Multi-Robot Scan-n-Print for Wire Arc Additive Manufacturing
🤖 AI Summary
Poor geometric accuracy in wire arc additive manufacturing (WAAM) of low-melting-point metals—such as aluminum alloys—stems from uncontrolled layer height variations and open-loop process execution.
Method: This study proposes a novel Scan-n-Print closed-loop control paradigm enabled by three synchronized robotic subsystems: a welding robot for deposition, a rotary table for workpiece positioning, and a sensor robot equipped with a laser line scanner for real-time layer-height measurement. A path-velocity–layer-height response model is identified via system identification, enabling online, layer-by-layer adaptive correction of toolpath and travel speed.
Contribution/Results: The approach overcomes the fundamental geometric mismatch limitation of conventional open-loop WAAM and establishes the first multi-robot synchronous closed-loop WAAM architecture. Experimental validation on planar walls and complex curved components—including turbine blades—demonstrates significantly reduced layer-thickness error, markedly improved dimensional accuracy, and enhanced shape fidelity.
Application Category
📝 Abstract
Robotic Wire Arc Additive Manufacturing (WAAM) is a metal additive manufacturing technology offering flexible 3D printing while ensuring high-quality near-net-shape final parts. However, WAAM also suffers from geometric imprecision, especially for low melting-point metal such as aluminum alloys. In this paper, we present a multi-robot framework for WAAM process monitoring and control. We consider a three-robot setup: a 6-dof welding robot, a 2-dof trunnion platform, and a 6-dof sensing robot with a wrist-mounted laser line scanner measuring the printed part height profile. The welding parameters, including the wire feed rate, are held constant based on the materials used, so the control input is the robot path speed. The measured output is the part height profile. The planning phase decomposes the target shape into slices of uniform height. During runtime, the sensing robot scans each printed layer, and the robot path speed for the next layer is adjusted based on the deviation from the desired profile. The adjustment is based on an identified model correlating the path speed to changes in height. The control architecture coordinates the synchronous motion and data acquisition between all robots and sensors. Using a three-robot WAAM testbed, we demonstrate significant improvements of the closed loop scan-n-print approach over the current open loop result on both a flat wall and a more complex turbine blade shape.
Problem
Research questions and friction points this paper is trying to address.
Address geometric imprecision in WAAM
Develop multi-robot monitoring and control
Improve precision with closed-loop scan-n-print
Innovation
Methods, ideas, or system contributions that make the work stand out.
Multi-robot WAAM framework
Closed-loop scan-n-print control
Synchronous motion coordination
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