Abstract:
The invention relates to a system for the automatic manufacture of wind turbine blades using die halves ( 2,3 ) wherein by applying dry fiber mats, two complementary shells are molded whereby the attachment thereof will result in the blade to be obtained, head-bearing means ( 5,6 ) being arranged with respect to the die halves ( 2,3 ), said means being susceptible to selectively having demolding agent, paint, adhesive application accessories or a machining accessory, and head-bearing means ( 13 ) having a functional assembly capable of applying the dry fiber mats in the die halves ( 2,3 ).

Description:
FIELD OF THE ART 
       [0001]    The present invention relates to the manufacture of wind turbine blades, proposing a system whereby said manufacture is automatic based on using dry fiber mats, i.e., not impregnated, being impregnated with the resin necessary for consolidation during the manufacturing process. 
       STATE OF THE ART 
       [0002]    There are two options among the processes known for manufacturing wind turbine blades, one of which consists of using pre-impregnated composite mats, whereas in the second option basic raw material based on dry fiber mat, which will be referred to hereinafter as “cloth” is used, the said “cloth” mats being supplied by means of reels that can have dimensions which exceed even 4,000 mm in width. 
         [0003]    Until today, all known processes for manufacturing wind turbine blades, by means of dry fiber “cloth” are completely manual processes in all their phases, such that, for example, to manufacture one blade a day, over 50 operators in three shifts are required, which entails a slow and expensive process and furthermore does not offer suitable finish conditions, uniformity, precision, etc., since the different phases are performed manually and completely dependent on the operators&#39; criteria, training and skill. 
       OBJECT OF THE INVENTION 
       [0004]    The invention proposes a system for the manufacture of wind turbine blades by means of forming two halves like “shells” in respective die halves, based on a dry fiber “cloth” with an embodiment implementing an automatic process, overcoming the drawbacks of the conventional system that is implemented manually. 
         [0005]    According to this system object of the invention, a common gantry structure is arranged with respect to the die halves for forming the “shell” components of the blade, said structure being provided with two heads which are susceptible to incorporating paint, adhesive or demolding agent application accessories, and machining accessories for forming rough surfaces in the adhesive application areas, as well as for the planing and outer sanding of the area of attachment of the “shells”, whereas another individual gantry structure provided with two heads intended for placing the “cloth” in the application areas is arranged with respect to each die half, said heads incorporating cutting elements for trimming the “cloth” mat which is applied when needed according to the shape of the application areas so that there are no surplus parts. 
         [0006]    Nozzle-bearing accessories which are replaced in the heads of the common gantry structure arranged above the die halves are used for applying paint, adhesive and demolding agent, the corresponding deposits of the products to be applied being associated with said common gantry structure, whereas an application control system is arranged with respect to the system for applying those products. 
         [0007]    Said product application control can be by means of measuring the product outflow rate through the application nozzles combined with a machine vision system for viewing the surface of the product that is applied, such that the thickness of the application layer with a controlled forward movement speed is verified by means of the flow rate and surface color parameters. Another application control option is to use two line lasers combined with a machine vision system such that the thickness of the applied product layer is determined by means of controlling the geometry of the application areas. 
         [0008]    The heads of the individual gantry structures of the die halves are provided for different widths of the “cloth” to be applied, there being a control system by means of line laser and machine vision with respect to said heads to assure the correct placement of the “cloth” in the application areas. 
         [0009]    A system is thereby obtained which automatically performs the operations of the process for the manufacture of wind turbine blades, avoiding the mistakes that may result from depending on people affecting the conventional system of the same application, while at the same time the process is simplified and the blade manufacturing time reduced. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  shows a general perspective view of the installation of the proposed system according to one embodiment. 
           [0011]      FIG. 2  shows a perspective view of a multi-nozzle paint application accessory which can be incorporated in the heads of the common gantry structure that is arranged above the two die halves. 
           [0012]      FIG. 3  shows a perspective view of an adhesive application accessory which can be incorporated in the same heads of the common gantry structure arranged above the die halves. 
           [0013]      FIG. 4  shows a perspective view of a machining accessory which can in turn be incorporated in said heads of the common gantry structure arranged above the die halves. 
           [0014]      FIG. 5  shows a perspective view of a “cloth” mat applicator head of the type in the individual gantry structures arranged above the die halves. 
           [0015]      FIG. 6  is a perspective view of an enlarged detail of the end part of the head of the preceding figure, showing the adaptation to the shape of an application area. 
           [0016]      FIG. 7  is a front view of the detail of the preceding figure. 
           [0017]      FIG. 8  is a perspective view of an enlarged detail of the cutting element incorporated in the “cloth” mat applicator heads. 
           [0018]      FIG. 9  is a perspective view of an enlarged detail of adhesive projection element incorporated in the applicator heads for fixing the “cloth” in the areas where it tends to fall. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    The object of the invention relates to a system for the manufacture of wind turbine blades by means of applying dry fiber “cloth” mats ( 1 ), above two die halves ( 2  and  3 ) where respective halves or “shells” are formed making up the body of the desired blade when attached to one another. 
         [0020]    The process for the manufacture of the wind turbine blades according to the proposed system is done by means of an installation consisting of a common gantry structure ( 4 ) arranged above the assembly of the two die halves ( 2  and  3 ), one of which is fixed and the other one being susceptible of being turned over onto the former to attach the “shells” formed therein in opposition. 
         [0021]    Two heads ( 5  and  6 ) intended for operating respectively on the die halves ( 2  and  3 ) are arranged in said gantry structure ( 4 ), said heads ( 5  and  6 ) being able to have replaceable accessories for performing different types of operations, such as a multi-nozzle paint application accessory ( 7 ), depicted in  FIG. 2 , an adhesive application accessory ( 8 ), depicted in  FIG. 3 , and a machining accessory ( 9 ), for example for rough sanding, depicted in  FIG. 4 ; there being deposits ( 10 ) containing the products to be applied in the gantry structure ( 4 ) itself. 
         [0022]    The accessories ( 7 ,  8  and  9 ) as well as the different multi-nozzle paint or demolding agent application accessories ( 7 ) are automatically replaced from a warehouse for the operations in which each of them is required. 
         [0023]    Respective individual gantry structures ( 11  and  12 ) are further arranged above each of the die halves ( 2  and  3 ), each of which incorporates two heads ( 13 ) intended for applying the “cloth” mats ( 1 ) in the corresponding areas of the die halves ( 2  and  3 ). 
         [0024]    The heads ( 13 ) of each individual gantry structure ( 11  and  12 ) have the same structural formation but a different width, such that one of them can be used with “cloth” mats ( 1 ) having a width less than a certain value, whereas the other one can be used with “cloth” mats ( 1 ) having a greater width. 
         [0025]    As can be seen in  FIGS. 5 to 7 , each of said heads ( 13 ) is made up of a plurality of pneumatic cylinders ( 14 ), which are connected at the end of their rod to a shaft where there is assembled a series of rollers ( 15 ), the assembly of which can be adapted to different curve shapes, forming a continuous hold-down plate for applying the “cloth” mats ( 1 ) on the different areas of the die halves ( 2  and  3 ). The assembly of the pneumatic cylinders ( 14 ) together with the rollers ( 15 ) associated with them are arranged in an assembly which allows adjusting the width for being adapted to the width of the “cloth” mats ( 1 ) used in each case. 
         [0026]    An automatic loader (not depicted) incorporating the reels ( 16 ) of the “cloth” mats ( 1 ) is provided in a threading arrangement with respect to said heads ( 13 ), which allows achieving reel ( 16 ) changing times that are less than fifteen seconds. This is an advantageous reduction of the process time for manufacturing wind turbine blades, because manufacturing a blade requires placing over two-hundred layers of “cloth” ( 1 ) to form each “shell”, it being necessary to move between forty and fifty reels, over half of which are large, being able to weigh nine-hundred kilos, making it necessary to change the reels in the process for manufacturing a blade about a hundred times. 
         [0027]    Therefore, the wind turbine blade is manufactured with the system of the invention as follows: 
         [0028]    The demolding agent is applied in the die halves ( 2  and  3 ) and then this is painted with a paint referred to as gel-coat, intended for forming the outer surface of the blade to be manufactured through the appropriate multi-nozzle accessories ( 7 ). 
         [0029]    For the mentioned demolding agent and gel-coat paint application, it is envisaged that the installation itself incorporates an application control system (not depicted) which control can be by means of measuring the outflow rate from the corresponding multi-nozzle accessory ( 7 ), combined with a machine vision system which controls the color of the surface of the applied product, such that with the flow rate and color parameters it is verified through an established program that the application of the product is correct, because a specific flow rate and controlled forward movement speed determine the application material thickness. Said control can also be done by using two line lasers combined with a machine vision system, such that the assembly allows controlling the geometry of the areas of the die halves ( 2  and  3 ), determining the thickness of the necessary layer of material. 
         [0030]    After applying the gel-coat paint, the heads ( 13 ) of the individual gantry structures ( 11  and  12 ) begin operating, depositing the “cloth” mats ( 1 ) on the die halves ( 2  and  3 ). 
         [0031]    Said heads ( 13 ) have a cutting system ( 17 ), whereby they cut the “cloth” ( 1 ) that is applied so that it is within established tolerances depending on the areas of the die halves ( 2  and  3 ) where the cloth will be applied, i.e., the “cloth” ( 1 ) to be applied is patterned in the heads ( 13 ) themselves, so that there is no projecting surplus on the edges of the formation of the “shells” component of the blade being manufactured. 
         [0032]    The heads ( 13 ) themselves further have an adhesive projection nozzle ( 18 ) for fixing the “cloth” ( 1 ) in the application areas where it tends to fall as it is vertical. Said nozzle ( 18 ) can be replaced with a sewing unit for fixing the “cloth” ( 1 ) in the mentioned areas where it tends to fall. 
         [0033]    A control system (not depicted) is also arranged with respect to said heads ( 13 ), said control preferably being by means of line laser and machine vision to assure that the “cloth” mats ( 1 ) are suitably arranged in the placement areas without creases, air pockets or similar defects. 
         [0034]    Once the entire “cloth” ( 1 ) assembly for forming the corresponding “shell” in each die half ( 2  and  3 ) is deposited, the necessary resin is infused and it is cured, to later machine the areas intended for attaching the “shells” to one another by means of the heads ( 5 ,  6 ) of the gantry structure ( 4 ) themselves for the purpose of determining a rough surface in said areas which allows better actuation of the bonding adhesive. 
         [0035]    To that end, the areas to be machined and the bonding adhesive application path are established by means of the line laser and machine vision systems, said adhesive being applied by means of the heads ( 5 ,  6 ) with the corresponding accessory ( 8 ) incorporated therein. 
         [0036]    After applying the adhesive, the movable die half ( 3 ) is turned over onto the fixed die half ( 2 ) such that the “shells” formed therein are attached to one another by the glued areas, determining the assembly of the wind turbine blade. 
         [0037]    The die halves ( 2  and  3 ) are removed when the blade is thus formed, and all the dimensions and shapes are determined through the line laser and machine vision systems for the same heads ( 5 ,  6 ) of the gantry structure ( 4 ) to plane and sand the outer part of the attachment between the “shells” so that the outer surface of the formed blade is perfectly uniform, so the attachment line between the “shells” is checked with accuracy by means of line laser and machine vision systems, planing and sanding the defined path based on said attachment line and the areas located thereon which need to be touched up. A protective layer using gel-coat paint or other materials is applied on the assembly of the blade after planing and sanding the attachment to prevent external agents from affecting the outer surface. 
         [0038]    For the sake of simplicity of the description, the installation of the system has been considered with two die halves ( 2  and  3 ) for the manufacture of a wind turbine blade, but the system is also applicable for manufacturing several blades at a time, the gantry structures ( 4 ,  11  and  12 ) being able to be shared either by moving said structures with respect to the different assemblies of die halves ( 2  and  3 ), or by moving the latter with respect to the mentioned structures. 
         [0039]    The functional concept of the system is also viable if robotic arms instead of gantry structures ( 4 ,  11  and  12 ) are used to support and move the heads for performing the different functions. 
         [0040]    In the same sense, a gantry structure ( 4 ) has been provided for incorporating the elements for “dirty” operations (painting, adhesive application, machining) separately from the operating elements for placing the “cloths” ( 1 ), but it is functionally possible to arrange all the operating element in a single common gantry structure.