A Multi-Inlet Extrusion System for Closed-Loop Spatial Profile Control in Large-Format Additive Manufacturing

Abstract

Rectangular nozzles are attractive for large-format additive manufacturing (LFAM) due to their improved deposition efficiency. However, single-inlet feeding of high-aspect-ratio nozzles inherently induces lateral pressure gradients, causing center-heavy flow and eliminating localized control during dynamic trajectories. We introduce a distributed multi-inlet extrusion testbed featuring three independently actuated inlets. Functioning as a programmable fluid manifold, this architecture actively manages the internal flow field. In-line laser profilometry is integrated as a continuous state estimator to quantify cross-sectional bead geometry. Experiments confirm this distributed architecture regularizes flow, achieving nominal steady-state extrusion with 33% less input flow and a 78% reduction in required plunger velocity per actuator compared to a single-inlet baseline. Furthermore, differential actuation enables high-resolution lateral steering and improves deposition under simulated outlet constraints with high allocation efficiency. This work establishes the hardware and state-estimation foundation for dynamically reconfigurable nozzle outlets by mapping inputs to spatial outputs.