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Article
Publication date: 20 September 2021

Tugce Tezel and Volkan Kovan

The purpose of this paper is to determine the optimum nozzle diameter for parts production with polylactic acid using a three-dimensional printer. The additive…

Abstract

Purpose

The purpose of this paper is to determine the optimum nozzle diameter for parts production with polylactic acid using a three-dimensional printer. The additive manufacturing method used was fused filament fabrication.

Design/methodology/approach

Designers and researchers have focused on the effects of these parameters on part strength. Additionally, production time is one of the disadvantages of this manufacturing method that researchers are trying to overcome. The production parameters that stand out at this point are nozzle diameter and layer thickness.

Findings

As a result of the study, it was determined that the increased nozzle diameter led to increased part strength. At the same time, layer thickness had the most significant effect on surface quality. The increased nozzle diameter and part density led to decreased production time. It was concluded that larger nozzle diameter and lower layer thickness should be used for parts with superior properties.

Research limitations/implications

The experimental printing parameters used in the study were nozzle diameter (0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 mm), layer thickness (0.1, 0.2 and 0.3 mm) and printing orientation (0°, 45° and 90°). The effects of printing parameters on part strength, dimensional accuracy, surface quality and part density were analyzed experimentally.

Originality/value

The effects of several printing parameters have been examined in the literature. However, the effect of different nozzle diameters has been ignored. There are limited experimental studies that examine the effect of nozzle diameter on mechanical properties, surface roughness, dimensional quality and production time. In this regard, the results obtained from various nozzle diameters used in this study will significantly contribute to the literature.

Details

Rapid Prototyping Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 17 May 2021

Jesús Miguel Chacón, Miguel Ángel Caminero, Pedro José Núñez, Eustaquio García-Plaza and Jean Paul Bécar

Fused filament fabrication (FFF) is one of the most popular additive manufacturing (AM) technologies due to its ability to build thermoplastic parts with complex…

Abstract

Purpose

Fused filament fabrication (FFF) is one of the most popular additive manufacturing (AM) technologies due to its ability to build thermoplastic parts with complex geometries at low cost. The FFF technique has been mainly used for rapid prototyping owing to the poor mechanical and geometrical properties of pure thermoplastic parts. However, both the development of new fibre-reinforced filaments with improved mechanical properties, and more accurate composite 3D printers have broadened the scope of FFF applications to functional components. FFF is a complex process with a large number of parameters influencing product quality and mechanical properties, and the effects of the combined parameters are usually difficult to evaluate. An array of parameter combinations has been analysed for improving the mechanical performance of thermoplastic parts such as layer thickness, build orientation, raster angle, raster width, air gap, infill density and pattern, fibre volume fraction, fibre layer location, fibre orientation and feed rate. This study aims to assess the effects of nozzle diameter on the mechanical performance and the geometric properties of 3D printed short carbon fibre-reinforced composites processed by the FFF technique.

Design methodology approach

Tensile and three-point bending tests were performed to characterise the mechanical response of the 3D printed composite samples. The dimensional accuracy, the flatness error and surface roughness of the printed specimens were also evaluated. Moreover, manufacturing costs, which are related to printing time, were evaluated. Finally, scanning electron microscopy images of the printed samples were analysed to estimate the porosity as a function of the nozzle diameter and to justify the effect of nozzle diameter on dimensional accuracy and surface roughness.

Findings

The effect of nozzle diameter on the mechanical and geometric quality of 3D printed composite samples was significant. In addition, large nozzle diameters tended to increase mechanical performance and enhance surface roughness, with a reduction in manufacturing costs. In contrast, 3D printed composite samples with small nozzle diameter exhibited higher geometric accuracy. However, the effect of nozzle diameter on the flatness error and surface roughness was of slight significance. Finally, some print guidelines are included.

Originality value

The effect of nozzle diameter, which is directly related to product quality and manufacturing costs, has not been extensively studied. The presented study provides more information regarding the dependence of the mechanical, microstructural and geometric properties of short carbon fibre-reinforced nylon composite components on nozzle diameter.

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Article
Publication date: 4 January 2021

Jianghong Zhao and Xin Li

Vortex grippers use tangential nozzles to form vortex flow and are able to grip a workpiece without any physical contact, thus avoiding any unintentional workpiece damage…

Abstract

Purpose

Vortex grippers use tangential nozzles to form vortex flow and are able to grip a workpiece without any physical contact, thus avoiding any unintentional workpiece damage. This study aims to use experimental and theoretical methods to investigate the effects of nozzle diameter on the performance.

Design/methodology/approach

First, various suction force-distance curves were developed to analyze the effects of nozzle diameter on the maximum suction force. This study determines the tangential velocity distribution on the workpiece surface by substituting the experimental pressure distribution data into simplified Navier-Stokes equations and then used these equations to analyze the effects on the flow field. Subsequent theoretical analysis of the distribution of pressure and circumferential velocity further validated the experimental results. Next, by rearranging these relationships, the study considered the effects of nozzle diameter on the inherent vortex gripper characteristics. In addition, this study developed various suction force-energy consumption curves to analyze the effects of nozzle diameter.

Findings

The results of this study indicated that the vortex gripper’s circumferential velocity and maximum suction force decrease with increasing nozzle diameter. Nozzle diameter did not significantly affect the inherent frequency of the vortex gripper-workpiece inertial system or the corresponding suspension stability of the workpiece. However, an increase in nozzle diameter did effectively increase the vortex gripper’s suspension region. Finally, as the nozzle diameter increased, the energy required to achieve the same maximum suction force decreased.

Originality/value

This study’s findings can enable optimization of nozzle design in emerging vortex gripper designs and facilitate informed selection among existing vortex grippers.

Details

Assembly Automation, vol. 41 no. 1
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 8 June 2021

M. Balasubramanian and S. Madhu

The purpose of the study is to machine the composites at lower machining time with higher accuracy without causing delamination.

Abstract

Purpose

The purpose of the study is to machine the composites at lower machining time with higher accuracy without causing delamination.

Design/methodology/approach

Abrasive jet machining is the technology appropriate for machining composite materials to obtain good dimensional accuracy without causing de-lamination. The central composite design was followed in deciding the number of experiments to be carried out.

Findings

The influence of abrasive jet machining process parameters on machining time, material removal rate (MRR) and kerf characteristics were investigated. The experimental results proved the newly designed internal threaded nozzle increased MRR, thereby reducing the machining time.

Originality/value

Machining of glass fibre reinforced polymer (GFRP) is one of the challenging tasks given its non-linear and in-homogeneous properties. In this investigation, newly developed threaded and unthreaded nozzles in machining were used for making holes on the GFRP composites.

Details

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

Keywords

Content available
Article
Publication date: 18 November 2021

Joanna Grochowalska, Piotr Jaworski, Łukasz Jan Kapusta and Jerzy Kowalski

In the cylinders of a marine diesel engine, self-ignition occurs in a very short time after the fuel injection into the combustion chamber. Therefore, this paper aims to…

Abstract

Purpose

In the cylinders of a marine diesel engine, self-ignition occurs in a very short time after the fuel injection into the combustion chamber. Therefore, this paper aims to develop a model of diesel fuel spray for the early stage of fuel spray in the marine diesel engine. The main technical aspects such as nozzle diameter of the marine engine injector and backpressure in the combustion chamber were taken into consideration.

Design/methodology/approach

In this paper, laboratory experimental studies were carried out to determine parameters of fuel spray in an early stage of injection in the marine diesel engine. The optical measuring Mie scattering technique was used to record the fuel injection process. The working space was a constant volume chamber. The backpressure parameters in the constant volume chamber were the same as during the operation of the marine diesel engine. Based on the experimental studies and important Hiroyasu and Arai models of fuel spray presented in literature was proposed new model of fuel spray parameters for marine diesel injectors.

Findings

In this paper, the proposed new model of the two main parameters described fuel spray evolution”: new model of spray tip penetration (STP) and spray cone angle (SCA). New model propagation of fuel STP in time was included the influence of nozzle diameter and backpressure. The proposed model has a lower error, about 15%–34%, than the model of Hiroyasu and Arai. Moreover, a new model of the evolution over time of the SCA is developed.

Research limitations/implications

In the future research of fuel spray process must be taken influence of the fuel temperature. Diesel fuel has a different density and viscosity in dependence of fuel temperature. Therefore are predicted of the expansion about influence of fuel temperature, new model of fuel spray for a marine diesel engine. The main limitations occurring in the research are not possible to carry out the research while real operation marine diesel engine.

Originality/value

An experimental test was carried out for a real fuel injector of a marine diesel engine. Design parameters and fuel injection parameters were selected on the basis of the actual one. In the literature, SCA is defined as a constant parameter for the specific preliminary data. A new model for the early stage of fuel spray of SCA propagation in time has been proposed. The early stage of fuel spray is especially important, because in this time comes in there to fuel self-ignition.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 18 April 2017

Baihong Chi, Zhiwei Jiao and Weimin Yang

3D printing based on additive manufacturing has advantages in manufacturing products with high geometrical complexity. However, there are many limitations to print plastic…

Abstract

Purpose

3D printing based on additive manufacturing has advantages in manufacturing products with high geometrical complexity. However, there are many limitations to print plastic products with the existing commercial 3D printers. The polymer materials processing industry needs new devices which can satisfy the trend of processing individual units and small batch sizes of plastic parts.

Design/methodology/approach

In this study, a freeform fabrication system with the method of polymer melt droplet deposition is proposed. The performance of this system under different conditions was studied by changing the operating parameters. Furthermore, the dimensional uniformity of droplets and their deposition process are analyzed, and a plastic sample was fabricated with this system as an example.

Findings

The results show a clear correlation between the processing parameters and the droplet diameter. In the experiment for examining the dimensional uniformity of the droplet, the droplets become spindles, and there appears a melt filament between the droplets. The variation of the droplet’s diameters is within 5 per cent. Furthermore, a successfully processed rectangular plastic sample verified the feasibility of this technology for the printing of plastic products.

Originality/value

A freeform fabrication system with polymer melt droplet deposition is proposed, which can process a wide variety of materials in the form of standard granulates like injection molding or extrusion. Based on the principle of droplet deposition, multi-component or colorful materials can be printed.

Details

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

Keywords

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Article
Publication date: 20 November 2020

S. Madhu and M. Balasubramanian

The purpose of this study is for solving many issues in production that includes processing of complex-shaped profile, machining of high-strength materials, good surface…

Abstract

Purpose

The purpose of this study is for solving many issues in production that includes processing of complex-shaped profile, machining of high-strength materials, good surface finish with high-level precision and minimization of waste. Among the various advanced machining processes, abrasive jet machining (AJM) is one of the non-traditional machining techniques used for various applications such as polishing, deburring and hole making. Hence, an overview of the investigations done on carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GRFP) composites becomes important.

Design/methodology/approach

Discussion on various approaches to AJM, the effect of process parameters on the glass fiber and carbon fiber polymeric composites are presented. Kerf characteristics, surface roughness and various nozzle design were also discussed.

Findings

It was observed that abrasive jet pressure, stand-off distance, traverse rate, abrasive size, nozzle diameter, angle of attack are the significant process parameters which affect the machining time, material removal rate, top kerf, bottom kerf and kerf angle. When the particle size is maximum, the increased kinetic energy of the particle improves the penetration depth on the CFRP surface. As the abrasive jet pressure is increased, the cutting process is enabled without severe jet deflection which in turn minimizes the waviness pattern, resulting in a decrease of the surface roughness.

Research limitations/implications

The review is limited to glass fiber and carbon fiber polymeric composites.

Practical implications

In many applications, the use of composite has gained wide acceptance. Hence, machining of the composite need for the study also has gained wide acceptance.

Social implications

The usage of composites reduces the usage of very costly materials of high density. The cost of the material also comes down.

Originality/value

This paper is a comprehensive review of machining composite with abrasive jet. The paper covers in detail about machining of only GFRP and CFRP composites with various nozzle designs, unlike many studies which has focused widely on general AJM of various materials.

Details

World Journal of Engineering, vol. 18 no. 2
Type: Research Article
ISSN: 1708-5284

Keywords

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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…

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

Keywords

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Article
Publication date: 1 March 2001

A.A. Tseng and M. Tanaka

Two newly invented deposition techniques for the freeform fabrication of metal and ceramic parts are presented. The first deposition technique studied is one that can…

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Abstract

Two newly invented deposition techniques for the freeform fabrication of metal and ceramic parts are presented. The first deposition technique studied is one that can deposit variable sizes of filaments in a controlled manner. The second technique consists of layer deposition using an adjustable planar nozzle to generate layers directly. Laboratory scale apparatus has been built to study the behavior of filament and layer formation of these two techniques. Experiments are conducted in typical operation ranges. Analytical solutions are also developed to parametrically study the effects of changing major operational parameters as well as to provide necessary information for designing the apparatus. All results indicate that the analytical predictions agree very well with the experimental observation. Finally, recommendations on the future development of these two techniques are given.

Details

Rapid Prototyping Journal, vol. 7 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 11 September 2019

Jiwoon Lee, Jesse Walker, Sanjay Natarajan and Sung Yi

Extrusion-based additive manufacturing (AM) has been considered as a promising technique to fabricate scaffolds for tissue engineering due to affordability, versatility…

Abstract

Purpose

Extrusion-based additive manufacturing (AM) has been considered as a promising technique to fabricate scaffolds for tissue engineering due to affordability, versatility and ability to print porous structures. The reliability and controllability of the printing process are necessary to produce 3D-printed scaffolds with desired properties and depend on the geometric characteristics such as porosity and pore diameter. The purpose of this study is to develop an analytical model and explore its effectiveness in the prediction of geometric characteristics of 3D-printed scaffolds.

Design/methodology/approach

An analytical model was developed to simulate the geometric characteristics of scaffolds produced by extrusion-based AM using fluid mechanics. Polycaprolactone (PCL) was chosen as a scaffold material and was assumed to be a non-Newtonian fluid for the model. The effectiveness of the model was verified through comparison with the experimental results.

Findings

A comparison study between simulation and experimental results shows that strut diameter, pore size and porosity of scaffolds can be predicted by using extrusion pressure, temperature, nozzle diameter, nozzle length and printing speed. Simulation results demonstrate that geometric characteristics have a strong relationship with processing parameters, and the model developed in this study can be used for predicting the scaffold properties for the extrusion-based 3D bioprinting process.

Originality/value

The present study provides a prediction model that can simulate the printing process by a simple input of processing parameters. The geometric characteristics can be predicted prior to the experimental verification, and such prediction will reduce the process time and effort when a new material or method is applied.

Details

Rapid Prototyping Journal, vol. 26 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

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