The integration of manufacturing planning activities into early design decisions is paramount. Manufacturing constraints and opportunities should be investigated early in a product development (PD) stages to launch products successfully. Set-based concurrent engineering (SBCE) paradigm is pronounced in literature and believed to form the foundation of lean thinking in PD. In SBCE, alternative product-subsystems are explored simultaneously and weak design choices are progressively eliminated as more knowledge about manufacturability becomes known. However, there is a methodological gap on how to execute SBCE in practice and integrate manufacturing process planning.This paper aims at conceptualizing the requirements to start manufacturing planning in the realm of SBCE paradigm. At the same time, the paper proposes a dialogue mechanism through which designers and manufacturing process planners are able to explore and evaluate alternative conceptual designs and process plans in parallel. Moreover, the methodology enables design and process knowledge to be effectively integrated for a better decision making.