Patent Application
20170274563
The present invention relates to a system and method for the manufacture of equipment for use in the manufacture of wind turbine blades, in particular a wind turbine blade mould or a plug for a wind turbine blade mould.
Wind turbines are the prime example of renewable power generation technology which is in a state of continuous global deployment. Due to increased difficulties in transport and/or increased local content requirements, wind turbine manufacture continues to experience a drive towards localised manufacture and assembly. One such trend is in the area of “pop-up” factories, characterised by a relatively quick, low-cost ramp-up from zero to full-scale production. Such factories rely on the use of low-cost equipment, which can be deployed in a short timeframe to facilitate the fast start-up time of such a facility.
One of the challenges to the use of such “pop-up” factories is the provision of high-quality wind turbine blade moulds and/or associated mould plugs. Such manufacturing equipment often requires time-consuming, high-accuracy tooling. Furthermore, common blade manufacturing systems require that such blade mould be hinged, to allow for the turning and closing of blade shells to form a wind turbine blade. PCT publication number WO2013113815 describes a wind turbine blade manufacturing system having stationary moulds, which reduces the cost involved in setup of a blade manufacturing facility. However, the provision of high-quality moulding surfaces continues to require the use of accurate blade mould plugs and subsequent moulds to produce blade shells of acceptable standards. Such mould plugs and/or moulds can require expensive and time-consuming production techniques and materials. For example, the production of a single blade mould for a wind turbine blade may require a manufacturing time of 4-5 months from initial order to installation on a factory floor.
DE 20 2014 000999 U1 discloses a mould for manufacturing wind turbine blade shells of different sizes and shaped. The mould comprises an upwardly facing recess in which interchangeable mould sections may be arranged to as to form a negative mould for manufacturing a wind turbine blade shell.
It is an object of the invention to provide a system and method for the manufacture of wind turbine blade manufacturing equipment which combines relative low-cost with high speed production systems.
Accordingly, there is provided a method of manufacturing a mould for a wind turbine blade shell, wherein the method comprises the steps of:
By cutting a mould geometry from a plurality of blanks, a wind turbine blade mould can be manufactured in a relatively quick and efficient manner, allowing for ease of automation of the cutting and/or assembly processes. In addition, the manufacturing process can be relatively easily adapted for differences in mould scale or geometry, with relatively minor adjustment of supply chain dynamics. The use of such a low-cost, high-speed manufacturing technique can result in a manufacturing time of the order of 2-3 weeks for the construction of a new blade mould, compared to prior art systems requiring several months' construction time.
The term “spanwise direction” will be understood to refer to the longitudinal direction extending between the tip end and the root end of a wind turbine blade or a wind turbine blade mould, or an associated geometry. The term “chordwise direction” will be understood to refer to the lateral or transverse direction of such a wind turbine blade or wind turbine blade mould or an associated geometry, the chordwise direction extending between a leading edge and a trailing edge of a wind turbine blade or mould.
Preferably, the method further comprises the step of applying a coating to said plurality of cut surfaces. Preferably, said step of applying a coating is performed after said step of assembling.
In one aspect, said step of applying a coating acts to provide a resilient mould surface. In an additional or alternative aspect, said step of applying a coating acts to substantially adhere said plurality of cut mould elements to each other. Furthermore, the step of applying a coating may act to smoothen or mask relatively minor imperfections or discontinuities in the consolidated wind turbine blade mould surface.
Preferably, said step of cutting is performed using a robotic cutting member, preferably a CNC cutting apparatus and/or a robotic articulated manipulator arm. In one aspect, said step of cutting is performed using a hot-wire cutting member.
Preferably, the method further comprises the steps of smoothing said consolidated wind turbine blade mould surface. The smoothing may comprise a further cutting, grinding, or polishing operation. It will be understood that said step of smoothing may be performed on the cut surfaces of the cut mould elements before and/or after a step of applying a coating to the cut surfaces.
If the blanks are formed from a light-weight material which can be easily processed, it may be suitable to perform a smoothing operation directly on the cut surfaces. Additionally or alternatively, the coating material may be formed of a substance allowing for ease of smoothing, e.g. during the application process and/or before curing or hardening of the coating.
Preferably, said step of applying a coating comprises applying an elastomer coating, preferably a polyurea coating.
Providing an elastomer coating results in a resilient mould surface which is resistant to operational wear-and-tear.
Preferably, said mould blank element is formed from a low-weight material, preferably a foam material. In a preferred aspect, said mould blank element is formed from a polymer material which can include, but is not limited to, polystryrene or expanded polystyrene (EPS). Examples of suitable materials may include Styrofoam™, from The Dow Chemical Company, or Styropor®, from BASF SE.
Preferably, said step of dividing said wind turbine blade mould geometry comprises dividing said geometry into a plurality of spanwise and/or chordwise segments. It will be understood that said plurality of spanwise and/or chordwise segments may comprise segments of varying length and/or width.
Breaking the mould geometry into a number of different segments allows for increased ease of processing of the mould blanks, as the relatively complex curve geometry of the mould surface can be broken into separate, relatively smaller, geometrically simpler, segments.
In a preferred embodiment, said step of dividing comprises:
In one aspect, at least some of said plurality of spanwise surface sections comprise a substantially straight-line profile shape in the spanwise direction of the spanwise surface sections.
Additionally or alternatively, said step of dividing comprises:
In one aspect, at least some of said plurality of chordwise surface sections comprise a substantially straight-line profile shape in the chordwise direction of the chordwise surface sections.
The division of the surface geometry into segments having a straight-line shape in one direction of the segments provides for an approximation of the desired surface geometry which can be re-created using straight-line cutting devices. For example, a hot wire cutter is typically arranged to perform a straight-line cut of a material, which would be suitable for the above process. It will be understood that the step of dividing may comprise a combination of spanwise and chordwise surface sections.
Preferably, at least some of said plurality of spanwise surface sections comprise a curved profile in the chordwise direction of the spanwise surface sections. Similarly, at least some of said plurality of chordwise surface sections may comprise a curved profile in the spanwise direction of the chordwise surface sections
While the segments may be substantially straight in a first spanwise or chordwise direction, the second chordwise or spanwise direction of the segments may be curved, wherein the curve may be recreated by controlling the depth of the cut made by a straight-line cutting device.
In an alternative embodiment, said step of dividing comprises:
In one aspect, each of said plurality of spanwise and/or chordwise segments may comprise a single one of said plurality of planar surfaces. In an alternative aspect, each of said plurality of spanwise and/or chordwise segments may comprise a number of said plurality of planar surfaces.
While it will be understood that the cut surfaces of said cut mould elements may comprise a single, substantially planar surface, it will also be understood that the cut surfaces of each of said cut mould elements may comprise a number of differently-oriented planar surfaces, to form an approximated geometrical slice of the wind turbine blade mould geometry.
Furthermore, while the cut surfaces may be provided as straight-line or planar in one or both of the spanwise and chordwise directions of a segment, it will be understood that the cut surfaces may comprise a degree of twist around a spanwise or chordwise axis of the segment.
As the orientation of a hot-wire cutter may be adjusted during a cutting operation to provide for the cutting of a relatively complex geometry, therefore the cut surface may comprise a degree of twist to more accurately comply with the desired mould geometry.
Preferably, said step of approximating is performed wherein said plurality of surfaces or surface sections follow the curved surface profile within a tolerance margin. Preferably, said tolerance margin is within approximately 10 mm, preferably within approximately 5 mm, further preferably within approximately 1 mm.
The mould blank elements may comprise a plane lower surface, and an upper surface corresponding to a part of the consolidated wind turbine blade mould surface. The mould blank elements may in a top view have a rectangular outline.
There is further provided a wind turbine blade mould manufactured according to any aspect of the above method.
There is also provided a method of manufacturing a mould plug for a wind turbine blade shell, wherein the method comprises the steps of:
Similar to the mould blank elements, the plug blank elements may also be made of a low-weight material, such as a foamed polymer, and may further be coated with a resilient coating, such as an elastomer coating, e.g. a polyuria coating.
There is also provided a method of manufacturing at least a portion of a wind turbine blade mould or a wind turbine blade mould plug, the method comprising the steps of:
It will be understood that a plurality of mould blank elements may be provided, wherein each of said mould blank elements may be cut to have cut surfaces with different surface profiles. The different surface profiles may correspond to different portions of the template geometry. It will be further understood that the template geometry may comprise a series of curved surface portions, wherein said reshaping is performed such that the flexible cutting device is shaped to substantially correspond with the curved surface portions of the template geometry.
In one aspect, said step of reshaping is performed prior to said cutting step. This may be performed by bending the cutting device to assume the desired profile. In an additional or alternative aspect, said step of reshaping may be performed dynamically during said step of cutting. The cutting device may be provided with adjustable components, e.g. piezoelectric actuator devices, to adjust the profile of the cutting device before or during a cutting operation.
Preferably, said flexible cutting device comprises a hot wire cutting device. Such a device is generally provided as a relatively thin, taut metal wire, formed from a metallic material, e.g. nichrome or stainless steel. The wire is heated via electrical resistance to approximately 200° C., wherein the heat of the wire acts to cut through the material by burning or vaporisation of the material. Such a cutting device is suitable for cutting of polystyrene and similar foam materials.
Preferably, said step of reshaping comprises:
Preferably, the step of reshaping comprises:
Preferably, the method comprises providing first and second opposed flexible bearing surfaces, wherein the first and second opposed flexible bearing surfaces form a flexible clamping apparatus used to reshape the flexible cutting device.
By providing for a shaped cutting profile as opposed to a planar cut, accordingly the different sections or slices of the cutting are not as limited with regards to a tolerance margin of the planar surface approximation to the actual curved geometry. As a result, the entire mould geometry may be approximated using a smaller number of geometrical slices.
There is also provided an apparatus for shaping a flexible cutting device comprising:
Preferably, the apparatus comprises an array of actuators acting on a first side of said at least one flexible bearing surface, said array of actuators operable to shape said at least one flexible bearing surface. Preferably, the apparatus comprises an array of linear actuators.
Preferably, the apparatus comprises first and second flexible bearing surfaces arranged opposite each other, such that said first and second bearing surfaces are operable to form complimentarily-shaped bearing surfaces, the flexible cutting device to be received between said first and second bearing surfaces.
Preferably, the at least one flexible bearing surface is formed from a flexible material, e.g. a rubber material.
In one aspect, a receiving channel may be defined in said at least one flexible bearing surface, wherein the receiving channel is arranged to receive at least a portion of a flexible cutting device.
Preferably, the apparatus further comprises a controller operable to adjust said at least one flexible bearing surface, wherein said controller is arranged to receive a template geometry, said controller arranged to adjust said at least one flexible bearing surface to correspond to at least a portion of the received template geometry.
In a preferred aspect, the template geometry comprises at least a portion of a template geometry for a wind turbine blade mould or a wind turbine blade mould plug.
While aspects of the invention may be described above in terms of features for the manufacture of a wind turbine blade mould, it will be understood that any of the above features may also apply to the manufacture of a wind turbine mould plug.
There is further provided a mould plug for a wind turbine blade mould manufactured according to any aspect of the above method.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
It will be understood that elements common to the different embodiments of the invention have been provided with the same reference numerals in the drawings. In addition, it will be understood that the drawings are for illustrative purposes, and are not provided to scale.
The airfoil region 34 (also called the profiled region) has an ideal or almost ideal blade shape with respect to generating lift, whereas the root region 30 due to structural considerations has a substantially circular or elliptical cross-section, which for instance makes it easier and safer to mount the blade 10 to the hub. The diameter (or the chord) of the root region 30 is typically constant along the entire root area 30. The transition region 32 has a transitional profile 42 gradually changing from the circular or elliptical shape 40 of the root region 30 to the airfoil profile 50 of the airfoil region 34. The chord length of the transition region 32 typically increases substantially linearly with increasing distance r from the hub.
The airfoil region 34 has an airfoil profile 50 with a chord extending between the leading edge 18 and the trailing edge 20 of the blade 10. The width of the chord decreases with increasing distance r from the hub.
It should be noted that the chords of different sections of the blade normally do not lie in a common plane, since the blade may be twisted and/or curved (i.e. pre-bent), thus providing the chord plane with a correspondingly twisted and/or curved course, this being most often the case in order to compensate for the local velocity of the blade being dependent on the radius from the hub.
Airfoil profiles are often characterised by the following parameters: the chord length c, the maximum camber f, the position df of the maximum camber f, the maximum airfoil thickness t, which is the largest diameter of the inscribed circles along the median camber line 62, the position dt of the maximum thickness t, and a nose radius (not shown). These parameters are typically defined as ratios to the chord length c. Thus, a local relative blade thickness t/c is given as the ratio between the local maximum thickness t and the local chord length c. Further, the position dp of the maximum pressure side camber may be used as a design parameter, and of course also the position of the maximum suction side camber.
The wind turbine blade 10 generally comprises a shell made of fibre-reinforced polymer, and is typically made as a pressure side or upwind shell part 24 and a suction side or downwind shell part 26 that are glued together along bond lines 28 extending along the trailing edge 20 and the leading edge 18 of the blade 10. Wind turbine blades are generally formed from fibre-reinforced plastics material, e.g. glass fibres and/or carbon fibres which are arranged in a mould and cured with a resin to form a solid structure. Wind turbine blades are generally formed as two half-shells in separate blade shell moulds which are subsequently joined together to form a consolidated wind turbine blade. It will be understood that the terms “blade mould” and “blade shell mould” may be used interchangeably in this specification.
Modern wind turbine blades can often be in excess of 30 or 40 metres in length, having blade root diameters of several metres. Wind turbine blades are generally designed for relatively long lifetimes and to withstand considerable structural and dynamic loading.
The wind turbine blade may preferably be manufactured using a two-stage manufacturing system, wherein wind turbine blade shells can be formed in a simple blade mould before being transferred to a post-moulding cradle for closing and finishing. Such a system is described in PCT publication number WO2013113815, the contents of which are incorporated by reference herein.
In an effort to provide for a low-cost, high-speed manufacturing method for a wind turbine blade mould, the invention provides for a system wherein a wind turbine blade mould is manufactured from a plurality of blank elements which can be cut to form portions of the blade mould. A process diagram for an embodiment of the invention is illustrated in
Initially, a desired wind turbine blade mould geometry is provided in step 100. The geometry may define a plurality of different characterising features for the desired wind turbine blade mould, e.g. spanwise length, chordwise length, depth, bolt circle diameter, desired airfoil profile, etc. An example desired mould geometry is illustrated at 70,
In one aspect, the mould geometry may comprise a plurality of mould surface cross-sections, defining the shape of the mould for a plurality of transverse cross-sections of the mould. The consolidated mould geometry may be interpolated by a smoothing function applied between said plurality of mould surface cross-sections. Additionally or alternatively, the mould geometry may comprise a point cloud of a number of points defined in a three-dimensional space, wherein the point cloud defines the surface profile geometry of the blade mould.
It will be understood that the mould geometry may be provided as a software file or computer code which may be stored on a computer-readable storage medium. The mould geometry may be generated as part of the method of the invention, or the system may be arranged to receive a mould geometry, e.g. in the form of a computer-readable file or set of instructions.
It will be understood that the mould geometry may be produced based on a newly-designed wind turbine blade geometry, wherein the wind turbine blade mould is a new mould design. Alternatively, the mould geometry may be produced based on an appropriate scanning or other sampling of an existing wind turbine blade mould, wherein it is desired to replicate the existing wind turbine blade mould.
Once the desired mould geometry is received, further processing of the mould geometry data is performed, to provide a plurality of cutting templates, step 102, which may be used as an input for a cutting apparatus. In a first aspect, the mould geometry is divided into a plurality of separate geometrical slices.
With reference to
With reference to
Preferably, the segments are selected such that the spanwise planar or straight-line surface defined by the sections follows the curved surface profile within a tolerance margin. Preferably, said tolerance margin is within approximately 10 mm, preferably within approximately 5 mm, further preferably within approximately 1 mm.
It will be understood that the particular dimensions of the spanwise segments S1-S8 may vary based on the particular mould geometry used. For example, if the mould geometry is relatively straight and unchanging in the spanwise direction, the length of the individual spanwise segments may be relatively long in the spanwise direction while still satisfying best-fit conditions. By contrast, for a pre-bent wind turbine blade, the mould geometry may have a large pre-bend in the spanwise direction, which may require a relatively large number of spanwise segments to accurately follow the pre-bend curvature of the mould geometry. In the example shown in
Similarly, a mould geometry having relatively shallow camber or curvature may require a lower number of spanwise segments, as the mould geometry may be approximated within acceptable best-fit threshold margins using a smaller number of segments or sections than a mould geometry having a relatively more complex curvature or mould shape.
The spanwise segments define cutting templates for a cutting apparatus, such that an approximation of a mould surface geometry profile may be cut or machined from a cutting blank element, step 104. The spanwise segments are preferably formed by a cut made in a surface of a blank element, the cut performed in a direction corresponding to a chordwise direction. With reference to
In
The cutting apparatus is passed through the mould blank element 78 to form cut mould elements 80 having a cut surface 82 defined thereon,
With reference to
With reference to
In a preferred aspect, each spanwise segment S1-S8 may define a cutting template having a plurality of separate cutting orientations and/or cutting depths within the cutting template in the chordwise direction, based on a best-fit orientation calculated for the area within that spanwise segment. In this regard, a single cutting operation may be performed for each spanwise segment of the mould profile, the cutting apparatus making a pass through the blank 78 in a direction corresponding to the chordwise direction of the mould profile. For this configuration, the mould blank elements 78 may be initially provided to match with the number and outline dimensions of the separate spanwise segments S1-S8.
In an alternative aspect, separate cutting templates may be defined by a plurality of chordwise or transverse sections, wherein separate cutting operations are performed for each of the chordwise sections.
With reference to
For this embodiment, the cutting direction of the mould blank elements may be performed in a direction corresponding to the spanwise direction of the mould geometry 70, and/or in a direction corresponding to the chordwise direction of the mould geometry 70.
The use of a spanwise cutting direction may be more effective method of cutting for areas of the blade geometry having relatively complex curvature, e.g. around the areas of max chord and/or in the area of the tip region, where the spanwise profile of the mould geometry varies considerably along the chordwise direction. In such areas, a chordwise straight line cut, e.g. as illustrated in
With reference to
For this configuration, the cut surface 82 of each cut mould element 80 may define a single chordwise section of the divided mould geometry, as indicated in the cut mould element 80 shown in
With reference to
It will be understood that the cuts may be made in any suitable direction on the mould blank elements relative to the desired mould geometry, e.g. (a) in a spanwise or longitudinal direction, substantially parallel to the longitudinal axis of a wind turbine blade mould between a root end and a tip end of such a mould; (b) in a chordwise or transverse direction, extending between the leading edge and trailing edge of a wind turbine blade mould; or (c) a combination of cuts in both spanwise and chordwise directions.
A further embodiment of the method of the invention is illustrated in
In
For areas having a relatively complex or changing curvature along the chordwise direction of the segment, e.g. those segments in the area of max chord S2″-S3″, the tip region of the mould S7″, the spanwise segments may be further divided into a plurality of sequential chordwise segments, indicated generally as C2″, C3″, C7″. For such chordwise segments, the surface profile may be formed by the cutting of mould blank elements in a spanwise and/or a chordwise cutting direction. As these areas of relatively complex curvature are divided into smaller sections, the mould surface geometry can be more accurately approximated into separate sections for ease of manufacture and assembly.
Also as described above, areas of the mould having a relatively complex or changing curvature, such as in the transition region, at the area of max chord and at the tip end of the mould, may be formed from a plurality of different chordwise cut mould elements formed using chordwise and/or spanwise cuts of mould blank elements.
While the cut directions are described in the above embodiments as made in a chordwise and/or spanwise direction, it will be understood that the cut direction may be made in a direction generally in line with a chordwise and/or spanwise direction, e.g. within +/−20 degrees of a spanwise or a chordwise axis at the location of the cut.
It will further be understood that for some areas of the mould geometry, the cut may be performed along a sweeping or curved direction, e.g. from a substantially chordwise direction to a substantially spanwise direction, or vice versa. Such cuts may be appropriate in areas of relatively high curvature, e.g. in the region of the tip end of the mould geometry.
In addition, it will be understood that the start and/or end locations of the cuts may be arranged to define the profile of the leading and/or the trailing edges of that segment of the mould geometry. Such an adjustment of the start and/or end locations may be accomplished through appropriate sweeping or variation of the cut direction for that segment of the mould geometry.
The assembly of the individual cut mould elements 80 may be secured together using any suitable attachment means, e.g. bolting, adhesive, snap-fit connections, etc.
In one aspect, the consolidated profile presented by the assembled cut surfaces 82 may be within tolerance limits and sufficiently accurate to present a finished mould surface. Preferably, however, a coating layer is applied to the consolidated profile, step 108, to present a finished mould surface suitable to receive material for the moulding of a wind turbine blade shell. The coating layer may also act as an adhesive, to bond the separate cut mould elements 80 together to form a consolidated wind turbine blade mould. Preferably, the coating layer comprises an elastomer coating material, preferably a polyurea coating, which can provide a resilient coating resistant to operational wear-and-tear.
A finishing operation may be performed on the assembled cut surfaces of the cut mould elements, and/or on the coating layer applied to the consolidated mould surface. The finishing operation may comprise a further cutting, grinding, and/or polishing operation, to provide for a smooth surface of the finished mould, and to resolve any surface discontinuities between the edges of the assembled cut surfaces.
A further aspect of the invention is illustrated in the process diagram of
In step 200, a desired element geometry is provided, which may define the profile shape of, for example, a wind turbine blade mould surface or a wind turbine blade mould plug geometry. Such a geometry may be received by a suitable controller for the equipment manufacturing process, and may be provided from any suitable system, for example as a result of the equipment design process, and/or through appropriate scanning and mapping of an existing equipment profile.
With reference to
Through appropriate adjustment of the position of the actuators in the arrays 88a, 88b, the respective flexible membranes 90a, 90b may be deformed to assume a profile shape. Such adjustment is performed based on the desired element geometry of the wind turbine blade mould or mould plug, at step 202. As a result, the shaped flexible membranes 90a, 90b form a pair of opposed bearing or clamping surfaces for the re-shaping of a flexible cutting device. It will be understood that the actuator arrays 88a, 88b are preferably adjusted to form complementarily-shaped bearing surfaces of the reshaping apparatus 86. While the apparatus 86 shown utilises a pair of opposed bearing surfaces, in an alternative configuration the apparatus may be provided with a single adjustable bearing surface, wherein a flexible cutting device may be applied against the single surface and/or the single surface may be pressed against the cutting device.
The actuator arrays 88a, 88b and the respective flexible membranes 90a, 90b are provided as separate sub-assemblies of the reshaping apparatus 86, such that the upper array 88a and membrane 90a may be moved relative to the lower array 88b and membrane 90b, preferably in a clamping action, following the arrows indicated at Y in
In step 204, a flexible cutting device in the form of a hot wire cutter 74a is positioned between the opposed shaped flexible membranes 90a, 90b. It will be understood that a receiving channel may be provided in the surface of at least one of the flexible membranes 90a, 90b, to provide for accurate positioning of the wire between the opposed surfaces. While
In step 206, the opposed clamping surfaces are brought together in a clamping action, as indicated by the arrows Y in
The reshaped wire cutter may then be used in the manufacturing method as shown in
An example of the advantages presented by the use of the reshaped wire cutter is illustrated in
By contrast to the cross-sectional profile of
It will be understood that while features of the above embodiments are described in the context of the manufacture of a wind turbine blade mould, the features of the embodiments may equally apply to the manufacture of a wind turbine blade mould plug, which can be understood as a negative of a blade mould, used for the manufacture of wind turbine blade moulds. The plug may be an exact representation of the shape of a wind turbine blade shell to be manufactured in such a blade mould.
The use of a manufacturing method according to the invention for such wind turbine blade process equipment provides for a low-cost, high-speed manufacturing method, which allows for a flexible and efficient start-up process for a new manufacturing facility production line.
The invention is not limited to the embodiments described herein, and may be modified or adapted without departing from the scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 14181425.1 | Aug 2014 | EP | regional |
| 1415217.7 | Aug 2014 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/068966 | 8/18/2015 | WO | 00 |
