Wire arc additive manufacturing (WAAM) is developing quickly due to its advantages such as high productivity and low cost. Cold metal transfer (CMT) is the most well-known gas metal arc welding process (GMAW) which is widely used in WAAM. CMT is a unique process due to its minimized heat input compared to other welding techniques. However, the lower heat input impacts the geometry of the welding bead in the WAAM part. Similarly, Pulsed Multi Control (PMC) by Fronius provides controlled material deposition and bead geometry management through its advanced pulsing technique, offering a distinct approach within WAAM.

Institutions like GKN, Volvo Penta, BAE system among others use WAAM in their industryand the final geometry of the WAAM part determines the application of use in the manufacturing sector. Therefore, it is important to study the bead geometry of WAAM parts and to understand how different input parameters and conditions affect their geometry. To encourage wider adoption of the WAAM technique in various industries, it is imperative to conduct essential research into the mechanical characteristics of WAAM materials. In pursuit of this objective, we have conducted an extensive investigation into the correlation between the bead geometry and input parameters within WAAM processes.

The aim of this work is to examine the relationship between bead geometry and the low heat input WAAM process of CMT, and to compare these findings with those of PMC, another distinct variant within the GMAW spectrum. This process involves a comprehensive analysis of the metallographic samples, wherein penetration depth, bead width, height, and toe angle are measured with the assistance of advanced image software. The study involves a literature review with a focus on critical welding parameters, current, voltage and heat input, with an emphasis on understanding the distinctive influences of CMT and PMC in WAAM. Data measurements are conducted using the program Zeisscore 2.7 and the outcomes arethoroughly analyzed and presented in this report.

In this study comparing eight WAAM samples, we found that CMT, with its lower heat input, leads to shallower penetration and finer bead geometry. In contrast, PMC offers deeper penetration and wider bead dimensions. This highlights the necessity of choosing the right WAAM process (CMT or PMC) based on specific manufacturing needs, significantly influencing the quality and suitability of the final product.