@misc{Bhatti, type = {Master Thesis}, author = {Bhatti, Saad Ali}, title = {Investigating the possibilities of AC GMA welding for in-situ alloying in additive manufacturing}, school = {Hochschule Rhein-Waal}, abstract = {Additive manufacturing is a transformative approach of building 3D objects by layer-upon-layer method, adding digital flexibility and efficiency into the industrial production process. Different categories of materials such as plastics, metals, concrete, etc., can be used for Additive Manufacturing. At present, WAAM (Wire Arc Additive Manufacturing) is of high interest for many industries, as it allows creating large-scaled metallic components of moderate complexity with high density and good mechanical properties. In this master's Thesis, the capabilities of Gas Metal Arc (GMA) welding for in-situ alloying in multi-material WAAM are being investigated. A 6-axis FD-V6 welding robot by OTC Daihen along with Welbee W400 power supply was used to produce weldments both, with alternating current (AC), as well as pulsed direct current (DC). Two of Photron's High-Frequency cameras were used to investigate the process behavior. An All-in-one oscilloscope, Yokogawa DL850E ScopeCorder, was used to record the voltage and current signals. Single-layer, straight weldments were made to investigate the impact of different welding parameters over the weld seam shape and deposition rate. Later, the setup was extended to induce cold wire to change the chemical composition of the weld seams by in-situ alloying. Therefore, a clamp with adjustable angle, height, and distance was created to position the cold wire feeder along with the GMA welding nozzle. Cross-sections of weldments were taken to extract geometrical information related to the weld seam. In the end, combined experiments were done to investigate the process capabilities of generating weld seams of equal shape but different chemical composition by changing the wire feed speeds and the process parameters. This was the fundamental step for making the process ready for multi-material additive manufacturing. To demonstrate the process performance, two multi-material demonstrator components have been manufactured at the end of the thesis.}, language = {en} }