Microscale mixing enables rapid, precise reactions and the synthesis of particles within a narrow size distribution, supporting a wide range of biomedical and chemical uses. However, widespread adoption of such microfluidic devices is constrained by cleanroom-dependent photolithography/DRIE. Moreover, low-Reynolds-number laminar flow suppresses turbulence, motivating active and accessible approaches. This work presents a sharp-edge acoustofluidic mixer fabricated using 3D-printed resin molds as a low-cost alternative to silicon microfabrication. PDMS devices were actuated by a piezoelectric transducer through a signal amplifier, and mixing performance was quantified from fluorescence videos by extracting cross-sectional intensity profiles (ImageJ) and computing a mixing index (Python). Collectively, these results deliver an optimized design that lays the groundwork for an integrated, portable, all-in-one mixing system.