Search results

1 – 10 of over 1000
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…

1437

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 which can…

4703

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: 1 August 2002

Hongkyu Kwon, Satish Bukkapatnam, Behrokh Khoshnevis and Jason Saito

This paper presents the experimentation and modeling efforts at the University of Southern California, Los Angeles, to study the material flow patterns in the extrusion and…

1028

Abstract

This paper presents the experimentation and modeling efforts at the University of Southern California, Los Angeles, to study the material flow patterns in the extrusion and deposition stages of the Contour Crafting (CC) process. A preliminary finite element analysis (FEA) was conducted for extrusion and deposition mechanisms of CC with ceramic materials (e.g. clay) as the fabrication material. Using the FEA simulations, certain basic understandings of the effect of extrusion orifice geometry on the performance of CC were derived. A square orifice was found to be aptly suited, both in terms of delivering excellent fusion between layers as well as creating the desired external surface profile. The experimental observations support these results.

Details

Rapid Prototyping Journal, vol. 8 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

Content available
Article
Publication date: 29 May 2007

225

Abstract

Details

Anti-Corrosion Methods and Materials, vol. 54 no. 3
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 15 November 2018

Leander Schmidt, Klaus Schricker, Jean Pierre Bergmann, Felix Hussenöder and Mathias Eiber

This study aims to characterize the suitability of a direct extrusion process in the fused layer manufacturing (FLM)-method under processing of granulated plastics.

Abstract

Purpose

This study aims to characterize the suitability of a direct extrusion process in the fused layer manufacturing (FLM)-method under processing of granulated plastics.

Design/methodology/approach

In this paper, a granulate-based direct extrusion system in the FLM method is presented. This system is characterized with respect to the strand deposition mechanism and resulting component properties (geometrically and mechanically).

Findings

The extruder output could be identified as a linear relation between the applied extruder speed and the resulting mass flow. A developed model for the material and temperature-dependent strand deposition process was validated under experimental investigations. Further, it was possible to define process windows to realize desired strand widths and strand heights. In addition, analyses were conducted to determine the tensile strength transversely to the orientation of the layer plane.

Research limitations/implications

The extrusion system was characterized under the processing of materials ABS Magnum 8434 and PLA Ingeo 4043D. Due to the restricted choice of materials, further investigations are planned under an extension of the test materials. Furthermore, the degree of the geometric complexity of the test components should be increased to finally characterize the process.

Originality/value

By means of the characterization of the direct extrusion system, it is possible for users to classify the process and to use the process in specific application areas. In comparison to filament-based extrusion systems, significant advantages can be achieved by means of direct extrusion. These include, for example, the use of less expensive work materials (by factor >10), the use of existing test certificates and the advantage of higher mechanical properties. This makes it possible to meet modern product requirements and to produce competitive components.

Details

Rapid Prototyping Journal, vol. 25 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 August 1998

Jaroslav Mackerle

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, powder…

4528

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, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/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 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.

Details

Engineering Computations, vol. 15 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 10 February 2022

Hassan Araman and Yahya Saleh

This paper aims to investigate the sources of variation in aluminum profiles hot extrusion process for the purpose of process capability improvement at National Aluminum and…

1923

Abstract

Purpose

This paper aims to investigate the sources of variation in aluminum profiles hot extrusion process for the purpose of process capability improvement at National Aluminum and Profiles Company (NAPCO) in Palestine. The critical-to-quality characteristics (CTQ) have been determined as base variables to measure the process capability.

Design/methodology/approach

The DMAIC (Define, Measure, Analyze, Improve, and Control) Lean Six Sigma (LSS) approach has been adopted to conduct this study. More specifically, historical data analysis and PARETO charts have been employed. The defects' root causes have been determined using the cause-and-effect diagram and decision matrix. A course of suggested actions has been established to help in improving extrusion process capability. Minitab-18 software was used for conducting inferential statistical analysis. A case study considering a geometry CTQ of D3 dimension of bottom sash aluminum profiles 4,332 was selected for analysis.

Findings

The results indicated a reduction in DPMO from 89,649 to 15,659, sigma level was improved from 2.84 to 3.65, process yield was improved from 91.04% to 98.43% and cost was reduced from U$75,972 to U$13,250.9 (i.e. a saving of U$62,721). Studying and improving the sigma level of the extrusion process would yield fewer defective products and consequently fewer customer complaints. A validation process which has been conducted during the year 2019 showed a consistent improvement that aligns with the first stage of improvement made on October 1, 2018.

Research limitations/implications

This study focuses on only one critical quality characteristic (CTQ), namely, a geometry CTQ of D3 dimension of bottom sash aluminum profiles 4,332 produced by NAPCO was selected for analysis.

Practical implications

This study would be useful for researchers and practitioners to improve the process capability in aluminum profiles manufacturing industries in general and hot extrusion processes in particular.

Originality/value

Many previous studies on applying LSS-DMAIC methodology have been conducted in aluminum industries in developed countries. According to the literature, it is highly recommended to have more case studies of applying LSS-DMAIC in different industries in developing countries. NAPCO is the only aluminum manufacturing plant in Palestine that hotly extrudes and coats aluminum profiles. Hence, the present study is the first of its kind in NAPCO and in Palestine. Projecting the assessment of the impact of process improvement opportunities and capability analyses into monetary measures are also innovative.

Details

The TQM Journal, vol. 35 no. 2
Type: Research Article
ISSN: 1754-2731

Keywords

Article
Publication date: 20 March 2017

Morteza Vatani and Jae-Won Choi

This work aims to present a guideline for ink development used in extrusion-based direct-write (DW) (also referred to as direct-print [DP]) technique and combine the extrusion…

1156

Abstract

Purpose

This work aims to present a guideline for ink development used in extrusion-based direct-write (DW) (also referred to as direct-print [DP]) technique and combine the extrusion with instant photopolymerization to present a solvent-free DP photopolymerization (DPP) method to fill the gap between 3D printing and printing multi-functional 3D structures.

Design/methodology/approach

A DP process called DPP was developed by integration of a screw-driven micro-dispenser into XYZ translation stages. The process was equipped with direct photopolymerization to facilitate the creation of 3D structures. The required characteristics of inks used in this technique were simulated through dispersion of fumed silica particles into photocurable resins to transform them into viscoelastic inks. The characterization method of these inks and the required level of shear thinning and thixotropic properties is presented.

Findings

Shear thinning and thixotropic properties are necessary components of the inks used in DPP process and other DP techniques. These properties are desirable to facilitate printing and filament shape retention. Extrusion of viscoelastic inks out of a nozzle generates a filament capable of retaining its geometry. Likewise, instant photopolymerization of the dispensed filaments prevents deformation due to the weight of filaments or accumulated weight of layers.

Originality/value

The DPP process with material-reforming methods has been shown, where there remain many shortcomings in realizing a DP-based 3D printing process with instant photopolymerization in existing literature, as well as a standard guideline and material requirements. The suggested method can be extended to develop a new commercial 3D printing system and printable inks to create various functional 3D structures including sensors, actuators and electronics, where nanoparticles are involved for their functionalities. Particularly, an original contribution to the determination of a rheological property of an ink is provided.

Details

Rapid Prototyping Journal, vol. 23 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 15 November 2019

Jie Leng, Junjie Wu, Ning Chen, Xiang Xu and Jie Zhang

This paper aims to develop an integrated and portable desktop 3D printer using direct extruding technology to expand applied material field. Different from conventional fused…

Abstract

Purpose

This paper aims to develop an integrated and portable desktop 3D printer using direct extruding technology to expand applied material field. Different from conventional fused deposition modeling (FDM) which uses polymer filaments as feedstock, the developed system can fabricate products directly using polymer pellets. And its printing properties are also investigated.

Design/methodology/approach

A conical screw-based extrusion deposition (CSBED) system was developed with a large taper conical screw to plasticize and extrude fed materials. The 3D printer was developed with assistance of precision positioning and controlling system. Biocompatible thermoplastic polyurethane (TPU) pellets were selected as raw materials for experiments. The influences of four processing parameters: nozzle temperature, fill vector orientation, layer thickness and infill density on the product’s internal structure and tensile properties were investigated.

Findings

It is concluded that the customized system has a high manufacturing accuracy with a diminutive global size and is suitable for printing soft materials such as TPU. Theoretical calculation shows the developed conical screw is more effective in plasticizing and extruding compared with conventional screw. Printed samples can achieve applicable tensile properties under harmonious parameter cooperation. Deposited materials are found to have voids among adjacent roads under unbefitting parameters.

Originality/value

The developed system efficiently improves material limitations compared to commercial FDM systems and exhibits great potential in medical field because soft materials such as biocompatible TPU pellets can be directly used.

Details

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

Keywords

Article
Publication date: 30 July 2019

Jianzhong Shang, Xin Li, Zhuo Wang, Rong Wang and Hong Zhu

This study aims to investigate rheological and extrusion behavior of thermosetting epoxy resins, which to find the universal property and printing parameters for extrusion-based…

Abstract

Purpose

This study aims to investigate rheological and extrusion behavior of thermosetting epoxy resins, which to find the universal property and printing parameters for extrusion-based rapid prototyping applications.

Design/methodology/approach

The thickener proportion greatly influences its viscosity and rheological behavior and therefore plays an important role in the shape of the cross-section of the extrudate.

Findings

A pseudoplastic (shear-thinning) is a basic requirement for obtaining extruded lines with plump cross-sections. In addition to the effects of the rheological behavior of the composite, shape maintenance and its wettability on the substrate, the cross-sectional geometry of the extrudate is also strongly affected by printing process parameters including the extrusion nozzle height, nozzle moving speed, extrusion rate and critical nozzle height. Proper combinations of these process parameters are necessary to obtain single-line extrudates with plump cross-sections and 3-D objects with dimensional accuracy, uniform wall thickness, good wall uprightness and no wall slumping. Formulas and procedures for determining these extrusion parameters are proposed and demonstrated in experiments.

Originality/value

The results obtained have been explained in terms of the interactions among the rheological properties of the composite, the shear rate imposed on the composite during extrusion, the wettability of the composite on the substrate and the shape maintenance of the composite during extrusion.

Details

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

Keywords

1 – 10 of over 1000