<p>The introduction of powder bed fusion (PBF) is crucial for advancing the next-generation automotive industry. However, the PBF faces challenges such as size constraints and difficulties in mass production, necessitating effective welding methods to integrate PBF-produced components with conventionally manufactured counterparts. Among various welding methods, integrating resistance spot welding in the assembly of PBFed products with conventionally fabricated ones may address the inherent PBF challenges. But, our findings revealed that during the resistance spot welding of PBF-fabricated stainless steel (STS) 316L, excessive heat generation caused weld expulsion at relatively low welding current. This expulsion reduced the effective weld volume, resulting in significant degradation in weld strength. To understand the root cause of this phenomenon, this study investigated the origin of the excessive heat and its impact on weldability when connecting the PBFed parts to CRed counterparts. The results show that welding PBF-produced STS 316L to CR-produced STS 316L generated significant heat due to the high surface roughness and unique microstructure of the PBF material. These factors led to weld expulsion and decreased weldability. However, by analyzing these thermal characteristics, we optimized welding parameters and enhanced mechanical properties. Ultimately, we demonstrate that PBF-produced components can be effectively welded to traditionally manufactured parts, providing crucial insights for improving the integration of PBF components in the automotive industry.</p> Graphic Abstract <p></p>