Search results

1 – 10 of over 3000
Click here to view access options
Article
Publication date: 22 July 2019

Farui Du, Jinqian Zhu, Xueping Ding, Qi Zhang, Honglin Ma, Jie Yang, Hongzhong Cao, Zemin Ling, Guoyu Wang, Xuanming Duan and Shuqian Fan

A wire-based additive manufacturing system works with high manufacturing efficiency and low dimensional precision. The purpose of this paper is to study the dimensional…

Downloads
214

Abstract

Purpose

A wire-based additive manufacturing system works with high manufacturing efficiency and low dimensional precision. The purpose of this paper is to study the dimensional characteristics of Ti-6Al-4V thin-walled parts with wire-based multi-laser additive manufacturing in vacuum.

Design/methodology/approach

Wire-based multi-laser additive manufacturing was carried out to understand the effect brought from different parameters. The Ti-6Al-4V thin-walled parts were formed by different height increments, power inputs and inter-layer cooling times in vacuum.

Findings

The result shows that, with the number of layers increment, the layer width of thin-walled part increases gradually in the beginning and stabilizes soon afterward. Height increment, laser power and inter-layer cooling time could affect the energy input to the deposited bead and heat accumulation of thin-walled part. The layer width decreases, while the height increment increases. The increment of laser power could increase the layer width. And, the increment of inter-layer cooling time (more than 5 s) has little effect on the layer width.

Originality/value

The heat dissipation mode of thin-walled parts in vacuum and the influence of different parameters on layer width are explained in this paper. It provides a reference for further understanding and controlling dimension precision of Ti-6Al-4V thin-walled part with wire-based multi-laser additive manufacturing in vacuum. At the same time, it provides a reference for researches of dimensional characteristics in the additive manufacturing industry.

Details

Rapid Prototyping Journal, vol. 25 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

Click here to view access options
Article
Publication date: 28 January 2020

David Downing, Martin Leary, Matthew McMillan, Ahmad Alghamdi and Milan Brandt

Metal additive manufacturing is an inherently thermal process, with intense localised heating and for sparse lattice structures, often rapid uneven cooling. Thermal…

Abstract

Purpose

Metal additive manufacturing is an inherently thermal process, with intense localised heating and for sparse lattice structures, often rapid uneven cooling. Thermal effects influence manufactured geometry through residual stresses and may also result in non-isotropic material properties. This paper aims to increase understanding of the evolution of the temperature field during fabrication of lattice structures through numerical simulation.

Design/methodology/approach

This paper uses a reduced order numerical analysis based on “best-practice” compromise found in literature to explore design permutations for lattice structures and provide first-order insight into the effect of these design variables on the temperature field.

Findings

Instantaneous and peak temperatures are examined to discover trends at select lattice locations. Insights include the presence of vertical struts reduces overall lattice temperatures by providing additional heat transfer paths; at a given layer, the lower surface of an inclined strut experiences higher temperatures than the upper surface throughout the fabrication of the lattice; during fabrication of the lower layers of the lattice, isolated regions of material can experience significantly higher temperatures than adjacent regions.

Research limitations/implications

Due to the simplifying assumptions and multi-layer material additions, the findings are qualitative in nature. Future research should incorporate additional heat transfer mechanisms.

Practical implications

These findings point towards thermal differences within the lattice which may manifest as dimensional differences and microstructural changes in the built part.

Originality/value

The paper provides qualitative insights into the effect of local geometry and topology upon the evolution of temperature within lattice structures fabricated in metal additive manufacturing.

Details

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

Keywords

Click here to view access options
Article
Publication date: 6 February 2017

Yuran Jin, Shoufeng Ji, Xin Li and Jiangnan Yu

Additive manufacturing has achieved rapid development in recent years. The purpose of this paper is to visualize the intellectual landscapes of additive manufacturing and…

Downloads
1136

Abstract

Purpose

Additive manufacturing has achieved rapid development in recent years. The purpose of this paper is to visualize the intellectual landscapes of additive manufacturing and identify the hotspots and emerging trends of additive manufacturing, which can provide references for scholars, enterprises and governments to promote the development of theory and practice in the additive manufacturing field.

Design/methodology/approach

Science mapping is a fast-growing interdisciplinary field originated in information science and technology. Based on this methodology, guided by a computational approach, the paper visualizes the co-occurring keywords network and co-citation references network by CiteSpaceIII software to explore the hotspots and emerging trends of additive manufacturing by the following five indicators: highly cited keywords, burst keywords, clusters, landmark references and burst references.

Findings

Additive manufacturing,” “3D printing,” “3D powder printing,” “consolidation phenomena,” “microstructure,” “rapid prototyping,” etc., are the main hotspots of additive manufacturing. The trends of additive manufacturing generally consist of three stages: the fundamental concepts stage from 1995 to 2000 (“rapid prototyping,” “additive manufacturing,” etc.), the approaches and techniques applications stage from 2001 to 2010 (“stereolithography,” “scaffold,” etc.), and the emerging trends stage from 2011 to the present (“stem cell”, “selective laser,” “ti-6al-4v,” etc.). The research is most abundant in 2010 and 2012. The medical field is an important hotspot of additive manufacturing. Additive manufacturing has been researched in interdiscipline.

Originality/value

The paper maps the perspective of additive manufacturing and explore the hotspots and emerging trends of additive manufacturing.

Details

Journal of Manufacturing Technology Management, vol. 28 no. 1
Type: Research Article
ISSN: 1741-038X

Keywords

Click here to view access options
Article
Publication date: 1 August 2019

Elnaz Asadollahi-Yazdi, Julien Gardan and Pascal Lafon

This paper aims to provide a multi-objective optimization problem in design for manufacturing (DFM) approach for fused deposition modeling (FDM). This method considers the…

Abstract

Purpose

This paper aims to provide a multi-objective optimization problem in design for manufacturing (DFM) approach for fused deposition modeling (FDM). This method considers the manufacturing criteria and constraints during the design by selecting the best manufacturing parameters to guide the designer and manufacturer in fabrication with FDM.

Design/methodology/approach

Topological optimization and bi-objective optimization problems are suggested to complete the DFM approach for design for additive manufacturing (DFAM) to define a product. Topological optimization allows the shape improvement of the product through a material distribution for weight gain based on the desired mechanical behavior. The bi-objective optimization problem plays an important role to evaluate the manufacturability by quantification and optimization of the manufacturing criteria and constraint simultaneously. Actually, it optimizes the production time, required material regarding surface quality and mechanical properties of the product because of two significant parameters as layer thickness and part orientation.

Findings

A comprehensive analysis of the existing DFAM approaches illustrates that these approaches are not developed sufficiently in terms of manufacturability evaluation in quantification and optimization levels. There is no approach that investigates the AM criteria and constraints simultaneously. It is necessary to provide a decision-making tool for the designers and manufacturers to lead to better design and manufacturing regarding the different AM characteristics.

Practical implications

To assess the efficiency of this approach, a wheel spindle is considered as a case study which shows how this method is capable to find the best design and manufacturing solutions.

Originality/value

A multi-criteria decision-making approach as the main contribution is developed to analyze FDM technology and its attributes, criteria and drawbacks. It completes the DFAM approach for FDM through a bi-objective optimization problem which deals with finding the best manufacturing parameters by optimizing production time and material mass because of the product mechanical properties and surface roughness.

Details

Rapid Prototyping Journal, vol. 25 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

Click here to view access options
Article
Publication date: 6 August 2019

Yongxiang Hu, Mengqi Lai, Zonghao Hu and Zhenqiang Yao

Laser additive manufacturing is widely utilized to fabricate the Ti6Al4V alloy, but it requires post-processing to improve its performance. This paper aims to propose…

Abstract

Purpose

Laser additive manufacturing is widely utilized to fabricate the Ti6Al4V alloy, but it requires post-processing to improve its performance. This paper aims to propose laser peening (LP) as an effective way to improve the surface characteristics of the Ti6Al4V alloy fabricated by direct laser deposition (DLD).

Design/methodology/approach

Surface integrity including surface roughness, porosity, residual stress and microhardness are investigated in detail before and after LP treatment. Microstructure evolution is characterized by the electron backscatter diffraction (EBSD) to analyze crystal phase, grain boundary misorientation and texture.

Findings

Multiple overlapping layers of LP treatment result in slight influence on the polished surface of DLD-built samples. Porosity measured by the Archimedes test is found to be greatly decreased after LP treatment. Compressive residual stresses are significantly induced, the magnitude of which is greatly increased by increasing layers of LP treatment. And, local weakening or enhancement of residual stress in depth is observed because of pore and inclusion defects in the DLD-built Ti6Al4V alloy. Favorable hardness property can be obtained after multiple overlapping layers of LP treatment. EBSD analysis shows that LP treatment with multiple layers can introduce a large amount of lower-angle boundaries, indicating that dislocations beneath the top surface could induce a strain-hardened layer. The microtexture of the DLD-built Ti6Al4V alloy cannot be eliminated to decrease the anisotropy of the mechanical property.

Research limitations/implications

The variation of porosity observed after LP inside the DLD-built Ti-Al-4V is attractive but requires more detailed work to analyze the evolution of pore geometry.

Practical implications

Surface treatment of an additive manufactured titanium alloy was carried out to improve its fatigue resistance.

Originality/value

This work is original in proposing LP as an effective post process for the surface treatment of an additive manufactured titanium alloy through analyzing the surface integrity and microstructure evolution.

Details

Rapid Prototyping Journal, vol. 25 no. 8
Type: Research Article
ISSN: 1355-2546

Keywords

Click here to view access options
Article
Publication date: 12 March 2018

Azadeh Haghighi and Lin Li

Quantifying and controlling the quality characteristics of parts produced by additive manufacturing (AM) processes has attracted significant interest in the research…

Abstract

Purpose

Quantifying and controlling the quality characteristics of parts produced by additive manufacturing (AM) processes has attracted significant interest in the research community. However, to increase the sustainability of AM processes, such quality characteristics need to be assessed together with life cycle performance of AM processes such as energy and material consumption and manufacturing cost. Although a few studies have been performed for several quality characteristics, i.e. surface roughness and tensile strength, the relationship between dimensional performance and manufacturing cost is still not well known for AM processes.

Design/methodology/approach

In this paper, a comprehensive study of the dimensional performance and manufacturing cost of fused deposition modeling AM process is performed. Design of experiment technique is used, and the correlation of different cost components and the dimensional accuracy of parts are statistically studied.

Findings

The optimum process parameters for simultaneously optimizing the dimensional performance and manufacturing cost are identified. The analysis shows that as opposed to traditional manufacturing processes, obtaining a better dimensional performance is not necessarily associated with higher cost in the AM processes.

Originality/value

Almost no study and analysis for the combined dimensional performance and manufacturing cost has been performed for AM processes in the literature. It is known that within the context of traditional manufacturing processes, a natural trade-off governs the pursuit of higher dimensional performance and the manufacturing cost. However, as the AM process has a different nature compared with traditional manufacturing processes, the relationship between manufacturing cost and dimensional performance of parts has to be studied. Understanding this relationship will also help to establish a cost-optimal and sustainable tolerance allocation strategy in assemblies with AM components.

Details

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

Keywords

Click here to view access options
Article
Publication date: 8 August 2020

Dongqing Yang, Jun Xiong and Rong Li

This paper aims to fabricate inclined thin-walled components using positional wire and arc additive manufacturing (WAAM) and investigate the heat transfer characteristics…

Downloads
156

Abstract

Purpose

This paper aims to fabricate inclined thin-walled components using positional wire and arc additive manufacturing (WAAM) and investigate the heat transfer characteristics of inclined thin-walled parts via finite element analysis method.

Design/methodology/approach

An inclined thin-walled part is fabricated in gas metal arc (GMA)-based additive manufacturing using a positional deposition approach in which the torch is set to be inclined with respect to the substrate surface. A three-dimensional finite element model is established to simulate the thermal process of the inclined component based on a general Goldak double ellipsoidal heat source and a combined heat dissipation model. Verification tests are performed based on thermal cycles of locations on the substrate and the molten pool size.

Findings

The simulated results are in agreement with experimental tests. It is shown that the dwell time between two adjacent layers greatly influences the number of the re-melting layers. The temperature distribution on both sides of the substrate is asymmetric, and the temperature peaks and temperature gradients of points in the same distance from the first deposition layer are different. Along the deposition path, the temperature distribution of the previous layer has a significant influence on the heat dissipation condition of the next layer.

Originality/value

The established finite element model is helpful to simulate and understand the heat transfer process of geometrical thin-walled components in WAAM.

Details

Rapid Prototyping Journal, vol. 26 no. 9
Type: Research Article
ISSN: 1355-2546

Keywords

Click here to view access options
Article
Publication date: 24 July 2019

Rong Li and Jun Xiong

The purpose of this study is to present how the thermal energy transmission of circular parts produced in robotized gas metal arc (GMA)-based additive manufacturing was…

Abstract

Purpose

The purpose of this study is to present how the thermal energy transmission of circular parts produced in robotized gas metal arc (GMA)-based additive manufacturing was affected by the substrate shape through finite element analysis, including distributions of thermal energy and temperature gradient in the molten pool and deposited layers.

Design/methodology/approach

Three geometric shapes, namely, square, rectangle and round were chosen in simulation, and validation tests were carried out by corresponding experiments.

Findings

The thermal energy conduction ability of the deposited layers is the best on the round substrate and the worst on the rectangular substrate. The axial maximum temperature gradients in the molten pool along the deposition path with the round substrate are the largest during the deposition process. At the deposition ending moment, the circumferential temperature gradients of all layers with the round substrate are the largest. A large temperature gradient usually stands for a good heat conduction condition. Altogether, the round substrate is more suitable for the fabrication of circular thin-walled parts.

Originality/value

The predicted thermal distributions of the circular thin-walled part with various substrate shapes are helpful to understand the influence of substrate shape on the thermal energy transmission behavior in GMA-based additive manufacturing.

Details

Rapid Prototyping Journal, vol. 25 no. 7
Type: Research Article
ISSN: 1355-2546

Keywords

Click here to view access options
Article
Publication date: 16 April 2018

J. Norberto Pires and Amin S. Azar

This paper aims to introduce the ideas of practical implications of using industrial robots to implement additive/hybrid manufacturing. The process is discussed and…

Downloads
2067

Abstract

Purpose

This paper aims to introduce the ideas of practical implications of using industrial robots to implement additive/hybrid manufacturing. The process is discussed and briefly demonstrated. This paper also introduces recent developments on human–machine interface for robotic manufacturing cells, namely the ones used for additive/hybrid manufacturing, as well as interoperability methods between the computer-aided design (CAD) data and material modeling systems. It is presented – using a few solutions developed by the authors – as a set of conceptual guidelines discussed throughout the paper and as a way to demonstrate how they can be applied and their practical implications.

Design/methodology/approach

The possibility to program the system from CAD information, which is argued to be crucial, is explored, and the methods necessary for connecting the CAD data to material modeling systems are introduced. This paper also discusses in detail the main requirements (also from a system point-of-view) needed for a full implementation of the presented ideas and methods. A few simulations to better characterize the interactions from heat conduction and physical metallurgy were conducted in an effort to better tune the additive manufacturing process. The results demonstrate how the toolpath planning and deposition strategies can be extracted and studied from a CAD model.

Findings

The paper fully demonstrates the possibility to use a robotic setup for additive manufacturing applications and shows the first steps of an innovative system designed with that objective.

Originality/value

Using the aimed platform, unsupervised net-shaping of complex components will substitute the cumbersome processes, and it is expected that such a visionary concept brings about a significant reduction in cost, energy consumption, lead time and production waste through the introduction of optimized and interactive processes. This can be considered as a breakthrough in the field of manufacturing and metal processing as the performance is indicated to increase significantly compared to the current instruction-dependent methods.

Details

Industrial Robot: An International Journal, vol. 45 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

Click here to view access options
Article
Publication date: 21 March 2016

Ana Pilipović, Bogdan Valentan and Mladen Šercer

The purpose of this paper is the selection of production parameters in selective laser sintering – SLS for the production of quality products (e.g. good mechanical…

Abstract

Purpose

The purpose of this paper is the selection of production parameters in selective laser sintering – SLS for the production of quality products (e.g. good mechanical properties). The manufacturing procedure affects the properties, which is especially significant in additive procedures, as the products are not cheap and the procedure and material need to be optimally selected.

Design/methodology/approach

The paper presents an analysis of the fabrication parameters in selective laser sintering (SLS) that affect the flexural properties of the finished product.

Findings

The influence of a new parameter has been found, the overlay ratio, and using the mathematical and scheme method, the selection of parameters for obtaining the optimal flexural properties has been proposed.

Originality/value

The paper presents a new mathematical model for the calculation of the processing parameters in SLS of polymer products and gives a diagram for the determination of which parameters are the best to use for practical purposes.

Details

Rapid Prototyping Journal, vol. 22 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

1 – 10 of over 3000