Multi-piece mould design is a moulding technology that involves three-dimensional spatial construction of two or more mould pieces in a manner similar to assembling/dissembling a three-dimensional puzzle to build production parts. Using such a moulding technology, complex parts with intricate geometries can be made for limited run productions. Compared to traditional two-piece moulds and rapid prototyping, the multi-piece mould approach has many advantages with respect to part complexity and production speed, etc.; however, the technology has challenges in designing the actual multi-piece moulds. Previous methodologies address this problem primarily using heuristics. We present a multi-piece mould design MPMD framework that is based on a mixed-integer programming approach. The method constructs the MPMD by minimising the number of mould pieces that is required for a given Computer-Aided Design CAD model. The solution strategy for the formulated linear mixed-integer optimisation problem is presented. The algorithmic strategy for solving the resulting mixed-integer programming problem is also provided with examples that illustrate the effectiveness and efficiency of the approach.