With advancements in computational capacity, molecular dynamics (MD) simulations have emerged as a powerful tool for exploring the mechanical properties and dynamics of polymers. For instance, Ge et al. employed CGMD simulations to investigate the enhancement of interfacial mechanical properties in linear polymers. Their findings revealed that interfacial strength saturates before polymers diffuse by the distance of their radius of gyration and that the dominant failure mode shifts from interfacial chain pullout to chain scission as strength increases. Cunha and Robbins 23 examined the effect of molecular alignment on polymer diffusion and welding strength using CGMD simulations, reporting that the diffusion rate normal to the interface is independent of molecular alignment. Building on these modeling efforts, we begin our study with CGMD simulations of the welding phenomenon of linear and branched polymer of the identical building blocks. We conducted CGMD simulations to study the welding behavior of branched polymers with varying grafting densities. The CGMD simulation findings were subsequently verified with lap shear testing using commercially available linear and branched polyethylene. Our findings elucidate the underlying co-dependent factors of molecular weight and topology in the formation of a robust interface, providing an insight into the interfacial adhesion mechanisms that can significantly contribute to the optimization of material design and FDM processes, enhancing design flexibility and improving process efficiency. Additionally, this knowledge can enable the development of high-performance parts produced via FDM.