Standoff Distance Driven Control of Elementary Performance in Thin Wall Steel Structures Fabricated by CMT-WAAM
Year: 2026
Type: book-chapter
Abstract: Wire Arc Additive Manufacturing (WAAM) has emerged as a promising large-scale metal additive manufacturing technique owing to its high deposition rate and cost efficiency.Among various WAAM variants, Cold Metal Transfer (CMT) based WAAM is particularly attractive due to its low heat input and enhanced arc stability.However, geometric accuracy and mechanical integrity of thin wall structures remain highly sensitive to process parameters, especially the standoff distance (SOD) between the torch and the substrate.Despite its significance, systematic investigations on the influence of controlled SOD variation on microstructural evolution and mechanical behavior of thin wall WAAM components remain limited.The study produced thin walled ER70S-6 steel structures using CMT-WAAM while varying the standoff distance in a controlled, systematic manner.A robotic WAAM system was used to combine a Fronius TPS 400i welding power source with a six axis Fanuc ARC Mate 100iD robot.Mechanical properties were assessed using tensile tests, microhardness mapping, and impact tests, and the microstructure was examined by optical microscopy, SEM, and XRD.A deposition method based on controlled, layer by layer increases in SOD was carried out using custom robotic programming.The results indicate about standoff distance largely controls bead geometry, layer stability, dilution, and the degree of microstructural refinement.At the appropriate SOD, the material formed a fine equiaxed ferrite-pearlite microstructure, with higher tensile strength and more uniform hardness.A high SOD caused an unstable arc, increased porosity, and reduced mechanical properties.The study quantifies the relationship among SOD, thermal history, microstructure, and mechanical behavior, and explains the relationships to inform parameter selection for WAAM thin wall fabrication.
Institution: Visvesvaraya National Institute of Technology
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7204853190