6. Case studyFigure 12 shows a thin

6. Case studyFigure 12 shows a thin-wall plastic moulded part with four through-hole under- cut features in the side surfaces. The parting direction and the parting lines are determined using the authors’ previous study and they are shown in figure 12a. Since all the parting line edges are in the same plane and the parting surfaces generated by extruding them to the bounding box are also in the same plane, hence, the type of parting surfaces belongs to flat parting. Based on the methodology to generate the parting surfaces and core/cavity blocks presented in this research, the four through-hole undercut features should be patched and the BRDO between the core/cavity bounding box and the moulding can be carried out. First of all, four respective characteristic undercut solids are generated and united to the moulding to patch the four through-hole undercut features in the moulded part. Next, a bounding box is generated. The dimensions of the bounding box are determined based on experience, considering the strength of the mould materials and the moulding par- ameters. In the practical computer-aided mould design system, these dimensions can be determined from built-in knowledge-based database. The parting surfaces are generated according to the known parting lines and then are sewn together. Finally, the bounding box is subtracted by the moulded part using BRDO and the bounding box is then split by the sewn parting surface. The two mould halves, namely the core and cavity blocks, are generated.