Automated fixation of dry carbon fibre fabrics with RTM6 for autonomous draping and sensor-aided preforming

摘要

Manual preforming of dry CF-layers is still one of the biggest cost factors for infusion process. Compare to the manual preform process, the difficulty for the automated process lies in pick-and-place system, in gripper deformation depending on components curvature and in fixation of all the individual CF-layers. DLR has developed gripper for fully automated pick-and-place system, which can manage challenges caused by material properties such as low material rigidity and draping for complex geometry. Until now, thermoplastic binding material or double-sided adhesive tape was used for fixing the CF-layers. The main focus of this work is the combination of the newly developed fixation method with RTM6 resin and gripper system. Due to subsequent infiltration with the same resin additional binding material can be avoided. For new automated preform process fixing end-effector sprays automatically a thin layer of RTM6 (0,094 g/m) on the surface before placing the fabric. The resin quantity and spray position depends on CF-layer size and deformation of gripper. The resin can also be applied during the lay-up process. Thereafter adhesive bonding between two CF-layers or between CF-layer and mold is generated by applying a minimum pressure with the gripper. As the gripper is developed for best draping process the fixation area, where pressure must be applied, has been simulated. Only on these simulated position RTM6 has been sprayed automatically with robot. Afterwards the additional press-on movement for robot was realized with automatic pick-and-place system. This complete automated preform process has been validated on 4 m diameter Pressure-Bulkhead.