The paper deals with the integration of design, process planning and manufacturing using Constructive Solid Geometry (CSG) design operations. This integration is achieved by mapping CSG design operations onto manufacturing operations. The mapping is realised such that the manufacturability of the current design can be guaranteed while designing and that a right-first-time production can be realised. Especially the mapping of the CSG operator "unite two solids" onto the material removal manufacturing technique milling will be dealt with extensively in this paper. The chosen approach is described and explained using an example.