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1 – 10 of over 17000
Article
Publication date: 19 October 2015

Yashpal Patel, Aashish Kshattriya, Sarat B Singamneni and A. Roy Choudhury

Layered manufacturing with curved layers is a recently proposed rapid prototyping (RP) strategy for the manufacture of curved, thin and shell-type parts and the repair of worn…

Abstract

Purpose

Layered manufacturing with curved layers is a recently proposed rapid prototyping (RP) strategy for the manufacture of curved, thin and shell-type parts and the repair of worn surfaces, etc. The present investigation indicates another possible application area. In case of flat-layered RP of computer-aided design models having randomly located, small-dimensioned but critical surface features, adaptive slicing is resorted to. Large number of thin slices have to be employed to preserve the critical features. In contrast, a considerably lower number of curved thin slices would be required to preserve such surface features in case of RP with curved layers.

Design/methodology/approach

The method of preservation of critical features by RP with curved layers is formulated and demonstrated for two clusters of critical features on the surface of a part. A minimum number of such curved layers is identified by application of genetic algorithms (GAs) in case of a simple example. GA evolves the shape of the curved layer passing through the lower cluster so as to make a curved layer pass through the upper cluster of critical features.

Findings

In the example part, a 21 per cent reduction in the number of layers is achieved by the application of adaptive curved layers over adaptive straight layers.

Originality/value

The novelty of the concept is the proposed use of curved layered RP with adaptive slicing for the preservation of critical features in final prototyped part. This methodology, applied to part with two distinct clusters, leads to reduced number of layers compared to that obtained in flat-layered RP.

Details

Rapid Prototyping Journal, vol. 21 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 15 June 2015

Bin Huang and Sarat B Singamneni

This paper aims to develop a new slicing method for fused deposition modelling (FDM), the curved layer adaptive slicing (CLAS), combining adaptive flat layer and curved layer…

2073

Abstract

Purpose

This paper aims to develop a new slicing method for fused deposition modelling (FDM), the curved layer adaptive slicing (CLAS), combining adaptive flat layer and curved layer slicing together.

Design/methodology/approach

This research begins with a review of current curved layer and adaptive slicing algorithms employed in the FDM and further improvement of the same, where possible. The two approaches are then integrated to develop the adaptive curved layer slicing based on the three-plane intersection method for curved layer offsetting and consideration of facet angles together with the residual heights for adaptive slicing. A practical implementation showed that curved layer adaptive layers respond in similar lines to the flat layer counterparts in terms of the mechanical behaviour of FDM parts.

Findings

CLAS is effective in capturing sharply varying surface profiles and other finer part details, apart from imparting fibre continuity. Three-point bending tests on light curved parts made of curved layers of varying thicknesses prove thicker curved layers to result in better mechanical properties.

Research limitations/implications

The algorithms developed in this research can handle relatively simple shapes to develop adaptive curved slices, but further developments are necessary for more complex shapes. The test facilities also need further improvements, to be able to programmatically implement adaptive curved layer slicing over a wide range of thicknesses.

Practical implications

When fully developed and implemented, CLAS will allow for better FDM part construction with lesser build times.

Originality/value

This research fills a gap in terms of integrating both curved layer and adaptive slicing techniques to better slice and build a part of given geometry using FDM.

Details

Rapid Prototyping Journal, vol. 21 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 10 February 2022

Yue Zhou, El Mehdi Abbara, Dayue Jiang, Arad Azizi, Mark D. Poliks and Fuda Ning

This study aims to uncover the multiscale relations among geometry, surface finish, microstructure and fatigue properties of curved-surface AlSi10Mg parts fabricated by powder bed…

Abstract

Purpose

This study aims to uncover the multiscale relations among geometry, surface finish, microstructure and fatigue properties of curved-surface AlSi10Mg parts fabricated by powder bed fusion (PBF) additive manufacturing.

Design/methodology/approach

This paper investigated the high-cycle tensile and bending fatigue behaviors of PBF-built AlSi10Mg parts with curved surfaces. Besides, the surface finish, porosity and microstructure around various curvatures were characterized. Meanwhile, the stress distributions of the fatigue specimens with curved surfaces under the dynamic tensile/bending loading were analyzed via theoretical analysis and ANSYS simulation.

Findings

The results showed that the as-built specimens with the smallest curvature exhibited the best surface quality, smallest grain sizes and thinnest grain boundaries. In addition, the tensile fatigue fracture occurred around the largest curvature position of fatigue specimens, which was consistent with the simulated fatigue safety factor results. Moreover, the bending fatigue specimens with the largest curvature presented the shortest fatigue life due to the highest bending and shear stresses along the loading direction.

Originality/value

So far, most studies have focused on the fatigue behavior of as-built AlSi10Mg parts with planar structures only. The investigation on fatigue properties of as-built AlSi10Mg parts with curved surfaces remains unexplored. This study provides new insights into the characterization and quantification of the fatigue performance of PBF-built metal parts with complex geometries, the knowledge of which can promote their adoption in real industries.

Details

Rapid Prototyping Journal, vol. 28 no. 7
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 8 June 2021

Sanatan Das, Akram Ali and Rabindra Nath Jana

Outstanding features such as thermal conductivity and superior electrical conductivity of nanofluids unfold a new window in the context of their extensive applications in…

Abstract

Purpose

Outstanding features such as thermal conductivity and superior electrical conductivity of nanofluids unfold a new window in the context of their extensive applications in engineering and industrial domains. The purpose of this study to simulate numerically the magneto-nanofluid flow and heat transfer over a curved stretching surface. Heat transport is explored in the presence of viscous dissipation. At the curved surface, the convective boundary condition is adopted. Three different nanoparticles, namely, copper, aluminium oxide and titanium dioxide are taken into consideration because of easily available in nature.

Design/methodology/approach

The basic flow equations are framed in terms of curvilinear coordinates. The modelled partial differential equations are transformed into a system of non-linear ordinary differential equations by means of appropriate similarity transformation. The subsequent non-linear system of equations is then solved numerically by using the Runge–Kutta–Felhberg method with the shooting scheme via bvp4c MATLAB built-in function. Impacts of various physical parameters on velocity, pressure and temperature distributions, local skin-friction coefficient, local Nusselt number and wall temperature are portrayed through graphs and tables followed by a comprehensive debate and physical interpretation.

Findings

Graphical results divulge that augmenting values of the magnetic parameter cause a decline in velocity profiles and stream function inside the boundary layer. The magnitude of the pressure function inside the boundary layer reduces for higher estimation of curvature parameter, and it is also zero when the curvature parameter goes to infinity. Furthermore, the temperature is observed in a rising trend with growing values of the magnetic parameter and Biot number.

Practical implications

This research study is very pertinent to the expulsion of polymer sheet and photographic films, metallurgical industry, electrically-conducting polymer dynamics, magnetic material processing, rubber and polymer sheet processing, continuous casting of metals, fibre spinning, glass blowing and fibre, wire and fibre covering and sustenance stuff preparing, etc.

Originality/value

Despite the huge amount of literature available, but still, very little attention is given to simulate the flow configuration due to the curved stretching surface with the convective boundary condition. Very few papers have been examined on this topic and found that its essence inside the boundary layer is not any more insignificant than on account of a stretching sheet. A numerical comparison with the published works is conducted to verify the accuracy of the present study.

Details

World Journal of Engineering, vol. 18 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 11 March 2014

Mohammad Hayasi and Bahram Asiabanpour

The main aim of this study is to generate curved-form cut on the edge of an adaptive layer. The resulting surface would have much less geometry deviation error and closely fit its…

Abstract

Purpose

The main aim of this study is to generate curved-form cut on the edge of an adaptive layer. The resulting surface would have much less geometry deviation error and closely fit its computer aided design (CAD) model boundary.

Design/methodology/approach

This method is inspired by the manual peeling of an apple in which a knife's orientation and movement are continuously changed and adjusted to cut each slice with minimum waste. In this method, topology and geometry information are extracted from the previously generated adaptive layers. Then, the thickness of an adaptive layer and the bottom and top contours of the adjacent layers are fed into the proposed algorithm in the form of the contour and normal vector to create curved-form sloping surfaces. Following curved-form adaptive slicing, a customized machine path compatible with a five-axis abrasive waterjet (AWJ) machine will be generated for any user-defined sheet thicknesses.

Findings

The implemented system yields curved-form adaptive slices for a variety of models with diverse types of surfaces (e.g. flat, convex, and concave), different slicing direction, and different number of sheets with different thicknesses. The decrease in layer thickness and increase of the number of the sloped cuts can make the prototype as close as needed to the CAD model.

Research limitations/implications

The algorithm is designed for use with five-axis AWJ cutting of any kind of geometrical complex surfaces. Future research would deal with the nesting problem of the layers being spread on the predefined sheet as the input to the five-axis AWJ cutter machine to minimize the cutting waste.

Practical implications

The algorithm generates adaptive layers with concave or convex curved-form surfaces that conform closely to the surface of original CAD model. This will pave the way for the accurate fabrication of metallic functional parts and tooling that are made by the attachment of one layer to another. Validation of the output has been tested only as the simulation model. The next step is the customization of the output for the physical tests on a variety of five-axis machines.

Originality/value

This paper proposes a new close to CAD design sloped-edge adaptive slicing algorithm applicable to a variety of five-axis processes that allow variable thickness layering and slicing in different orientations (e.g. AWJ, laser, or plasma cutting). Slices can later be bonded to build fully solid prototypes.

Details

Rapid Prototyping Journal, vol. 20 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 4 April 2022

Yuli Zhang and Chen Wang

Marketing persuasive materials are often displayed on a curved surface (e.g. a curved hallway). This study aims to investigate how the curvature (concave vs convex) of a display…

Abstract

Purpose

Marketing persuasive materials are often displayed on a curved surface (e.g. a curved hallway). This study aims to investigate how the curvature (concave vs convex) of a display surface influences the persuasion of the marketing appeals presented on it.

Design/methodology/approach

The conceptual framework was tested in a field experiment, a lab experiment and two online experiments on Amazon Mechanical Turk. Analyses of variance and mediation analysis were used to test the hypotheses.

Findings

This research demonstrates that a concave (vs convex) display surface may increase persuasion for marketing materials with social appeals. This occurs because a concave surface enhances consumers’ perception of self–other overlap, which is matched with the content of the social appeal presented on it, thereby enhancing the appeal’s persuasiveness. It further identifies the appeal content as an important moderator of the effect; a convex (vs concave) display would enhance persuasion when the marketing materials contain personal appeals.

Research limitations/implications

Future research could investigate how a time delay (e.g. hours, days) and the curvature of a display board or wall would play a role in the effect of display curvature.

Practical implications

The findings offer a novel, simple and cost-effective approach to enhance persuasion for both nonprofit and for-profit marketing materials.

Originality/value

This research contributes to the persuasion literature by investigating the impact of one ubiquitous but overlooked aspect of the message setting (i.e. the curvature of the message’s display surface) on persuasion while holding the message source and content constant. It also advances knowledge on consumer shape perception by examining an underexplored shape (i.e. the curved shape of a display surface) that is nondiagnostic in message persuasion.

Details

European Journal of Marketing, vol. 56 no. 4
Type: Research Article
ISSN: 0309-0566

Keywords

Article
Publication date: 10 September 2019

Zhenpeng Wu, Vanliem Nguyen, Zhihong Zhang and Liangcai Zeng

The stepped topography of the friction pairs mainly causes the fluid film thickness to change in the direction of motion. In this region, there have very few topographical design…

Abstract

Purpose

The stepped topography of the friction pairs mainly causes the fluid film thickness to change in the direction of motion. In this region, there have very few topographical design methods for continuous or non-linear distribution of the fluid film. The purpose of this study is to analyze the effect of the curved surface on the performance of the liquid film.

Design/methodology/approach

First, a numerical simulation is used to solve the optimal bearing capacity and friction coefficient of the liquid film under the condition of the minimum film thickness. Then, the curved surface described by the sinusoidal curve equation is applied in the transitional region of maximum and minimum film thickness. The bearing capacity and the friction coefficient of the liquid film are respectively simulated and compared in the same condition of the minimum film thickness.

Findings

The research results show that the liquid film using the curved surface transition model, the optimal bearing capacity is significantly increased by 32 per cent while the optimal friction coefficient is clearly reduced by 38 per cent in comparison with using stepped surface model.

Originality/value

The friction pair with curved transition enables better lubrication performance of the liquid film and better adaptability under unstable conditions.

Details

Industrial Lubrication and Tribology, vol. 72 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 30 March 2020

Donghua Zhao, Tianqi Li, Beijun Shen, Yicheng Jiang, Weizhong Guo and Feng Gao

The purpose of this paper is to design and develop a rotary three-dimensional (3D) printer for curved layer fused deposition modeling (CLFDM), and discuss some technical…

Abstract

Purpose

The purpose of this paper is to design and develop a rotary three-dimensional (3D) printer for curved layer fused deposition modeling (CLFDM), and discuss some technical challenges in the development.

Design/methodology/approach

Some technical challenges include, but are not limited to, the machine design and control system, motion analysis and simulation, workspace and printing process analysis, curved layer slicing and tool path planning. Moreover, preliminary experiments are carried out to prove the feasibility of the design.

Findings

A rotary 3D printer for CLFDM has been designed and developed. Moreover, this printer can function as a polar 3D printer for flat layer additive manufacturing (AM). Compared with flat layer AM, CLFDM weakens the staircase effect and improves geometrical accuracy and mechanical properties. Hence, CLFDM is more suitable for parts with curved surfaces.

Research limitations/implications

Double extruders have brought improved build speed. However, this paper is restricted to complex process planning and mechanical structures, which may lead to collisions during printing. Meanwhile, the rotation range of the nozzle is limited by mechanical structures, affecting the manufacturing capability of complex curved surfaces.

Originality/value

A novel rotary 3D printer, which has four degrees of freedom and double extruders, has been designed and manufactured. The investigation on the prototype has proved its capability of CLFDM. Besides, this rotary 3D printer has two working modes, which brings the possibility of flat layer AM and CLFDM.

Article
Publication date: 27 July 2022

Donghua Zhao, Gaohan Zhu, Jiapeng He and Weizhong Guo

With the development of 3D printing or additive manufacturing (AM), curved layer fused deposition modeling (CLFDM) has been researched to cope with the flat layer AM inherited…

Abstract

Purpose

With the development of 3D printing or additive manufacturing (AM), curved layer fused deposition modeling (CLFDM) has been researched to cope with the flat layer AM inherited problems, such as stair-step error, anisotropy and the time-cost and material-cost problems from the supporting structures. As one type of CLFDM, cylindrical slicing has obtained some research attention. However, it can only deal with rotationally symmetrical parts with a circular slicing layer, limiting its application. This paper aims to propose a ray-based slicing method to increase the inter-layer strength of flat layer-based AM parts to deal with more general revolving parts.

Design/methodology/approach

Specifically, the detailed algorithm and implementation steps are given with several examples to enable readers to understand it better. The combination of ray-based slicing and helical path planning has been proposed to consider the nonuniform path spacing between the adjacent paths in the same curved layer. A brief introduction of the printing system is given, mainly including a 3D printer and the graphical user interface.

Findings

The preliminary experiments are successfully conducted to verify the feasibility and versatility of the proposed and improved slicing method for the revolving thin-wall parts based on a rotary 3D printer.

Originality/value

This research is early-stage work, and the authors are intended to explore the process and show the initial feasibility of ray-based slicing for revolving thin-wall parts using a rotary 3D printer. In general, this research provides a novel and feasible slicing method for multiaxis rotary 3D printers, making manufacturing revolving thin-wall and complex parts possible.

Article
Publication date: 17 October 2017

Ashu Garg, Anirban Bhattacharya and Ajay Batish

The purpose of this paper is to investigate the influence of low-cost chemical vapour treatment process on geometric accuracy and surface roughness of different curved and…

342

Abstract

Purpose

The purpose of this paper is to investigate the influence of low-cost chemical vapour treatment process on geometric accuracy and surface roughness of different curved and freeform surfaces of fused deposition modelling (FDM) specimens build at different part building orientations.

Design/methodology/approach

Parts with different primitive and curved surfaces are designed and modelled to build at three different part orientations along X orientation (vertical position resting on side face), Y orientation (horizontal position resting on base) and Z orientation (upright position). Later, the parts are post-processed by cold vapours of acetone. Geometric accuracy and surface roughness are measured both before and after the chemical treatment to investigate the change in geometric accuracy, surface roughness of FDM parts.

Findings

The results indicate that surface roughness is reduced immensely after cold vapour treatment with minimum variation in geometric accuracy of parts. Parts build vertically over its side face (X orientation) provides the overall better surface finish and geometric accuracy.

Originality/value

The present study provides an approach of post-built treatment for FDM parts and observes a significant improvement in surface finish of the components. The present approach of post-built treatment can be adopted to enhance the surface quality as well as to achieve desired geometric accuracy for different primitive, freeform/curved surfaces of FDM samples suitable for functional components as well as prototypes.

Details

Rapid Prototyping Journal, vol. 23 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

1 – 10 of over 17000