Dynamic Magnetic Alignment Boosts Remanence and Fabrication Reliability in DLP Manufacturing of Magnetic Functional Materials.

Abstract

Magnetic functional soft materials using hard-magnetic particles as inlays exhibit remarkable actuation and sensing performance, enabled by continuously evolving fabrication methods that achieve sophisticated structural and magnetization designs. Among these, magnetic field-assisted digital light processing (MFA-DLP) offers unique advantages in material design freedom, yet faces challenges including low remanence due to incomplete alignment and printing defects caused by pre-magnetized particles' aggregation. To address these limitations, this work proposes a dynamic magnetic field-assisted DLP (DMFA-DLP) method, where time-varying fields induce particle-level rotational dynamics and overcome interparticle attractive barriers, thereby ensuring homogeneous particle dispersion before each alignment cycle. Through such strategy, this approach enhances alignment efficiency, mitigates aggregation accumulation, and guarantees consistency across multiple alignment processes. Experimental results demonstrate that this method effectively improves alignment efficiency and boosts remanence, even doubling the alignment ratio (212%) at weaker alignment field. Various samples featuring complex structures and magnetic arrangements are fabricated to validate the method's manufacturing capability and enhanced reliability. A 10-mm-diameter, 24-pole magnetic ring is successfully produced and implemented as an angle sensor, demonstrating the method's capacity for fabricating high-resolution multi-directional magnetic patterns. This work overcomes fundamental limitations of MFA-DLP, establishing a robust platform for high-performance magnetic soft material manufacturing.