The biggest tornado
7 meters in diameter. That's the size of the turntable they've made in Gernika. It will be used in the manufacture of wind
turbine tower rings. It is the largest mechanical turntable in the world; until now the largest one had a diameter of 5 meters and its size has made a real odyssey the work of manufacture that should have been habitual.
The main calculations had to be made to organize the structure in order to solve the problems that generated such large pieces.
ALAIN CLAVIER; TDG: The pieces to be joined and mounted on this lathe are very large and very heavy, of several tons. This has given us difficulties. On the other hand, maintaining accuracy has also been a problem.
Once the model is created, the manufacturing process of the piece itself begins. The first step is to make the mold.
The customer has submitted a 3-dimensional design. Programming is performed on this to start the subsequent mechanization.
The raw material is polystyrene plates of 500 x 1200 centimeters. To provide the required thickness, the plates are glued together until the desired dimension is achieved.
The numerical control milling machine mechanizes the plates, i.e., removes the excess material, drills it and turns the plates until the blank of the model is obtained. The dimensions are secured before the mold is finished by comparison with the design.
This has been the largest round mold ever made in this plant and cannot be made in a single piece. By the way, the problem of transport has been solved.
RAUL ESPINOSA; Models Belako: We had to do it in five parts. Four sectors, and a round piece of 4 meters of interior.
To avoid the need for special transport, it has been essential to do it in four parts. Then the piece will be cast in two parts.
the 7-meter diameter mold weighs almost 200 kilos and will become an iron piece of almost 40 tons.
With such a large and unique piece, a lost model is prepared.
RAUL ESPINOSA; Models Belako: We make the piece out of polystyrene, and then they fill the foundry with sand. The sand will be the mold. The grease is poured onto the mold, and the part will become iron, steel, depending on the material used.
The replacement of polystyrene will be carried out in a foundry in Vitoria.
Before casting, the mold must be prepared. All holes and spaces are filled with sand and tightened well to prevent sand from moving during casting.
For this piece, 73 tons of iron have been cast, at the level
of 1.535. The laundry takes the place of polystyrene.
The result will be two pieces of iron, the two parts of the turntable. But they'll still be full of garbage.
It takes 1,500 hours of machining to remove the barbs, roughen the piece and turn it into what will be the final piece. This will be done in Aviles. Machining shall be carried out by means of lathes, milling machines or boring machines. The surplus is removed and the piece is given a real shape.
BENJAMIN GARCIA; ASTURFEITO: In this case, it’s about giving it an external shape, the roundness it has to have, the internal shape, the boxes that the milling machine will make for it, and all this according to the dimensions that the project gives us.
First goes the milling machine and performs the first stage of grinding. It takes away the excess material, but not everything. The pieces are joined together for adjustment, and the lathe machines the outer diameters, the outer diameters, the inner diameters and the heights. The machining is done slowly, then to avoid problems and to have quality at the end.
Here, too, the size of the piece determines the work.
BENJAMIN GARCIA; ASTURFEITO: First we make the central pizza; then, individually, the two exteriors, and finally the three come together, sewing. We're at the end of the job.
The most difficult is the final finish and the finish of the mechanical jaw housings.
In the Workshops of Gernika the rest of the pieces have been made to adapt to the three parts that make up the dish.
IRATXE MADARIAGA; TDG: We’ve made the inner core, which is then called the base claw, long, and now the adjustments are important. The pieces can't dance, they have to penetrate deeply, and the adjustment is..., there could be a difference of a little ten
To achieve this, a final correction must be made to all the pieces.
After the last assembly, the operation has been certified.
The result has been a turntable that offers several options.
IRATXE MADARIAGA; TDG: It is a dish that combines different functions. Not only automatic or manual, the piece could also be moored with some special claws called separately the retaining block...
Disassembling the dish and preparing it for transport is the final step of this project. The final destination will be the German workplace that manufactures wind turbine towers.
Buletina
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Teknopolis
