Development of a kinematic scheme for an advanced stretch bending press

The article focuses on the development of a new kinematic scheme for an advanced stretch bending press designed for manufacturing aircraft frame segments. An analysis of existing technologies for frame production was conducted, including milling from plates, isothermal stamping, and stretch bending. The main disadvantages of traditional stretch bending presses were identified, particularly the occurrence of blank compression during bending due to improper positioning of the rotation axes of pivot arms. A new kinematic scheme has been proposed that involves moving the rotation axes of pivot arms during the bending process, which completely eliminates material compression and enables pure tension operation. A mathematical model of the ideal blank trajectory without compression was developed, and the trajectory for moving the centers of rotation of bending levers was determined. The structural implementation of the new scheme using lead screws and guide sliders is presented. An economic analysis demonstrates significant advantages of the developed technology: a reduction in manufacturing cost by 110 thousand rubles and processing time by 17 hours compared to traditional milling.