Optimizing the Efficiency in Direct Laser Deposition Process Using Vibrations of Nozzle to Control the Flow of Powder

Author(s):  
Kamran Nazir ◽  
Chang Hyun Sohn ◽  
Fahad Hassan ◽  
Muhammad Awais ◽  
Muhammad Ali ◽  
...  

In direct laser deposition (DLD), metallic powder is injected into the melt pool in order to join different metals to develop fully dense and near net shape part. The cost of powder wasted in commercial DLD machines has been a major concern to the industries. More than 60% of the powder is wasted and is being disposed off which make the system economically and environmentally expensive. Recycling of powder is not feasible in many sectors, because of the fear of drop in the quality of the product. The objective of this study is to enhance the deposition efficiency of the DLD process, so that to minimize the amount of powder wasted. In present study, flow of powder is achieved by vibration of the powder delivery nozzle at sonic frequencies. Experimental studies are performed to analyze the deposition of powder by varying laser intensities, powder flow rate and laser scanning speed. The mass flow during certain time is weighed and the actual clad weight that is formed during the same period is weighted. The difference of the two is used to calculate the powder efficiency. Different set of experiments are performed. Powder mass flow rates are increased subsequently and Taguchi matrix are prepared for each set of experiment. Mass flow rate in initial experiments is from 0.044 grams/sec to 0.244 g/s and increases up to 0.86 g/s in the final set of experiments. Laser power during these experiments varies between 1KW to 2 KW, while laser scanning speeds varies from 100 mm/min to 350 mm/min. Maximum deposition efficiency is achieved in initial set of experiments and is up to 70%, which is significant improvement in the form of deposition efficiencies available in literature.

Author(s):  
Christopher Katinas ◽  
Shunyu Liu ◽  
Yung C. Shin

Understanding the capture efficiency of powder during direct laser deposition (DLD) is critical when determining the overall manufacturing costs of additive manufacturing (AM) for comparison to traditional manufacturing methods. By developing a tool to predict the capture efficiency of a particular deposition process, parameter optimization can be achieved without the need to perform a costly and extensive experimental study. The focus of this work is to model the deposition process and acquire the final track geometry and temperature field of a single track deposition of Ti–6Al–4V powder on a Ti–6Al–4V substrate for a four-nozzle powder delivery system during direct laser deposition with a LENS™ system without the need for capture efficiency assumptions by using physical powder flow and laser irradiation profiles to predict capture efficiency. The model was able to predict the track height and width within 2 μm and 31 μm, respectively, or 3.3% error from experimentation. A maximum of 36 μm profile error was observed in the molten pool, and corresponds to errors of 11% and 4% in molten pool depth and width, respectively. Based on experimentation, the capture efficiency of a single track deposition of Ti–6Al–4V was found to be 12.0%, while that from simulation was calculated to be 11.7%, a 2.5% deviation.


Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1550
Author(s):  
Artur Vildanov ◽  
Konstantin Babkin ◽  
Ruslan Mendagaliyev ◽  
Andrey Arkhipov ◽  
Gleb Turichin

Direct laser deposition technology is used for the manufacture of large-size products with complex geometries. As a rule, trial samples with small dimensions are made to determine the deposition parameters. In order for the resulting products to have the required performance characteristics, it is necessary to minimize the number of internal macrodefects. Non-fusion between the tracks are defects that depend on the technological mode (power, speed, track width, etc.). In this work, studies have been carried out to determine the power level at which non-fusion is formed, dwell time between the tracks on the model samples. This paper considers the issue of transferring the technological parameters of direct laser deposition from model samples to a large-sized part, and describes the procedure for making model samples.


Author(s):  
Swathi Routhu ◽  
Divya Kanakanala ◽  
Jianzhong Ruan ◽  
Xiaoqing Frank Liu ◽  
Frank Liou

The zigzag and offset path have been the two most popular path patterns for tool movement in machining process. Different from the traditional machining processes, the quality of parts produced by the metal deposition process is much more dependent upon the choice of deposition paths. Due to the nature of the metal deposition processes, various tool path patterns not only change the efficiency but also affect the deposition height, a critical quality for metal deposition process. This paper presents the research conducted on calculating zigzag pattern to improve efficiency by minimizing the idle path. The deposition height is highly dependent on the laser scanning speed. The paper also discussed the deposition offset pattern calculation to reduce the height variation by adjusting the tool-path to achieve a constant scanning speed. The results show the improvement on both efficiency and height.


Author(s):  
S Marimuthu ◽  
D Clark ◽  
J Allen ◽  
AM Kamara ◽  
P Mativenga ◽  
...  

The shape complexity of aerospace components is continuously increasing, which encourages researchers to further refine their manufacturing processes. Among such processes, blown powder direct laser deposition process is becoming an economical and energy efficient alternative to the conventional machining process. However, depending on their magnitudes, the distortion and residual stress generated during direct laser deposition process can affect the performance and geometric tolerances of manufactured components. This article reports an investigation carried out using the finite element analysis method to predict the distortion generated in an aero-engine component produced by the direct laser deposition process. The computation of the temperature induced during the direct laser deposition process and the corresponding distortion on the component was accomplished through a three-dimensional thermo-structural finite element analysis model. The model was validated against measured distortion values of the real component produced by direct laser deposition process using a Trumpf DMD505 CO2 laser. Various direct laser deposition fill patterns (orientation strategies/tool movement) were investigated in order to identify the best parameters that will result in minimum distortion.


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