High layer thickness influence on melt pool sizes and defects appearing of Ti6Al4V at high scan speeds

Author(s):  
Nada Hassine ◽  
Sami Chatti ◽  
Mouna Ben Slama
Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 876 ◽  
Author(s):  
Sapam Ningthemba Singh ◽  
Sohini Chowdhury ◽  
Yadaiah Nirsanametla ◽  
Anil Kumar Deepati ◽  
Chander Prakash ◽  
...  

Investigation of the selective laser melting (SLM) process, using finite element method, to understand the influences of laser power and scanning speed on the heat flow and melt-pool dimensions is a challenging task. Most of the existing studies are focused on the study of thin layer thickness and comparative study of same materials under different manufacturing conditions. The present work is focused on comparative analysis of thermal cycles and complex melt-pool behavior of a high layer thickness multi-layer laser additive manufacturing (LAM) of pure Titanium (Ti) and Inconel 718. A transient 3D finite-element model is developed to perform a quantitative comparative study on two materials to examine the temperature distribution and disparities in melt-pool behaviours under similar processing conditions. It is observed that the layers are properly melted and sintered for the considered process parameters. The temperature and melt-pool increases as laser power move in the same layer and when new layers are added. The same is observed when the laser power increases, and opposite is observed for increasing scanning speed while keeping other parameters constant. It is also found that Inconel 718 alloy has a higher maximum temperature than Ti material for the same process parameter and hence higher melt-pool dimensions.


2020 ◽  
Vol 26 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Tobias Kolb ◽  
Reza Elahi ◽  
Jan Seeger ◽  
Mathews Soris ◽  
Christian Scheitler ◽  
...  

Purpose The purpose of this paper is to analyse the signal dependency of the camera-based coaxial monitoring system QMMeltpool 3D (Concept Laser GmbH, Lichtenfels, Germany) for laser powder bed fusion (LPBF) under the variation of process parameters, position, direction and layer thickness to determine the capability of the system. Because such and similar monitoring systems are designed and presented for quality assurance in series production, it is important to present the dominant signal influences and limitations. Design/methodology/approach Hardware of the commercially available coaxial monitoring QMMeltpool 3D is used to investigate the thermal emission of the interaction zone during LPBF. The raw images of the camera are analysed by means of image processing to bypass the software of QMMeltpool 3D and to gain a high level of signal understanding. Laser power, scan speed, laser spot diameter and powder layer thickness were varied for single-melt tracks to determine the influence of a parameter variation on the measured sensory signals. The effects of the scan direction and position were also analysed in detail. The influence of surface roughness on the detected sensory signals was simulated by a machined substrate plate. Findings Parameter variations are confirmed to be detectable. Because of strong directional and positional dependencies of the melt-pool monitoring signal a calibration algorithm is necessary. A decreasing signal is detected for increasing layer thickness. Surface roughness is identified as a dominating factor with major influence on the melt-pool monitoring signal exceeding other process flaws. Research limitations/implications This work was performed with the hardware of a commercially available QMMeltpool 3D system of an LPBF machine M2 of the company Concept Laser GmbH. The results are relevant for all melt-pool monitoring research activities connected to LPBF, as well as for end users and serial production. Originality/value Surface roughness has not yet been revealed as being one of the most important origins for signal deviations in coaxial melt-pool monitoring. To the best of the authors’ knowledge, the direct comparison of influences because of parameters and environment has not been published to this extent. The detection, evaluation and remelting of surface roughness constitute a plausible workflow for closed-loop control in LPBF.


Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 139 ◽  
Author(s):  
Mateusz Skalon ◽  
Michael Görtler ◽  
Benjamin Meier ◽  
Siegfried Arneitz ◽  
Nikolaus Urban ◽  
...  

The current work presents the results of an investigation focused on the influence of process parameters on the melt-track stability and its consequence to the sample density printed out of NdFeB powder. Commercially available powder of Nd7.5Pr0.7Fe75.4Co2.5B8.8Zr2.6Ti2.5 alloy was investigated at the angle of application in selective laser melting of permanent magnets. Using single track printing the stability of the melt pool was investigated under changing process parameters. The influence of changing laser power, scanning speed, and powder layer thickness on density, porosity structure, microstructure, phase composition, and magnetic properties were investigated. The results showed that energy density coupled with powder layer thickness plays a crucial role in melt-track stability. It was possible to manufacture magnets of both high relative density and high magnetic properties. Magnetization tests showed a significant correlation between the shape of the demagnetization curve and the layer height. While small layer heights are beneficial for sufficient magnetic properties, the remaining main parameters tend to affect the magnetic properties less. A quasi-linear correlation between the layer height and the magnetic properties remanence (Jr), coercivity (HcJ) and maximum energy product ((BH)max) was found.


Materials ◽  
2016 ◽  
Vol 9 (12) ◽  
pp. 975 ◽  
Author(s):  
Xuezhi Shi ◽  
Shuyuan Ma ◽  
Changmeng Liu ◽  
Cheng Chen ◽  
Qianru Wu ◽  
...  

2010 ◽  
Vol 93-94 ◽  
pp. 63-66 ◽  
Author(s):  
Kitiya Wasoontararat ◽  
Waraporn Suvannapruk ◽  
Jintamai Suwanprateeb

Influence of using different layer thickness in three dimensional printing process of calcium sulfate based sample prior to phosphorization process was studied. Phase composition and mechanical properties of the resulting structure were characterized by x-ray diffraction and three-point bending techniques. It was seen that transformation rate, phase composition and flexural strength were all affected by the change in layer thickness. Too high layer thickness, 0.2 mm, caused the disintegration of sample during phosphorization while too low layer thickness, 0.08 mm, decreased the transformation rate. The optimised layer thickness in this study which gave both high conversion rate and flexural properties was found to be 0.1 mm.


F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 1286
Author(s):  
Chockalingam Palanisamy ◽  
Hong Kiat Aaron Tay Hong Kiat

Background: High quality 3D printed products are in high demand, resulting in an increase in the production of 3D printed parts with precise tolerances, improved surface roughness, and overall durability. The processing parameters of 3D printers have a significant impact on the quality of 3D printed parts. Three-dimensionally printed parts must be durable, especially in terms of tensile strength, and its impact on the printer's process parameters must be investigated. Methods: Tensile test specimens were printed in the Makerbot 3D printer with aluminium polylactic acid (PLA) material. The three controllable input parameters taken into consideration were layer thickness, infill density and number of shells. The three levels for each of the respective parameters were 0.1mm, 0.2mm and 0.3mm for layer thickness; 2,3 and 4 for number of shells; 20% 40% and 60% for Infill density. Tensile testing was carried out on the specimens and data was tabulated. Using these data, an artificial neural network model was created using Matlab R2021b software’s neural network toolbox (alternatively Scilab can be used). Results: A high layer thickness (0.3mm) and a 40% infill density were found to be the most effective among all other parameters. The specimen with the lowest layer thickness of 0.1mm, four shells, and a 20% infill density had the highest tensile strength. With the tensile test data, a Matlab ANN model was developed. Validation was done by comparing the values obtained from the model with the experimental data by using random layer thickness, infill density, and number of shells. Conclusions:  In conclusion, higher layer thickness has lower tensile strengths. However, as the number of shells and infill density increases, the tensile strength increases. In summary an ANN model was successfully developed and validated to predict 3D printed aluminium parts.


2014 ◽  
Vol 933 ◽  
pp. 196-201 ◽  
Author(s):  
Mohd Rizal Alkahari ◽  
Tatsuaki Furumoto ◽  
Takashi Ueda ◽  
Akira Hosokawa

Selective Laser Sintering/Selective Laser Melting (SLS/SLM) is one of Additive Manufacturing (AM) processes that utilize layer by layer powder deposition technique and successive laser beam irradiation based on Computer Aided Design (CAD) data. During laser irradiation on metal powders, melt pool was formed, which then solidified to consolidated structure. Therefore, melt pool is an important behavior that affects the final quality of track formation. The study investigates the melt pool behavior through visualization of the consolidation process during the single track formation on the first layer. In order to understand the transformation process of metal powder to consolidated structure and mechanism involved, high speed camera was used to monitor the process. Yb:fiber laser beam was irradiated on metal powder at maximum power of 150W. The laser processing parameters such as laser power, scan speed and layer thickness were varied in order to investigate their influence on the consolidation process. The result shows the size of melt pool increased with laser power and decreasing with increment in scan speed. Furthermore, with the increase of layer thickness, melt pool formation was unstable with chaotic movement. Significant amount of molten powder splattering was recorded from the melt pool. At high layer thickness also, the molten powder formed spherical shaped and the solidified molten powder failed to wet with the substrate.


2013 ◽  
Vol 465-466 ◽  
pp. 55-59 ◽  
Author(s):  
M.N. Hafsa ◽  
Mustaffa Ibrahim ◽  
Md. Saidin Wahab ◽  
M.S. Zahid

Selection of the most suitable Rapid Prototyping (RP) and manufacturing process for a specific part creation is a difficult task due to the development of RP processes and materials. Most current RP processes can build with more than one type of material. The paper presents the evaluation on Acrylonitrile Butadiene Styrene (ABS) and Polylactic acid (PLA) part produced from Fused Deposition Modeling (FDM) as a master pattern for Investment Casting (IC) process. The main purpose of this research is to evaluate the dimensional accuracy and surface roughness for hollow and solid part of FDM pattern for IC process with different layer thickness. The value were taken for both before and after the casting process. Results show that model fabricated with hollow internal pattern structure (ABS material) that produced by low layer thickness is better than other models in terms of its dimensional accuracy (-0.19666mm) and surface roughness (1.41μm). Even though the ABS built part performed better as the model, the PLA build part produces better overall casting result. Final part fabricated with solid pattern (PLA material) that produced by high layer thickness is better than other final parts which its dimensional accuracy (-0.12777mm) and surface roughness (3.07μm).


Materials ◽  
2017 ◽  
Vol 10 (9) ◽  
pp. 1055 ◽  
Author(s):  
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