Abstract:
An apparatus is disclosed for charging molds used to mold wind turbine blades in which the molds have a root end and a tip end. The apparatus includes a first and second gantries located at the root end of the mold and capable of moving to the tip end of the mold. A layup end effector on the first gantry receives a length of reinforcing ply material and temporarily stores the ply material on the layup end effector. A clamping end effector mounted on the second gantry has a clamping board that is shaped to fit the root end of the mold. The clamping end effector grips the end of the ply material temporarily stored on the layup end effector secures the end of the ply material to the root end of the mold while the first gantry lays the ply material in the mold.

Description:
FIELD 
       [0001]    The described device relates to an automated process and apparatus for charging wind turbine blade molds. 
       BACKGROUND 
       [0002]    The commercial demand for wind turbine blades steadily increases as the cost of power generation continues to rise. Wind turbine blades range in size from twenty to sixty meters in length and are generally formed from glass or carbon fiber reinforced resin. The blades are hollow and are formed in two halves, an upwind half and a downwind half that splits the blade along the longitudinal axis. Once the blade halves have been formed on molds and cured, the two halves are fastened together with adhesive to form the finished blade. 
         [0003]    Blade manufacture and the process of charging the molds is largely a manual process. The two blade halves are formed in side-by-side molds so that the resulting halves can be mated together with a minimum amount of movement required. A gel coat is first sprayed into the mold halves. Reinforcing fibers such as glass, carbon fibers or aramid fibers are then placed into the mold halves. The fibers may be woven into a cloth-like fabric, in which case the fabric has to be correctly positioned in the mold halves. Because the cross section of the finished blades is not a cylinder, and the circumference of the blades changes from the root end to the tip, the cloth reinforcing material has to be cut to the correct shape prior to being placed in the molds. Typical blades are forty meters in length, so positioning the reinforcing cloth in the molds can be a cumbersome and time consuming process. If the cloth is placed along the length of the blade, a forty meter length of cloth is required, and cutting the cloth to the proper taper for fitting the cloth to the edges of the mold is a difficult task. If the cloth is placed across the width of the blade, care must be taken where the edges of adjacent cloth pieces come together so that the resulting laminate structure does not have gaps in the reinforcing cloth, or does not have overlapping areas of cloth that would increase the thickness of the resulting laminate beyond acceptable tolerances. After the reinforcing materials have been properly located in the mold halves, resin is applied to the fibers and the two molded blade halves are allowed to cure. Once the cure is complete, adhesive is applied to the interior of the blade for core pieces and shear webs that will be mounted in the blade, and those elements are added to the blade. Adhesive is applied to the edges of at least one of the blade halves and to the top surfaces of the core pieces and the shear webs. The two molded halves are then brought together, usually by lifting and placing the half without the adhesive (the moving half) onto the half with the adhesive (the resting half). After the adhesive cures, the resulting complete blade can be removed from the mold holding the resting half. 
         [0004]    It would be desirable to decrease the amount of manual labor required to charge a wind turbine blade mold and to manufacture a wind turbine blade as discussed above. It would further be desirable to mechanize the application of gel coat to the mold halves. It would also be desirable to mechanize the placement of fiber reinforcement material into the mold halves in the manufacture of wind turbine blades. It would further be desirable to mechanize the application of adhesive to the edges of the two blade halves prior to joining the two blade halves together. It would additionally be desirable to mechanize the placement of the moving blade half onto the resting blade half in order to form the completed wind turbine blade. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a perspective view of an installation for molding wind turbine blades. 
           [0006]      FIG. 2  is a side view of a ply generator positioned in front of a multi-roll magazine of reinforcing material. 
           [0007]      FIG. 3  is a perspective view of a layup end effector. 
           [0008]      FIG. 4  is an overhead perspective view of the layup gantries and the clamping gantries positioned at the root end of the mold halves. 
           [0009]      FIG. 5  is a detail view of a clamping end effector. 
           [0010]      FIG. 6  is a detail view of the end effectors used for gel coat and adhesive dispensing. 
           [0011]      FIG. 7  shows a gel coat dispenser head positioned in the mold cavity. 
           [0012]      FIG. 8  shows adhesive dispensing heads positioned on the edges of a molded part. 
           [0013]      FIG. 9  shows powered hinge units being used mate two molded blade halves together. 
       
    
    
     DESCRIPTION 
       [0014]    Turning now to the drawing figures,  FIG. 1  shows an installation for molding two wind turbine blades generally designated by the reference numeral  10 . Two elongated mold halves  12  are used for molding wind turbine blades and are positioned longitudinally side-by-side. Each mold half  12  is held by a supporting frame  14  so that the concave surface of the mold half is facing upward. Each mold half is positioned with the root end  16  of the mold, the end that will mold the portion of the blade that attaches to the hub, in the foreground of the drawing, and the tip end  18  of the mold, the end that will mold the tip portion of the blade, in the background of the drawing. Several rolls  20  of reinforcing ply material in different widths and in different weaves and composition are located in a multi-roll magazine  22  that is positioned adjacent to a ply generator  24  at the root end of the mold. Plies of fiber reinforcing material are generated at the ply generator  24 , and the plies are robotically placed in the molds  12  as described more fully below. Two gantries  26  and  28  are located at the root end  16  of each mold. The two gantries  26  and  28  are independently movable along the length of the mold, and are used to carry out different operations during the molding cycle. 
         [0015]      FIG. 2  shows the ply generator  24  that is positioned between the magazine  22  that carries the rolls  20  of reinforcing material and the root end  16  of the mold. The ply generator  24  selects the correct material from the rolls  20  of material, cuts the material to the desired shape, and uses a ply delivery conveyor  30  to deliver the ply material to a robotic end effector  36  for automated placement in the mold as described more fully below. The layup end effector  36  has a layup spool  38  that is used to spool up the ply material that is generated by the ply generator  24 . The end effector  36  may be rotated about a vertical axis to position the layup spool  38  in a position to receive material from the ply delivery conveyor  30  as shown. The layup spool  38  has a gripping mechanism (not shown) that grips the end of the ply and winds it onto the layup spool. 
         [0016]      FIG. 3  is a perspective view of the layup end effector  36 . The end effector  36  is mounted on the end of a robot arm  37 , and includes a layup spool  38  and a pair of powered brushes. In use, after the layup spool  38  has received a length of ply material from the ply conveyor  30 , the end effector  36  is rotated about the vertical axis to orient the layup spool in a position to deliver ply material into the mold  12 . After the end of the ply material is clamped in place in the mold by the clamping end effector  34  as described below, then the layup gantry  26  travels from the root end  16  of the mold to the tip end  18 , and the ply material is unwound from the layup spool  38  and laid into the mold. The powered brushes  40  are used to press the ply material from the layup spool  38  into the mold  12 , and to smooth the material onto the mold surface. 
         [0017]      FIG. 4  is an overhead perspective view from the mold  12  toward the two gantries  26  and  28  at the root end of the mold. The lay-up gantry  26  is closest to the mold  12  and the clamping gantry  28  is next to the magazine  24  that holds the rolls  20  of reinforcing ply material. The clamping gantry  28  supports a robot arm  32  with a clamping end effector  34  that is designed to anchor the ply material at its starting point in the mold as described below. The clamping end effector  34  is used to grip the end of the reinforcing material that has been wound onto the spool  38  of the lay-up gantry, and to clamp the end of the reinforcing material against the root end  16  of the mold as the reinforcing material is spooled from the lay-up gantry  26  into the mold. 
         [0018]      FIG. 5  shows in detail the clamping end effector  34  that is carried by the clamping gantry. The clamping end effector  34  has a forming board  42  with a lower surface  44  that is shaped to fit into the interior of the root end  16  of the mold. A powered clamp  45  uses a band  46  that can be tightened around the lower surface  44  the forming board  42  to clamp the end of a ply against the forming board. Once the ply material is clamped against the forming board  42 , the clamping gantry  28  then moves to position the forming board  42  over the root end  16  of the mold, and the robot arm  32  that supports the end effector  34  lowers the forming board until it comes into contact with the root end  16  of the mold. This clamps the end of the ply material in place in the root end  16  of the mold. The lay-up gantry  26  then travels from the root end  16  to the tip end  18  of the mold, laying the ply from the layup spool  38  in place in the mold cavity. As the lay-up gantry  26  travels to the tip end  18  of the mold, the powered brushes  40  may be used to press the ply material down onto the mold surface, and to smooth out any wrinkles in the ply material. 
         [0019]    The clamping gantry  28  remains at the root end of the mold as the layup gantry  26  travels from the root end  16  to the tip end  18  of the mold. After the ply has been laid along the length of the mold, the clamp band  46  is released from the forming board  42  and the ply material is freed from the clamp  45  by moving the forming board  42  away from the root end of the mold until the end of the ply is no longer held by the clamp band  46 . The clamp band  46  is then expanded and moved to a point where the next ply that will be laid into the mold is spooled. The end of the next ply is gripped against the forming board  42  by the clamping band  46 , the forming board  42  is lowered to the desired location in the mold to position the ply in the mold, and the process of laying the material into the mold is repeated. 
         [0020]    Both gantries  26  and  28  are capable of travel along the length of the molds  12  during the molding process. Both gantries  26  and  28  can be equipped with a Z-axis robot arm  50  as shown in  FIG. 6  with end effectors  52  equipped with spray heads  54  for applying gel coat to the mold halves, and with applicators  56  for applying adhesive to the interior surface or to the edges of the molded blade halves as may be required by the blade manufacturing process. The adhesive applicators  56  may be different sizes for applying different width adhesive stripes to the mold halves as desired. The use of the two gantries  26  and  28  to apply gel-coat to the mold halves during the molding process, or adhesive to the edges of the molded blade halves before the halves are mated together to form a complete blade reduces the amount of time required to perform these operations. 
         [0021]    Each robot arm  50  may include a standard tool change mechanism (not shown) mounted to the Z-axis housing. During gel-coat operations, the adhesive applicators  56  will be secured in a receptacle on the tool changer, and during adhesive dispensing operations, the gel coat spray heads  54  will be secured in a receptacle on the tool changer. Other tools may be provided for deployment by the tool changer mechanism as desired. 
         [0022]      FIG. 7  shows a robot arm  50  with an end effector  62  used for mold preparation prior to molding. The end effector  62  may be used to apply a coating such as a gel-coat to the interior surface of the mold  12 . Each end effector may be provided with a bulk supply system (not shown) for coatings, resins, adhesives and other materials that may be used during the blade manufacturing process. The end effectors  62  may have interchangeable spray heads for the particular material that is being applied to the mold. 
         [0023]      FIG. 8  shows the robot arm  50  with adhesive applicators  56  being used to apply adhesive to the edges  64  of the molded blade half  66  prior to the half being mated to the other half to form a complete blade. As shown, two robot arms  50  may be used simultaneously to apply adhesive to the two edges  64  of the molded blade half  66  to reduce the amount of time required to complete the operation. 
         [0024]    As shown in  FIG. 9 , after adhesive has been applied to the mating surfaces  64  of the two molded blade halves  66 , powered hinge units  68  may be provided to flip the moving half  70  of the molded blade onto the resting half  72  to form a complete blade. 
         [0025]    Having thus described the invention, various modifications and alterations will occur to those skilled in the art, which modifications and alterations will deemed to be within the scope of the invention as defined by the appended claims.