Design for Manufacturing (DfM) involves trade-offs between design objectives and manufacturing cost/efficiency. However, contemporary software packages consider DfM in a unilateral (manufacturing centric) way. Ad-hoc rating systems used in these packages can lead to bad decisions. Also, uncertainty in estimating design attributes and manufacturing costs must be accounted for. This paper presents a theoretical framework for DfM that incorporates the above factors. The applicability and rationality of Benefit-Cost analysis to DfM is demonstrated. Present value of net benefit is proposed as the only rational measure of DfM. A domain independent shell for DfM analysis is developed. The shell can be customized for evaluating both technical feasibility and economics of manufacturing.