"Development of surface parameter in L-PBF - time to adjust the contour area!"
The development of surface parameter is strongly underestimated in L-PBF. The reason for this is the resulting dependencies on the previously developed volume area ("hatch"), border porosity and the resulting dimensional accuracy of the printed components.
If one has previously managed to create a high density component, everything can change again during the development of the surface parameters. Border porosity (small pores between volume and contour) can occur if the energy is not adjusted perfectly. The final result shows a nice looking component on the outside, but the pores accumulate in the inner contour area and the desired performance of the component is not longer achievable.
Therefore, there are again a number of parameters which have to be modified in studies to develop a robust surface parameter. Two simple parameters can be seen in the illustration below.
Pre-Contour: Here you first run the contour scan and then the volume scan (hatch). Advantages can be process reliability, porosity and subsequent dimensional accuracy of the part.
Post-Contour: First the volume and then the contour area. Advantages can also be derived here from the increasing robustness in the process and a lower level of porosity at the borders.
As always everything depends on pre selected material and parameters, which is why process engineers are still so important. 💪
In the next post, we will take a look at the overhang area. Then we can forget everything discussed and start again from zero. Additive is simply great! 😄
What was your first experience with the development of contour parameters? Have you passed the quality check directly? Looking forward to your experiences.