Handling Glue Issue on Thermal Bonding

Abstract

The Thermal Bonding process is a critical stage in smartphone assembly, where thermal glue is dispensed onto the mainboard to improve heat transfer between electronic components and the cooling system. Inconsistent glue weight may lead to insufficient or excessive glue, reducing thermal bonding quality, product reliability, and increasing manufacturing defects. Therefore, process parameter optimization is required to ensure consistent glue application and compliance with product specifications. This study aims to optimize the dispensing speed parameter of the Thermal Bonding machine to improve glue weight consistency. Root cause analysis was performed using a Fishbone Diagram, followed by the Design of Experiments (DOE) method to determine the optimal dispensing speed. The selected parameter was implemented and evaluated using 7QC Tools and process capability analysis to compare process performance before and after optimization. The results show that optimizing the dispensing speed improved process stability, reduced glue weight variation, and produced a more consistent glue weight distribution around the target specification. Process capability analysis also showed significant improvement, with the CPK value increasing from 0.86 before optimization to 12.57 after optimization, indicating that the optimized process consistently met the specified glue weight requirements. The optimized dispensing speed can be adopted as a standard process parameter to improve Thermal Bonding quality, production consistency, and smartphone product reliability.