The inner and outer car panels for bonnet, door, and trunk lid are assembled by hemming rather than welding. To achieve successful fabrication of these panels, the complicated timing chart of hemming units for pre-and main hemming stages should be made to optimal one. In this study, a design system for automatic timing chart generation is developed. Using AutoCAD VBA and EXCEL data chart, hemming die design parameters and guidelines were put into the program to give hemming unit drawings and consequent timing charts. Then the prepared timing charts were checked and modified. The effectiveness of the system is verified by applying it successfully to hemming unit design for bonnet panel joining.