Manufacturability as a Verifiable Reward for CAD Code Generation

Design for Manufacturability (DFM) is a set of principles used by design and manufacturing engineers to optimize Computer-Aided Design (CAD) models for feasible and cost-effective product development. Recent work in text-to-CAD generation mostly optimizes for 3D similarity, ignoring manufacturing feasibility. To address this, we formalize manufacturability as a verifiable reward with deterministic and interpretable checks on the part's geometry based on DFM principles for three processes: Fused Deposition Modeling (FDM) printing, Computer Numerical Control (CNC) machining, and Injection molding. These checks are independent of any LLM acting as a judge and apply to any existing CAD dataset. We introduce a translator that converts CAD programs from FeatureScript to CadQuery, enabling training on a diverse set of objects and operations. Our post-training pipeline with SFT followed by GRPO on our DFM reward improves manufacturability scores across multiple datasets and manufacturing processes while preserving the original design intent.