Cameras ensure quality during laser melting

Global, dynamic monitoring

Global process monitoring of the PBF-LB/M at different color and exposure settings with the IDS camera U3-3040CP-C-HQ Rev.2.2 and the software IDS peak. © Aalen University

The U3-3040CP-C-HQ Rev.2.2 delivers high image quality even in low light and with fast movements. This is ensured by the global shutter CMOS sensor IMX273 from Sony's Pregius series with its sensitivity and dynamic range. With a resolution of 1.58 megapixels (1456 x 1088 px), it achieves a frame rate of 251 frames per second - ideal for detailed video and image analysis of dynamic processes. "Depending on the setting of the industrial camera, various process characteristics such as material evaporation or the quantity and direction of splashes can be observed and quantified during the PBF-LB/M," says Kolb, describing the application. "The knowledge gained from this provides us with important information to understand the laser-material interactions of the additive manufacturing process in greater depth and to be able to individually adjust the manufacturing parameters depending on the material or, for example, the component geometry."

To determine suitable process parameters, cube-shaped test components were first manufactured and the entire production process was analyzed using a USB3 uEye CP camera. This made it possible to determine the optimum laser parameters for manufacturing new types of soft magnetic components from the difficult-to-process iron-silicon alloy FeSi6.5 (6.5% by weight silicon) - a material with great potential for more efficient electric motors.

Additively manufactured soft magnetic stator half-shell of a transverse flux machine made of FeSi6.5 on a construction platform. © Aalen University

Based on this, a stator half-shell made of FeSi6.5 was developed, which is specially tailored to the requirements of transverse flux machines thanks to its optimized 3D magnetic flux guidance. Thanks to the high electrical resistance of the material and the design freedom of the PBF-LB/M process, eddy current losses can be reduced, power density increased and additional functions such as integrated cooling structures implemented. Such complex geometries and the brittle material FeSi6.5 can hardly be realized with conventional manufacturing processes - this is where additive manufacturing shows its particular strengths.

Observation of the powder layers

Certain camera properties are particularly important for the static, high-resolution observation of powder layers and component layer geometries. The sensor must be able to recognize details below 40 µm in order to reliably identify defects in the layers. At the same time, an image field of at least 100 mm × 100 mm and a format that is as square as possible (1:1) are required. The U3-3990SE Rev.1.2 industrial camera with 20.36 megapixels (4512 × 4512 px) meets these requirements. It is equipped with the large-format 1.1" IMX541 CMOS sensor from the Sony Pregius S series, which offers high resolution and performance. Thanks to BSI technology ("Back Side Illuminated"), it enables smaller pixels (2.74 µm), higher resolution and improved quantum efficiency and sensitivity.

"Thanks to the particularly user-friendly IDS cameras, which can be flexibly integrated, the necessary adjustments to the test setup could be implemented quickly and easily, allowing the USB3 uEye SE to be positioned at a defined angle," explains Kolb. The almost vertical observation of the individual powder component geometry layers will provide valuable insights into the component quality and potential manufacturing errors once the final adjustments have been made. In this way, crucial information about the properties of additively manufactured components can be obtained and used specifically to optimize the manufacturing process.

Research in the field of PBF-LB/M is crucial for developing new alloys and producing high-performance component geometries - sometimes even as multi-materials. A better understanding of the process helps to avoid defects and realize designs that would not be possible with conventional methods. IDS cameras provide valuable insights into the process and support research, development and technology transfer, for example in the processing of new materials or the production of complex, application-specific components.

In future, artificial intelligence will be used to automatically evaluate dynamic and static process monitoring. This will make it possible to analyze spatter formation, its trajectories and the formation of defects even more precisely. The aim is to better understand the highly dynamic interaction between laser and material and to further optimize the process in terms of resource efficiency and sustainability.