The development of flexible, reliable, and cost-effective microheaters is critical for applications requiring precise thermal management. This study presents a novel approach for fabricating flexible silver microheaters using a solution-based polyimide metallization process. By integrating the surface modification ion exchange (SMIE) method with electronic craft cutting, we enhanced electrode adhesion and achieved consistent pattern quality, making the fabrication process more accessible and scalable. The heaters demonstrated excellent thermal properties with a high decomposition temperature of 620°C and enhanced thermal stability. Thermal characterization using thermogravimetric analysis and differential scanning calorimetry confirmed improved stability, whereas heating performance evaluation showed consistent temperature regulation. The heating performance tests showed rapid temperature increases, achieving approximately 160°C at 1.50 V and stable temperatures maintained for 60 min under continuous operation. Elemental composition and surface morphology analyses revealed a uniform distribution of silver particles and decreased porosity at higher voltages, enhancing electrical and thermal conductivity. X-ray Diffraction analysis confirmed increased crystallinity at higher voltages, which was correlated with improved material quality. The mechanical durability tests indicated that the heaters could withstand over 5000 bending cycles without significant performance degradation, confirming their robustness for flexible applications. This approach presents a scalable, low-cost alternative to traditional microheater fabrication, opening new opportunities in wearable electronics and point-of-care diagnostics.