Another challenge is to get comparable information from completely different measurement techniques. Further on a subjective assessment of the surface quality by haptic testing is aimed at. For this purpose suitable test specimens are used and assessed through blind-testing by different test persons. Finally, we aim to get a correlation of subjective and objective assessment of different surfaces. The resulting surface quality for different machine parameters (e.g. layer thickness, laser and scanning parameters) and powder quality (virgin powder vs. used powder) is tested with the methods developed previously. Especially the orientation of a surface in respect to the layer orientation has a huge influence on the surface quality, too.
The post process is an important factor using the laser sintering process. In this part of the project the post process regarding the different post process parameter shall be investigated. For example at shot blasting the blasting time, the blasting distances as well as the blasting pressure are the most important parameters. Further on the blasting material shall be investigated as well. Next to the abrasive blasting method other promising methods like grinding and chemical etching will be used. The challenges here are also to find the right materials and parameters. Because of a lower surface quality, compared to injection molding, laser sintered parts are not used in visible areas of the manufacturing fields at the moment. The main focus is on a smoother surface with a minimal effort of manual labor.
The last part of the project deals with the ageing of post processed and untreated parts. Therefore the test specimens will exposed to light, humidity and temperature for different durations under laboratory conditions as well exposure to nature conditions. On one side the ageing will be simulated with a defined exposure of above mentioned impacts and then compared to ageing by real weather of Paderborn. Measurements will be done to evaluate the influences on surface quality.