Camera-based high precision position detection for hybrid Additive Manufacturing with Laser Powder Bed Fusion

Abstract

Additive manufacturing (AM) in general and laser powder bed fusion (PBF-LB/M) in particular are becoming increasingly important. Especially the high achievable accuracies and the great freedom in design makes PBF-LB/M interesting for the manufacturing and repair of gas turbine blades. Part repair involves building AM-geometries onto an existing component. To minimize the offset between component and AM-geometry, a precise knowledge of the position of the component in the PBF-LB/M machine is mandatory. However, components cannot be inserted into the PBF-LB/M machine with repeatable accuracy, so the actual position will differ for each part. For an offset-free build-up, the actual position of the component in the PBF-LB/M machine has to be determined. In this paper, a camera-based position detection system is developed considering PBF-LB/M constraints and system requirements. This includes finding a suitable camera position and analyzing the process coordinate systems. In addition, a workflow is developed to align different coordinate systems and simultaneously correct the perspective distortion in the acquired camera images. Thus, position characteristics can be determined from images by image moments. The precision of the system developed is evaluated in tests with 2D objects. A precision of up to 30 µm in translational direction and an angular precision of 0.021° is achieved. Finally, a 3D demonstrator was built using the hybrid process. The offset between base component and AM-geometry is determined by 3D scanning and is 69 µm.

Enhancing Additive Restoration of Damaged Polymer Curved Surfaces through Compensated Support Beam Utilization

“…Currently, prevalent additive manufacturing methods for repair encompass powder bed fusion, directed energy deposition, and cold spray additive manufacturing. B. Merz et al [13] conducted the repair of gas turbine blades utilizing laser powder bed melting technology. With the aim of overcoming the technical challenge of the irrecoverable loss of mechanical properties caused by the high heat input of traditional fusion welding, Hamilton et al [14] determined different parameters for directed energy deposition (DED), maximizing the strength and fatigue life of repaired cast iron, while A. Saboori et al [15] explored the application of directed energy deposition in the repair process.…”

Tensile and Low‐Cycle Fatigue Behavior of Laser Powder Bed Fused Inconel 718 at Room and High Temperature

“…Frequently cited benefits of metal AM include geometric design flexibility, mass customization, weight, and operating cost savings as well as opportunities for waste reduction, shortening of process chains, the possibility to produce parts with compositional gradients and integrated functionality, and for component repair. [1][2][3][4] Laser powder bed fusion (PBF-LB/M) is the most widespread metal AM technology. PBF-LB/M also has the possibility to specifically adjust the microstructures (e.g., crystallographic textures, grain sizes, substructures) via the process parameters and even to generate appropriately graded microstructures (tailored to the operating conditions).In terms of its application, manufacturing component for safety-critical applications is now also becoming a focus of interest.…”