Manufacturing method of longitudinally-segmented wind power blade mold

Abstract

The invention discloses a manufacturing method of a longitudinally-segmented wind power blade mold. The mold manufacturing method comprises the following steps: firstly, manufacturing an over-wide mold section by adopting a longitudinal segmentation mode on a model, and erecting a metal clamping plate at the segmentation position; secondly, after the surface of the model is pretreated, carbon felt, glass fiber biaxial cloth, glass fiber four-axial cloth, an aluminum net, an L-shaped aluminum sheet, glass fiber four-axial cloth and a vacuum auxiliary material are sequentially laid, an inner structure layer is formed through a vacuum infusion technology, and then an electric heating wire is arranged to obtain a heating layer; glass fiber four-axial-direction cloth and vacuum auxiliary materials are sequentially laid on the heating layer, and an outer structure layer is formed through a vacuum infusion technology; polishing the glass fiber reinforced plastics at the metal clamping plates at the segmentation positions, and welding and segmenting the mold steel frame; and finally, the mold is cured and demolded, and split mold assembling is conducted. The manufactured longitudinally-segmented blade mold can be transported separately and then assembled in a customer factory; the transportation route planning of the large blade mold becomes easier, the transportation cost is reduced, and the transportation time is shortened.

Description

Technical Field

[0001] The present invention relates to the field of glass fiber reinforced plastic composite material forming technology, and in particular to a method for manufacturing a longitudinally segmented wind turbine blade mold. Background Art

[0002] As a renewable green and clean energy, wind power generation has attracted more and more attention from the country. With the rapid and vigorous development of the wind power industry, the size of wind turbine blades has gradually become larger, and the length and area of ​​the blades have continued to increase, resulting in the length and width of the matching blade molds also continuing to increase.

[0003] Existing wind turbine blades are manufactured by dividing them into transverse segments along the length direction, generally divided into 3-4 segments. After being manufactured, they are transported to the customer's factory in segments for installation. The mold shell consists of an inner structure, a heating layer, and an outer structure. The inner and outer structures are fiberglass layers, manufactured through a vacuum infusion process, and the bottom of the mold is coated with insulation material as an insulation layer. The manufactured multi-segment blade molds are transported to the customer's blade factory separately and spliced ​​and assembled into blade molds of the full length. The existing segmented blade molds are manufactured by transverse segmentation along the length direction. However, with the large-scale development of wind turbine blades, the length and width of the blade molds are also increasing. The width of some mold segments is too wide, causing transportation difficulties.

[0004] A mold section that is too wide will make it difficult to choose a transportation route during the mold transportation process. The general highway lane plus the emergency parking lane is 7 meters wide. Now the maximum width of the mold has reached 7.5 meters. It can only be transported by auxiliary roads. Moreover, the transportation route is difficult to plan, and the transportation cost and time will increase a lot, which will also cause a tight schedule.

[0005] Existing blade mold manufacturing technology is highly mature. Currently, blade molds are segmented horizontally along their length, with each segment being fabricated on a corresponding segmented model. Each segment is transported to the customer's facility for on-site assembly. The mold's elevation and profile are adjusted, and the steel frames at the segmented sections are connected and secured. Finally, fiberglass reinforced plastic is poured into the joints between the segments to create a cohesive whole.

[0006] Existing blade molds are segmented horizontally along their length. A mold with a total length of over 100 meters can typically be divided into 3-4 segments several dozen meters long. However, this segmentation does not reduce the maximum width of the mold, especially as blade molds are becoming increasingly wider as mold manufacturing becomes increasingly large. This segmentation approach does not address the transportation difficulties caused by excessive mold width. Excessively wide molds are difficult to transport on main roads, limiting the choice of transportation options, increasing transportation costs and time, and also creating tight deadlines. Summary of the Invention

[0007] In response to the problem in the prior art that wind turbine blade molds are produced in transverse sections and their excessive width leads to difficulty in mold transportation, high transportation costs, and long transportation time, the present invention provides a method for producing wind turbine blade molds in longitudinal sections, which abandons the original method of producing molds in all transverse sections. The blade mold will become narrower and narrower towards the tip of the blade. The narrower mold segments can be transported normally without longitudinal section production. For wider mold segments, the blade mold is manufactured in a longitudinal section manner. The overly wide mold segments are longitudinally sectioned in the width direction, and an overall wider mold segment is split into two narrower split molds, one of which is in a "C-shape", and the other split mold is just embedded in the "C-shaped" notch. The two split molds are fitted together and transported to the customer's factory for assembly, thereby solving the problem of transportation difficulties.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] A method for manufacturing a longitudinally segmented wind turbine blade mold comprises the following steps:

[0010] (1) Model segmentation design: The wind turbine blade mold is divided into upper and lower molds along the cross section and formed separately. The corresponding mold forming model is designed according to the upper and lower mold cavities, and the over-wide mold section is made by longitudinal segmentation on the model;

[0011] The model is longitudinally segmented to produce two split molds from the overly wide mold section, with one split mold forming a "C-shape" according to the segmentation method, and the other split mold just fitting into the "C-shaped" gap; and metal clips are erected at the segmented positions and bonded to the model surface with putty, the metal clips including two transverse metal clips and one longitudinal metal clip, forming a "C-shape" on the model surface;

[0012] A wooden boss is provided on each side of the metal pallet, and the boss and the metal pallet are bonded with putty; the platform height of the boss is 7 to 9 mm, the platform lengths on both sides are 110 to 130 mm, and the slope lengths are 70 to 90 mm, which facilitates the subsequent assembly process of the split mold manufactured by longitudinal segmentation;

[0013] The function of the metal pallet is to make a flange at the segmentation. The width of the pallet is the width of the flange, which is generally 10 to 12 cm (applicable to all blade molds). If the width is too wide, the excess width will be cut off after demoulding. The thickness of the metal pallet is 1 to 2 cm, which determines the width of the joint seam of the longitudinal segmented split mold (applicable to all blade molds).

[0014] The surface of the model is formed by machine tool processing, matches the mold cavity of the wind turbine blade mold, and is supported by a steel frame below;

[0015] (2) Model surface pretreatment: Before mold making, apply cleaning water, sealing agent and release agent on the model surface in sequence;

[0016] The film cleaning water is applied at least twice, the sealing agent is applied at least twice, and the release agent is applied at least five times;

[0017] (3) Production of the inner structural layer of the mold: The inner structural layer is laid on the surface of the pre-treated model as a whole, and 2 to 3 layers of carbon felt, 2 to 3 layers of glass fiber biaxial cloth, and 10 to 11 layers of glass fiber quad-axial cloth are laid in sequence. Then, a layer of aluminum mesh is laid on the glass fiber quad-axial cloth, and an L-shaped aluminum sheet is placed every 10 to 12 meters on the aluminum mesh on both sides of the mold for static electricity conduction. Then, 3 to 4 layers of glass fiber quad-axial cloth are laid, and finally vacuum auxiliary materials are laid, and the vacuum infusion process is used for molding;

[0018] Finally, the glass fiber quad-axial cloth is laid to fix the aluminum sheet;

[0019] The carbon felt has a gram weight of 20 g / m 2 ;

[0020] The fiber direction of the glass fiber biaxial cloth is 0° / 90°, and the weight is 400g / m 2 ;

[0021] The fiber directions of the glass fiber four-axial cloth are 0° / 45° / 90° / -45°, and the weight is 800g / m 2 ;

[0022] The aluminum sheet preferably has a length, width, and thickness of 90 mm, 30 mm, and 2 mm, respectively, and a standing height of 40 mm;

[0023] (4) Preparation of mold heating layer: Arrange electric heating wires on the inner structure layer laid out in step (3), divide the surface into areas where the electric heating wires are arranged, and disconnect the areas where the electric heating wires are arranged at the metal clips at the segmented positions to obtain a heating layer;

[0024] The spacing between the electric heating wires is 20 to 30 mm, and the area of ​​each arrangement area is 2 to 3 m 2 , arrange the electric heating wires and extend the two heating wires to the end surface of the segmented card;

[0025] (5) Production of the outer structural layer of the mold: laying the outer structural layer on the heating layer obtained in step (4), that is, laying 6 to 8 layers of glass fiber four-axial cloth and vacuum auxiliary materials in sequence, and then forming by vacuum infusion process;

[0026] The glass fiber four-axial cloth has a fiber direction of 0° / 45° / 90° / -45° and a gram weight of 800g / m 2 ;

[0027] (6) Grinding and connecting the mold segments: Grind the inner and outer structural fiberglass layers of the metal plate at the segmented position, and grind off the fiberglass directly above the metal plate to ensure that the molds on both sides of the plate are separated and not connected;

[0028] (7) Mold steel frame welding and segmentation processing: integrally weld the steel frame, use a crane to hoist the steel frame to the mold outer structure layer, and fix the steel frame and the mold outer structure layer by hand lay-up;

[0029] The connecting square tubes of the steel frame at the longitudinal segments are cut, and a splicing connecting plate and a non-positioning steel frame flange are welded at the positions of the cut square tubes. The splicing connecting plate and the non-positioning steel frame flange are aligned with the hole positions and fixed with bolts;

[0030] (8) Mold curing and demolding: The blade mold obtained by the final molding is pre-cured, and then the steel frame is hoisted by an overhead crane for demolding. The fixing bolts of the splicing connecting plates and the non-positioning steel frame flange at the demolded mold steel frame segment are removed, and the two split molds of the longitudinal segment are separated. The end face of the fiberglass flange at the mold segment is roughened. After the mold produced by longitudinal segmentation is separated, the width of the mold is greatly reduced, which is conducive to planning the transportation route and saving transportation costs and transportation time.

[0031] The pre-curing comprises: heating at 60-70° C. for 12-16 hours;

[0032] (9) Assembling the split mold: Splice the two split molds of the longitudinal segmentation, align the two split molds with the position of the splicing connecting plate and the non-positioning steel frame flange, that is, the position of the splicing connecting plate and the non-positioning steel frame flange removed in step (8), fix them with bolts, and then adjust the elevation of the front and rear edges of the mold, and use a laser tracker to test and adjust the mold surface until it is qualified; and process the splicing seams and grooves, and finally polish the segmentation to make it smooth, clean the surface, and reassemble the two split molds of the longitudinal segmentation into a whole as the upper mold or lower mold of the blade mold, and then combine the upper and lower molds into the overall mold of the wind turbine blade;

[0033] The grooves of the longitudinal segments of the mold are formed by the bosses on the model;

[0034] The joint seam treatment process is as follows: a mixture is filled in the longitudinal segmented joint seams, and two electric heating wires are connected to ensure the temperature uniformity of the segmented areas; the mixture is a mixture of chopped glass fiber cloth, resin, and white carbon black;

[0035] The groove treatment process is as follows: 12 to 15 layers of four-axial cloth are laid in the grooves of the longitudinal segment of the mold, vacuum infusion is performed, and then heating is performed at 60 to 70°C for 12 to 16 hours with a heating blanket, and then heating at 90 to 95°C for 24 to 30 hours to cure;

[0036] The fiber directions of the four-axial cloth laid in the groove are 0° / 45° / 90° / -45°, and the weight is 800g / m 2 .

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The longitudinally segmented blade molds produced by the present invention can be transported separately and then assembled in the customer's factory; this makes it easier to plan the transportation route of large blade molds, reduces transportation costs, and shortens transportation time; and the reduction in transportation time allows for more post-debugging time, which is more conducive to improving the quality of mold installation and debugging. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the structure of the longitudinally segmented upper mold or lower mold of the present invention.

[0040] Figure 2 The model surface is provided with longitudinal segments according to the present invention.

[0041] Figure 3 This is a side view of the metal clip plate of the present invention.

[0042] Figure 4 It is a partial schematic diagram of the spliced ​​connecting plate of the present invention.

[0043] Figure 5 This is a partial schematic diagram of the non-positioning steel frame flange of the present invention.

[0044] Figure 6 Schematic diagram of the joint seam and groove area at the longitudinal segment of the mold according to the present invention.

[0045] The markings in the figure are: 1 metal clamping plate, 2, 3 bosses, 4 splicing connecting plate, 5 non-positioning steel frame flange, 6 groove, 7 splicing seam. DETAILED DESCRIPTION

[0046] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0047] Example

[0048] A method for manufacturing a longitudinally segmented wind turbine blade mold, characterized by comprising the following steps:

[0049] (1) A longitudinal segmented blade mold is made on a blade mold model with a length of 23 meters and a maximum width of 5.9 meters. Metal pallets are placed at the segmented positions of the model. Wooden blocks are used as bosses on both sides of the metal pallet. Putty is used to bond the metal pallet to the model, and putty is used to bond the bosses to the metal pallet.

[0050] The platform height of the boss is 8mm, the platform lengths on both sides are 120mm, and the slope lengths are 80mm;

[0051] The width of the metal card plate is 12 cm, and the thickness of the metal card plate is 1 cm;

[0052] The surface of the model is formed by machine tool processing, matches the mold cavity of the wind turbine blade mold, and is supported by a steel frame below;

[0053] (2) Apply 2 coats of cleaning water, 2 coats of sealing agent, and 5 coats of release agent on the surface of the model in sequence;

[0054] (3) Fabrication of the inner structural layer of the mold: The inner structural layer is laid on the pre-treated surface of the model, and 2 layers of carbon felt, 2 layers of glass fiber biaxial cloth, and 10 layers of glass fiber quad-axial cloth are laid in sequence. Then, a layer of aluminum mesh is laid on the glass fiber quad-axial cloth, and an L-shaped aluminum sheet is placed on the aluminum mesh for static electricity conduction. Then, 4 layers of glass fiber quad-axial cloth are laid, and finally vacuum auxiliary materials are laid, and the vacuum infusion process is used for molding;

[0055] The carbon felt has a gram weight of 20 g / m 2 ;

[0056] The fiber direction of the glass fiber biaxial cloth is 0° / 90°, and the weight is 400g / m 2 ;

[0057] The fiber directions of the glass fiber four-axial cloth are 0° / 45° / 90° / -45°, and the weight is 800g / m 2 ;

[0058] The length, width and thickness of the aluminum sheet are 90mm, 30mm and 2mm respectively, and the standing height is 40mm;

[0059] (4) Production of mold heating layer: electric heating wires are arranged on the inner structure layer, and the surface is divided into areas where the electric heating wires are arranged. The areas where the electric heating wires are arranged are disconnected at the metal clamping plates at the segmented positions to obtain the heating layer;

[0060] The spacing between the electric heating wires is 25 mm, and the area of ​​each arrangement area is 2.5 m 2 , arrange the electric heating wires and extend the two heating wires to the end surface of the segmented card;

[0061] (5) Production of the outer structural layer of the mold: laying the outer structural layer on the heating layer, that is, laying 6 layers of glass fiber four-axial cloth and vacuum auxiliary materials in sequence, and then forming by vacuum infusion process;

[0062] The glass fiber four-axial cloth has a fiber direction of 0° / 45° / 90° / -45° and a gram weight of 800g / m 2 ;

[0063] (6) Grind the inner and outer structural layers of the fiberglass reinforced plastics at the segmented metal plate, and grind off the fiberglass reinforced plastics directly above the metal plate to ensure that the molds on both sides of the plate are separated and not connected;

[0064] (7) Integrally weld the steel frame, hoist the steel frame onto the outer structure layer of the mold with an overhead crane, and fix the steel frame and the outer structure layer of the mold with hand lay-up; the connecting square tubes of the steel frame are cut at the longitudinal segmentation, and the splicing connecting plate and the non-positioning steel frame flange are welded at the position of the cut square tubes. The splicing connecting plate and the non-positioning steel frame flange are aligned with the hole positions and fixed with bolts;

[0065] (8) The blade mold obtained by the final molding is pre-cured, and then the steel frame is hoisted by the overhead crane for demoulding. The fixing bolts of the splicing connecting plate and the non-positioning steel frame flange at the demoulding mold steel frame segment are removed, and the two split molds of the longitudinal segment are separated, and the fiberglass flange end faces at the mold segment are roughened; after the longitudinal segmented mold is separated, the width of the mold is greatly reduced, which is conducive to planning the transportation route and saving transportation costs and transportation time;

[0066] The pre-curing comprises: heating at 60°C for 12 hours;

[0067] (9) Split mold assembly: The two split molds of the longitudinal segmentation are 5.4 meters and 2.1 meters respectively, and are spliced ​​together. The two split molds are aligned with the position of the splicing connection plate and the non-positioning steel frame flange, that is, the position of the splicing connection plate and the non-positioning steel frame flange removed in step (8), and are fixed with bolts. Then, the elevation of the front and rear edges of the mold is adjusted, and the mold surface is tested and adjusted by a laser tracker until it is qualified; and the splicing seams and grooves are processed, and finally the segmentation is polished and smoothed, and the surface is cleaned. The two split molds of the longitudinal segmentation are reassembled into a whole as the upper mold or lower mold of the blade mold, and then the upper and lower molds are combined into an integral mold of the wind turbine blade;

[0068] The grooves of the longitudinal segments of the mold are formed by the bosses on the model;

[0069] The joint seam treatment process is as follows: a mixture is filled in the longitudinal segmented joint seams, and two electric heating wires are connected to ensure the temperature uniformity of the segmented areas; the mixture is a mixture of chopped glass fiber cloth, resin, and white carbon black;

[0070] The groove treatment process is as follows: 14 layers of four-axial cloth are laid in the groove of the longitudinal segment of the mold, vacuum infusion is performed, and then covered with a heating blanket and heated at 60°C for 12 hours, and then heated at 90°C for 24 hours to cure; the fiber directions of the four-axial cloth laid in the groove are 0° / 45° / 90° / -45°, and the gram weight is 800g / m 2 .

[0071] The longitudinally segmented blade mold produced by the embodiment of the present invention is used to segment the overly wide mold segment longitudinally in the width direction, and to split an integral wider mold segment into two narrower split molds, which can be transported separately and then assembled in the customer's factory; this makes it easier to plan the transportation route of large blade molds, reduces transportation costs, and shortens transportation time.

Claims

1. A method for manufacturing a longitudinally segmented wind turbine blade mold, characterized in that: The steps include: (1) Model segmentation design: The wind turbine blade mold is divided into upper and lower molds along the cross section and formed separately. The corresponding mold forming model is designed according to the upper and lower mold cavities, and the over-wide mold section is made by longitudinal segmentation on the model; The model is divided into two separate molds by longitudinal segmentation, and metal clips are erected at the segment positions and bonded to the model surface with putty. The metal clips include two transverse metal clips and one longitudinal metal clip, forming a "C-shape" on the model surface. A wooden boss is provided on each side of the metal card plate, and the boss and the metal card plate are bonded with putty; (2) Model surface pretreatment: Before mold making, apply cleaning water, sealing agent and release agent on the model surface in sequence; (3) Fabrication of the inner structural layer of the mold: The inner structural layer is laid out on the pre-treated surface of the model, and carbon felt, glass fiber biaxial cloth, and glass fiber quadriaxial cloth are laid in sequence. Then, a layer of aluminum mesh is laid on the glass fiber quadriaxial cloth, and an L-shaped aluminum sheet is placed every 10 to 12 meters on the aluminum mesh on both sides of the mold. Then, the glass fiber quadriaxial cloth is laid, and finally, vacuum auxiliary materials are laid, and the vacuum infusion process is used for molding; (4) Preparation of mold heating layer: Arrange electric heating wires on the inner structure layer laid out in step (3), divide the surface into areas where the electric heating wires are arranged, and disconnect the areas where the electric heating wires are arranged at the metal clips at the segmented positions to obtain a heating layer; (5) Production of the outer structural layer of the mold: laying the outer structural layer on the heating layer obtained in step (4), that is, laying the glass fiber four-axial cloth and vacuum auxiliary materials on the whole in sequence, and then forming it by vacuum infusion process; (6) Grinding and connecting the mold segments: Grind the inner and outer structural fiberglass layers of the metal plate at the segmented position, and grind off the fiberglass directly above the metal plate to ensure that the molds on both sides of the plate are separated and not connected; (7) Mold steel frame welding and segmentation processing: integrally weld the steel frame, use a crane to hoist the steel frame to the mold outer structure layer, and fix the steel frame and the mold outer structure layer by hand lay-up; The connecting square tubes of the steel frame at the longitudinal segments are cut, and a splicing connecting plate and a non-positioning steel frame flange are welded at the positions of the cut square tubes. The splicing connecting plate and the non-positioning steel frame flange are aligned with the hole positions and fixed with bolts; (8) Mold curing and demolding: The blade mold obtained by the final molding is pre-cured, and then the steel frame is hoisted by an overhead crane for demolding. The fixing bolts of the splicing connecting plate and the non-positioning steel frame flange at the demolded mold steel frame segment are removed, and the two split molds of the longitudinal segment are separated. The end face of the fiberglass flange at the rough mold segment is polished; (9) Split mold assembly: Splice the two split molds that are longitudinally segmented. Align the two split molds with the positions of the splicing connection plate and the non-positioning steel frame flange, that is, the positions of the splicing connection plate and the non-positioning steel frame flange removed in step (8). Fix them with bolts, then adjust the elevation of the front and rear edges of the mold, and use a laser tracker to test and adjust the mold surface until it is qualified. After that, the joints and grooves are processed, and finally the segments are polished and smoothed, the surface is cleaned, and the two longitudinally segmented separate molds are reassembled into a whole, which serves as the upper mold or lower mold of the blade mold. The upper and lower molds are then combined into the overall mold of the wind turbine blade; The grooves of the longitudinal segments of the mold are formed by producing bosses on the model.

2. The method for manufacturing a longitudinally segmented wind turbine blade mold according to claim 1, characterized in that: The platform height of the boss in step (1) is 7-9 mm, the platform lengths on both sides are 110-130 mm, and the slope lengths are 70-90 mm; The width of the metal card plate is 10 to 12 cm, and the thickness of the metal card plate is 1 to 2 cm.

3. The method for manufacturing a longitudinally segmented wind turbine blade mold according to claim 1, characterized in that: The model surface in step (1) is formed by machine tool processing, matches the mold cavity of the wind turbine blade mold, and is supported by a steel frame at the bottom.

4. The method for manufacturing a longitudinally segmented wind turbine blade mold according to claim 1, characterized in that: In step (2), the membrane cleaning water is applied at least twice, the sealing agent is applied at least twice, and the release agent is applied at least five times.

5. The method for manufacturing a longitudinally segmented wind turbine blade mold according to claim 1, characterized in that: In step (3), the carbon felt is laid in 2 to 3 layers, the glass fiber is laid in biaxial direction in 2 to 3 layers, the glass fiber quadriaxial cloth under the aluminum mesh is laid in 10 to 11 layers, and the last layer of glass fiber quadriaxial cloth is laid in 3 to 4 layers; The carbon felt has a gram weight of 20 g / m 2 ; The fiber direction of the glass fiber biaxial cloth is 0° / 90°, and the weight is 400g / m 2 ; The fiber directions of the glass fiber four-axial cloth are 0° / 45° / 90° / -45°, and the weight is 800g / m 2 .

6. The method for manufacturing a longitudinally segmented wind turbine blade mold according to claim 1, characterized in that: The spacing between the electric heating wires in step (4) is 20 to 30 mm, and the area of ​​each layout area is 2 to 3 m 2 , arrange the electric heating wires and extend the two heating wires to the end surface of the segmented card.

7. The method for manufacturing a longitudinally segmented wind turbine blade mold according to claim 1, characterized in that: The glass fiber four-axial cloth described in step (5) is laid in 6 to 8 layers; The glass fiber four-axial cloth has a fiber direction of 0° / 45° / 90° / -45° and a gram weight of 800g / m 2 .

8. The method for manufacturing a longitudinally segmented wind turbine blade mold according to claim 1, characterized in that: The pre-curing process in step (8) includes heating at 60-70° C. for 12-16 hours.

9. The method for manufacturing a longitudinally segmented wind turbine blade mold according to claim 1, characterized in that: The process for treating the joint seams in step (9) is as follows: filling the joint seams of the longitudinal segments with a mixture and simultaneously connecting two electric heating wires; The mixed material is a mixture of chopped glass fiber cloth, resin and white carbon black.

10. The method for manufacturing a longitudinally segmented wind turbine blade mold according to claim 1, characterized in that: The groove treatment process in step (9) is as follows: laying 12 to 15 layers of four-axial cloth in the groove of the longitudinal segment of the mold, performing vacuum infusion, heating at 60 to 70°C for 12 to 16 hours with a heating blanket, and then heating at 90 to 95°C for 24 to 30 hours to cure; The fiber directions of the four-axial cloth laid in the groove are 0° / 45° / 90° / -45°, and the weight is 800g / m 2 .

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