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Article
Publication date: 10 July 2020

Swapnil Vyavahare, Shailendra Kumar and Deepak Panghal

This paper aims to focus on an experimental study of surface roughness, dimensional accuracy and time of fabrication of parts produced by fused deposition modelling (FDM…

Abstract

Purpose

This paper aims to focus on an experimental study of surface roughness, dimensional accuracy and time of fabrication of parts produced by fused deposition modelling (FDM) technique of additive manufacturing. The fabricated parts of acrylonitrile butadiene styrene (ABS) material have pyramidal and conical features. Influence of five process parameters of FDM, namely, layer thickness, wall print speed, build orientation, wall thickness and extrusion temperature is studied on response characteristics. Furthermore, regression models for responses are developed and significant process parameters are optimized.

Design/methodology/approach

Comprehensive experimental study is performed using response surface methodology. Analysis of variance is used to investigate the influence of process parameters on surface roughness, dimensional accuracy and time of fabrication in both outer pyramidal and inner conical regions of part. Furthermore, a multi-response optimization using desirability function is performed to minimize surface roughness, improve dimensional accuracy and minimize time of fabrication of parts.

Findings

It is found that layer thickness and build orientation are significant process parameters for surface roughness of parts. Surface roughness increases with increase in layer thickness, while it decreases initially and then increases with increase in build orientation. Layer thickness, wall print speed and build orientation are significant process parameters for dimensional accuracy of FDM parts. For the time of fabrication, layer thickness and build orientation are found as significant process parameters. Based on the analysis, statistical non-linear quadratic models are developed to predict surface roughness, dimensional accuracy and time of fabrication. Optimization of process parameters is also performed using desirability function.

Research limitations/implications

The present study is restricted to the parts of ABS material with pyramidal and conical features only fabricated on FDM machine with delta configuration.

Originality/value

From the critical review of literature it is found that some researchers have made to study the influence of few process parameters on surface roughness, dimensional accuracy and time of fabrication of simple geometrical parts. Also, regression models and optimization of process parameters has been performed for simple parts. The present work is focussed on studying all these aspects in complicated geometrical parts with pyramidal and conical features.

Details

Rapid Prototyping Journal, vol. 26 no. 9
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 28 May 2021

Supphachai Nathaphan and Worrasid Trutassanawin

This work aims to investigate the interaction effects of printing process parameters of acrylonitrile butadiene styrene (ABS) parts fabricated by fused deposition modeling…

Abstract

Purpose

This work aims to investigate the interaction effects of printing process parameters of acrylonitrile butadiene styrene (ABS) parts fabricated by fused deposition modeling (FDM) technology on both the dimensional accuracy and the compressive yield stress. Another purpose is to determine the optimum process parameters to achieve the maximum compressive yield stress and dimensional accuracy at the same time.

Design/methodology/approach

The standard cylindrical specimens which produced from ABS by using an FDM 3D printer were measured dimensions and tested compressive yield stresses. The effects of six process parameters on the dimensional accuracy and compressive yield stress were investigated by separating the printing orientations into horizontal and vertical orientations before controlling five factors: nozzle temperature, bed temperature, number of shells, layer height and printing speed. After that, the optimum process parameters were determined to accomplish the maximum compressive yield stress and dimensional accuracy simultaneously.

Findings

The maximum compressive properties were achieved when layer height, printing speed and number of shells were maintained at the lowest possible values. The bed temperature should be maintained 109°C and 120°C above the glass transition temperature for horizontal and vertical orientations, respectively.

Practical implications

The optimum process parameters should result in better FDM parts with the higher dimensional accuracy and compressive yield stress, as well as minimal post-processing and finishing techniques.

Originality/value

The important process parameters were prioritized as follows: printing orientation, layer height, printing speed, nozzle temperature and bed temperature. However, the number of shells was insignificant to the compressive property and dimensional accuracy. Nozzle temperature, bed temperature and number of shells were three significant process parameters effects on the dimensional accuracy, while layer height, printing speed and nozzle temperature were three important process parameters influencing compressive yield stress. The specimen fabricated in horizontal orientation supported higher compressive yield stress with wide processing ranges of nozzle and bed temperatures comparing to the vertical orientation with limited ranges.

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Article
Publication date: 22 August 2017

Parlad Kumar Garg, Rupinder Singh and IPS Ahuja

The purpose of this paper is to optimize the process parameters to obtain the best dimensional accuracy, surface finish and hardness of the castings produced by using…

Abstract

Purpose

The purpose of this paper is to optimize the process parameters to obtain the best dimensional accuracy, surface finish and hardness of the castings produced by using fused deposition modeling (FDM)-based patterns in investment casting (IC).

Design/methodology/approach

In this paper, hip implants have been prepared by using plastic patterns in IC process. Taguchi design of experiments has been used to study the effect of six different input process parameters on the dimensional deviation, surface roughness and hardness of the implants. Analysis of variance has been used to find the effect of each input factor on the output. Multi-objective optimization has been done to find the combined best values of output.

Findings

The results proved that the FDM patterns can be used successfully in IC. A wax coating on the FDM patterns improves the surface finish and dimensional accuracy. The improved dimensional accuracy, surface finish and hardness have been achieved simultaneously through multi-objective optimization.

Research limitations/implications

A thin layer of wax is used on the plastic patterns. The effect of thickness of the layer has not been considered. Further research is needed to study the effect of the thickness of the wax layer.

Practical implications

The results obtained by the study would be helpful in making decisions regarding machining and/or coating on the parts produced by this process.

Originality/value

In this paper, multi-objective optimization of dimensional accuracy, surface roughness and hardness of hybrid investment cast components has been performed.

Details

Rapid Prototyping Journal, vol. 23 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

Content available
Article
Publication date: 27 June 2019

Younss Ait Mou and Muammer Koc

This paper aims to report on the findings of an investigation to compare three different three-dimensional printing (3DP) or additive manufacturing technologies [i.e…

Abstract

Purpose

This paper aims to report on the findings of an investigation to compare three different three-dimensional printing (3DP) or additive manufacturing technologies [i.e. fused deposition modeling (FDM), stereolithography (SLA) and material jetting (MJ)] and four different equipment (FDM, SLA, MJP 2600 and Object 260) in terms of their dimensional process capability (dimensional accuracy and surface roughness). It provides a comprehensive and comparative understanding about the level of attainable dimensional accuracy, repeatability and surface roughness of commonly used 3DP technologies. It is expected that these findings will help other researchers and industrialists in choosing the right technology and equipment for a given 3DP application.

Design/methodology/approach

A benchmark model of 5 × 5 cm with several common and challenging features, such as around protrusion and hole, flat surface, micro-scale ribs and micro-scale long channels was designed and printed repeatedly using four different equipment of three different 3DP technologies. The dimensional accuracy of the printed models was measured using non-contact digital measurement methods. The surface roughness was evaluated using a digital profilometer. Finally, the surface quality and edge sharpness were evaluated under a reflected light ZEISS microscope with a 50× magnification objective.

Findings

The results show that FDM technology with the used equipment results in a rough surface and loose dimensional accuracy. The SLA printer produced a smoother surface, but resulted in the distortion of thin features (<1 mm). MJ printers, on the other hand, produced comparable surface roughness and dimensional accuracy. However, ProJet MJP 3600 produced sharper edges when compared to the Objet 260 that produced round edges.

Originality/value

This paper, for the first time, provides a comprehensive comparison of three different commonly used 3DP technologies in terms of their dimensional capability and surface roughness without farther post-processing. Thus, it offers a reliable guideline for design consideration and printer selection based on the target application.

Details

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

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Article
Publication date: 12 March 2018

Azadeh Haghighi and Lin Li

Quantifying and controlling the quality characteristics of parts produced by additive manufacturing (AM) processes has attracted significant interest in the research…

Abstract

Purpose

Quantifying and controlling the quality characteristics of parts produced by additive manufacturing (AM) processes has attracted significant interest in the research community. However, to increase the sustainability of AM processes, such quality characteristics need to be assessed together with life cycle performance of AM processes such as energy and material consumption and manufacturing cost. Although a few studies have been performed for several quality characteristics, i.e. surface roughness and tensile strength, the relationship between dimensional performance and manufacturing cost is still not well known for AM processes.

Design/methodology/approach

In this paper, a comprehensive study of the dimensional performance and manufacturing cost of fused deposition modeling AM process is performed. Design of experiment technique is used, and the correlation of different cost components and the dimensional accuracy of parts are statistically studied.

Findings

The optimum process parameters for simultaneously optimizing the dimensional performance and manufacturing cost are identified. The analysis shows that as opposed to traditional manufacturing processes, obtaining a better dimensional performance is not necessarily associated with higher cost in the AM processes.

Originality/value

Almost no study and analysis for the combined dimensional performance and manufacturing cost has been performed for AM processes in the literature. It is known that within the context of traditional manufacturing processes, a natural trade-off governs the pursuit of higher dimensional performance and the manufacturing cost. However, as the AM process has a different nature compared with traditional manufacturing processes, the relationship between manufacturing cost and dimensional performance of parts has to be studied. Understanding this relationship will also help to establish a cost-optimal and sustainable tolerance allocation strategy in assemblies with AM components.

Details

Rapid Prototyping Journal, vol. 24 no. 2
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 July 2001

Garry D. Coleman, C. Patrick Koelling and E. Scott Geller

This paper addresses the problem of using accuracy index values based on the squared difference between participant scores and true scores, the D2 index, at the practical…

Abstract

This paper addresses the problem of using accuracy index values based on the squared difference between participant scores and true scores, the D2 index, at the practical level. It clarifies ambiguity existing in the literature regarding the use of these index values to evaluate the scoring accuracy of human raters (evaluators). The paper critically investigates the effect of frame‐of‐reference (FOR) training on improving the accuracy of third‐party evaluators’ scores for organisations, such as those going through the Malcolm Baldrige National Quality Award (MBNQA) self‐assessment exercise. It discusses a case study where 90 individual participants took part. The scores of these participants were recorded before training was given to them (no training) and after receiving FOR training. The study showed that providing FOR training has an effect on improving the elevation accuracy index (p < 0.05) in five of the seven categories used in this exercise. An observed leniency effect was also reduced. However, no improvement in the DA was observed. Thus, the evaluators’ ability to assign an accurate overall score was improved, while the ability to discriminate between relative strengths and weaknesses did not show improvement. This implies evaluator training, particularly for heterogeneous pools of volunteers like those of corporate and state and local quality awards, should include more content on the performance dimensions.

Details

International Journal of Quality & Reliability Management, vol. 18 no. 5
Type: Research Article
ISSN: 0265-671X

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Article
Publication date: 1 January 2006

D. Dimitrov, W. van Wijck, K. Schreve and N. de Beer

The research was undertaken to characterise the three dimensional printing (3DP) process in term of the achievable dimensional and geometric accuracy.

Abstract

Purpose

The research was undertaken to characterise the three dimensional printing (3DP) process in term of the achievable dimensional and geometric accuracy.

Design/methodology/approach

New benchmark models were developed that represent characteristics needing to be investigated. The parts were fabricated in different materials. A program was written to measure the features on a numerically controlled coordinate measurement machine. Finally, a statistical analysis was done. The results are reported in terms of statistical parameters and international tolerance (IT) grades.

Findings

The paper provides general IT grades of the 3DP process for parts printed using different materials (powders).

Research limitations/implications

The research is limited to specific materials and equipment.

Practical implications

The data is very useful for designing products to be manufactured on 3DP machines applying either direct or indirect methods.

Originality/value

3DP is more and more used for rapid prototyping with great potential towards rapid manufacturing. Designers need to know the capability profile of the process they are going to use. There is a significant lack of published data on the 3DP process characteristics. This research was conducted to fill this gap and provide much needed accuracy information.

Details

Rapid Prototyping Journal, vol. 12 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 14 December 2018

Tomaz Brajlih, Urska Kostevsek and Igor Drstvensek

One of the main problems of selective laser sintering (SLS) manufacturing process is the dimensional accuracy of products. Main causes of dimensional deviations are…

Abstract

Purpose

One of the main problems of selective laser sintering (SLS) manufacturing process is the dimensional accuracy of products. Main causes of dimensional deviations are material shrinkage and size of laser heat affected zone (LHAZ). This paper aims to present a new method of adapting SLS manufacturing shrinkage and LHAZ compensation parameters to the geometrical characteristics of processed parts to improve their accuracy.

Design/methodology/approach

The first part of this work presents a hypothesis asserting that the shrinkage and the LHAZ size depend on geometrical properties of products. A method that defines geometrical properties by numerical influence factors is described in the continuation. A multi-factorial experiment with adaptable test part is set up. Then, test builds are manufactured on an SLS machine and measured with a three-dimensional optical scanner. Afterwards, the results are analysed in relation to the presumed hypothesis.

Findings

The analysis of variance of multi-factorial experiment proves the hypothesis and the influence of the geometrical properties on the accuracy of the SLS manufacturing process. Afterwards, a part is manufactured with adapted values of compensation parameters and the archived accuracy is discussed.

Research limitations/implications

Presented research is limited on a single SLS material. Also, some numerical factors are directly linked to the build volume dimensions of the SLS machine that was used in the experiment. However, results can be generalised and some guidelines for shrinkage and LHAZ compensation method are presented. Also, some guidelines for future research are proposed.

Practical implications

Based on the presented results, it can be determined that using constant shrinkage and LHAZ values on an SLS machine will not yield the same results in terms of accuracy if the geometrical properties of parts change significantly.

Social implications

By correctly adapting compensation values, the overall achievable accuracy of the SLS process can be achieved, enabling a more reliable production of mass-customised end-user parts such as customised medical accessories and devices for example.

Originality/value

A similar method of numerically describing geometrical properties of part in regard to SLS and directly adapting shrinkage and LHAZ compensation values to them for every individual build has not yet been proposed.

Details

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

Keywords

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Article
Publication date: 2 November 2018

Jason M. Weaver, T.J. Barton, John Linn, Derrik Jenkins, Michael P. Miles and Robert Smith

The purpose of this paper is to describe the use of a test artifact proposed by NIST to quantify the dimensional accuracy of a metal additive manufacturing process…

Abstract

Purpose

The purpose of this paper is to describe the use of a test artifact proposed by NIST to quantify the dimensional accuracy of a metal additive manufacturing process. Insights from this paper are given concerning both the performance of the machine, a concept laser Mlab cusing machine, and the applicability of the NIST test artifact in characterizing accuracy. Recommendations are given for improving the artifact and standardizing a process for evaluating dimensional accuracy across the additive manufacturing industry.

Design/methodology/approach

Three builds of the NIST additive manufacturing test artifact were fabricated in 316 stainless steel on a concept laser Mlab cusing machine. The paper follows the procedure described by NIST for characterizing dimensional accuracy of the additive process. Features including pins, holes and staircase flats of various sizes were measured using an optical measurement system, a touch probe and a profilometer.

Findings

This paper describes the accuracy of printed features’ size and position on the test artifact, as well as surface finish on flat and inclined surfaces. Trends in variation of these dimensions are identified, along with possible root causes and remedies. This paper also describes several strengths and weaknesses in the design of the test artifact and the proposed measurement strategy, with recommendations on how to improve and standardize the process.

Originality/value

This paper reviews a previously proposed design and process for measuring the capabilities of additive manufacturing processes. It also suggests improvements that can be incorporated into future designs and standardized across the industry.

Details

Rapid Prototyping Journal, vol. 25 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 28 September 2012

Yongqiang Yang, Jian‐bin Lu, Zhi‐Yi Luo and Di Wang

The purpose of this paper is to investigate the research approach to optimize shape accuracy, dimensional accuracy and density of customized orthodontic production…

Abstract

Purpose

The purpose of this paper is to investigate the research approach to optimize shape accuracy, dimensional accuracy and density of customized orthodontic production fabricated by selective laser melting (SLM).

Design/methodology/approach

A series of process experiments were applied to fabricating customized brackets directly by SLM, using 316L stainless steel. Shape accuracy can be optimized through the study on fabricating characteristics of non‐support overhanging structure. A scanning strategy combining contour scanning with orthogonal scanning, which differ in scanning speed and spot compensations, was proposed to improve dimensional accuracy. Scanning laser surface re‐melting was added to enhance the SLM density.

Findings

Optimized SLM parameters lead to high shape precision of customized brackets, and the average size error of bracket slot is less than 10 μm. The customized brackets density is more than 99 per cent, and the surface quality and mechanical properties meet the requirements.

Originality/value

The paper presents the state of the art in SLM of customized production (especially medical appliances) by optimizing part properties. It is the first time that SLM is employed in the manufacturing of customized orthodontic products. It shows the original research on overhanging structure and compound scanning strategy, approach to optimize SLM part accuracy. An improved laser surface re‐melting is employed in the density optimization.

Details

Rapid Prototyping Journal, vol. 18 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

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