Defects in L-PBF
Common defects of the L-PBF process
Laser Powder Bed Fusion is a complex process with a multitude of causes that can lead to defects in the final parts. In this section we have summarized some of the most common defects and the reason behind them that can occur during data preparation, the AM process itself and during post processing.
What you will find in this section
Disregard of design guidelines
Reason
- Insufficient wall thickness
- Unsupported structures like overhangs and holes
- Orientation of the part
Mitigation
- Follow design rules of the specific process and material
- Optimize process parameters depending on geometry.
Insufficient 3D CAD data
Reason
- Resolution of stl file too low
- Defect stl file
Mitigation
- Adapt CAD program settings (increase resolution of tesselation)
- Adapt conversion settings and repair STL file
Poor powder quality
Reason
- Insufficient flowability due to particle shape and size, humidity and virgin powder
- Contamination due to poor recycling process
Mitigation
- Improve storage of powder
- Follow giving handling and recycling guidelines
- Check regularly
Deformation
Reason
- Process induced internal stresses
- Insufficient support structures
- Poor orientation
Mitigation
- Improve support structures, orientation, process parameters and scanning strategy
Incorrect process parameters
Reason
- Energy input too low / high
- Poor scanning strategy
Mitigation
- Development of robust material and part specific process parameters
Insufficient heat treatment
Reason
- Incorrect heat treatment parameters (e.g. temperature, duration, inert gas)
Mitigation
- Improve heat treatment in accordance to material and part design