Wire and Arc Additive Manufacturing is a novel Additive Manufacturing technology. As a result, the process for progressing from a solid model to manufacturing code, i.e. the Part Programming process, is undeveloped. In this report the Part Programming process, unique for Wire and Arc Additive Manufacturing, has been investigated to answer three questions; What is the Part Programming process for Wire and Arc Additive Manufacturing? What are the requirements on the Part Programming process? What software can be used for the Part Programming process? With a systematic review of publications on Wire and Arc Additive Manufacturing and related subjects, the steps of the Part Programming process and its requirements have been clarified. The Part Programming process has been used for evaluation of software solutions, resulting in multiple recommendations for implemented usage. Verification of assumptions, made by the systematic review, has been done by physical experiments to give further credibility to the results.

This research describes the process of manufacturing and machining of wire and arc additive manufactured (WAAM) thin wall structures on integrated and non¬integrated WAAM systems. The overall aim of this thesis is to obtain a better understanding of deposition and machining of WAAM wall parts through an integrated system. This research includes the study of the comparison of deposition of WAAM wall structures on different WAAM platforms, namely an Integrated SAM Edgetek grinding machine, an ABB robot and a Friction Stir Welding (FSW) machine. The result shows that WAAM is a robustly transferable technique that can be implemented across a variety of different platforms typically available in industry. For WAAM deposition, a rise in output repeatedly involves high welding travel speed that usually leads to an undesired humping effect. As part of the objectives of this thesis was to study the travel speed limit for humping. The findings from this research show that the travel speed limit falls within a certain region at which humping starts to occur. One of the objectives of this thesis was to study the effect of lubricants during sequential and non-sequential machining/deposition of the WAAM parts. Conventional fluid lubricants and solid lubricants were used. In addition, the effect of cleaning of deposited wall samples with acetone was also studied. A systematic study shows that a significant amount of solid lubricant contamination can be found in the deposited material. Furthermore, the results indicate that even cleaning of the wire and arc additive manufactured surfaces with acetone prior to the weld deposition can affect the microstructure of the deposited material.

Wire and arc additive manufacturing (WAAM) is a manufacturing method using a numerical controlled motion system and a welding system to additively manufacture three dimensional components. The motion system is programmed from three dimensional computer aided design model data (3D-CAD) of the intended geometry which is then sliced in to layers and welded on additively. There are seven process categories within additive manufacturing (AM), each with their own benefits and drawbacks. One of these process categories is directed energy deposition (DED) which uses an energy source to melt material onto a build plate. Instead of filling the build plate with material and selectively melting or sintering the material, DED only deposit material which is to be melted. WAAM is a process within the DED process category. BAE Systems Hägglunds manufactures relatively large components with requirements for mass reduction. Hägglunds has therefor invested in a WAAM laboratory, for testing and investigation on how to utilize this technology to their advantage. During the master thesis a geometrical correlation between the overhang angle and the material deposition on the edges of the overhangs has been found. A slicing strategy utilising this correlation has proven useful in combatting an issue where the top surface of a parallelepiped ends up unwantedly not parallel to the substrate plate. This master thesis has also increased the capability from 30° to 45° overhang angle. A numeric simulation of cooling times in the WAAM process has been developed. The simulation had a maximum error of one minute or about 69 % longer measured than simulated cooling time at worst case.

WAAM is a relatively unexplored additive manufacturing method. Although research in this area has been performed for some years and the hardware is relatively cheap, the method is not widely used. As the name suggest, it uses wire and an arc welding equipment to deposit beads on top of each other to create a geometry. As WAAM is a near net-shape method, the parts must be machined to its net-shape after the beads has been deposited. BAE Systems Hägglunds AB are investigating the use of WAAM in an industrial robot cell and this Master’s thesis has been written with the purpose of enabling the use of WAAM for manufacturing parts at the company. This report investigates how a part is prepared for WAAM and near net-shape machining. A formula for approximating the cost of manufacturing a part is investigated. A software for slicing a .STL file for generating a toolpath is developed in Matlab. The software then exports the toolpath to a code that the robot can read. It can also generate a digital model of the work piece for net-shape machining through CATIA macro. A model for calculating the cost of using the WAAM-cell once the toolpath for a part is known is presented. The investigated areas and the developed software are then applied to a part, and the results of the report is discussed.

Wire and Arc Additive Manufacturing (WAAM) is a novel Additive manufacturing method. It is a high deposition rate process which can be suitable for producing low to medium quantities of medium to large sized components. Because it is such a novel method, there are still somechallenges to solve for the method to be useful. This project have been focusing on how to dealwith these challenges and how to manufacture a torque arm with WAAM. This includes the process on how to go from a CAD model to a printed product. Tests have been done during the project parallel with the design of the torque arm. The design have been modied according to the results from the tests. The result of the project was a more specic description how the softwares can be used to optimizethe process for a successful print. The used slicing software, Simplify3D, have some limitations and other options should be considered. Some limitations for the part design have been identied and some known challenges have been solved. The torque arm was successfully printed but with more time and refinement, the added offset could be reduced. The process was time consuming and needs to be more automated in the future. Some proposals on what should be further tested and evaluated is also stated in this report.

This thesis describes advancements in the modelling, optimisation, process control and mechanical performance of novel high deposition rate gas metal arc welding processes for large scale additive manufacturing applications. One of the main objectives of this study was to develop fundamental understanding of the mechanisms involved during processing with particular focus on single layer welds made of carbon steel using both pulsed-current gas metal arc welding and cold metal transfer processes. The effects of interactions between critical welding process variables and weld bead and plate fusion characteristics are studied for single and multi-layers. It was shown that several bead and plate fusion characteristics are strongly affected by the contact tip to work distance, TRIM, wire feed speed, wire feed speed to travel speed ratio, and wire diameter in pulsed-current gas metal arc welding. The arc-length control, dynamic correction and the contact tip to work distance are shown to strongly influence the weld bead geometry in the cold metal transfer process. This fundamental knowledge was essential to ensure the successful development of predictive interaction models capable of determining the weld bead geometry from the welding process parameters. The models were developed using the least-squares analysis and multiple linear regression method. The gas tungsten constricted arc welding process was utilised for the first time for out-of-chamber fabrication of a large scale and high-quality Ti-6Al-4V component. The main focus was, however, in the use of the cold metal transfer process for improving out-of-chamber deposition of Ti-6Al-4V at much higher deposition rates. The effect of the cold metal transfer process on the grain refinement features in the fusion zone of single layer welds under different torch gas shielding conditions was investigated. It was shown that significant grain refinement occurs with increasing helium content. The morphological features and static mechanical performance of the resulting multi-layered Ti-6Al-4V walls were also examined and compared with those in gas tungsten constricted arc welding. The results show that a considerable improvement in static tensile properties is obtained in both testing directions with cold metal transfer over gas tungsten constricted arc welding. It was suggested that this improvement in the mechanical behaviour could be due to the formation of more fine-grained structures,which are therefore more isotropic. The average ultimate tensile strength and yield strength of the as-deposited Ti-6Al-4V material processed via cold metal transfer meet the minima specification values recommended for most Ti-6Al-4V products. Neutron diffraction technique was used to establish the effect of repeated thermo-mechanical cycling on the generation, evolution and distribution of residual stresses during wire and arc additive manufacturing. The results show a significant redistribution of longitudinal residual stresses along both the substrate and multi-bead with repeated deposition. However, a nearly complete relaxation occurs along the built, once the base plate constraint is removed.