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Residual Stress Formation Mechanisms in Laser Powder Bed Fusion-A Numerical Evaluation
Moritz Kaess1, Martin Werz1, Stefan Weihe1
1Materials Testing Institute (MPA), University of Stuttgart, Pfaffenwaldring 32, D-70569 Stuttgart, Germany.
Materials (Basel, Switzerland)
|March 29, 2023
Summary
Laser powder bed fusion (LPBF) causes residual stresses and distortion. Preheating the build plate and reducing energy per unit length during LPBF of stainless steel 316L significantly lowers these issues, improving process safety.
Area of Science:
- Materials Science
- Manufacturing Engineering
- Mechanical Engineering
Background:
- Additive manufacturing, specifically laser powder bed fusion (LPBF), allows for complex geometries but introduces residual stresses and distortion.
- These defects negatively impact part quality, increase scrap rates, and can disrupt the manufacturing process.
Purpose of the Study:
- Investigate the mechanisms of residual stress and distortion generation in stainless steel 316L during LPBF.
- Identify methods to mitigate these effects, enhancing process safety and efficiency.
Main Methods:
- Utilized finite element modeling (FEM) to simulate the LPBF process at the scale of melt tracks and layers.
- Analyzed the influence of build plate temperature, laser power and speed, and layer thickness on residual stresses and distortion.
Main Results:
- Demonstrated a strong correlation between build plate preheating, energy per unit length, and the resulting residual stresses.
- Higher build plate temperatures and reduced energy per unit length were found to decrease residual stresses.
Conclusions:
- Optimizing build plate temperature and energy input is crucial for minimizing residual stresses and distortion in LPBF.
- Findings contribute to improved process control and reliability for stainless steel 316L additive manufacturing.
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