Traditional design-for-manufacturing (DFM) strategies focus on efficiency and design simplification and tend to be too restrictive for optimization-based design methods; recent advances in manufacturing technologies have opened up many new and exciting design options, but it is necessary to have a wide design space in order to take advantage of these benefits. What is needed is a simple but effective approach for restricting the design space to designs which are guaranteed to be manufacturable, but which leave intact as much of the design space as possible. Work has been done in this area for some specific domains, but a general method for accomplishing this has not yet been refined. This article presents an exploration of this problem and developed a framework for mapping practical manufacturing knowledge into mathematical manufacturability constraints in mechanical design problem formulations. The steps for completing this mapping and the enforcing the constraints are discussed and demonstrated. Three case studies (a milled heat exchanger fin, a 3-D printed topologically-optimized beam, and a pulley requiring a hybrid additive-subtractive process for production) were completed to demonstrate the concepts; these concepts include problem formulation, the generation and enforcement of the manufacturability constraints, and fabrication of the resulting designs with and without constraints.