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Article
Publication date: 1 October 2001

K.W. Dalgarno

This paper is a summary of the session topic “Production grade tooling via rapid manufacture” which was part of the Internet conference on the future of RP which ran from December…

933

Abstract

This paper is a summary of the session topic “Production grade tooling via rapid manufacture” which was part of the Internet conference on the future of RP which ran from December 2000 to February 2001, hosted at Rapid‐Discussion.comTM. The original position paper which was used to prompt discussion is reported. Three major discussion topics emerged: other layer manufacture based tool manufacturing techniques, finishing/accuracy, and economics. It is concluded that in order to develop a bigger market for production grade tooling manufactured using layer manufacture techniques two things are required: technical developments, notably with regard to accuracy, surface finish, and durability; and an increased awareness of the economics of volume manufacture and of the importance of tooling within that economic framework.

Details

Rapid Prototyping Journal, vol. 7 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 20 March 2017

Stephen Oluwashola Akande, Kenny Dalgarno and Javier Munguia

The purpose of this research is to determine what tests can be most useful in quality assurance and control when using fused filament fabrication (FFF) 3D printing machines. The…

629

Abstract

Purpose

The purpose of this research is to determine what tests can be most useful in quality assurance and control when using fused filament fabrication (FFF) 3D printing machines. The quality of the bond between layers is critical for the structural integrity of the fused filament fabricated parts.

Design/methodology/approach

Therefore, to determine the influence of process parameters on the quality of parts’ tensile, flexural, notched and un-notched impact, test specimens were fabricated in polylactic acid (PLA) using FFF with different layer thicknesses, fill densities, orientation and print speeds. The mechanical properties were then assessed along with the accuracy and mass of the samples.

Findings

It is concluded that a notched impact test gives a measure of interlayer bond strength which can be used across build styles to track machine performance, and that this, together with the mass and dimensions of the impact-test specimens, offers an appropriate set of tests capable of tracking the mechanical properties of parts produced using the FFF technique.

Originality/value

Therefore, this research finding will be of value in benchmarking FFF machines for quality parts fabrications.

Details

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

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Article
Publication date: 1 September 2004

K.W. Dalgarno and R.D. Goodridge

This paper reports the results of a compression test benchmarking study carried out to investigate the mechanical properties of layer manufactured metal components in order to…

917

Abstract

This paper reports the results of a compression test benchmarking study carried out to investigate the mechanical properties of layer manufactured metal components in order to assess their suitability in load bearing applications. Compression tests were carried out on the DTM LaserForm ST‐100 material, ARCAM processed H13 tool steel, EOS DirectSteel (50 μm), and the ProMetal material. It is concluded that the LaserForm ST‐100 material, the ARCAM H13 tool steel material, and the ProMetal material all exhibit responses to compressive loads which make them suitable for use in load bearing situations, whilst the EOS DirectSteel (50 μm) exhibits a small permanent set in compression, making it less suitable in these situations.

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Rapid Prototyping Journal, vol. 10 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 5 October 2010

Ismet Ilyas, Chris Taylor, Kenny Dalgarno and John Gosden

The purpose of this paper is to report on the use of a combination of indirect selective laser sintering (SLS) and machining processes to create injection mould tools, an approach…

4271

Abstract

Purpose

The purpose of this paper is to report on the use of a combination of indirect selective laser sintering (SLS) and machining processes to create injection mould tools, an approach designed to offer the capability to create conformal cooling channels in the core/cavity inserts together with the levels of surface finish and accuracy required to meet typical injection mould tool specifications.

Design/methodology/approach

The research has been pursued through three industrial case studies. In each study, existing injection mold inserts have been redesigned to give a conformally cooled tool. These have then been manufactured using indirect SLS, high‐speed machining, electro‐discharge machining and polishing. The inserts have been evaluated in industrial trials to assess their performance in terms of cycle time, energy usage, durability and quality. The insights gained from the three case studies have then been developed into a series of design rules, which may be applied in the development of tooling for new applications.

Findings

The results show that significant productivity improvements and energy use reductions in injection moulding are possible through the implementation of conformal cooling, and that the material has sufficient wear resistance to be used in production applications. However, it is recommended that modelling is always used to understand the impact of conformal cooling channels, and manufacture is carefully planned to ensure that the required internal geometry is created.

Originality/value

The paper presents new results on the impact of conformal cooling on the productivity and energy efficiency of injection moulding, and on the durability of the indirect SLS material in injection moulding applications. A novel “cut‐out volume” technique for powder clearing is also presented, along with a set of design rules to support further application of the work.

Details

Rapid Prototyping Journal, vol. 16 no. 6
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 August 2001

Kenny Dalgarno and Todd Stewart

Presents procedures which were developed for the manufacture of production tooling using the DTM RapidSteel process, and on the methodology adopted in the generation of the…

1140

Abstract

Presents procedures which were developed for the manufacture of production tooling using the DTM RapidSteel process, and on the methodology adopted in the generation of the procedures. Accuracy and surface finish, the manufacturability of small features, unsupported features, and mechanical strength have all been investigated, as has the capability of the process for generating conformal cooling channels. An overall tool design and manufacture process is presented, and it is concluded that the DTM RapidSteel process is capable of generating conformally cooled production specification tooling, provided that it is accepted that finishing will be required, and that there are limits on small feature manufacture.

Details

Rapid Prototyping Journal, vol. 7 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 21 March 2016

Alkhair Almabrouk Mousa

This paper aims to investigate the curling behaviour of selective laser sintered polyamide/glass bead composites with changes in material compositions, part bed temperature…

932

Abstract

Purpose

This paper aims to investigate the curling behaviour of selective laser sintered polyamide/glass bead composites with changes in material compositions, part bed temperature, powder base thickness, laser power and layer cooling time.

Design/methodology/approach

The Taguchi parameter design method (design of experiments, DOE) and analysis of variance (ANOVA) technique were applied in the investigation to determine the optimal process parameter settings.

Findings

The results of statistical analysis and ANOVA provided evidence for the effectiveness of filler content and its surface treatment on reducing the amount of curling.

Research limitations/implications

Warping and curling phenomena is one of several aspects of this work that can be pursued further. The present investigation could be expanded to explore other fillers and interface adhesion using other modifiers. Experiments could be conducted with other complicated geometries, various sizes, different positions and locations to widen the knowledge base of geometric accuracy of selective laser sintering process.

Practical implications

This experimental work is beneficial for materials development and accuracy characterisation in rapid manufacturing techniques. The experimental techniques adopted are readily transferable to virtually any material system used in rapid manufacturing.

Originality/value

Although many materials have been developed, there is still a need for research into new materials. This work demonstrates that it is possible to improve the geometric accuracy of selective laser sintered components from glass bead- filled polyamide 12 and achieve near-zero curling by adding rigid multiphase-coated particle to the material system.

Details

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

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Article
Publication date: 25 September 2009

C.Z. Yan, Y.S. Shi, J.S. Yang and J.H. Liu

The purpose of this paper is to report a new method, the dissolution‐precipitation process, to prepare nylon‐coated metal powders for the indirect selective laser sintering (SLS…

978

Abstract

Purpose

The purpose of this paper is to report a new method, the dissolution‐precipitation process, to prepare nylon‐coated metal powders for the indirect selective laser sintering (SLS) process.

Design/methodology/approach

The nylon‐12 coated carbon steel powders were prepared by the dissolution‐precipitation process. The powder characteristics are examined by scanning electron microscope (SEM) and laser diffraction particle size analysis. The effect of the applied laser energy density on the three‐point bend strength and dimensional accuracy of the SLS specimens are studied. The influence of nylon‐12 content on the bend strength are also investigated.

Findings

The SEM and laser diffraction particle size analysis results indicate that the steel particles are well coated by nylon‐12 resin. The bend strength of the SLS specimens increases with increasing the applied energy density until it reaches a maximum value, and then further increasing energy density will cause the decrease in the bend strength. The bend strength of the SLS specimens increases with increasing the nylon‐12 content over the investigated range. The dimensional errors in the XY‐and Z‐directions are all increased with the increase in energy density.

Research limitations/implications

This paper only concerns the preparation and SLS of the coated powders. Further investigations are planned into post‐processing, such as binder decomposition and high‐temperature sintering, of the green parts made from the coated powders.

Originality/value

This paper provides a useful method for preparing nylon‐coated metal powders for making metal parts by the indirect SLS process.

Details

Rapid Prototyping Journal, vol. 15 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 December 2005

R. Shivpuri, X. Cheng, K. Agarwal and S. Babu

To investigate the ProMetal 3D printing technique for its application to dies, for low volume hot forging of 7075 aluminum helicopter parts.

1822

Abstract

Purpose

To investigate the ProMetal 3D printing technique for its application to dies, for low volume hot forging of 7075 aluminum helicopter parts.

Design/methodology/approach

Thermo‐mechanical and tribological behavior of the ProMetal 3D printed tools were characterized by hot upset and ring tests. Finite element simulations of the test application were conducted using special purpose metal forming simulation software FORGE3. Results obtained from the tests along with finite element analysis were used to validate behavior of the printed dies during forging trials.

Findings

ProMetal‐printed materials exhibited relatively low thermal conductivity and high friction. Cavities were printed, machined and evaluated in hot forging trials. Dies exhibited substantial settling during the manufacturing (3D printing) process. Some collapse of dies was also observed at locations where forging pressures were high.

Practical implications

After initial plastic settling, the printed dies provide satisfactory part tolerance for die temperatures and pressures up to 338°C and 689 MPa, respectively. Low thermal conductivity observed indicate a potential to forge aluminum with cooler dies. Coating or secondary polishing is necessary to achieve acceptable surface finish for forging of aluminum.

Originality/value

This paper demonstrates a need in RP industry to methodically match capabilities of the rapid prototyping process to the needs of the intended application through the use of finite element method and some fundamental characterization.

Details

Rapid Prototyping Journal, vol. 11 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 September 1999

Jaroslav Mackerle

This paper gives a review of the finite element techniques (FE) applied in the analysis and design of machine elements; bolts and screws, belts and chains, springs and dampers…

4388

Abstract

This paper gives a review of the finite element techniques (FE) applied in the analysis and design of machine elements; bolts and screws, belts and chains, springs and dampers, brakes, gears, bearings, gaskets and seals are handled. 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 this 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 the analysis/design of machine elements for 1977‐1997.

Details

Engineering Computations, vol. 16 no. 6
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 5 June 2007

L‐E. Rännar, A. Glad and C‐G. Gustafson

The purpose of this paper is to present a comparative study, regarding cooling time and dimensional accuracy, of conventional injection mold cooling channel layouts, using…

3540

Abstract

Purpose

The purpose of this paper is to present a comparative study, regarding cooling time and dimensional accuracy, of conventional injection mold cooling channel layouts, using straight holes and a baffle, and free‐form fabricated (FFF) layout, manufactured by the direct‐metal rapid tooling (RT) method electron beam melting (EBM). Many other methods have been proven useful for RT, but the authors have not found any publications where EBM has been used to manufacture injection molding tools.

Design/methodology/approach

A test part was designed in order to replicate a common and important issue: inadequate cooling in deep cores. The part and the different cooling layouts were analyzed in an injection molding simulation software and the numerical results were compared with corresponding experimental results.

Findings

The analyses showed an improvement in both cooling time and dimensional accuracy in favor of conformal FFF cooling channels manufactured by EBM. The experimental results correlate well with the numerical tests, however with some discrepancies.

Research limitations/implications

The results presented are based on the direct‐metal RT method EBM, and they were obtained using a specific test part.

Originality/value

This paper can be a useful aid when designing mold tools and especially when considering the usage of FFF cooling channels versus conventional cooling design. It can also serve as a reference when comparing the efficiency in terms of cooling time and dimensional accuracy between different layouts.

Details

Rapid Prototyping Journal, vol. 13 no. 3
Type: Research Article
ISSN: 1355-2546

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