High accuracy manufacturing of large parts
Intensive high-precision manufacturing of large parts (i.e. those over 10 m in length) can provide a welcome boost to European manufacturing. The EU-funded MEGAROB (Development of flexible, sustainable and automated platform for high accuracy manufacturing operations in medium and large complex components using spherical robot and laser tracker on overhead crane) project worked on overcoming major challenges associated with manufacturing and repairing such bulky parts. Generally, the lack of positioning accuracy arising as the size of the machine increases leads to an important gap between precision of small parts and large ones. Against this backdrop MEGAROB developed an automated system that produces close tolerance parts. The demonstrator is based on robotics and performs high-precision manufacturing on large pieces found in different industrial sectors. These include wind energy and civil engineering as well as aeronautics, rail and shipping. The high-accuracy prototype robotic system was mounted on an overhead travelling crane, monitored using a laser tracker system and controlled by a high-level control system along with the necessary software. This structure covers a very large work area and allows the robotic components to operate in a huge workspace. As such, the work area is split into discrete 3D cubes. MEGAROB incorporates different manufacturing processes such as milling, drilling, deburring, grinding, polishing, riveting, screwing, welding, coating and painting. In future, it could be adapted for additive or hybrid manufacturing. The system multifunctionality eliminates the need to invest in stand-alone machines that usually perform the production sequence step by step. The prototype, which is 20 m x 6 m x 5 m in size with an industrial robot and crane, was tested in manufacturing a composite beam and a windmill blade. It demonstrated an accuracy of +-0.3 mm on parts that are 10-12 m in length. The results were disseminated through the project website and through a video on YouTube, as well as through the media and workshops. The accuracy of big machines is based on their mechanical design. The flexible multi-process manufacturing machine under development is expected to reduce the investment of European factories in production machines as well as manufacturing and repairing times. With this in mind, the project partners have decided to exploit the outcomes of the project and have set ambitious plans to achieve this aim.
Keywords
Manufacturing, mechatronic, robotic, MEGAROB, industrial robot
