Hemming Process For Autobody Closure Of The Table-top Hemming Machine

Hemming is a complex manufacturing process frequently utilized in joining the inner and outer panels to assure the connection strength and appearance quality of the autobody closure during body welding. There is important theoretical significance and practical value to research the hemming machine structure and hemming process.Influence of different parameters on hemming quality and analysis about hemming machine were discussed mainly according to CAE software and experiments. The main contents are as follows:(1) Hemming process, hemming quality and process parameters are described first. Table-top hemming method is selected finally through the comparison for four different hemming technologies.(2) Influence of different pre-hem paths on the roll-in/out and hemming force is investigated. Among these paths could be vertical, horizontal, oblique and rotation. Vertical pre-hem path is a better choice according to the results.(3) Fraction factorial design is used to obtain three factors which have a big influence on roll-in/out among several factors. And then a roll-in/out response surface model is created to research these three factors further and their interaction. Nonlinear regression model and contour plots are presented.(4) Corner hemming mechanism and corner hemming steel are designed and corner hemming experiments are conducted. This mechanism can be used on corner hemming and arc-shaped cross section hemming steel make a better performance according to the experiments.(5) Dynamics simulation is conducted for two different climbing mechanisms (screw-toggle and triangle toggle link) based on ADAMS. The results show that triangle toggle link climbing mechanism can be a better choice. Fatigue life of the hemming steel is estimated through the nominal stress-finite life method.