ENERCON has opened its first flow production line for rotor blades in Aurich, Germany. Transportation was implemented on the basis of RoundTrack® technology from intra-logistics specialist STROTHMANN Machines Handling. RoundTracks® enable precise positioning without posing a barrier for forklift trucks and thereby prevailed over standard rails and chain conveyors. ENERCON constructed mobile production platforms that transport two rotor blade halves each.
Henry Ford was the first to systematically utilize the advantages of flow production. His recipe for success consisted of dividing the production process in chronological steps and their spatial separation. This enabled him to calculate and control throughput times and overall productivity. Each single station is equipped with the necessary material and tools. In comparison to box manufacturing, this saves a lot of space. It does, however, require well-organized supply logistics and suitable transport technology for the products. The latter point is all the more challenging the bigger, bulkier, and heavier the products are.
Making rotor blade production flow
ENERCON is the wind turbine provider with the largest vertical range of manufacture worldwide. The company produces generators, nacelles, concrete and tubular steel towers, controls, power electronics, various cast steel components, and of course the rotor blades which measure up to 50 m in length and weigh up to nine tons. The rotor blades are assembled from two halves that are manufactured by means of vacuum infusion: the fiberglass fabric laid out in the shells is saturated with epoxy resin under vacuum. This is a time-consuming process for which no economical automation solution exists yet. Through the new production organization, ENERCON achieves a much higher automation rate. The manufacturer constructed its own mobile work platforms for transporting the semi-finished rotor blades through the 463 m long factory hall. One platform can carry two half blades.
Which transport system is the right one?
ENERCON considered different transport systems including standard rails as well as chain conveyors. The company uses both technologies in other factories. But they did not fully meet the requirements in the new rotor blade factory. Among the choice of available rail transport systems, the RoundTrack® technology from STROTHMANN Machines Handling was the best for a variety of reasons. RoundTracks® are embedded in aluminum profiles in the floor with a precision of ± 1 mm per 5 m. A removable wedge profile secures the rails in place and enables them to be replaced at any time. This was an important feature for ENERCON: should the RoundTrack® ever be damaged, it can be easily removed, turned upside down, and replaced in the holding profile. There are additional advantages in comparison to standard rails. The wheels of the transport platforms have a concave running profile that only touches the rail at two points. The minimal contact surface ensures an extremely low rolling resistance and enables heavy loads to be moved with minimal energy. Since the rails only protrude a few millimeters from the hall floor, they pose no obstacle when walking or driving a cleaning machine or pallet truck across.
Installation of the transport system
RoundTracks® can be installed in existing as well as new buildings. If the floor needs to be opened, the cavities around the tracks are filled with non-shrinking, quickly drying mortar. Since ENERCON began planning early and the factory construction was still under way when the decision for RoundTracks® was made, the aluminum holding profiles could be installed directly before the screed was laid. STROTHMANN carried out the measurements, precise adjustment, and installation of the more than two kilometer long rail system. The transport platforms feature crossover mechanisms. When they reach the end of the production line, a second set of wheel assemblies mounted perpendicularly to the line is hydraulically lowered so that it takes the weight of the platform which can then be moved to one side and channeled back to the beginning of the line. ENERCON has constructed and implemented this solution with STROTHMANN providing the wheel sets which are also components of the RoundTrack® trolleys designed by the automation company.
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