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Article
Publication date: 2 September 2021

Mahyar Khorasani, AmirHossein Ghasemi, Bernard Rolfe and Ian Gibson

Additive manufacturing (AM) offers potential solutions when conventional manufacturing reaches its technological limits. These include a high degree of design freedom…

Abstract

Purpose

Additive manufacturing (AM) offers potential solutions when conventional manufacturing reaches its technological limits. These include a high degree of design freedom, lightweight design, functional integration and rapid prototyping. In this paper, the authors show how AM can be implemented not only for prototyping but also production using different optimization approaches in design including topology optimization, support optimization and selection of part orientation and part consolidation. This paper aims to present how AM can reduce the production cost of complex components such as jet engine air manifold by optimizing the design. This case study also identifies a detailed feasibility analysis of the cost model for an air manifold of an Airbus jet engine using various strategies, such as computer numerical control machining, printing with standard support structures and support optimization.

Design/methodology/approach

Parameters that affect the production price of the air manifold such as machining, printing (process), feedstock, labor and post-processing costs were calculated and compared to find the best manufacturing strategy.

Findings

Results showed that AM can solve a range of problems and improve production by customization, rapid prototyping and geometrical freedom. This case study showed that 49%–58% of the cost is related to pre- and post-processing when using laser-based powder bed fusion to produce the air manifold. However, the cost of pre- and post-processing when using machining is 32%–35% of the total production costs. The results of this research can assist successful enterprises, such as aerospace, automotive and medical, in successfully turning toward AM technology.

Originality/value

Important factors such as validity, feasibility and limitations, pre-processing and monitoring, are discussed to show how a process chain can be controlled and run efficiently. Reproducibility of the process chain is debated to ensure the quality of mass production lines. Post-processing and qualification of the AM parts are also discussed to show how to satisfy the demands on standards (for surface quality and dimensional accuracy), safety, quality and certification. The original contribution of this paper is identifying the main production costs of complex components using both conventional and AM.

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: 19 June 2007

Wolfgang Hafla, André Buchau, Wolfgang M. Rucker, Andreas Weinläder and Antoni Bardakcioglu

To show for magnetostatic problems, how the numerically expensive post‐processing with the integral equation method (IEM) can be accelerated with the fast multipole method…

Abstract

Purpose

To show for magnetostatic problems, how the numerically expensive post‐processing with the integral equation method (IEM) can be accelerated with the fast multipole method (FMM) and how this approach can be used to generate post‐processing data that allow for drawing streamlines.

Design/methodology/approach

In general, post‐processing with the IEM requires computation of the induced field due to solution variables, the field of permanent magnets and of free currents. For each of the three parts an approach to apply the FMM. With these approaches, large numbers of evaluation points can be used which are needed when streamlines are to be drawn. It is shown that this requires specially tailored meshes.

Findings

Post‐processing time can be largely reduced by applying the FMM. Additional memory requirements are acceptable even for high numbers of evaluation points. In order to obtain streamline breaks at material discontinuities, flat volume elements can be used.

Research limitations/implications

The presented application of the FMM is applicable only to static problems.

Practical implications

Application of the FMM during post‐processing allows for a large number of evaluation points which are often required to visualize electromagnetic fields. This approach in combination with specially tailored meshes allows for drawing of streamlines.

Originality/value

The FMM is used not only to solve the field problem, but also for post‐processing which requires using the FMM to compute induced magnetic fields as well as the field due to permanent magnets and free currents. This leads to a speedup which allows for a large number of evaluation points which can be used, e.g. for high‐precision drawing of streamlines.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 13 December 2018

Joseph Nsengimana, Jacobus Van der Walt, Eujin Pei and Maruf Miah

This paper aims to investigate the effect of post-processing techniques on dimensional accuracy of laser sintering (LS) of Nylon and Alumide® and fused deposition…

Abstract

Purpose

This paper aims to investigate the effect of post-processing techniques on dimensional accuracy of laser sintering (LS) of Nylon and Alumide® and fused deposition modelling (FDM) of acrylonitrile butadiene styrene (ABS) materials.

Design/methodology/approach

Additive manufacturing (AM) of test pieces using LS of Nylon and Alumide® powders, as well as the FDM of ABS materials, were first conducted. Next, post-processing of the test pieces involved tumbling, shot peening, hand finishing, spray painting, CNC machining and chemical treatment. Touch probe scanning of the test pieces was undertaken to assess the dimensional deviation, followed by statistical analysis using Chi-square and Z-tests.

Findings

The deviation ranges of the original built parts with those being subjected to tumbling, shot peening, hand finishing, spray painting, CNC machining or chemical treatment were found to be different. Despite the rounding of sharp corners and the removal of small protrusions, the dimensional accuracy of relatively wide surfaces of Nylon or Alumide® test pieces were not significantly affected by the tumbling or shot peening processes. The immersion of ABS test pieces into an acetone bath produced excellent dimensional accuracy.

Research limitations/implications

Only Nylon PA2200 and Alumide® processed through LS and ABS P400 processed through FDM were investigated. Future work could also examine other materials and using parts produced with other AM processes.

Practical implications

The service bureaus that produce prototypes and end-use functional parts through AM will be able to apply the findings of this investigation.

Originality/value

This research has outlined the differences of post-processing techniques such as tumbling, shot peening, hand finishing, spray painting, CNC machining and chemical treatment. The paper discusses the advantages and disadvantages of each of those methods and suggests that the immersion of ABS test pieces into an acetone bath produced excellent dimensional accuracy.

Details

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

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Article
Publication date: 19 June 2019

Vivek Kumar Tiwary, Arunkumar P., Anand S. Deshpande and Nikhil Rangaswamy

Due to intrinsic limitations, fused deposition modelling (FDM) products suffer from the bad surface finish and inaccurate dimensional accuracies restricting its usage in…

Abstract

Purpose

Due to intrinsic limitations, fused deposition modelling (FDM) products suffer from the bad surface finish and inaccurate dimensional accuracies restricting its usage in many applications. Hence, there is a need for processing polymer patterns before, during and after their productions. This paper aims to highlight the importance of pre- and post-processing treatments on the FDM-based acrylonitrile butadiene styrene patterns improving its surface quality so, that it can be used in rapid investment casting process for making medical implants and other high precision components.

Design/methodology/approach

As a part of pre-processing treatment, the machine parameters affecting the surface quality were identified and optimised using design of experiments. The patterns developed after the first stage of optimisation were given different post-processing treatments, which included vapour smoothening, chemical treatment and sand paper polishing. The results were compared and the best ones were used for making patterns for making medical implants via rapid investment casting technique. The surface quality was checked while the dimensional changes happening during the stages of this hybrid technique were recorded using a three-dimensional optical scanner.

Findings

The surface roughness of the FDM based ABS patterns reduced from 21.63 to 14.40 µm with pre-processing treatments. Chemical treatment (post-processing treatment) turned to be the most suitable technique for reducing the surface roughness further down to 0.30 µm. Medical implants that used these pre- and post-processing treatments gave an average surface roughness of 0.68 µm. Cost and lead time comparisons showed that rapid investment casting technique can be a better method for low volume, customised and with specific requirements.

Originality/value

FDM parts/medical implants produced by rapid investment casting technique suffer from the inferior surface finish and inaccurate dimensional accuracies limiting its applications. A systematic approach to overcome this issue is presented in this research paper. This will directly help the end users and the manufacturers of medical implants, wherein, better surface finish and dimensionally accurate components are expected.

Details

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

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Article
Publication date: 10 October 2018

Trieu Khoa Nguyen and Bong-Kee Lee

The purpose of this paper is to develop a novel post-processing technique of fused deposition modeling (FDM) parts to improve surface roughness and reduce heat absorption…

Abstract

Purpose

The purpose of this paper is to develop a novel post-processing technique of fused deposition modeling (FDM) parts to improve surface roughness and reduce heat absorption and for high-temperature application in thermoforming process.

Design/methodology/approach

The current technique consists of chemical treatment, drying and aluminum coating. First, surface morphology was investigated using FDM specimens with a flat surface. The heat absorption characteristic was also analyzed by Taguchi-based design of experiment and modified lump-capacity model. In addition, dimensional accuracy and uniformity were investigated under high-temperature conditions, which were similar to a typical thermoforming process, with specimens having concave and convex grooves.

Findings

It was verified that the proposed post-processing technique could efficiently improve surface quality of FDM parts with the arithmetic average surface roughness of 2.06 µm. In addition, the coated aluminum layer was found to reflect the heat radiation, resulting into a sufficient reduction of heat absorption. From the investigation of dimensional accuracy and uniformity, it was found that the current technique produced maximum change of 0.11 mm and uniform thickness of an aluminum layer within 0.07 mm.

Originality/value

The present study establishes a novel post-processing technique, enabling to treat the surface of FDM parts for high-temperature applications. It provides a simple way of using typical FDM parts for a thermoforming process as the mold cores. Furthermore, it can be used in other rapid tooling technologies, consequently widening the application areas of FDM.

Details

Rapid Prototyping Journal, vol. 24 no. 7
Type: Research Article
ISSN: 1355-2546

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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

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Article
Publication date: 19 April 2013

Lukas Löber, Christoph Flache, Romy Petters, Uta Kühn and Jürgen Eckert

The purpose of this paper is to compare different post processing techniques for improving the high surface roughness (SR) characteristic of parts generated by selected…

Abstract

Purpose

The purpose of this paper is to compare different post processing techniques for improving the high surface roughness (SR) characteristic of parts generated by selected laser melting (SLM).

Design/methodology/approach

Test parts were built by SLM and their surface was characterized via SEM and optical measurements. The surface of the as‐generated parts was then modified by grinding, sand blasting and electrolytic and plasma polishing to reduce the SR.

Findings

The change of the SR after the different surface treatments was quantified and compared. The effectiveness and usability of the post processing techniques and their combinations were determined. The results indicate that some of the post processes are only usable for simple structures.

Research limitations/implications

The amount of abrasion induced by the different surface treatments was not quantified. A major focus of future work should deal with this issue.

Practical implications

The surface quality of parts with simple geometry can be enhanced by simple methods such as grinding. Complex parts need more advanced techniques, such as electrolytic polishing.

Originality/value

The effect of different post processing techniques for improving the surface roughness of SLM‐generated parts has been analyzed for the first time. This paper can help to improve the SR of parts produced by SLM.

Details

Rapid Prototyping Journal, vol. 19 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 15 November 2018

Dejan Movrin, Ognjan Luzanin and Vera Guduric

This paper aims to propose a vacuum-assisted post-processing method for use in binder jetted technology. The method is based on six key technological parameters and uses…

Abstract

Purpose

This paper aims to propose a vacuum-assisted post-processing method for use in binder jetted technology. The method is based on six key technological parameters and uses standard, commercially available consumables to achieve improvement in tensile strength, as well as the microstructure and porosity of the infiltrated matrix.

Design/methodology/approach

Six key technological parameters were systematically varied as factors on three levels, using design of experiment, i.e. definitive screening design. Surface response methodology was used to optimize the process and yield optimal tensile strength for the given range of input factors. Thus obtained, the optimized factor settings were used in a set of confirmation runs, where the result of optimization was experimentally confirmed. To confirm improvement in microstructure of the infiltrated matrix, SEM analysis was performed, while the reduction of porosity was analyzed using mercury porosimetry.

Findings

The obtained results indicate that, compared to its conventional counterpart, the proposed, optimized infiltration method yields improvement in tensile strength which is significant from both the statistical and engineering point of view, while reducing porosity by 3.5 times, using only standard consumables. Scanning electron microscopy examination of fractured specimens’ micrographs also revealed significant morphological differences between the conventional and proposed method of post-processing. This primarily reflects in higher surface area under hardened epoxy infiltrate, which contributes to increased load capacity of specimen cross-section.

Research limitations/implications

At the present stage of development, the most important limitation of the proposed method is the overall size of models which can be accommodated in standard vacuum impregnation units. Although, in this study, the infiltration method did not prove statistically significant, further investigation is required with models of complex geometry, various sizes and mass arrangements, where infiltration would be more challenging and could possibly result in different findings.

Practical implications

The most important practical implication of this study is the experimentally verified result of optimization, which showed that tensile strength and matrix microstructure can be significantly improved, using just standard consumables.

Social implications

Improved strength contributes to reduction of material consumption, which, in a longer run, can be beneficial for environment protection and sustainable development.

Originality/value

Based on literature review, there have been no previous investigations which studied the tensile strength of infiltrated specimens through design of experiment, which involved specimen preheating temperature, level and duration of vacuum treatment of infiltrate mixture and infiltrated specimens and infiltration method.

Details

Rapid Prototyping Journal, vol. 25 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 18 April 2017

Jasgurpreet Singh Chohan and Rupinder Singh

The purpose of this paper is to review the various pre-processing and post-processing approaches used to ameliorate the surface characteristics of fused deposition…

Abstract

Purpose

The purpose of this paper is to review the various pre-processing and post-processing approaches used to ameliorate the surface characteristics of fused deposition modelling (FDM)-based acrylonitrile butadiene styrene (ABS) prototypes. FDM being simple and versatile additive manufacturing technique has a calibre to comply with present need of tailor-made and cost-effective products with low cycle time. But the poor surface finish and dimensional accuracy are the primary hurdles ahead the implementation of FDM for rapid casting and tooling applications.

Design/methodology/approach

The consequences and scope of FDM pre-processing and post-processing parameters have been studied independently. The comprehensive study includes dominance, limitations, validity and reach of various techniques embraced to improve surface characteristics of ABS parts. The replicas of hip implant are fabricated by maintaining the optimum pre-processing parameters as reviewed, and a case study has been executed to evaluate the capability of vapour smoothing process to enhance surface finish.

Findings

The pre-processing techniques are quite deficient when different geometries are required to be manufactured within limited time and required range of surface finish and accuracy. The post-processing techniques of surface finishing, being effective disturbs the dimensional stability and mechanical strength of parts thus incapacitates them for specific applications. The major challenge for FDM is the development of precise, automatic and controlled mass finishing techniques with low cost and time.

Research limitations/implications

The research assessed the feasibility of vapour smoothing technique for surface finishing which can make consistent castings of customized implants at low cost and shorter lead times.

Originality/value

The extensive research regarding surface finish and dimensional accuracy of FDM parts has been collected, and inferences made by study have been used to fabricate replicas to further examine advanced finishing technique of vapour smoothing.

Details

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

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Article
Publication date: 1 June 1995

Mukesh Agarwala, David Bourell, Joseph Beaman, Harris Marcus and Joel Barlow

Gives a brief overview of post‐processing of selective laser sintered (SLS) metal parts to improve structural integrity and/or to induce a material transformation…

Abstract

Gives a brief overview of post‐processing of selective laser sintered (SLS) metal parts to improve structural integrity and/or to induce a material transformation. Presents results which show the effect of post‐processing liquid phase sintering temperature and time on material properties. Describes the hot isostatic pressing process, and discusses its application to SLS metal parts. Results gained from using this process show that it is suitable for achieving almost full‐density parts.

Details

Rapid Prototyping Journal, vol. 1 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

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