Low-cost modular system for magneto-rheological testing in rheometers using 3D printing

In this study, a low-cost modular system was developed for the rheological characterization of ferrofluids under applied magnetic fields. The 3D-printed system is compatible with conventional rotational rheometers and includes two complementary components: a modular magnetic-field application accessory based on neodymium magnets and a gauge element for vectorial characterization of the magnetic field in a Cartesian coordinate system. This configuration enables alignment between the applied field and the rheometric geometry and provides clearance for future integration of thermal insulation or heating elements. Experimental validation was performed using magnetite ferrofluids in an ethylene glycol base at six solid concentrations ranging from 0.01 to 1 % Cv. The rheological response was evaluated under different magnetic field intensities, and measurements were performed in triplicate to assess repeatability and experimental dispersion. The results show that the proposed system is a practical and accessible platform for evaluating field-induced rheological variations in magnetic nanofluids within the tested operating range.