B) have been published since EBT3 is commercially available.

Design/methodology/approach

Two sets of UVA–LEDs were used as the UV radiation source in the experiment. The first set contains of four 5 mm low power UVA–LEDs with the 20° half angle and peak emission wavelength at 365, 375, 385 and 400 nm. The second set contains of five surface mount high power UVA–LEDs with the 60° half angle and peak emission wavelength at 365, 375, 385, 305 and 400 nm. The illumination setup for the two sets of LEDs is different between each other to obtain sufficient dose distribution on the films for spectroscopy analysis. This is due to the different illumination angle and irradiance intensity by each set of LEDs.

Findings

UV–LED with a peak emission of 365, 375 and 385 nm able to produce UV doses accurately measurable using EBT3 films, UVA–LEDs with peak emission at 395 nm and above produced much lower accuracy with R2. From both set of LEDs, it can be concluded that peak emission wavelength of UVA–LED does influence the discoloration of the films. Shorter wavelength (higher energy) of UVA–LEDs discolors EBT3 films much intense compared to longer wavelength for a given UV dose exposure.

Originality/value

Despite various practical applicability and advantages of UV–LEDs, there are still no standard methods in measuring UV–LED radiation output. The proposed approach not only allows us to obtain the dose of UV–LED, where the sensitivity of measurement is wavelength (energy) depended but also allows us to visually observe the illumination pattern of invisible UV radiation through the application of EBT3 films.

Details

Sensor Review, vol. 39 no. 4
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 26 April 2011

Yong Chen, Chi Zhou and Jingyuan Lao

Most current additive manufacturing (AM) processes are layer based. By converting a three‐dimensional model into two‐dimensional layers, the process planning can be…

Abstract

Purpose

Most current additive manufacturing (AM) processes are layer based. By converting a three‐dimensional model into two‐dimensional layers, the process planning can be dramatically simplified. However, there are also drawbacks associated with such an approach such as inconsistent material properties and difficulty in embedding existing components. The purpose of this paper is to present a novel AM process that is non‐layer based and demonstrate its unique capability.

Design/methodology/approach

An AM process named computer numerically controlled (CNC) accumulation has been developed. In such a layerless AM process, a fiber optic‐cable connected with an ultraviolet (UV) LED and related lens is served as an accumulation tool. The cable is then merged inside a tank that is filled with UV‐curable liquid resin. By controlling the on/off state of the UV‐LED and the multi‐axis motion of the cable, a physical model can be built by selectively curing liquid resin into solid.

Findings

It is found that the cured resin can be safely detached from the accumulation tool by applying a Teflon coating on the tip of the fiber‐optic cable, and controlling an appropriate gap between the cable and the base. The experimental results verified the curing and attaching force models.

Research limitations/implications

A proof‐of‐concept testbed has been developed based on a curing tool that has a diameter around 2 mm. The relatively large tool size limits the geometry resolution and part quality of the built parts.

Originality/value

By incorporating multi‐axis tool motion, the CNC accumulation process can be beneficial for applications such as plastic part repairing, addition of new design features, and building around inserts.

Details

Rapid Prototyping Journal, vol. 17 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 19 June 2009

Fan Zeng, Beshah Ayalew and Mohammed Omar

The purpose of this paper is to present a new closed‐loop radiative robotic paint curing process that could replace less efficient and bulky convection‐based paint curing…

Abstract

Purpose

The purpose of this paper is to present a new closed‐loop radiative robotic paint curing process that could replace less efficient and bulky convection‐based paint curing processes in automotive manufacturing.

Design/methodology/approach

The proposed robotic paint curing processes uses an Ultraviolet LED panel for a heat source, an infra‐red camera for non‐contact thermal signature feedback of cure level, and a robot control strategy that incorporates the cure‐level information in an inverse dynamics control of the robotic manipulator. To demonstrate the advantage of the closed‐loop process in improving cure uniformity, detailed models and discussions of the irradiation process, the robotics and the control strategy are presented.

Findings

A simulation‐based comparison of the closed‐loop robotic curing with the open‐loop robotic curing clearly shows the benefits of using thermal signature feedback in improving cure level uniformity.

Originality/value

This is a new approach proposed to exploit immerging technology and improve the efficiency of energy use in an automotive manufacturing process without sacrificing product quality.

Details

Industrial Robot: An International Journal, vol. 36 no. 4
Type: Research Article
ISSN: 0143-991X

Keywords

Content available

Abstract

Details

Pigment & Resin Technology, vol. 41 no. 4
Type: Research Article
ISSN: 0369-9420

Content available
Article
Publication date: 11 September 2009

Abstract

Details

Anti-Corrosion Methods and Materials, vol. 56 no. 5
Type: Research Article
ISSN: 0003-5599

Content available
Article
Publication date: 29 June 2012

Abstract

Details

Pigment & Resin Technology, vol. 41 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 18 January 2016

Marlon Wesley Machado Cunico and Jonas de Carvalho

The purpose of this study is to present a novel additive manufacturing (AM) technology which is based on selective formation of cellulose-acrylate composite. Besides…

Abstract

Purpose

The purpose of this study is to present a novel additive manufacturing (AM) technology which is based on selective formation of cellulose-acrylate composite. Besides proposing a process that combines the benefits of fibres and photopolymers, this paper reports the development of material, characterisation of a straight line composite formation, adherence between layers and functional feasibility of the proposed concept.

Design/methodology/approach

For the preliminary evaluation of the proposed process, a composite material based on cellulose-photopolymer was developed, while a multi-objective optimisation study indicated the formulation which results in the maximum values of layer adherence, tensile strength of composite and the effect of the water on the mechanical strength of material. For the characterisation of the process, three main subjects were analysed: the characterisation of straight line composite formation, the effect of composite formation process on previous layers and the functional feasibility of technology.

Findings

In the material development, the tensile strength of dry composite was identified between 20 and 30 MPa, while the tensile strength of wet composite was between 5 and 12 MPa. It is important to note that the dry and wet cellulose presented tensile strength, respectively, equal to 15 and 1 MPa, indicating the possibility of residual material removal only with the use of water or other soft solvent. The values of adherence between layers (peeling test) were found to be between 0.12 and 0.15 kgf, and the photopolymer formulation which resulted in the maximum adherence has monomer/oligomer ratio equal to 1.5 and 2 per cent wt of photoinitiator percentual. As result of the optimisation study, the material formulation was compounded by monomer – 10 ml, oligomer – 4.5 ml and photoinitiator – 2 per cent, being found suitable to characterise and evaluate the proposed process. The study of composite formation along a straight line showed values of line width between 1,400 and 3,500 μm in accordance with light power, laser velocity and laser beam diameter. On the other hand, the number of previous layers affected by the composite formation varied from 0 to 4, indicating a potential process limit. In the functional feasibility study, a feasible process window which resulted in the maximum dimensional deviation equal to 0.5 mm was identified. In addition, the mean mechanical tensile strength was found to be around 30 MPa for longitudinal laser trajectory (90°) and 15 MPa for transversal laser trajectory (0°), highlighting the anisotropic behaviour of final parts according to the manufacturing strategy.

Originality/value

This paper proposed a novel AM technology and also described studies related to the characterisation of this concept. This work might also be useful to the development of other AM processes and applications.

Content available
Article
Publication date: 22 March 2011

Abstract

Details

Pigment & Resin Technology, vol. 40 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 2 January 2018

Marlon Wesley Machado Cunico and Jonas de Carvalho

During the past years, numerous market segments have increasingly adopted additive manufacturing technologies for product development and complex parts design…

Abstract

Purpose

During the past years, numerous market segments have increasingly adopted additive manufacturing technologies for product development and complex parts design. Consequently, recent developments have expanded the technologies, materials and applications in support of emerging needs, in addition to improving current processes. The present work aims to propose and characterise a new technology that is based on selective formation of metal-polymer composites with low power source.

Design/methodology/approach

To develop this project, the authors have divided this work in three parts: material development, process feasibility and process optimisation. For the polymeric material development, investigation of metallic and composite materials assessed each material’s suitability for selective composite formation besides residual material removal. The primary focus was the evaluation of proposed process feasibility. The authors applied multivariable methods, where the main responses were line width, penetration depth, residual material removal feasibility, layer adherence strength, mechanical strength and dimensional deviation of resultant object. The laser trace speed, distance between formation lines and laser diameter were the main variables. Removal agent and polymeric material formulation were constants. In the last part of this work, the authors applied a multi-objective optimisation. The optimisation objectives minimized processing time and dimensional deviation while maximizing mechanical strength in xy direction and mechanical strength in z direction.

Findings

With respect to material development, the polymeric material tensile strength was found between 30 and 45 MPa at break. It was also seen that this material has low viscosity before polymerized (between 2 and 20 cP) essential for composite formation and complete material removal. In that way, the authors also identified that the residual material removal process was possible by redox reaction. In contrast with that the final object was marked by the polymer which covers the metallic matrix, protecting the object protects against chemical reactions. For the feasibility study, the authors identified the process windows for adherence between composite layers, demonstrating the process feasibility. The composite mechanical strength was shown to be between 120 and 135 MPa in xy direction and between 35 and 45 MPa in z direction. In addition, the authors have also evidenced that the geometrical dimensional distortion might vary until 5 mm, depending on process configuration. Despite that, the authors identified an optimised configuration that exposes the potential application of this new technology. As this work is still in a preliminary development stage, further studies are needed to be done to better understand the process and market segments wherein it might be applied.

Originality/value

This paper proposed a new and innovative additive manufacturing technology which is based on metal-polymer composites using low power source. Additionally, this work also described studies related to the investigation of concept feasibility and proposed process characterisation. The authors have focused on material development and studied the functional feasibility, which at the same time might be useful to the development of other additive manufacturing processes.

Details

Rapid Prototyping Journal, vol. 24 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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