scholarly journals In-Situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed Fusion

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2936
Author(s):  
Seyed Mohammad H. Hojjatzadeh ◽  
Qilin Guo ◽  
Niranjan D. Parab ◽  
Minglei Qu ◽  
Luis I. Escano ◽  
...  
Keyword(s):  
Pore Formation ◽  
Continuous Wave ◽  
Formation Mechanisms ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Subsequent Formation ◽  
Powder Bed ◽  
Formation Dynamics ◽  
Wave Laser

Laser powder bed fusion (LPBF) is an additive manufacturing technology with the capability of printing complex metal parts directly from digital models. Between two available emission modes employed in LPBF printing systems, pulsed wave (PW) emission provides more control over the heat input compared to continuous wave (CW) emission, which is highly beneficial for printing parts with intricate features. However, parts printed with pulsed wave LPBF (PW-LPBF) commonly contain pores, which degrade their mechanical properties. In this study, we reveal pore formation mechanisms during PW-LPBF in real time by using an in-situ high-speed synchrotron x-ray imaging technique. We found that vapor depression collapse proceeds when the laser irradiation stops within one pulse, resulting in occasional pore formation during PW-LPBF. We also revealed that the melt ejection and rapid melt pool solidification during pulsed-wave laser melting resulted in cavity formation and subsequent formation of a pore pattern in the melted track. The pore formation dynamics revealed here may provide guidance on developing pore elimination approaches.

On the use of spatter signature for in-situ monitoring of Laser Powder Bed Fusion

2017 ◽  
Vol 16 ◽  
pp. 35-48 ◽  
Author(s):  
Giulia Repossini ◽  
Vittorio Laguzza ◽  
Marco Grasso ◽  
Bianca Maria Colosimo
Keyword(s):  
In Situ Monitoring ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

Titanium Alloys Manufactured by In Situ Alloying During Laser Powder Bed Fusion

JOM ◽  
2017 ◽  
Vol 69 (12) ◽  
pp. 2725-2730 ◽  
Author(s):  
I. Yadroitsev ◽  
P. Krakhmalev ◽  
I. Yadroitsava
Keyword(s):  
Titanium Alloys ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

scholarly journals In Situ Analysis of Laser Powder Bed Fusion Using Simultaneous High-Speed Infrared and X-ray Imaging

JOM ◽  
2020 ◽  
Vol 73 (1) ◽  
pp. 201-211 ◽  
Author(s):  
Benjamin Gould ◽  
Sarah Wolff ◽  
Niranjan Parab ◽  
Cang Zhao ◽  
Maria Cinta Lorenzo-Martin ◽  
...  
Keyword(s):  
High Speed ◽  
In Situ Analysis ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
X Ray ◽  
X Ray Imaging

In-Situ Monitoring of Laser Powder Bed Fusion Process Anomalies via a Comprehensive Analysis of Off-Axis Camera Data

2020 ◽  
Author(s):  
Chaitanya Krishna Prasad Vallabh ◽  
Yubo Xiong ◽  
Xiayun Zhao
Keyword(s):  
Real Time ◽  
Network Architecture ◽  
Video Data ◽  
In Situ Monitoring ◽  
Process Efficiency ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Monitoring Method ◽  
Powder Bed

Abstract In-situ monitoring of a Laser Powder-Bed Fusion (LPBF) additive manufacturing process is crucial in enhancing the process efficiency and ensuring the built part integrity. In this work, we present an in-situ monitoring method using an off-axis camera for monitoring layer-wise process anomalies. The in-situ monitoring is performed with a spatial resolution of 512 × 512 pixels, with each pixel representing 250 × 250 μm and a relatively high data acquisition rate of 500 Hz. An experimental study is conducted by using the developed in-situ off-axis method for monitoring the build process for a standard tensile bar. Real-time video data is acquired for each printed layer. Data analytics methods are developed to identify layer-wise anomalies, observe powder bed characteristics, reconstruct 3D part structure, and track the spatter dynamics. A deep neural network architecture is trained using the acquired layer-wise images and tested by images embedded with artificial anomalies. The real-time video data is also used to perform a preliminary spatter analysis along the laser scan path. The developed methodology is aimed to extract as much information as possible from a single set of camera video data. It will provide the AM community with an efficient and capable process monitoring tool for process control and quality assurance while using LPBF to produce high-standard components in industrial (such as, aerospace and biomedical industries) applications.

scholarly journals Types of spatter and their features and formation mechanisms in laser powder bed fusion additive manufacturing process

2020 ◽  
Vol 36 ◽  
pp. 101438
Author(s):  
Zachary A. Young ◽  
Qilin Guo ◽  
Niranjan D. Parab ◽  
Cang Zhao ◽  
Minglei Qu ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Process ◽  
Formation Mechanisms ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed
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