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Article
Publication date: 8 June 2022

Valiollah Panahizadeh, Amir Hossein Ghasemi, Yaghoub Dadgar Asl and Mohammadmahdi Davoudi

This paper aims to study multiobjective genetic algorithm ability in determining the process parameter and postprocess condition that leads to maximum relative density (RD) and…

Abstract

Purpose

This paper aims to study multiobjective genetic algorithm ability in determining the process parameter and postprocess condition that leads to maximum relative density (RD) and minimum surface roughness (Ra) simultaneously in the case of a Ti6Al4V sample process by laser beam powder bed fusion.

Design/methodology/approach

In this research, the nondominated sorting genetic algorithm II is used to achieve situations that correspond to the highest RD and the lowest Ra together.

Findings

The results show that several situations cause achieving the best RD and optimum Ra. According to the Pareto frontal diagram, there are several choices in a close neighborhood, so that the best setup conditions found to be 102–105 watt for laser power followed by scanning speed of 623–630 mm/s, hatch space of 76–73 µm, scanning patter angle of 35°–45° and heat treatment temperature of 638–640°C.

Originality/value

Suitable selection of process parameters and postprocessing treatments lead to a significant reduction in time and cost.

Details

Rapid Prototyping Journal, vol. 28 no. 9
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 December 1998

V. Yevko, C.B. Park, G. Zak, T.W. Coyle and B. Benhabib

Current commercial rapid prototyping systems can be used for fabricating layered models for subsequent creation of fully‐dense metal parts using investment casting. Due to…

1356

Abstract

Current commercial rapid prototyping systems can be used for fabricating layered models for subsequent creation of fully‐dense metal parts using investment casting. Due to increased demand for shortened product development cycles however, there exists a demand to rapidly fabricate functional fully‐dense metal parts without hard tooling. A possible solution to this problem is direct layered rapid manufacturing of such parts, for example, via laser‐beam fusion of the metal powder. The rapid manufacturing process discussed herein is based on this approach. It involves selective laser‐beam scanning of a predeposited metal‐powder layer, forming fully‐dense claddings as the basic building block of individual layers. This paper specifically addresses only one of the fundamental issues of the rapid manufacturing process under investigation at the University of Toronto, namely the fabrication of single claddings. Our theoretical investigation of the influence of the process parameters on cladding’s geometrical properties employed thermal modeling and computer process simulation. Numerous experiments, involving fabrication of single claddings, were also carried out with varying process parameters. Comparisons of the process simulations and experimental results showed good agreement in terms of overall trends.

Details

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

Keywords

Article
Publication date: 15 June 2012

Ugur Caligulu, Mustafa Taskin, Haluk Kejanli and Ayhan Orhan

The purpose of this paper is to investigate interface characterization of CO2 laser welded AISI 304 austenitic stainless steel and AISI 1010 low carbon steel couple. Laser welding…

Abstract

Purpose

The purpose of this paper is to investigate interface characterization of CO2 laser welded AISI 304 austenitic stainless steel and AISI 1010 low carbon steel couple. Laser welding experiments were carried under argon and helium atmospheres at 2000, 2250 and 2500 W heat inputs and 200‐300 cm/min welding speeds.

Design/methodology/approach

The microstructures of the welded joints and the heat affected zones (HAZ) were examined by optical microscopy, SEM, EDS and X‐Ray analysis. The tensile strength of the welded joints was measured.

Findings

The result of this study indicated that the width of welding zone and HAZ became much thinner depending on the increased welding speed. On the other hand, this width widened depending on the increased heat input. Tensile strength values also confirmed this result. The best properties were observed at the specimens welded under helium atmosphere, at 2500 W heat input and at 200 cm/min welding speed.

Originality/value

There are many reports which deal with the shape and solidification structure of the fusion zone of laser beam welds in relation to different laser parameters. However, the effect of all influencing factors of laser welding has up to now not been extensively researched. Much work is required for understanding the combined effect of laser parameters on the shape and microstructure of the fusion zone. This paper, therefore, is concerned with laser power, welding speed, defocusing distance and type of shielding gas and their effects on the fusion zone shape and final solidification structure of some stainless steels.

Details

Industrial Lubrication and Tribology, vol. 64 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 December 2004

Robert W. Messler, Scot Bohnenstiehl, John Levene, Erika Johnson and Luo Chen

Being inherently a non‐pressure fusion process, laser‐beam welding (LBW) has been shown to have difficulty compared to resistance spot welding for weld‐bonding Al alloy…

Abstract

Being inherently a non‐pressure fusion process, laser‐beam welding (LBW) has been shown to have difficulty compared to resistance spot welding for weld‐bonding Al alloy structures, despite the many structural and manufacturing productivity advantages. Study of laser‐beam weld‐bonding of Al‐alloy structure for automobile assembly has led to a technique that appears to have both technical feasibility and production utility. The use of LBW through a hole in a pressure‐applying probe has proven to allow the production of contamination‐free spot welds through pre‐applied pre‐cured structural adhesive. The general approach, along with some details to still be overcome, is presented for both information and solution.

Details

Assembly Automation, vol. 24 no. 4
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 17 September 2021

Sareh Götelid, Taoran Ma, Christophe Lyphout, Jesper Vang, Emil Stålnacke, Jonas Holmberg, Seyed Hosseini and Annika Strondl

This study aims to investigate additive manufacturing of nickel-based superalloy IN718 made by powder bed fusion processes: powder bed fusion laser beam (PBF-LB) and powder bed…

Abstract

Purpose

This study aims to investigate additive manufacturing of nickel-based superalloy IN718 made by powder bed fusion processes: powder bed fusion laser beam (PBF-LB) and powder bed fusion electron beam (PBF-EB).

Design/methodology/approach

This work has focused on the influence of building methods and post-fabrication processes on the final part properties, including microstructure, surface quality, residual stresses and mechanical properties.

Findings

PBF-LB produced a much smoother surface. Blasting and shot peening (SP) reduced the roughness even more but did not affect the PBF-EB surface finish as much. As-printed PBF-EB parts have low residual stresses in all directions, whereas it was much higher for PBF-LB. However, heat treatment removed the stresses and SP created compressive stresses for samples from both PBF processes. The standard Arcam process parameter for PBF-EB for IN718 is not fully optimized, which leads to porosity and inferior mechanical properties. However, impact toughness after hot isostatic pressing was surprisingly high.

Originality/value

The two processes gave different results and also responses to post-treatments, which could be of advantage or disadvantage for different applications. Suggestions for improving the properties of parts produced by each method are presented.

Article
Publication date: 1 December 1968

R. Graham

IT is generally agreed there would be a significant saving in weight and consequent improvement in efficiency, if aircraft could be assembled by welding, instead of by the use of…

Abstract

IT is generally agreed there would be a significant saving in weight and consequent improvement in efficiency, if aircraft could be assembled by welding, instead of by the use of mechanical fasteners. The size of the savings is indicated and the reasons for the currently limited use of welded assemblies are listed. A short list has been chosen of those conventional and more recently developed welding procedures which might be considered suitable for assembling aircraft in future. The compatibility of these procedures and specific alloys is discussed. The relation between the welding procedures and the various components of the airframe is reviewed and some of the developments which might be possible through the use of welded construction are mentioned. There is a short discussion, also, on the joining of the composite materials which may be important in future airframe structures.

Details

Aircraft Engineering and Aerospace Technology, vol. 40 no. 12
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 31 July 2009

Lino Costa and Rui Vilar

The purpose of this paper is to review the state of the art of laser powder deposition (LPD), a solid freeform fabrication technique capable of fabricating fully dense functional…

4600

Abstract

Purpose

The purpose of this paper is to review the state of the art of laser powder deposition (LPD), a solid freeform fabrication technique capable of fabricating fully dense functional items from a wide range of common engineering materials, such as aluminum alloys, steels, titanium alloys, nickel superalloys and refractory materials.

Design/methodology/approach

The main R&D efforts and the major issues related to LPD are revisited.

Findings

During recent years, a worldwide series of R&D efforts have been undertaken to develop and explore the capabilities of LPD and to tap into the possible cost and time savings and many potential applications that this technology offers.

Originality/value

These R&D efforts have produced a wealth of knowledge, the main points of which are highlighted herein.

Details

Rapid Prototyping Journal, vol. 15 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 23 August 2021

Iván La Fé-Perdomo, Jorge Andres Ramos-Grez, Gerardo Beruvides and Rafael Alberto Mujica

The purpose of this paper is to outline some key aspects such as material systems used, phenomenological and statistical process modeling, techniques applied to monitor the…

Abstract

Purpose

The purpose of this paper is to outline some key aspects such as material systems used, phenomenological and statistical process modeling, techniques applied to monitor the process and optimization approaches reported. All these need to be taken into account for the ongoing development of the SLM technique, particularly in health care applications. The outcomes from this review allow not only to summarize the main features of the process but also to collect a considerable amount of investigation effort so far achieved by the researcher community.

Design/methodology/approach

This paper reviews four significant areas of the selective laser melting (SLM) process of metallic systems within the scope of medical devices as follows: established and novel materials used, process modeling, process tracking and quality evaluation, and finally, the attempts for optimizing some process features such as surface roughness, porosity and mechanical properties. All the consulted literature has been highly detailed and discussed to understand the current and existing research gaps.

Findings

With this review, there is a prevailing need for further investigation on copper alloys, particularly when conformal cooling, antibacterial and antiviral properties are sought after. Moreover, artificial intelligence techniques for modeling and optimizing the SLM process parameters are still at a poor application level in this field. Furthermore, plenty of research work needs to be done to improve the existent online monitoring techniques.

Research limitations/implications

This review is limited only to the materials, models, monitoring methods, and optimization approaches reported on the SLM process for metallic systems, particularly those found in the health care arena.

Practical implications

SLM is a widely used metal additive manufacturing process due to the possibility of elaborating complex and customized tridimensional parts or components. It is corroborated that SLM produces minimal amounts of waste and enables optimal designs that allow considerable environmental advantages and promotes sustainability.

Social implications

The key perspectives about the applications of novel materials in the field of medicine are proposed.

Originality/value

The investigations about SLM contain an increasing amount of knowledge, motivated by the growing interest of the scientific community in this relatively young manufacturing process. This study can be seen as a compilation of relevant researches and findings in the field of the metal printing process.

Details

Rapid Prototyping Journal, vol. 27 no. 10
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 30 September 2013

Mehmet Ermurat, Mehmet Ali Arslan, Fehmi Erzincanli and Ibrahim Uzman

This paper aims to investigate the effect of four important process parameters (i.e. laser focal distance, travel speed, feeding gas flow rate and standoff distance) on the size…

Abstract

Purpose

This paper aims to investigate the effect of four important process parameters (i.e. laser focal distance, travel speed, feeding gas flow rate and standoff distance) on the size of single clad geometry created by coaxial nozzle-based powder deposition by high power laser.

Design/methodology/approach

Design of experiments (DOE) and statistical analysis methods were both used to find optimum parameter combinations to get minimum sized clad, i.e. clad width and clad height. Factorial experiment arrays were used to design parameter combinations for creating experimental runs. Taguchi optimization methodology was used to find out optimum parameter levels to get minimum sized clad geometry. Response surface method was used to investigate the nonlinearity among parameters and variance analysis was used to assess the effectiveness level of each problem parameters.

Findings

The overall results show that wisely selected four problem parameters have the most prominent effects on the final clad geometry. Generally, minimum clad size was achieved at higher levels of gas flow rate, travel speed and standoff distance and at minimum spot size level of the laser focal distance.

Originality/value

This study presents considerable contributions in assessing the importance level of problems parameters on the optimum single clad geometry created laser-assisted direct metal part fabrication method. This procedure is somewhat complicated in understanding the effects of the selected problem parameters on the outcome. Therefore, DOE methodologies are utilized so that this operation can be better modeled/understood and automated for real life applications. The study also gives future direction for research based on the presented results.

Details

Rapid Prototyping Journal, vol. 19 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 24 June 2020

Subrata Deb Nath, Gautam Gupta, Martin Kearns, Ozkan Gulsoy and Sundar V. Atre

The purpose of this paper is to investigate effects of layer thickness on densification, surface morphology, microstructure and mechanical and corrosion properties of 420…

Abstract

Purpose

The purpose of this paper is to investigate effects of layer thickness on densification, surface morphology, microstructure and mechanical and corrosion properties of 420 stainless steel fabricated by laser-powder bed fusion (L-PBF).

Design/methodology/approach

Standard specimens were printed at layer thickness of 10, 20 and 30 µm to characterize Archimedes density, surface roughness, tensile strength, elongation, hardness, microstructural phases and corrosion performance in the as-printed and heat-treated condition.

Findings

Archimedes density slightly increased from 7.67 ± 0.02 to 7.70 ± 0.02g/cm3 and notably decreased to 7.35 ± 0.05 g/cm3 as the layer thickness was changed from 20 µm to 10 and 30 µm, respectively. The sensitivity to layer thickness variation was also evident in properties, the ultimate tensile strength of as-printed parts increased from 1050 ± 25 MPa to 1130 ± 35 MPa and decreased to 760 ± 35 MPa, elongation increased from 2.5 ± 0.2% to 2.8 ± 0.3% and decreased to 1.5 ± 0.2, and hardness increased from 55 ± 1 HRC to 57 ± 1 HRC and decreased to 51 ± 1 HRC, respectively. Following heat treatment, the ultimate tensile strength and elongation improved but the general trends of effects of layer thickness remained the same.

Practical implications

Properties obtained by L-PBF are superior to reported properties of 420 stainless steel fabricated by metal injection molding and comparable to wrought properties.

Originality/value

This study successfully the sensitivity of mechanical and corrosion properties of the as-printed and heat-treated parts to not only physical density but also microstructure (martensite content and tempering), as a result of changing the layer thickness. This manuscript also demonstrates porosity evolution as a combination of reduced energy flux and lower packing density for parts processed at an increasing layer thickness.

Details

Rapid Prototyping Journal, vol. 26 no. 7
Type: Research Article
ISSN: 1355-2546

Keywords

1 – 10 of 400