Search results

1 – 10 of over 2000
Article
Publication date: 1 May 1994

N. Brännberg and J. Mackerle

This paper gives a review of the finite element techniques (FE)applied in the area of material processing. The latest trends in metalforming, non‐metal forming and powder…

1405

Abstract

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming and powder metallurgy are briefly discussed. The range of applications of finite elements on the subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for the last five years, and more than 1100 references are listed.

Details

Engineering Computations, vol. 11 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 April 2006

Jaroslav Mackerle

To provide a selective bibliography for researchers working with bulk material forming (specifically the forging, rolling, extrusion and drawing processes) with sources…

4651

Abstract

Purpose

To provide a selective bibliography for researchers working with bulk material forming (specifically the forging, rolling, extrusion and drawing processes) with sources which can help them to be up‐to‐date.

Design/methodology/approach

A range of published (1996‐2005) works, which aims to provide theoretical as well as practical information on the material processing namely bulk material forming. Bulk deformation processes used in practice change the shape of the workpiece by plastic deformations under forces applied by tools and dies.

Findings

Provides information about each source, indicating what can be found there. Listed references contain journal papers, conference proceedings and theses/dissertations on the subject.

Research limitations/implications

It is an exhaustive list of papers (1,693 references are listed) but some papers may be omitted. The emphasis is to present papers written in English language. Sheet material forming processes are not included.

Practical implications

A very useful source of information for theoretical and practical researchers in computational material forming as well as in academia or for those who have recently obtained a position in this field.

Originality/value

There are not many bibliographies published in this field of engineering. This paper offers help to experts and individuals interested in computational analyses and simulations of material forming processes.

Details

Engineering Computations, vol. 23 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

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

Article
Publication date: 3 December 2021

Cristina Pascual-González, Cillian Thompson, Jimena de la Vega, Nicolás Biurrun Churruca, Juan P. Fernández-Blázquez, Iker Lizarralde, Diego Herráez-Molinero, Carlos González and Javier LLorca

This paper aims to develop a novel strategy to manufacture poly-lactic acid (PLA) filaments reinforced with Mg particles for fused filament fabrication of porous scaffolds…

Abstract

Purpose

This paper aims to develop a novel strategy to manufacture poly-lactic acid (PLA) filaments reinforced with Mg particles for fused filament fabrication of porous scaffolds for biomedical applications.

Design/methodology/approach

The mixture of PLA pellets and Mg particles was extruded twice, the second time using a precision extruder that produces a filament with zero porosity, constant diameter and homogeneous dispersion of Mg particles. The physico-chemical properties of the extruded filaments were carefully analysed to determine the influence of Mg particles on the depolymerisation of PLA during high temperature extrusion and the optimum melt flow index to ensure printability.

Findings

It was found that the addition of a polyethylene glycol (PEG) plasticizer was necessary to allow printing when the weight fraction of Mg was above 4%. It was possible to print porous face-centre cubic scaffolds with good geometrical accuracy and minimum porosity with composite filaments containing PEG.

Originality/value

The new strategy is easily scalable and seems to be very promising to manufacture biodegradable thermoplastic/metal composite filaments for 3D printing that can take advantage of the different properties of both components from the viewpoint of tissue engineering.

Article
Publication date: 1 November 1960

C.G. Keil

THE paper began with a brief historical survey of the cold extrusion process since its first practical use over sixty years ago. The extrusion of special materials such as…

Abstract

THE paper began with a brief historical survey of the cold extrusion process since its first practical use over sixty years ago. The extrusion of special materials such as molybdenum, beryllium and zirconium was described. The problems relating to the production of suitable tooling for the extrusion process and the preparation, heat treatment and lubrication of extrusion billets and slugs were discussed. Following discussion on temperature and speed effects, prestrain of work material, presses for extrusion and component design, the paper concluded with an outline of the applications and advantages of the cold extrusion process.

Details

Aircraft Engineering and Aerospace Technology, vol. 32 no. 11
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 30 September 2022

Abdul Kareem Abdul Jawwad, Adnan Al-Bashir, Muhammad Saleem and Bassam Hasanain

This study aims to investigate and model interrelationships between process parameters, geometrical profile characteristics and mechanical properties of industrially…

Abstract

Purpose

This study aims to investigate and model interrelationships between process parameters, geometrical profile characteristics and mechanical properties of industrially extruded aluminum alloys.

Design/methodology/approach

Statistical design of experiments (DOE) was applied to investigate and model the effects of eight factors including extrusion ratio, stem speed, billet-preheat temperature, number of die cavities, quenching media (water/air), time and temperature of artificial aging treatment and profile nominal thickness on four mechanical properties (yield strength, ultimate tensile strength, percent elongation and hardness). Experiments were carried out at an actual extrusion plant using 8-in. diameter billets on an extrusion press with 2,200 ton capacity.

Findings

Main factors and factor interactions controlling mechanical properties were identified and discussed qualitatively. Quantitative models with high prediction accuracy (in excess of 95%) were also obtained and discussed.

Practical implications

The obtained results are believed to be of great importance to researchers and industrial practitioners in the aluminum extrusion industry.

Originality/value

All practical and relevant parameters have been used to model all important mechanical properties in a collective manner in one study and within actual industrial setup. This is in contrast to all previous studies where either a partial set of parameters and/or mechanical properties are discussed and mostly under limited laboratory setup.

Details

Multidiscipline Modeling in Materials and Structures, vol. 18 no. 6
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 21 June 2013

H. Goodarzi Hosseinabadi and S. Serajzadeh

The purpose of this paper is to propose a mathematical model to estimate required energy and temperature distribution during cold extrusion process.

Abstract

Purpose

The purpose of this paper is to propose a mathematical model to estimate required energy and temperature distribution during cold extrusion process.

Design/methodology/approach

An admissible velocity field is generated based on stream function technique. Then, the required energy and the temperature distributions in the metal and the extrusion die are determined by a coupled upper bound‐finite element analysis.

Findings

To examine the proposed model, cold extrusion of AA6061‐10%SiCp is considered and the predicted extrusion force‐displacement diagrams in different reductions are compared with the experimental ones and reasonable agreement is observed. Furthermore, it is found that there is a linear relationship between maximum temperature and logarithm of ram velocity for the examined composite.

Originality/value

This approach requires shorter run‐time as compared with fully finite element analyses while the model is particularly appropriate for high speed extrusion processes where the adiabatic heating is of importance.

Details

Multidiscipline Modeling in Materials and Structures, vol. 9 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 28 June 2022

Rishi Parvanda and Prateek Kala

Fused deposition modelling (FDM) has gained popularity owing to its capability of producing complex and customized profiles at relatively low cost and in shorter periods…

Abstract

Purpose

Fused deposition modelling (FDM) has gained popularity owing to its capability of producing complex and customized profiles at relatively low cost and in shorter periods. The study aims to extend the use of FDM printers for 3D printing of low melting point alloy (LMPA), which has applications in the electronics industry, rapid tooling, biomedical, etc.

Design/methodology/approach

Solder is the LMPA with alloy’s melting temperature (around 200°C) lower than the parent metals. The most common composition of the solder, which is widely used, is tin and lead. However, lead is a hazardous material having environmental and health deteriorating effects. Therefore, lead-free Sn89Bi10Cu non-eutectic alloy in the form of filament was used. The step-by-step method has been used to identify the process window for temperature, print speed, filament length (E) and layer height. The existing FDM printer was customized for the present work.

Findings

Analysis of infrared images has been done to understand discontinuity at a certain range of process parameters. The effect of printing parameters on inter-bonding, width and thickness of the layers has also been studied. The microstructure of the parent material and deposited bead has been observed. Conclusions were drawn out based on the results, and the scope for the future has been pointed out.

Originality/value

The experiments resulted in the process window identification of print speed, extrusion temperature, filament length and layer height of Sn89Bi10Cu which is not done previously.

Details

Rapid Prototyping Journal, vol. 28 no. 10
Type: Research Article
ISSN: 1355-2546

Keywords

Open Access
Article
Publication date: 10 July 2019

Sigmund Arntsønn Tronvoll, Sebastian Popp, Christer Westum Elverum and Torgeir Welo

This paper aims to present the mathematical foundation of so-called advance algorithms, developed to compensate for defects during acceleration and deacceleration of the…

2541

Abstract

Purpose

This paper aims to present the mathematical foundation of so-called advance algorithms, developed to compensate for defects during acceleration and deacceleration of the print head in filament-based melt extrusion additive processes. It then investigates the validity of the mathematical foundation, its performance on a low-cost system and the effect of changing layer height on the algorithm’s associated process parameter.

Design/methodology/approach

This study starts with a compilation and review of literature associated with advance algorithms, then elaborates on its mathematical foundation and methods of implementation. Then an experiment displaying the performance of the algorithm implemented in Marlin machine firmware, Linear Advance 1.0, is performed using three different layer heights. The results are then compared with simulations of the system using Simulink.

Findings

Findings suggests that advance algorithms following the presented approach is capable of eliminating defects because of acceleration and deacceleration of the print head. The results indicate a layer height dependency on the associated process parameter, requiring higher compensation values for lower layer heights. It also shows higher compensation values for acceleration than deacceleration. Results from the simulated mathematical model correspond well with the experimental results but predict some rapid variations in flow rate that is not reflected in the experimental results.

Research limitations/implications

As there are large variations in printer design and materials, deviation between different setups must be expected.

Originality/value

To the best of authors’ knowledge, this study is the first to describe and investigate advance algorithms in academic literature.

Details

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

Keywords

Article
Publication date: 18 July 2018

Mohammad Abu Hasan Khondoker, Asad Asad and Dan Sameoto

This paper aims to target to print functionally gradient materials (FGM) devices made of immiscible polymers in multi-material fused deposition modelling (FDM) systems…

Abstract

Purpose

This paper aims to target to print functionally gradient materials (FGM) devices made of immiscible polymers in multi-material fused deposition modelling (FDM) systems. The design is intended to improve adhesion of dissimilar thermoplastics without the need for chemical compatibilization so that filaments from many different sources can be used effectively. Therefore, there is a need to invent an alternative solution for printing multiple immiscible polymers in an FDM system with the desired adhesion.

Design/methodology/approach

In this study, the authors have developed a bi-extruder for FDM systems which can print two thermoplastics through a single nozzle with a static intermixer to enhance bonding between input materials. The system can also change the composition of extrudates continuously.

Findings

The uniqueness of this extruder is in its easy access to the internal channel so that a static intermixer can be inserted, enabling deposition of mechanically interlocked extrudates composed of two immiscible polymers. Without this intermixer, the bi-extruder extrudes with simple side-by-side co-extrusion having no mechanical interlocking. The bi-extruder was characterized by printing objects using pairs of materials including polylactic acid, acrylonitrile butadiene styrene and high impact polystyrene. Microscope images of the cross-sections of the extrudates confirm the ability of this bi-extruder to control the composition as desired. It was also found that the mechanically interlocked extrudates composed of two immiscible polymers substantially reduces adhesion failures within and between filaments.

Originality/value

In this study, the first-ever FDM extruder with a mechanical blending feature next to the nozzle has been designed and used to successfully print FGM objects with improved mechanical properties.

Details

Rapid Prototyping Journal, vol. 24 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

1 – 10 of over 2000