Abstract
Direct Energy Deposition (DED) is an additive manufacturing (AM) method that is quickly being adopted across industries all over the world. Wire Arc Additive Manufacturing (WAAM), a subset of DED technology, uses welding systems to deposit layers of weld to near net shape part finishes. WAAM technology offers versatility and speed in type and rate of material deposition, making it ideal to produce high-value, use-specific parts. However, the lack of studies on multi-bead and multi-layer printing limits the commercial viability of WAAM to simplistic geometry. This causes the commercial adoption of WAAM to be limited to basic shapes. In addition, commercially available WAAM slicing software is not readily available, increasing the cost of WAAM research. This gap in knowledge creates variable costs due to unknown variables in WAAM development. This thesis outlines the attempts to slice a pipe-like object for printing using WAAM. Initial material characterization was done to determine the viability of the selected material, as well as confirmation of selected key parameters. A test for overhang printing was also done. After the initial material characterization was done, different printing strategies were attempted to try and print a complete part. The part consists of multi-bead, multi-layer sections with overhanging regions, to be printed only in a 2.5D method. These restrictions posed both material and geometric challenges to printing the part. Two different methods, medial axis based slicing and inward contour propagation, were devised to address these issues. The benefits and problems caused by each method will be covered in this paper. Several issues were found during the development process. Firstly, inadequacies in current research makes multi-bead multi-layer WAAM 3D printing inaccessible. This paper will highlight the inadequacies of thin wall printing for characterization, and the negative effects of the proliferation of such results. In addition, the material characterization process commonly performed for thin-wall components is sorely inadequate for printing 3 dimensional parts with overhang features. A plethora of issues, geometric and otherwise, threatened to derail the project. Issues such as porosity, oxide ‘skin’ build up, as well as poor bead shape prediction all highlight the need for a more holistic material characterization process. In conclusion, the author hopes that this process outlines the current challenges faced in the development of WAAM printed parts. It is hoped that the future of WAAM can be made more accessible to the industry by stepping on the successes and shortcomings of this foray into a pipe dream.