The increasing adoption of offsite and industrialised construction highlights a need to better align architectural design decisions with manufacturing and assembly processes. While Design for Manufacture and Assembly (DfMA) principles are increasingly referenced in offsite construction, their application at the concept design stage remains limited. This paper presents the development of a design framework and associated computational model that links concept design decisions to the manufacturing parameters for producing timber-framed composite wall panels made on an assembly line. The framework is implemented through a parametric model developed in Revit–Dynamo to explore how concept-stage design changes impact production flow along an eight-station assembly line. Each station, cutting, joining, framing, insulation, windows, cladding, finishing and quality control, is represented as a rule-based module that calculates task durations, idle times, and cumulative throughput. The framework establishes a dynamic feedback loop between design inputs and manufacturing outcomes, allowing building designers to explore the implications of design decisions on time and cost, line balancing and bottleneck rates in manufacturing. Verification with industry experts is ongoing; preliminary testing demonstrates the framework's potential to visualise assembly-line performance and identify design-driven bottlenecks, idle times, and manufacturing inefficiencies. The paper contributes a novel approach for adding DfMA logic within a computational design tool, supporting a transition toward more integrated, data-driven, and manufacturing-aware architecture and design processes.