## 3 Results and Discussion
### Benchmark Case: Simulation 1
EDM is an electrochemical process that can locally heat up the part and consequently locally affect the residual stresses, similar to the heat treatment itself. However, this work focusses on the aforementioned mechanical machining. The temperature simulation during the LPBF process is summarised in Figure 6. It shows the maximum temperature in the computational domain throughout the primary LPBF process. The maximum temperature reached during the process is the melting temperature of 1405 \({}^{\circ}\)C. This is expected, since the initial temperature in each element layer is the melting temperature, and there is no other heat source present in the simulation, which could increase the temperature. The graph in Figure 6  
Figure 5: Part geometry and process sequence; (**a**) the cantilever part that is used throughout this study; (**b**) the two different process sequences analysed in this work. In sequence A (top), the heat treatment immediately follows the primary LPBF process, before the part is removed from the base plate. Sequence B (bottom) reverses the order of the heat treatment and removal from the base plate. In the simulation, the beam simulated according to sequence A is in front, while the cantilever following sequence B is in the back. also shows the peaks in temperature, which are characteristic for the LPBF process. As expected, the number of peaks corresponds to the number of deposited element layers. Figure 7 shows the average temperature during the heat treatment. The temperature follows the imposed boundary condition, but obviously lags behind the prescribed profile. The remainder of this section will focus on the deformations and stresses in the part. Figure 8A shows the normal stresses in the longitudinal direction before the cantilever beam is cut from the base plate. The stresses in Figure 8A are shown at the surface of the part. As predicted, the stress at the top of the cantilever is in tension, while the bottom of the cantilever is subjected to compressive stress. Figure 8B shows the same longitudinal stresses in the centre of the first support for the horizontal beam, demonstrating the evolution from compressive to tensile stress. This is also illustrated in the normal stress on the cross-section of the cantilever in Figure 8D. It shows that the transition from compression to stress only occurs relatively close to the top surface of the part. Comparing the stress in Figure 8A to the one obtained by [PERSON] et al. [5] shows a similar profile of the stress field. When looking at the left-most support, the stress is highest on the top and the bottom, while dipping in between the two maxima. However, the precise value of the stress does differ; the simulations in this work predict a maximum stress, which is about three times larger: 1026 MPa compared to 330 MPa. This is most likely due to the different choice in material: [PERSON] et al. use an aluminium-silicon alloy, with a different thermal expansion coefficient, Young's modulus and yield strength. Similar stress profiles are shown in the works by [PERSON] et al. [48], [PERSON] and [PERSON] [49], [PERSON] et al. [50] or experimentally by [PERSON]  
Figure 6: The maximum temperature in the computational domain during the primary LPBF process. Figure 7: Average temperature in the computational domain during the stress relief heat treatment. et al. [51]. However, the work by [PERSON] et al. [24] indicates that this approach to model the LPBF process will result in an overprediction of the residual stress, both in the longitudinal and transversal directions. Additionally, the stresses in both beams before the post-processing are identical (illustrated in Figure 8C), allowing an easy evaluation of the effect of the change of the post-processing sequence. Finally, the deformation and stresses in the part after its release from the build plate are discussed. Comparing the stress before and after the part is heat treated but still attached to the build plate reveals that the maximal stress in the cantilever beam did not decrease significantly.