| About this Abstract |
| Meeting |
2023 AWS Professional Program
|
| Symposium
|
2023 AWS Professional Program
|
| Presentation Title |
Identifying Deposit Profile for Gas Metal Arc Directed Energy Deposition |
| Author(s) |
Sanghamitra Das, Amitava De |
| On-Site Speaker (Planned) |
Amitava De |
| Abstract Scope |
INTRODUCTION:
Gas metal arc direct energy deposition (GMA-DED) is capable of fabricating a three-dimensional part with a high deposition rate from a filler wire feedstock but maintaining a good dimensional consistency of the parts is a major challenge. Fabrication of dimensionally accurate and defect free by trial and error involves long time and is expensive. A prior estimation of the deposit profile using a computational model is an efficient recourse to help design of GMA-DED process. Such a computational model, based on suitable mechanistic relations and validated with contemporary experimental measurements, can further provide an insightful quantitative understanding of the process. (100 words)
TECHNICAL APPROACH:
GMA-DED involves melting of a filler wire under an electric arc and deposition of molten droplets on a substrate. As the filler wire droplet touches and wets the substrate, it spreads gradually till it attains a final shape. The spreading of the droplet is encouraged by surface tension force but opposed by the viscous force. The equilibrium contact angle between the filler wire droplet and the substrate also influences the nature of spreading of the filler wire droplet. The final shape of the filler wire droplet as it will solidify will be a function of these competing forces and the contact angle. An analytical approach is developed considering these factors in a simple yet realistic manner to estimate the spreading of a filler wire droplet and the final shape of the solidified deposit as a function of important process conditions in GMA-DED. (141 words)
RESULTS AND DISCUSSIONS:
The transient temperature of a filler wire droplet on a substrate and its solidification time are computed analytically using Rosenthal’s quasi-steady-state solution considering the arc heat input in a simplified manner. The final shape of the filler wire droplet as it solidifies to form a bead is determined by minimizing the net energy encapsulated within the molten droplet. The shape of the solidified deposit cross-section is estimated in terms of its width (w), height (h) and the contact angle (θ) between the droplet and substrate in an iterative manner over the solidification time of the molten droplet. The analytically computed deposit cross-sections are validated with the corresponding experimentally measured deposit profiles for single-layer multi-track and multi-layer multi-track depositions for a range of GMA-DED process conditions and filler wire alloys. The overall range of discrepancy between the analytically computed and the corresponding experimentally measured deposit cross-section profiles is found to be around 10 to 15%. (154 words)
CONCLUSIONS:
An in-depth understanding of the underlying mechanism in GMA-DED process is developing and has significant research scope. Trials and error experiments to realize the inherent impact of the process conditions on the deposit profile and associated defects such as dimensional inconsistency and lack-of-fusion are time consuming and expensive. A simple and easy-to-use analytical model is proposed here to estimate the cross-section profile of the deposited tracks / layers during GMA-DED as a function of important process conditions. It is envisaged that the proposed methodology shall aid in finding the suitable process parameters to achieve defect free and dimensionally consistent bead during GMA-DED. (100 words)
Keywords
Gas Metal Arc Directed Energy Deposition, Deposit profile, Surface energy, Contact angle |
| Proceedings Inclusion? |
Undecided |