Investigation of aging processes of Ti-6Al-4V powder material in laser melting

Laser melting of titanium material, e.g. Ti-6Al-4V, offers great potential in manufacturing automotive components, lightweight structures and medical implants. In order to achieve required mechanical properties of laser melted components quality of powder materials is essential. Unmelted powder is recycled and reused in a subsequent process. Due to repeated recycling it is suggested that powder material changes. In this paper aging processes of Ti-6Al-4V powder are studied. It was observed that powder particles coarsen and flowability increases. Comparing examined powder characteristics to bulk material properties it was noticed that there are significant effects of aged powder on laser melted components

Laser additive manufacturing of modified implant surfaces with osseointegrative characteristics

Additive Manufacturing technology, such as Selective Laser Melting, allows fabrication of complex metal parts with freeform surfaces. Using biocompatible metal alloys, e.g. TiAl6V4, medical implants can be produced. To increase osseointegrative behavior the ability to fabricate filigree lattice structures can be utilized to achieve a modified implant surface. In order to increase dimensional accuracy when applying a lattice structure on a curved surface, process constraints for single lattice bars are studied. The investigated lattice structure was thereupon applied on the surface of a medical implant. © 2011 Published by Elsevier Ltd.European Regional Development Fund and the Investitions- und Förderbank Niedersachsen – NBank

Low coherence interferometry in selective laser melting

© 2014 The Authors. Published by Elsevier B.V. Selective Laser Melting (SLM) is an additive layer manufacturing technology that offers several advantages compared to conventional methods of production such as an increased freedom of design and a toolless production suited for variable lot sizes. Despite these attractive aspects today's state of the art SLM machines lack a holistic process monitoring system that detects and records typical defects during production. A novel sensor concept based on the low coherence interferometry (LCI) was integrated into an SLM production setup. The sensor is mounted coaxially to the processing laser beam and is capable of sampling distances along the optical axis. Measurements during and between the processing of powder layers can reveal crucial topology information which is closely related to the final part quality. The overall potential of the sensor in terms of quality assurance and process control is being discussed. Furthermore fundamental experiments were performed to derive the performance of the system