Influence of the press ram motion on the joining characteristics during indentation plastic joining using a servo press

•The influence of the press ram motion on the indentation joining characteristics of aluminum bar and plate was examined.•A high indentation speed during indentation joining produced desirable characteristics in the indentation joining process.•The accelerated ram motion reduced the indentation pressure by 15% and the bonding strength was improved by 7%.•The bonding mechanism was clarified in terms of the seizure and the mechanical clamping associated with the process. A plastic joining method for fixing bars and hot plates, called “indentation plastic joining”, was carried out using a servo press with press ram speed control. The influence of the press ram motion control on the indentation joining characteristics of an aluminum alloy bar and plate was examined. The accelerated ram motion was effective in reducing the bar indentation pressure by approximately 15% and the bonding strength of the indented bar–plate was improved by approximately 7%. The bonding mechanism underlying the indention joining method under press ram motion control is discussed in terms of the seizure of the plate and the mechanical clamping associated with the process. It is found that the accelerated ram motion produces heavier seizure at the indented bar–plate interface, whereas the decelerated ram motion reduces the degree of the seizure.