scholarly journals Micro milling of additively manufactured AISI 316L: impact of the layerwise microstructure on the process results

2020 ◽  
Vol 112 (1-2) ◽  
pp. 361-373
Author(s):  
Sebastian Greco ◽  
Sonja Kieren-Ehses ◽  
Benjamin Kirsch ◽  
Jan C. Aurich
Keyword(s):  
Additive Manufacturing ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Micro Milling ◽  
Burr Formation ◽  
Layer By Layer ◽  
Aisi 316L ◽  
Building Components ◽  
Laser Scanning Speed ◽  
The Impact

AbstractIn the field of metal additive manufacturing (AM), one of the most used methods is selective laser melting (SLM)—building components layer by layer in a powder bed via laser. The process of SLM is defined by several parameters like laser power, laser scanning speed, hatch spacing, or layer thickness. The manufacturing of small components via AM is very difficult as it sets high demands on the powder to be used and on the SLM process in general. Hence, SLM with subsequent micromilling is a suitable method for the production of microstructured, additively manufactured components. One application for this kind of components is microstructured implants which are typically unique and therefore well suited for additive manufacturing. In order to enable the micromachining of additively manufactured materials, the influence of the special properties of the additive manufactured material on micromilling processes needs to be investigated. In this research, a detailed characterization of additive manufactured workpieces made of AISI 316L is shown. Further, the impact of the process parameters and the build-up direction defined during SLM on the workpiece properties is investigated. The resulting impact of the workpiece properties on micromilling is analyzed and rated on the basis of process forces, burr formation, surface roughness, and tool wear. Significant differences in the results of micromilling were found depending on the geometry of the melt paths generated during SLM.

Influence of Machine Type and Powder Batch During Laser-Based Powder Bed Fusion (L-PBF) of AISI 316L

2021 ◽  
Author(s):  
Sebastian Greco ◽  
Kevin Gutzeit ◽  
Hendrik Hotz ◽  
Marc Schmidt ◽  
Marco Zimmermann ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Scanning Speed ◽  
Industrial Applications ◽  
Raw Material ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
Aisi 316L ◽  
Powder Bed ◽  
Machine Type ◽  
Microhardness And Microstructure

Abstract The use of additive manufacturing (AM) in industrial applications is steadily increasing due to its near net shape production and high design-freedom. For metallic components, laser-based powder bed fusion (L-PBF) is currently one of the most widely used AM processes. During L-PBF, a component is manufactured layer by layer from a powdery raw material. The process is controlled by a multitude of parameters like the laser power, scanning speed and layer thickness, whose combination significantly influences the properties of the components. In this study, the influence of the L-PBF machine type and the influence of the powder batch are investigated by means of relative density, microhardness and microstructure of the components. For this purpose, three setups are defined, differing in the powder batch and machine type used. By comparing the process results of the additive manufacturing of different setups, the influence of the machine type and powder batch are determined. The considered material is stainless steel AISI 316L. The results revealed significant differences between all investigated properties of the additively manufactured components. Consequently, process parameter combinations cannot be transferred between different machine types and powder batches without verification of the component properties and, if necessary, special adaption of the process.

Dissolution Behavior of Cast WC Particles in NiCrBSi-WC Coatings by Laser Induction Hybrid Cladding

2013 ◽  
Vol 668 ◽  
pp. 283-287
Author(s):  
Sheng Feng Zhou ◽  
Xiao Qin Dai
Keyword(s):  
High Speed ◽  
Laser Scanning ◽  
Metallic Matrix ◽  
High Hardness ◽  
Scanning Speed ◽  
Eutectic Structure ◽  
Dissolution Behavior ◽  
Positive Role ◽  
Laser Scanning Speed ◽  
Laser Induction

In order to characterize the dissolution of cast WC particles in Ni-based WC coatings by laser induction hybrid rapid cladding, NiCrBSi+50 wt.% WC coatings are produced on A3 steel by low and high speed laser induction hybrid cladding (LIHC). When laser scanning speed is only 600 mm/min, the crack-free coating has pores and its dilution is as high as 45%. At the bottom of coating, the cast WC particles are dissolved completely and the herringbone M6C eutectics are precipitated. In the center of coating, the cast WC particles are also dissolved completely and the acicular, blocky and dendritic carbides with relatively low hardness are precipitated. At two sides of coating, some cast WC particles are dissolved partially and interact with Ni-based alloy to form an alloyed reaction layer, while others preserve the primary eutectic structure and high hardness. When laser scanning speed and powder feeding rate are increased to 1500 mm/min and 85.6 g/min, the coating has cracks but no pores. Its dilution can be markedly decreased to 7.8%. Moreover, a majority of WC particles are still composed of primary eutectic structure and keep their high hardness, which can play a positive role in strengthening Ni-based metallic matrix.

Liquation and Crystallization Cracks in Aluminum Alloy AA2024 during Selective Laser Melting

2021 ◽  
Vol 410 ◽  
pp. 203-208
Author(s):  
I.S. Loginova ◽  
N.A. Popov ◽  
A.N. Solonin
Keyword(s):  
Aluminum Alloy ◽  
Selective Laser Melting ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Melting Zone ◽  
Alloying Elements ◽  
Laser Melting ◽  
Laser Scanning Speed ◽  
Positive Effect

In this work we studied the microstructure and microhardness of standard AA2024 alloy and AA2024 alloy with the addition of 1.5% Y after pulsed laser melting (PLM) and selective laser melting (SLM). The SLM process was carried out with a 300 W power and 0.1 m/s laser scanning speed. A dispersed microstructure without the formation of crystallization cracks and low liquation of alloying elements was obtained in Y-modified AA2024 aluminum alloy. Eutectic Al3Y and Al8Cu4Y phases were detected in Y-modified AA2024 aluminum alloy. It is led to a decrease in the formation of crystallization cracks The uniform distribution of alloying elements in the yttrium-modified alloy had a positive effect on the quality of the laser melting zone (LMZ) and microhardness.

Formability of the Layer Additive Ceramic Part

2008 ◽  
Vol 594 ◽  
pp. 241-248 ◽  
Author(s):  
Fwu Hsing Liu ◽  
Yunn Shiuan Liao ◽  
Hsiu Ping Wang
Keyword(s):  
Surface Roughness ◽  
Laser Scanning ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Dimensional Accuracy ◽  
Scanning Speed ◽  
Laser Sintering ◽  
Single Line ◽  
Laser Scanning Speed ◽  
Silica Slurry

The material in powder state has long been used by selective laser sintering (SLS) for making rapid prototyping (RP) parts. A new approach to fabricate smoother surface roughness RP parts of ceramic material from slurry-sate has been developed in this study. The silica slurry was successfully laser-gelling in a self-developed laser sintering equipment. In order to overcome the insufficient bonding strength between layers, a strategy is proposed to generate ceramic parts from a single line, a single layer, to multi-layers of gelled cramic in this paper. It is found that when the overlap of each single line is 25% and the over-gel between layers is 30%, stronger and more accurate dimensional parts can be obtained under a laser power of 15W, a laser scanning speed of 250 mm/s, and a layer thickness of 0.1 mm. The 55:45 wt. % of the proportion between the silica powder and silica solution results in suitable viscosity of the ceramic slurries without precipitation. Furthermore, the effects of process parameters for the dimensional accuracy and surface roughness of the gelled parts are investigated and appropriate parameters are obtained.

Research on Microstructure and Wear Property of 45 Steel Quenched with Different Laser Power

2020 ◽  
Vol 861 ◽  
pp. 35-40
Author(s):  
Yu Liu ◽  
Tian Hao Xu ◽  
Ying Liu ◽  
Hai Cheng Zhang ◽  
Xing Xing Li ◽  
...  
Keyword(s):  
Laser Power ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Wear Volume ◽  
Wear Property ◽  
Steel Matrix ◽  
Wear Properties ◽  
Laser Scanning Speed ◽  
Friction And Wear Properties ◽  
Minimum Wear

The surface of 45 steel is quenched by CO2 laser with scanning speed 1000 mm/min and different laser power 1000W, 1200W, 1400W, 1600W and 1800W. Experiments are carried out to analyze microstructure, friction and wear properties of quenched 45 steel. The results show that the quenching layer thickness increases gradually with the increase of laser power,and the maximum value of quenching layer hardness increases first and then decreases. When the laser power is 1600W, the maximum hardness value is 883HV0.5. But when the laser power is 1800W, the hardness of quenching layer becomes to decrease. The reason is the surface of 45 steel becomes to melt. The wear volume increases first and then decreases too. When laser power is 1600W, the minimum wear volume is 0.08mm3, which is 6.4% to the wear volume of 45 steel matrix without laser quenching. Therefore, better microstructure and properties of 45 steel can be obtained when laser scanning speed is 1000mm/min and laser power is 1600W.

scholarly journals The Effects of Laser Remelting on the Microstructure and Performance of Bainitic Steel

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 912 ◽  
Author(s):  
Yuelong Yu ◽  
Min Zhang ◽  
Yingchun Guan ◽  
Peng Wu ◽  
Xiaoyu Chong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Laser Scanning ◽  
Production Efficiency ◽  
Scanning Speed ◽  
Bainitic Steel ◽  
Laser Remelting ◽  
Melted Layer ◽  
Laser Scanning Speed ◽  
And Performance ◽  
Nanoindentation Instrument

The surface of bainitic steel was remelted by fiber laser, and the microstructure and mechanical properties of the melted layer were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), a nanoindentation instrument, and wear equipment. The study of changing the laser scanning speed showed that the depth of the melted layer increases with decreases of the laser scanning speed. The wear-resistance property increased by 55% compared with the matrix and decreased with the reduction of laser scanning speed within a certain range. In the study of changing the laser-scanning space, the thermal effect of laser melting in the back channel on the front channel was further validated. At the same time, it was found that the solidified layer surface of hardness alternating with softness can be obtained by appropriately expanding the scanning space, which is conducive to improving the wear-resistant properties of the steel surface, and properly improving the production efficiency of the laser remelting treatment.

scholarly journals Research and Optimization of Surface Roughness in Milling of SLM Semi-Finished Parts Manufactured by Using the Different Laser Scanning Speed

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 9 ◽  
Author(s):  
Andrzej Matras
Keyword(s):  
Surface Roughness ◽  
Feed Rate ◽  
Laser Scanning ◽  
Cutting Tool ◽  
Scanning Speed ◽  
Milling Process ◽  
Face Milling ◽  
Machining Parameters ◽  
The Face ◽  
Laser Scanning Speed

The paper studies the potential to improve the surface roughness in parts manufactured in the Selective Laser Melting (SLM) process by using additional milling. The studied process was machining of samples made of the AlSi10Mg alloy powder. The simultaneous impacts of the laser scanning speed of the SLM process and the machining parameters of the milling process (such as the feed rate and milling width) on the surface roughness were analyzed. A mathematical model was created as a basis for optimizing the parameters of the studied processes and for selecting the sets of optimum solutions. As a result of the research, surface with low roughness (Ra = 0.14 μm, Rz = 1.1 μm) was obtained after the face milling. The performed milling allowed to reduce more than 20-fold the roughness of the SLM sample surfaces. The feed rate and the cutting width increase resulted in the surface roughness deterioration. Some milled surfaces were damaged by the chip adjoining to the rake face of the cutting tool back tooth.

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