Additive manufacturing, also known as 3D printing, is the production process in which objects are built up from the bottom, layer by layer. This can be combined with conventional or subtractive manufacturing to optimize wind energy production. This combination is called hybrid manufacturing.
Why Hybrid 3D Printing?
The use of small wind turbines could go up greatly, especially when it comes to disaster relief sites or rural areas.
However, the rising prices of nickel-based alloys, titanium alloys and stainless steel, coupled with the required complex geometry of the components, high standards of product quality, extreme precision requirements for machined parts, the need for a higher speed of production, and a lower rate of rejection, make a better strategy crucial to making wind power affordable and accessible.
The inability to meet production parameters using conventional processes has led to the emergence of hybrid manufacturing. This provides both the high level of accuracy required and the ability to machine post-3D printing. This can be built into an efficient and highly adaptable flexible manufacturing system (FMS) by the addition of a 3D scanning system and a completely automatic part handling platform. The inclusion of new processes helps manufacturers to achieve the right part geometries and to repair damaged components.
Accurately machined parts require the removal of up to 90 percent of material, increasing the effort, the costs and the processing time. Hybrid 3D printing offers enormous potential for lowering costs because material required is only a third or less of that needed for conventional manufacturing processes. This is a huge savings with expensive materials or those that are difficult to machine.
Turbine blades are among the costliest of wind energy investments. They account for a fifth of the cost of manufacturing for onshore turbines, and a tenth for offshore turbines.
Every component of the turbine is under scrutiny to identify those which could be benefited by 3D printing, by making it possible to produce complex shapes and contours, or to reduce the time required for manufacture, or the cost. The greatest advantage is likely to be for complex parts which are difficult to produce by conventional techniques, since this capability will offset the extra cost.
3D printing will enable the more efficient development of more aerodynamic designs and reduce the cost of wind energy. For one thing, advanced blade designs can optimize turbine loads, making other components less costly in turn.
Hybrid manufacturing processes add the ability to deposit specific high-wear materials in a specific pattern and in extremely thin layers at certain areas that are exposed to high stresses, thus increasing the reliability and resistance of the component, while preserving its geometry of the work piece.
If 3D printing is used to directly build a blade mold, the total process time will go down by 35 percent, as well as saving on costs. 3D printing allows internal channel creation, reduces the weight and integrates multiple functions. In the future, gear internal channels could allow standard sensors to be used for pressure detection. These will warn in case of cracks due to metal fatigue.
Currently, energy manufacturers use 3D printing mainly for the rapid prototyping of new products in the development pipeline. This helps assess their impact on the value chain at reduced cost, and speeds up the time to market.
Experts in energy generation predict that 3D printing of components in wind turbines will reach large scale in about five years from now. This will facilitate rapid and innovative designs that will optimize wind farm productivity in future.
Traditionally, wind turbine towers are made of steel, and most towers in the US are about 80 m high, on average. However, some innovators are exploring the possibility of concrete additive manufacturing technology to build much taller towers, about 140 m high, which would increase the generated power by over 20 percent at lower cost.
Hybrid Manufacturing and the Value Chain
Hybrid 3D printing can also have a huge impact on the supply chain. Not only are much fewer subcomponents required, but on-demand in situ production of components in any of a number of locations close to or (in the distant future) right on the wind farm where they are required will become possible. This avoids transportation and storage hassles instantaneously. The availability of spare parts will also reduce maintenance and operational costs and downtime. Holding inventory often consumes a fourth of total inventory costs, and this is freed up by on-demand production.
Many separate components can be manufactured as a single complex component with hybrid AM manufacturing. This reduces labor and costs, a concept called ‘complexity for free’, and increases the lifespan of the machine.
Another benefit from the use of hybrid 3D printing in wind turbines is the ability to produce one-of-a-kind components on demand. This avoids waste and optimizes customization of essential parts. Each customer can obtain customized offers, while the suppliers can react quickly to changes in marketplace demand.
Turbines which are not being produced but are still in operation could be repaired the same way to extend the turbine’s life and save on replacement costs. Repair of the blades involves inspection and examination of the part, removal of damaged areas, restoration of the damaged part by additive manufacturing and finally the reprocessing of the repaired area using milling and polishing processes. A hybrid machine allows the automation of the whole cycle, while drastically reducing the time required, avoiding waiting times, boosting repeatability, ensuring uniform quality, and cutting down on rejects, rework costs and total processing costs.
In summary, hybrid AM manufacturing has numerous effects on supply chain economics, including leaner manufacturing processes, simplified production, 5% lower costs, more flexibility, more rapid and on-demand supply of components, and decentralized production.