Collaborative robot for composite manufacturing for the PASSARO project

Clean Sky 2 ITD-Airframe’s PASSARO project collaborates with Airbus Defence and Space (ADS) as one of the goals and contributions of ITD AIR to research and develop the concept of collaborative robotic composite manufacturing methods. The project’s activities are led by OPTIMAL and its main goal is to develop a practical and cost-effective automation solution that replaces traditional hand-laying with qualified materials.

Traditionally, composite prepreg assembly manufacturing is essentially a handcrafted activity, but steps are being taken to automate it. In the past decade, several relatively simple automated placement solutions for geometric parts have emerged. These solutions are often very expensive and often require the factory to be designed from the ground up for installation. As an alternative, collaborative robots can be integrated into existing manufacturing workflows to bring automation and productivity to certain tasks. This solution can be integrated without completely changing the surrounding environment. Industrial robots are fast, robust and have good accuracy and repeatability, but they were developed only for the optimization of the final result.

A special environment must be used, usually in the form of an isolated unit with a dedicated safety system. CoBot intelligently skips these requirements. They are slower, less accurate, and handle smaller payloads than before, but have the features needed to automate simple tasks, especially when used with humans, at a relatively low cost. These robots have load sensors that detect the smallest impact and stop safely. OPTIMAL’s goal in developing these technologies is to improve the ability of itself and other companies to provide better products, more repeatable, high volume and low price.

In PASSARO’s Work Package 10, three main steps were developed using a collaborative robot: layer picking and sorting directly from an automated laminate cutter; using a dedicated battery stripping layer; positioning and stacking in the tool. To achieve these activities, a unit was developed that receives the prepreg layers from the laminate cutter and automatically peels them off and stacks them on the mold.

The positioning and stacking tasks are done by robotic arms, which are achieved by prepreg treatment using special suction cups. The peeler is a more complex machine that uses compressed air to strip the prepreg. These materials are protected by two coatings, usually a plastic and a paper, or simply two plastics. The peeling concept is based on the fact that different materials tend to vibrate at different frequencies when the same stimulus is applied. Different vibration frequencies help create air pockets between the prepreg and the cover layer. The plate resonator adjusts the vibration amplitude of different materials. For a particular material, the prototype achieves a nearly 100% successful peel rate, and in each of the two degrees of freedom of the mold plane, the stacking accuracy is ±0.5 mm,

The system uses a modular approach that does not depend on the size of the layer. By adjusting the stripper opening range, add more parallel stripping modules and lengths to cover the width. Compared to operators, this technology can significantly improve process accuracy, repeatability, and especially cycle time, by up to 70%.