Current research on design and fabrication of planar part assemblies focuses on generative design methods, leaving analysis and evaluation of assemblability to be studied with empirical methods such as physical mockups. As a consequence, there is little understanding on whether a design is assemblable, or on how much time the assembling process might take. This paper proposes a new formal method to evaluate assemblability of interlocking planar parts that uses Network Analysis to evaluate assembly structure and System Dynamics to evaluate performance of assembling process.