Effect of layer thickness on the overhanging surface quality manufactured by selective laser melting

2021 ◽  
pp. 095440622110528
Author(s):  
Weipeng Duan ◽  
Meiping Wu ◽  
Jitai Han ◽  
Yiqing Ma ◽  
Xiaojin Miao
Keyword(s):  
Experimental Data ◽  
Optimal Condition ◽  
Layer Thickness ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Molten Pool ◽  
Laser Melting ◽  
Surface Flatness ◽  
Increasing Demand ◽  
The Relationship

With the increasing demand for the precision of lightweight part, overhanging surface quality has attracted more and more attentions in recent years. In this work, the relationship between overhanging surface quality and layer thickness was studied. The testing results revealed that with the increasing of the layer thickness, surface quality, especially the surface flatness, showed a significant decreasing trend due to the decreasing of the bending deformation. When layer thickness was ranged from 0.15 to 0.18, it reached a relative optimal condition while the sinking distance and flatness within 0.095 mm–0.1 mm and 0.076 mm–0.078 mm, respectively. With the further increasing of the layer thickness, both sinking distance and surface flatness had a quite significant decreasing due to the increasing gravity of the overhanging layer powder and bonded powder caused by the molten pool sinking. Combined to the experimental data and the analysis given above, the structure of the overhanging surface was optimized and the surface quality showed a further increase.

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.

Effects of the Processing Parameters on the Forming Quality of Stainless Steel Parts by Selective Laser Melting

2011 ◽  
Vol 189-193 ◽  
pp. 3668-3671 ◽  
Author(s):  
Qing Song Wei ◽  
Xiao Zhao ◽  
Li Wang ◽  
Rui Di Li ◽  
Jie Liu ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Selective Laser Melting ◽  
Molten Pool ◽  
Laser Power ◽  
Single Layer ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Powder Layer ◽  
Laser Melting

Selective Laser Melting (SLM) can produce high-performance metal parts with complex structures. However, it’s difficult to control the processing parameters, because many factors involves. From the perspective of the molten pool, the study focuses on the effects of processing parameters, including scanning speed, laser power, scanning space, layer thickness, and scanning strategies, on the surface quality, the balling effect, the density of SLM parts, by conducting experiments of single track, single layer and block forming. The results show that the quality of the molten pool is affected by laser power and scanning speed. Scanning drove in the strategy of “jumping and turning”，a smooth surface and a less balling effect will be obtained. The thicker the powder layer is, the lower density will be obtained. The optimal parameters from series of experiments are: laser power of 98W; scanning speed of 90mm/s; scanning space of 0.07mm; layer thickness of 0.1mm; and scanning strategy of “jumping and turning”.

scholarly journals Effect of Selective Laser Melting Process Parameters on Microstructure and Properties of Co-Cr Alloy

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1546 ◽  
Author(s):  
Jian-Hong Wang ◽  
Jie Ren ◽  
Wei Liu ◽  
Xiao-Yu Wu ◽  
Ming-Xiang Gao ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Process Parameters ◽  
Molten Pool ◽  
Laser Energy ◽  
Melting Process ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Laser Melting ◽  
The Relationship ◽  
Cobalt Chromium Alloy

Due to the rapid melting and solidification mechanisms involved in selective laser melting (SLM), CoCrMo alloys fabricated by SLM differ from the cast form of the same alloy. In this study, the relationship between process parameters and the morphology and macromechanical properties of cobalt-chromium alloy micro-melting pools is discussed. By measuring the width and depth of the molten pool, a theoretical model of the molten pool is established, and the relationship between the laser power, the scanning speed, the scanning line spacing, and the morphology of the molten pool is determined. At the same time, this study discusses the relationship between laser energy and molding rate. Based on the above research, the optimal process for the laser melting of cobalt-chromium alloy in the selected area is obtained. These results will contribute to the development of biomedical CoCr alloys manufactured by SLM.

Investigation on the relationship between bending angle of the overhanging surface and overhanging surface quality printed using selective laser melting

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Weipeng Duan ◽  
Jitai Han ◽  
Qingfneg Xia ◽  
Keqing Wang ◽  
Meiping Wu ◽  
...  
Keyword(s):  
Surface Quality ◽  
Molten Pool ◽  
Bending Angle ◽  
Content Type ◽  
Factors Affecting ◽  
Overall Performance ◽  
Increasing Demand ◽  
The Relationship ◽  
Bending Angles

Purpose With the increasing demand for lightweight parts, the quality of the inner structure gained growing attention from different kinds of fields. As the quality of the overhanging surface was one of the most important factors affecting inner structure formation, its quality still needs to improve. This paper aims to clarify the change of the overhanging surface quality caused by different bending angles. Design/methodology/approach The structure of the inner hole was redesigned according to the different performances of the overhanging and side inner surface. The experimental results revealed why different surface qualities can be seen under different bending angles. According to the experimental data, the inner structure was redesigned to increase its overall performance. Findings The results revealed that when the bending angle was small, the slope of the overhanging surface increased which lead to the decreasing length of the powder-supported layer. However, less space on bending angle resulted in the accumulation of unmelted powder which leads to the increasing of sinking distance. When the bending angle was too large, the slope of the overhanging surface decreased and the length of the molten pool which was supported by powder increased. It resulted in the sinking of the molten pool caused by the gravity of powder and its attachment. Originality/value This paper is the first work to study the relationship between bending angle and overhanging surface quality as far as the authors know. The different performances of left and right overhanging surfaces also have not been revealed in other research studies to the best of the knowledge.

Mathematical Model of Ti-6Al-4V Single Track Formed by Selective Laser Melting

2012 ◽  
Vol 602-604 ◽  
pp. 2074-2077 ◽  
Author(s):  
Jian Feng Sun ◽  
Yong Qiang Yang ◽  
Jie Liu ◽  
Di Wang
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Fourier Series ◽  
Layer Thickness ◽  
Selective Laser Melting ◽  
Single Track ◽  
Laser Melting ◽  
Functional Relationships ◽  
The Mathematical Model

The single track is the basis of the multi-track overlapping and multi-layer molding in the accumulative manufacturing, and its quality determines the quality of the parts after their being manufactured. The single track experiment on Ti-6Al-4V powders has used Matlab software to fit the experimental data so as to establish the mathematical model. As a result, the experiment has revealed the functional relationships among the width, layer thickness, and power/speed of Ti-6Al-4V selective laser melting single track; and its relationships between its width and layer thickness, width and power/speed, with the period T1=0.0753，T2=0.0542 respectively, satisfy the Fourier series.

Selective laser melting (SLM) of pure gold for manufacturing dental crowns

2014 ◽  
Vol 20 (6) ◽  
pp. 471-479 ◽  
Author(s):  
Mushtaq Khan ◽  
Phill Dickens
Keyword(s):  
Mechanical Properties ◽  
Layer Thickness ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Processing Parameters ◽  
Pure Gold ◽  
Laser Melting ◽  
Content Type ◽  
Dental Crowns ◽  
Suitable Processing

Purpose – This paper aims to present the application aspect of the work to manufacturing premolar and molar dental crowns by selective laser melting (SLM) of pure gold. Over the years different metals have been processed using laser-based Additive Manufacturing processes, but very little work has been published on the SLM of gold (Au). Previously published work presented suitable processing parameters for SLM of pure gold. Design/methodology/approach – Suitable processing parameters were used to manufacture premolar and molar dental crowns using SLM system. Different layer thickness was used to analyse the effect on surface quality of crowns. Mechanical properties are checked using nanoindentation and micro Computerized Tomography scanning. Findings – Dental crowns were successfully manufacturing using new build platform and suitable processing parameters. Parts were manufacturing using minimal supports which prevented parts from damaging during removal. A bed temperature of 100°C was found suitable for reducing warpage in the layers. Layer thickness of 50μm was found to have better surface quality and structural integrity as compared to 75μm. Porosity was found to be predominantly inter-layer. Small difference in mechanical properties of dental crowns is associated with the laser processing. Originality/value – This research is the first of its kind which presents dental crown manufacturing using SLM of pure gold.

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.

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