Abstract

The high degree of design freedom is a major advantage of additive manufacturing processes and enables the production of highly complex structures that cannot be realized with conventional manufacturing methods. This makes AM processes such as Powder Bed Fusion of Metal with Laser Beam (PBF-LB/M) an attractive option for different industries. However, the production process can be interrupted for various reasons. In addition to a planned pause, e.g., for the production of smart components, various technical issues can lead to an unwanted interruption of the process. In any cases, if the user continues the production process after an interruption, the temperature histories of the produced components and the PBF-LB/M machine are different compared to a non-interrupted process. The literature shows that the cool-down of the system and the components during the process interruption results in various types of component defects. According to our current state of knowledge, the formation of the interruption marks is the most critical defect resulting from a process interruption. Due to the resulting notch effect, the global component properties are often severely impaired even for short interruption times. The easiest way to eliminate the influence of the interruption marks is therefore to remove them by machining the components. An unplanned post-processing using traditional methods like milling or turning is usually difficult or even impossible as the necessary requirements for the component geometry are often not met. In many cases, machining is also not economically viable. In order to address this challenge, three different processing methods were tested in the present study: blasting, vibratory finishing, and manual grinding. These methods are not restricted in the mentioned way and can be used spontaneously to remove the marks quickly and simply. The extent to which the methods affect the surface, the geometry of the interruption marks and the residual stresses was investigated. Fatigue tests were performed to assess the capability of these methods to reduce the negative effects of a process interruption. The results show that the investigated post-processing methods have different effects on the component properties and fatigue strength. All three methods have shown that the negative effects of the interruption marks and thus the scrap rate due to an interruption in the PBF-LB/M can be significantly reduced using appropriate post-processing methods.

 

URL

https://link.springer.com/article/10.1007/s40964-025-01011-w