Binder injection additive manufacturing

Abstract

Purpose
This paper introduces binder injection, a novel hybrid process combining elements of material extrusion and binder jetting. The research paper aims to establish binder injection as a versatile, scalable and cost-effective method for producing geometrically complex parts using a diverse range of powdered materials, including low-cost and recycled options.

Design/methodology/approach
A modified delta 3D printer was adapted for binder injection additive manufacturing (AM). Experimental investigations were conducted to evaluate the effects of binder injection rates, nozzle-powder interactions and self-intersecting toolpaths. A wide range of binder-powder combinations was tested, and post-processing methods were applied to enhance part properties. Theoretical models predicting track geometry were developed and validated against experimental data.

Findings
Binder injection demonstrated high compatibility with varied materials, achieving build rates comparable to or exceeding other AM processes. The developed model accurately predicted track geometry under specific conditions. Post-processing methods significantly improved mechanical properties, with compressive strengths increasing by over 250% for certain materials. The process proved robust, enabling self-intersecting toolpaths without quality degradation.

Research limitations/implications
This study focused on adhesive and reactive binders, leaving scope to explore thermal, dissolving and displacing binders further. Future research should investigate multi-binder systems, smaller nozzle sizes for higher resolution and scalability through parallel printing.

Practical implications
Binder injection’s compatibility with low-cost and recycled powders suggests it potential as a sustainable method for producing large-scale parts, such as architectural elements and furniture. Post-processing methods further expand its applicability to high-strength applications.

Originality/value
This paper presents a novel AM process with industrial potential. The versatility and material inclusivity of binder injection suggest it has promise as a novel direction in sustainable manufacturing research.