scholarly journals Optimising the process parameters of selective laser melting for the fabrication of Ti6Al4V alloy

2018 ◽  
Vol 24 (1) ◽  
pp. 150-159 ◽  
Author(s):  
Zhonghua Li ◽  
Ibrahim Kucukkoc ◽  
David Z. Zhang ◽  
Fei Liu
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
High Surface ◽  
Optimum Process ◽  
Laser Melting ◽  
Vertical Side ◽  
Content Type

Purpose Surface roughness is an important evaluation index for industrial components, and it strongly depends on the processing parameters for selective laser molten Ti6Al4V parts. This paper aims to obtain an optimum selective laser melting (SLM) parameter set to improve the surface roughness of Ti6Al4V samples. Design/methodology/approach A response surface methodology (RSM)-based approach is proposed to improve the surface quality of selective laser molten Ti6Al4V parts and understand the relationship between the SLM process parameters and the surface roughness. The main SLM parameters (i.e. laser power, scan speed and hatch spacing) are optimized, and Ti6Al4V parts are manufactured by the SLM technology with no post processes. Findings Optimum process parameters were obtained using the RSM method to minimise the roughness of the top and vertical side surfaces. Obtained parameter sets were evaluated based on their productivity and surface quality performance. The validation tests have been performed, and the results verified the effectivity of the proposed technique. It was also shown that the top and vertical sides must be handled together to obtain better top surface quality. Practical implications The obtained optimum SLM parameter set can be used in the manufacturing of Ti6Al4V components with high surface roughness requirement. Originality/value RSM is used to analyse and determine the optimal combination of SLM parameters with the aim of improving the surface roughness quality of Ti6Al4V components, for the first time in the literature. Also, this is the first study which aims to simultaneously optimise the surface quality of top and vertical sides of titanium alloys.

The mechanism of process parameters influencing the AlSi10Mg side surface quality fabricated via laser powder bed fusion

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shimin Dai ◽  
Hailong Liao ◽  
Haihong Zhu ◽  
Xiaoyan Zeng
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Process Parameters ◽  
Laser Power ◽  
Side Surface ◽  
Laser Powder Bed Fusion ◽  
Scanning Velocity ◽  
Content Type ◽  
Powder Bed

Purpose For the laser powder bed fusion (L-PBF) technology, the side surface quality is essentially important for industrial applicated parts, such as the inner flow parts. Contour is generally adopted at the parts’ outline to enhance the side surface quality. However, the side surface roughness (Ra) is still larger than 10 microns even with contour in previous studies. The purpose of this paper is to study the influence of contour process parameters, laser power and scanning velocity on the side surface quality of the AlSi10Mg sample. Design/methodology/approach Using L-PBF technology to manufacture AlSi10Mg samples under different contour process parameters, use a laser confocal microscope to capture the surface information of the samples, and obtain the surface roughness Ra and the maximum surface height Rz of each sample after analysis and processing. Findings The results show that the side surface roughness decreases with the increase of the laser power at the fixed scanning velocity of 1,000 mm/s, the side surface roughness Ra stays within the error range as the contour velocity increases. It is found that the Ra increases with the scanning velocity increasing and the greater the laser power with the greater Ra increases when the laser power of contour process parameters is 300 W, 350 W and 400 W. The Rz maintain growth with the contour scanning velocity increasing at constant laser power. The continuous uniform contour covers the pores in the molten pool of the sample edge and thus increase the density of the sample. Two mechanisms named “Active adhesion” and “Passive adhesion” cause sticky powder. Originality/value Formation of a uniform and even contour track is key to obtain the good side surface quality. The side surface quality is determined by the uniformity and stability of the contour track when the layer thickness is fixed. These research results can provide helpful guidance to improve the surface quality of L-PBF manufactured parts.

scholarly journals The Influence of Process Parameters and Scanning Strategy on Lower Surface Quality of TA15 Parts Fabricated by Selective Laser Melting

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1228
Author(s):  
Junjie Jiang ◽  
Jianming Chen ◽  
Zhihao Ren ◽  
Zhongfa Mao ◽  
Xiangyu Ma ◽  
...  
Keyword(s):  
Surface Quality ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Flexible Manufacturing ◽  
Molten Pool ◽  
Lower Surface ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Influence Of Process Parameters

With superior flexible manufacturing capability, selective laser melting (SLM) has attracted more and more attention in the aerospace, medical, and automotive industries. However, the poor quality of the lower surface in overhanging structures is still one of the factors that limits the wide application of SLM. In this work, the influence of process parameters and scanning strategy on the lower surface quality of SLMed TA15 (Ti-6Al-2Zr-1Mo-1V) titanium alloy parts were studied. The results showed that the laser surface energy density (EF) had a significant influence on the quality of the lower surface. Excessive EF led to obvious sinking of the molten pool and a serious slag hanging phenomenon. However, the too low EF easily contributed to the insufficient powder fusion in the lower surface area, which led to the agglomeration of a molten pool during core processing, resulting in slag hanging, pores, and powder spalling that reduced the quality of the lower surface. Moreover, the cross-remelting strategy and non-remelting strategy gained better surface quality at the low EF and high EF, respectively. In addition, it was found that the quality of the lower surface could be quickly and accurately evaluated by the cooling time of the molten pool during the processing of the lower surface. This research can increase the understanding of the forming mechanism of the lower surface and has certain guiding significance for the process optimization of the lower surface.

scholarly journals Effect of build orientation on the surface quality, microstructure and mechanical properties of selective laser melting 316L stainless steel

2018 ◽  
Vol 24 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Hamza Hassn Alsalla ◽  
Christopher Smith ◽  
Liang Hao
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Mechanical Performance ◽  
Laser Melting ◽  
Content Type ◽  
Microstructure And Mechanical Properties ◽  
Conventional Material

Purpose The purpose of this paper is to investigate the density, surface quality, microstructure and mechanical properties of the components of the selective laser melting (SLM) parts made at different building orientations. SLM is an additive manufacturing technique for three-dimensional parts. The process parameters are known to affect the properties of the eventual part. In this study, process parameters were investigated in the building of 316L structures at a variety of building orientations and for which the fracture toughness was measured. Design/methodology/approach Hardness and tensile tests were carried out to evaluate the effect of consolidation on the mechanical performance of specimens. Optical and electron microscopy were used to characterise the microstructure of the SLM specimens and their effects on properties relating to fracture and the mechanics. It was found that the density of built samples is 96 per cent, and the hardness is similar in comparison to conventional material. Findings The highest fracture toughness value was found to be 176 MPa m^(1/2) in the oz. building direction, and the lowest value was 145 MPa m^(1/2) in the z building direction. This was due to pores and some cracks at the edge, which are slightly lower in comparison to a conventional product. The build direction does have an effect on the microstructure of parts, which subsequently has an effect upon their mechanical properties and surface quality. Dendritic grain structures were found in oz. samples due to the high temperature gradient, fast cooling rate and reduced porosity. The tensile properties of such parts were found to be better than those made from conventional material. Originality/value The relationship between the process parameters, microstructure, surface quality and toughness has not previously been reported.

scholarly journals Effect of Selective Laser Melting Process Parameters on the Quality of Al Alloy Parts: Powder Characterization, Density, Surface Roughness, and Dimensional Accuracy

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2343 ◽  
Author(s):  
Ahmed Maamoun ◽  
Yi Xue ◽  
Mohamed Elbestawi ◽  
Stephen Veldhuis
Keyword(s):  
Surface Roughness ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Dimensional Accuracy ◽  
High Strength ◽  
Melting Process ◽  
Al Alloys ◽  
Al Alloy ◽  
Laser Melting

Additive manufacturing (AM) of high-strength Al alloys promises to enhance the performance of critical components related to various aerospace and automotive applications. The key advantage of AM is its ability to generate lightweight, robust, and complex shapes. However, the characteristics of the as-built parts may represent an obstacle to the satisfaction of the parts’ quality requirements. The current study investigates the influence of selective laser melting (SLM) process parameters on the quality of parts fabricated from different Al alloys. A design of experiment (DOE) was used to analyze relative density, porosity, surface roughness, and dimensional accuracy according to the interaction effect between the SLM process parameters. The results show a range of energy densities and SLM process parameters for AlSi10Mg and Al6061 alloys needed to achieve “optimum” values for each performance characteristic. A process map was developed for each material by combining the optimized range of SLM process parameters for each characteristic to ensure good quality of the as-built parts. This study is also aimed at reducing the amount of post-processing needed according to the optimal processing window detected.

scholarly journals Surface Quality Research for Selective Laser Melting of Ti-6Al-4V Alloy

2016 ◽  
Vol 61 (3) ◽  
pp. 1291-1296 ◽  
Author(s):  
M. Król ◽  
T. Tański
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Scanning Speed ◽  
Innovative Technology ◽  
Metal Powders ◽  
Laser Melting ◽  
Influence Of Process Parameters

Abstract One of the innovative technology of producing the components is Selective Laser Melting (SLM) belongs to additive manufacturing techniques. SLM technology has already been successfully applied in the automotive, aerospace and medical industries. Despite progress in material flexibility and mechanical performances, relatively poor surface finish still presents a significant weakness in the SLM process. The scope of the present article is the study the influence of selective laser melting parameters such as laser power, scanning speed, exposure time and hatch spacing through additive manufacturing as well as the orientation of the model corresponding to the laser beam on the surface characteristic of the components made from Ti-6Al-4V alloy. By using optimized process parameters, a low surface roughness can be obtained. In research, the machine for the selective laser melting of metal powders Renishaw AM 125 device was used. Based on experiment plan, 32 models were produced, which were examined to define the surface roughness and thus represent an influence of process parameters and the orientation on the model surface quality. The article discusses the fundamental factors determining the roughness that gives invaluable knowledge to improve the surface quality of SLM parts.

Effect of the strut size and tilt angle on the geometric characteristics of selective laser melting AlSi10Mg

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Baopeng Zhang ◽  
Xuesong Han ◽  
Changpeng Chen ◽  
Wenqi Zhang ◽  
Hailong Liao ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Compressive Strength ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Tilt Angle ◽  
Lattice Structure ◽  
Dimensional Accuracy ◽  
Optimal Process ◽  
Laser Melting ◽  
Content Type

Purpose The purpose of this study is to investigate the effect of the strut size and tilt angle on the densification behavior, surface roughness and dimensional accuracy of the selective laser melting AlSi10Mg lattice structure was investigated in this study. In this study, the characteristics such as the density, up-skin and down-skin roughness and dimensional accuracy of selective laser melting forming technology manufacturing (SLMed) AlSi10Mg cellular lattice structure were carried. This work reveals the effect of the strut size and tilt angle on the geometric characteristics of SLMed AlSi10Mg and is benefit for controlling the forming performance of the SLMed cellular lattice structure. Design/methodology/approach Based on AlSi10Mg powder, the influence of the tilt angle changed from 10° to 45° with an increment of 5° were investigated, the influence of the strut size was varied from 0.4 mm to 1.2 mm with an increment of 0.2 mm were investigated. The characteristics such as the density, up-skin and down-skin roughness, dimensional accuracy and mechanical properties of SLM-ed AlSi10Mg cellular lattice structure was carried. Findings Greater than 99% relative density can be achieved for different strut size when optimal process parameters are used. In the optimized process interval, the struts with a tilt angle of 10° can still be formed well, which is higher than the design limit of the inclined angle given in the related literature. The tilt angle has a significant effect on the surface roughness of the strut. The microhardness reached to 157 ± 3 HV, and the maximum compressive strength was 58.86 MPa, with the optimal process parameters. Originality/value In this study, the characteristics such as the density, up-skin and down-skin roughness and dimensional accuracy of SLMed AlSi10Mg cellular lattice structure were carried. With the optimal geometric parameters, the authors tested microhardness and compressive strength of the cellular lattice structure. The results of this study provide theoretical and experimental basis for the realization of high-quality manufacturing and optimization design of aluminum alloy cellular lattice structure, which will meet more diversified industrial needs.

scholarly journals Effect of Process Parameters and Layer Thickness on the Quality and Performance of Ti-6Al-4V Fabricated by Selective Laser Melting

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1323
Author(s):  
Yanlong Jing ◽  
Peng Wang ◽  
Xiaoling Yan
Keyword(s):  
Surface Quality ◽  
Selective Laser Melting ◽  
Exposure Time ◽  
Process Parameters ◽  
Laser Power ◽  
Single Track ◽  
Laser Melting ◽  
Powder Bed ◽  
Point Distance

To improve the quality of thick powder bed and realize the matching of thick powder bed and thin powder bed in the later stage, the influence of process parameters for the single-track, multi-layer fabrication, relative density, surface quality, defect, remelting, and boundary optimization performance of different layer thicknesses of Ti-6Al-4V fabricated by selective laser melting were investigated. It is more conducive to the stable forming of single-track when the point distance is half the diameter of the laser beam, and the exposure time is appropriately extended. The thin powder bed needs the corresponding point distance and exposure time under the laser power of 280–380 W to obtain high-density specimens. The thick powder bed needs to be able to ensure the formation of high-quality specimens under the smaller point distance and longer exposure time under higher laser power of 380 W. Both thick powder bed and thin powder bed will cause un-melted defects between molten pools, spheroidization defects caused by splashing, and microporous defects. The remelting process can significantly improve the surface quality of the formed specimen, but the surface quality of the thick powder bed is worse than that of the thin powder bed. The boundary quality of thick powder bed is worse than that of thin powder bed, and the boundary shape has a greater influence on the quality of the SLM forming boundary. Different strategies should be adopted to form the boundary of different shapes. Increasing the boundary count and increasing the laser power are more conducive to the improvement of boundary quality.

scholarly journals Improving surface quality in selective laser melting based tool making

2021 ◽  
Author(s):  
Filippo Simoni ◽  
Andrea Huxol ◽  
Franz-Josef Villmer
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Melting Process ◽  
Laser Remelting ◽  
Laser Melting ◽  
Great Cost ◽  
Starting Point ◽  
Processing Techniques

AbstractIn the last years, Additive Manufacturing, thanks to its capability of continuous improvements in performance and cost-efficiency, was able to partly replace and redefine well-established manufacturing processes. This research is based on the idea to achieve great cost and operational benefits especially in the field of tool making for injection molding by combining traditional and additive manufacturing in one process chain. Special attention is given to the surface quality in terms of surface roughness and its optimization directly in the Selective Laser Melting process. This article presents the possibility for a remelting process of the SLM parts as a way to optimize the surfaces of the produced parts. The influence of laser remelting on the surface roughness of the parts is analyzed while varying machine parameters like laser power and scan settings. Laser remelting with optimized parameter settings considerably improves the surface quality of SLM parts and is a great starting point for further post-processing techniques, which require a low initial value of surface roughness.

Sign in / Sign up

Export Citation Format

Share Document