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- Title
Development and evaluation of a closed-loop z-axis control strategy for wire-and-arc-additive manufacturing using the process signal.
- Authors
Hölscher, Lennart Vincent; Hassel, Thomas; Maier, Hans Jürgen
- Abstract
Wire-and-arc-additive manufacturing (WAAM) is an additive manufacturing technology with a high deposition rate. WAAM usually employs a layer wise build-up strategy. This makes it necessary to know the height of each deposited layer to determine the height the z-axis has to travel after each layer. Current bead geometry models (BGM) lead to variations, which can gradually accumulate over the layers. The present study focuses on the development of a closed-loop control system capable of keeping the contact tube working distance (CTWD) constant during short-circuit gas metal arc welding (GMAW) based WAAM. The algorithm calculates the CTWD based on the resistance during the short circuit. The closed-loop strategy is compared to an open-loop control strategy, which moves along a predefined height step after each layer. Using the proposed control strategy, WAAM becomes a fully automated process without the need for preliminary experiments to determine the height step. Only a short calibration slope is necessary for a complete closed-loop additive build-up. To study the influence of the control strategy on the workpiece the energy input, mechanical strength, microhardness, porosity, and microstructure were analyzed. It is shown that the CTWD of the open-loop deposited component increases slowly. Due to the novel control approach, this is prevented by the closed-loop control, while the mechanical strength and microhardness remain.
- Subjects
GAS metal arc welding; MANUFACTURING processes; SIGNAL processing; CLOSED loop systems; GEOMETRIC modeling
- Publication
International Journal of Advanced Manufacturing Technology, 2023, Vol 128, Issue 3/4, p1725
- ISSN
0268-3768
- Publication type
Article
- DOI
10.1007/s00170-023-12012-w