Fraunhofer ILT. launched a new LPBF (Laser Powder Bed Fusion)-preheating concept using VCSEL (Vertical Cavity Surface Emitting Laser), additive manufacturing materials and enhanced software for accurate cost and construction time calculations for LPBF processes.
The Fraunhofer Institute in Germany enjoys a worldwide reputation, focusing on optics and laser manufacturing technology. From the development of new laser beam sources and components to industrial laser processing, the institute has recently proposed innovative solutions.
Up to 2.5kW, working plane preheating, independent of total height
Direct process layer preheating is being developed, which is a perfect substitute for today’s preheating concept. The new concept is being developed as part of the digital photonics production DPP in the research park. The most important aspect of this direct process layer preheating technology is the integration of a vertical surface emitting laser (VCSEL) into the PBF laboratory setting. The new heating process uses a set of six vertical cavity surface emitting laser bars (VCSEL), each 400W , Installed in the processing room. By emitting 808nm infrared radiation, the array can heat the device to hundreds of degrees Celsius from above during the construction process. The bars can be controlled individually, making possible the sequence of different modes, and using infrared cameras to monitor the heating process.
In order to test the VCSEL heating technology, the project engineer manufactured a part. According to reports, the deformation of the part was significantly reduced and the part was heated to 500°C. The use of VCSEL heating reduced the thermal gradient and expanded the internal stress to make it possible to produce higher Components, while minimizing the risk of deformation or cracking.
The new method also provides opportunities for the manufacture of special difficult-to-process materials. Project engineers expect to start using titanium aluminum compounds for testing in the near future. For this material, the VCSEL method is used to heat the component to approximately 900°C. Titanium aluminides are commonly used in turbomachinery components, such as the hot gas part of turbochargers. In addition to turbomachinery, the process has also opened up new potential applications in other industrial fields, where the thermally induced stress in the AM process must be reduced.
