scholarly journals Fabrication of Mesh Patterns Using a Selective Laser-Melting Process

2019 ◽  
Vol 9 (9) ◽  
pp. 1922 ◽  
Author(s):  
Tae Woo Hwang ◽  
Young Yun Woo ◽  
Sang Wook Han ◽  
Young Hoon Moon
Keyword(s):  
Selective Laser Melting ◽  
Laser Scanning ◽  
Dimensional Accuracy ◽  
Base Plate ◽  
Steel Powder ◽  
Melting Process ◽  
304 Stainless Steel ◽  
Process Conditions ◽  
Laser Melting ◽  
Metal Mesh

The selective laser-melting (SLM) process can be applied to the additive building of complex metal parts using melting metal powder with laser scanning. A metal mesh is a common type of metal screen consisting of parallel rows and intersecting columns. It is widely used in the agricultural, industrial, transportation, and machine protection sectors. This study investigated the fabrication of parts containing a mesh pattern from the SLM of AISI 304 stainless steel powder. The formation of a mesh pattern has a strong potential to increase the functionality and cost-effectiveness of the SLM process. To fabricate a single-layered thin mesh pattern, laser layering has been conducted on a copper base plate. The high thermal conductivity of copper allows heat to pass through it quickly, and prevents the adhesion of a thin laser-melted layer. The effects of the process conditions such as the laser scan speed and scanning path on the size and dimensional accuracy of the fabricated mesh patterns were characterized. As the analysis results indicate, a part with a mesh pattern was successfully obtained, and the application of the proposed method was shown to be feasible with a high degree of reliability.

Benchmark test artifacts for selective laser melting – a critical review

2021 ◽  
Vol 15 ◽  
Author(s):  
Weishi Li ◽  
Kuanting Wang ◽  
Shiaofen Fang
Keyword(s):  
Selective Laser Melting ◽  
High Surface ◽  
Dimensional Accuracy ◽  
Melting Process ◽  
Design Guidelines ◽  
Laser Melting ◽  
Specific Test ◽  
Benchmark Test ◽  
High Surface Quality ◽  
Machine Performance

Background: Selective laser melting is the best-established additive manufacturing technology for high-quality metal part manufacturing. However, the widespread acceptance of the technology is still underachieved, especially in critical applications, due to the absence of a thorough understanding of the technology, although several benchmark test artifacts have been developed to characterize the performance of selective laser melting machines. Objective: The objective of this paper is to inspire new designs of benchmark test artifacts to understand the selective laser melting process better and promote the acceptance of the selective laser melting technology. Method: The existing benchmark test artifacts for selective laser melting are analyzed comparatively, and the design guidelines are discussed. Results: The modular approach should still be adopted in designing new benchmark test artifacts in the future, and task-specific test artifacts may also need to be considered further to validate the machine performance for critical applications. The inclusion of the design model in the manufactured artifact, instead of the conformance to the design specifications, should be evaluated after the artifact is measured for the applications requiring high-dimensional accuracy and high surface quality. Conclusion: The benchmark test artifact for selective laser melting is still under development, and a breakthrough of the measuring technology for internal and/or inaccessible features will be beneficial for understanding the technology.

Water Atomized 17-4 PH Stainless Steel Powder as a Cheaper Alternative Powder Feedstock for Selective Laser Melting

2018 ◽  
Vol 941 ◽  
pp. 698-703 ◽  
Author(s):  
Milad Ghayoor ◽  
Sunil B. Badwe ◽  
Harish Irrinki ◽  
Sundar V. Atre ◽  
Somayeh Pasebani
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Selective Laser Melting ◽  
Steel Powder ◽  
Melting Process ◽  
Stainless Steel Powder ◽  
Laser Melting ◽  
Austenitic Phase ◽  
Process Gas

Water atomized and gas atomized 17-4 PH stainless steel powder were used as feedstock in selective laser melting process. Gas atomized powder revealed single martensitic phase after printing and heat treatment. As-printed water atomized powder contained dual martensitic and austenitic phase. The H900 heat treatment cycle was not effective in enhancing mechanical properties of the water atomized powder after laser melting. However, after solutionizing at 1315 oC and aging at 482oC fully martensitic structure was observed with yield strength of 1000 MPa and ultimate tensile strength of 1261 MPa which are comparable to those of gas atomized, 1254 MPa and 1300 MPa, respectively. Improved mechanical properties in water atomized powder was found to be related to presence of finer martensite. Our results imply that water atomized powder is a promising cheaper feedstock alternative to gas atomized powder.

Numerical Study of Porosity Formation With Implementation of Laser Multiple Reflection in Selective Laser Melting

2019 ◽  
Author(s):  
Bo Cheng ◽  
Charles Tuffile
Keyword(s):  
Selective Laser Melting ◽  
Laser Scanning ◽  
Numerical Study ◽  
Fluid Model ◽  
Melting Process ◽  
Scanning Speed ◽  
Powder Layer ◽  
Cfd Model ◽  
Laser Melting ◽  
Porosity Formation

Abstract In selective laser melting (SLM) process, the build part quality is determined by process parameters such as laser scanning speed and power. The presence of porosity, a major printing defect that significantly affects part performance, may arise in laser melting process due to insufficient or excess energy input. The improvement of build quality heavily depends on fundamental understanding of porosity formation in the SLM process. In this study, the discrete element method (DEM) has been utilized to simulate the creation of a newly deposited powder layer. A computational fluid dynamics (CFD) model was developed to simulate the melting and solidification process of Ti-6Al-4V powders in the SLM process. The thermo-fluid model includes effect of surface tension and recoil pressure as well as laser ray multi-reflection in keyhole. The predictability of the developed CFD model has been validated against literature experimental data. It is found that the collapse of an unstable deep keyhole was responsible for the formation of pores. In addition, higher laser scanning speeds tend to form unstable melt pools, e.g., melt pool break-up.

scholarly journals Selective Laser Melting of 18NI-300 Maraging Steel

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4268 ◽  
Author(s):  
Mariusz Król ◽  
Przemysław Snopiński ◽  
Jiří Hajnyš ◽  
Marek Pagáč ◽  
Dariusz Łukowiec
Keyword(s):  
Relative Density ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Aging Treatment ◽  
Steel Powder ◽  
Process Conditions ◽  
Laser Melting ◽  
Microstructure Observation ◽  
High Relative Density ◽  
Wide Range

In the present study, 18% Ni 300 maraging steel powder was processed using a selective laser melting (SLM) technique to study porosity variations, microstructure, and hardness using various process conditions, while maintaining a constant level of energy density. Nowadays, there is wide range of utilization of metal technologies and its products can obtain high relative density. A dilatometry study revealed that, through heating cycles, two solid-state effects took place, i.e., precipitation of intermetallic compounds and the reversion of martensite to austenite. During the cooling process, one reaction took place (i.e., martensitic transformation), which was confirmed by microstructure observation. The improvements in the Rockwell hardness of the analyzed material from 42 ± 2 to 52 ± 0.5 HRC was improved as a result of aging treatment at 480 °C for 5 h. The results revealed that the relative density increased using laser speed (340 mm/s), layer thickness (30 µm), and hatch distance (120 µm). Relative density was found approximately 99.3%. Knowledge about the influence of individual parameters in the SLM process on porosity will enable potential manufacturers to produce high quality components with desired properties.

Experimental evaluation of selective laser melting process for optimized lattice structures

2018 ◽  
Vol 233 (4) ◽  
pp. 763-775 ◽  
Author(s):  
G De Pasquale ◽  
F Luceri ◽  
M Riccio
Keyword(s):  
Selective Laser Melting ◽  
Statistical Approach ◽  
Dimensional Accuracy ◽  
Melting Process ◽  
Lattice Structures ◽  
Metal Powders ◽  
Laser Melting ◽  
Material Density ◽  
Volume Energy ◽  
Appreciable Reduction

Lattice structures fabricated with micromelting of metal powders are promising solutions for lightweight applications. Additive manufacturing processes as selective laser melting are largely used to build bulk components, but the influence of laser settings on lattice struts morphology is not jet fully investigated. Previous studies demonstrate the effect of laser speed and layers thickness on the material density and lattice struts dimensions. In this paper, the effects of the laser volume energy density associated with the process setup parameters are analyzed in relation to the dimensional accuracy of lattice struts. The statistical approach based on design of experiments used in this paper allows getting appreciable reduction of the average errors of struts dimensions (from 48% to 16% and from 22% to 7% in horizontal and vertical orientations, respectively).

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.

Dimensional Accuracy Study of Open Cellular Structure CoCrMo Alloy Fabricated by Selective Laser Melting Process

2016 ◽  
Vol 1133 ◽  
pp. 280-284 ◽  
Author(s):  
Zahrul Adnan Mat Taib ◽  
Wan Sharuzi Wan Harun ◽  
Saiful Anwar Che Ghani ◽  
Mohd Fadzil Faisae Ab Rashid ◽  
Mohd Asnawi Omar ◽  
...  
Keyword(s):  
Surface Area ◽  
Selective Laser Melting ◽  
Dimensional Accuracy ◽  
Melting Process ◽  
Laser Melting ◽  
Cocrmo Alloy ◽  
Orthodontic Implants ◽  
Accuracy Study ◽  
Manufacturing Techniques ◽  
Metal Additive

Designing orthodontic implants with desired physical and biological performances and to fabricate net shape with complex anatomical shapes is still a challenge. Cautious design approaches followed by systematic manufacturing techniques that can achieve balanced physical performance in mono block implants mechanics is necessary to accomplish this objective. Metal additive manufacturing (MAM) technique such as selective laser melting (SLM) process is progressively being utilized for new biomaterials such as cobalt-chrome-molybdenum (CoCrMo). This study was designed to determine a dimensional accuracy of open cellular structures CoCrMo samples with designing volume based porosity ranging between 0 % (full dense) to 80 %. A maximum 2.10 % shrinkage was obtained by 80 % designed porosity sample. Samples with higher volume-to-surface area (full dense) demonstrated the low total amount of shrinkage as compared to lower volume-to-surface area (80 % designed porosity).

Analysis of Selective Laser Melting Process Parameters Effect on Mechanical and Material Properties for Stainless Steel 316L

2016 ◽  
Vol 258 ◽  
pp. 579-582
Author(s):  
Pavlína Trubačová ◽  
Miroslav Piska ◽  
Jana Horníková ◽  
Pavel Šandera ◽  
Karel Slámečka
Keyword(s):  
Mechanical Properties ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Melting Process ◽  
Material Behavior ◽  
Process Conditions ◽  
Stainless Steel 316L ◽  
Laser Melting ◽  
Scanning Velocity ◽  
Focus Plane

This paper deals with a testings of the Selective Laser Melting (SLM) process parameters on mechanical properties, material behavior, surface quality and on machinability of austenitic steel 316L. The SLM process conditions were changed to assess their effect on mechanical properties of the sintered material measured in tensile testing. The laser power, the scanning velocity of laser beam, the layer thickness and the laser focus plane were set to find the most appropriate set of process parameters to obtain the mechanical properties of parts.

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