| Abstract Scope |
Large-format 3D printing with thermoplastics is constrained by slow production, high material consumption, and limited design flexibility. We present a new method to overcome these limitations through Blow Extrusion (BX) 3D printing, which forms hollow strands by extruding and inflating tubes directly at the nozzle. This allows variable strand diameters (up to 1.5x nozzle size) and opens up new design possibilities. We implement this in two MEX processes: Fused Filament Fabrication Blow Extrusion (FFFBX), allowing multi-material and multi-color printing, and Fused Granular Fabrication Blow Extrusion (FGFBX), optimized for high throughput. Using custom-designed print heads and precise control of the air for inflation, BX significantly increases volumetric throughput (≥60 cm³/min), reduces material usage and weight by over 85%, and shortens cooling times. This approach benefits lightweight applications such as aerospace or façades, enables integrated functions like insulation, sensing, or actuation, and supports novel shapes for use in architecture and design. |