CN117067639B

CN117067639B - Forming method and product of small-fillet composite material outer lining

Info

Publication number: CN117067639B
Application number: CN202311226071.9A
Authority: CN
Inventors: 刘晓婷; 孙德权; 夏吉升; 张建坤; 王岩; 张立明
Original assignee: Jiangxi Jiuyou Aviation Equipment Co ltd; Harbin Yuanchi Aviation Equipment Co ltd
Current assignee: Jiangxi Jiuyou Aviation Equipment Co ltd; Harbin Yuanchi Aviation Equipment Co ltd
Priority date: 2023-09-22
Filing date: 2023-09-22
Publication date: 2023-12-29
Anticipated expiration: 2043-09-22
Also published as: CN117067639A

Abstract

The application relates to the technical field of polymer composite material forming, and discloses a forming method and a product of a small-fillet composite material outer liner, wherein the method solves the problem that the prior art cannot meet the processing requirements of different radius of curvature of inner and outer fillets, and comprises the following steps: preforming the prepreg; providing a female die, forming an outer lining in the female die, paving at least one layer of first prepreg in the cavity of the die, and covering the inner chamfer after shaping the at least one layer of first prepreg; paving prepreg blocks on at least one layer of first prepreg, and attaching the round tip parts of the prepreg blocks to the positions of at least one layer of first prepreg corresponding to the inner chamfer angles; at least one layer of second prepreg is paved on the at least one layer of first prepreg and the prepreg, and the at least one layer of second prepreg is covered on the arc surface of the prepreg after being shaped layer by layer; a vacuum bag is pasted on the female die, and an outer lining is formed in a hot press forming mode, so that the difference of curvature radiuses of the inner corners and the outer corners can be effectively ensured, and the quality of products is improved.

Description

Forming method and product of small-fillet composite material outer lining

Technical Field

The invention relates to the technical field of polymer composite material molding, in particular to a molding method and a product of a small-fillet composite material outer liner.

Background

The current design of box-shaped parts in aviation equipment has very strict requirements, in order to ensure the product performance, the box-shaped parts on a pressing plate have strict requirements, and the prior art generally has the following requirements in the forming process of certain box-shaped part products: the radius of curvature of the fillet and the fillet are different for the box product, and the minimum fillet requirement for the box product is less than 2mm. However, the prior art does not meet the processing requirements of the box-type products.

Disclosure of Invention

In view of the above-mentioned drawbacks or shortcomings in the prior art, it is desirable to provide a method for forming a small-fillet composite outer liner and a product thereof, wherein the forming method is simple, can effectively ensure that the radius of curvature of the fillet and the radius of curvature of the bullnose are different, has the manufacturing requirement of the small-fillet composite outer liner, improves the process quality of the product, has simple process, and is beneficial to improving the production efficiency.

In a first aspect, the present invention provides a method of forming a small radius composite outer liner having a mounting cavity, the outer liner comprising an inner surface for providing a mounting surface for mating with an external workpiece and an outer surface for providing a profile surface; the inner surface is provided with a first circular chamfer and the outer surface is provided with a second circular chamfer, the radius of curvature of the first circular chamfer is greater than the radius of curvature of the second circular chamfer, the method comprising:

Preforming a prepreg, wherein the cross section of the prepreg is close to a triangle, the prepreg comprises a circular tip part and a circular arc surface, the circular arc surface is matched with the shape of the first circular chamfer, and the curvature radius of the circular arc surface is equal to that of the first circular chamfer; the shape of the round tip part is matched with that of the second round chamfer, and the curvature radius of the round tip part is equal to that of the second round chamfer;

providing a female die and forming an outer liner in the female die, wherein the female die comprises a first half female die and a second half female die, the first half female die and the second half female die are detachably combined and define a die cavity, the die cavity is used for forming the outer liner, the die cavity is provided with an inner chamfer, the shape of the inner chamfer is matched with the shape of a second round chamfer, and the curvature radius of the inner chamfer is equal to that of the second round chamfer; wherein, at die internal shaping outer lining, include:

at least one layer of first prepreg is paved in the cavity of the model, shaped layer by layer and then covered on the inner chamfer in a shape-following manner;

paving prepreg blocks on at least one layer of first prepreg, and attaching the round tip parts of the prepreg blocks to the positions of at least one layer of first prepreg corresponding to the inner chamfer angles;

at least one layer of second prepreg is paved on the at least one layer of first prepreg and the prepreg, and the at least one layer of second prepreg is shaped layer by layer and then covered on the arc surface of the prepreg along with the shape;

And pasting a vacuum bag on the female die, and forming the outer lining in a hot press forming mode.

Alternatively, the at least one layer of the first prepreg layer-by-layer shaping comprises:

shaping, paving and prepressing the first prepregs layer by layer, detecting the curvature radius of each first prepreg with a certain layer number at intervals, and continuously paving the rest first prepregs until the paving is completed;

the at least one layer of the second prepreg layer-by-layer shaping comprises:

and (3) shaping, paving and prepressing the second prepregs layer by layer, detecting the curvature radius of the second prepregs at certain intervals, and continuously paving the rest of the second prepregs until the paving is completed.

Alternatively, the outer liner comprises a side wall, a first flat wall and a second flat wall arranged at two ends of the side wall, wherein the side wall comprises a first side flat wall and a second side flat wall which are arranged in parallel, and an arc-shaped connecting wall arranged between the first side flat wall and the second side flat wall;

the edges of the first flat wall, the second flat wall, the first side flat wall and the second side flat wall surround to form an opening.

Alternatively, the opening is arranged at an included angle with the first flat wall and the second flat wall; the first side flat wall and the second side flat wall are provided with mounting holes;

the bus of the arc connecting wall forms an included angle with the first flat wall and the second flat wall;

The first planar wall includes a first curvilinear edge contiguous with the side wall and the second planar wall includes a second curvilinear edge contiguous with the side wall, the perimeter of the first curvilinear edge being less than the perimeter of the second curvilinear edge.

Alternatively, a first chamfering area is arranged on the first curve edge, and a second chamfering area is arranged on the second curve edge;

the prepreg comprises a first prepreg strip and a second prepreg strip, wherein the first prepreg strip is used for forming a first round chamfer and a second round chamfer on the first chamfer area, and the second prepreg strip is used for forming the first round chamfer and the second round chamfer on the second chamfer area.

Alternatively, in a first direction along which the first flat wall points to the center of the opening, the width of the installation appearance corresponding to the part of the outer surface gradually increases, and the width of the installation cavity corresponding to the inner surface is unchanged, wherein the width of the installation appearance is the distance between the outer surface and the installation cavity along the second direction, and the width of the installation cavity is the distance between the inner surface and the installation cavity along the second direction;

in the first direction of pointing to the center of the opening along the second flat wall, the width of the installation appearance corresponding to part of the outer surface is unchanged, and the width of the installation cavity corresponding to the inner surface is unchanged.

Alternatively, a partial prepreg is arranged between two adjacent second prepregs, and multiple layers of partial prepregs are arranged at positions of the side walls away from the first flat wall and are used for forming a mounting cavity with unchanged width.

Alternatively, the second prepreg includes a first prepreg portion for forming the first flat wall and a second prepreg portion for forming the second flat wall, the first prepreg portion covering at least the first curved edge and extending onto a portion of the side wall, the second prepreg portion covering at least the second curved edge and extending onto a portion of the side wall;

the number of layers of the second prepreg section for forming the first flat wall is smaller than the number of layers of the second prepreg section for forming the second flat wall;

the second prepreg portion for forming the second flat wall extends from the second flat wall position to the first flat wall position to form the partial prepreg.

Alternatively, the radius of curvature of the first round chamfer is greater than or equal to 4mm, and the radius of curvature of the second round chamfer is less than or equal to 2mm.

In a second aspect, the present invention provides a small radius composite outer liner, the small radius composite being formed by the method according to the first aspect.

The invention relates to a method for forming a small-fillet composite outer lining, which comprises the steps of pre-forming a prepreg, adopting a combination mold mode, enabling a female mold to comprise a first half female mold and a second half female mold, combining the first half female mold and the second half female mold to form a mold cavity, respectively paving at least one layer of first prepreg, the prepreg and the second prepreg in the mold cavity, and finally obtaining the composite outer lining through vacuum hot-press curing and forming; the arrangement of the prepreg is beneficial to increasing the curvature radius of the paving surface in the paving process, so that the curvature radius of the first round chamfer of the composite material outer lining is beneficial to being larger than that of the second round chamfer; and moreover, the combined die is used, so that the die is convenient to demould, the prepreg is paved layer by layer along with the shape in the die cavity of the combined die, the small-fillet composite material outer lining is facilitated to be obtained, the forming quality of the small-fillet composite material outer lining is ensured, the operation is simple, and the realization is easy.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the following drawings, in which:

FIG. 1 is a schematic diagram of a female die (with composite product built in) according to the present invention;

FIG. 2 is a schematic view of a first half of the female die of the present invention;

FIG. 3 is a schematic view of a first half of the die of the present invention (with composite product built-in);

FIG. 4 is a schematic view of the structure of an outer liner of the present invention;

FIG. 5 is a top view (top-down direction) of FIG. 4;

fig. 6 is a right side view (right-to-left direction) of fig. 4;

FIG. 7 is a schematic view of another outer liner of the present invention;

FIG. 8 is a schematic view of the structure of a prepreg according to the present invention;

FIG. 9 is a schematic lay-up front view of a matrix prepreg of the present invention;

FIG. 10 is a layup side schematic view of a matrix prepreg of the present invention;

FIG. 11 is a schematic illustration of an arrangement of a prepreg block of the present invention;

FIG. 12 is a schematic ply-side view of another matrix prepreg of the invention;

FIG. 13 is a schematic view of a prepreg cut according to the present invention;

FIG. 14 is a schematic view of the structure of a composite heated outer liner of the present invention;

FIG. 15 is an exploded view of a heating layer according to the present invention;

FIG. 16 is a schematic diagram of a metal trace on a heating layer according to another embodiment of the present invention;

FIG. 17 is a schematic diagram of a metal trace on a heating layer according to another embodiment of the present invention.

In the drawing the view of the figure,

100. a female die; 200. an outer liner; 11. a first half female die; 111. a fixed zone; 112. a molding zone; 12. a second half-die; 13. a mold cavity; 14. an inner chamfer;

210. a base; 211. an inner surface; 212. an outer surface; 213. a first round chamfer; 214. a second round chamfer;

20. presoaking blocks; 21. a rounded tip; 22. an arc surface; 23. a first plane; 24. a second plane; 201. a first prepreg tape; 202. a second prepreg;

220. a heating layer; 221. a first organic insulating layer; 222. a second organic insulating layer; 223. a metal wiring; 224. cutting the mouth; 224-1, a first cutout; 224-2, a second cutout; 225. a through hole;

30. a sidewall; 40. a first flat wall; 50. a second flat wall; 60. an opening; 70. a mounting cavity; 80. a mounting hole; 31. a first side planar wall; 32. a second side flat wall; 33. an arc-shaped connecting wall; 41. a first curvilinear edge; 51. a second curvilinear edge;

300. a first prepreg; 310. cutting the mouth; 400. a second prepreg; 410. a first prepreg section; 420. and a second prepreg section.

Detailed Description

The present application is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be noted that, for convenience of description, only the portions related to the invention are shown in the drawings.

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Based on the above-mentioned problems, the present application provides a die 100 for a small fillet composite material outer lining product, as shown in fig. 1-3, the die 100 includes:

the first half die 11 and the second half die 12 are detachably combined, and define a mold cavity 13, the mold cavity 13 having an opening for laying a first prepreg 300, a second prepreg 400, or a prepreg 20 inside the mold cavity 13, the first prepreg 300, the second prepreg 400, or the prepreg 20 each including a polymer material, respectively;

the inside of the mold cavity 13 has an inner chamfer in the form of a rounded corner, and the radius of curvature of the inner chamfer is 2mm or less, preferably 1.5mm.

It should be noted that the female die according to the embodiments of the present application is suitable for processing various polymer composite products, such as, but not limited to, various resin-based materials, and the resin-based composite materials have excellent properties such as high specific strength, high specific modulus, good fatigue resistance, unique materials and structural designability, and thus find increasingly wide application in aviation aircrafts.

It can be appreciated that the first half die 11 and the second half die 12 are combined to form a die cavity 13, the wall surface of the die cavity 13 is used as a carrier for carrying and laying the first prepreg 300, the second prepreg 400 or the prepreg 20, the first prepreg 300 or the second prepreg 400 is laid layer by layer along with the shape of the wall surface of the die cavity 13, and the composite material product is obtained through compacting, curing and other processes; the first prepreg 300, the second prepreg 400 or the prepreg 20 generally comprises glass fiber cloth or carbon fiber cloth, and the glass fiber cloth or the carbon fiber cloth is easy to cover the surface of the model cavity 13 along with the shape, so that the fit degree between the glass fiber cloth or the carbon fiber cloth and the surface of the model cavity 13 is good; the sizing material of the prepreg comprises resin, and the resin is melted by heating, so that the bonding strength of the composite material can be improved; the embodiment of the application forms the mould cavity through first half die and second half die combination, is favorable to being favorable to making things convenient for the drawing of patterns after the shaping of combined product material when reliably processing combined product, compares in prior art adoption and has the die of a completion confined cavity, and the die of this application embodiment easy operation, convenient drawing of patterns.

The shapes and the sizes of the first half die 11 and the second half die 12 may be completely consistent, and of course, the shapes and the sizes of the first half die 11 and the second half die 12 may also be different, and in actual processing, the structure of the part to be processed may be adjusted according to needs.

In a specific embodiment, a fixing structure is further arranged between the first half die 11 and the second half die 12, the first half die 11 and the second half die 12 respectively comprise a fixing area 111 and a forming area 112, the fixing area 111 is used for fixing the first half die 11 and the second half die 12 after being clamped, and the forming area 112 is used for forming a die cavity 13; the fixing structure comprises a plurality of threaded holes and pin holes which are respectively formed in the fixing areas 111 of the first half female die 11 and the second half female die 12, after the first half female die 11 and the second half female die 12 are closed, the fixing structure is positioned in advance through the matching of the positioning pins and the pin holes, then the first half female die 11 and the second half female die 12 are fixed through the matching of the fastening bolts and the threaded holes, and when demoulding, the fastening bolts and the positioning pins are detached in sequence.

It will also be appreciated that the interior of the mould cavity 13 has an internal chamfer 14 in the form of a rounded corner for forming a second rounded corner 214 on the outer surface 212 of the composite product, and that the radius of curvature of the rounded corner is less than or equal to 2mm, which is advantageous in that the formed composite product has a small rounded corner that meets the requirements.

The concave die solves the problems that when the minimum round angle of a product is smaller than 2mm, the product requirement cannot be met and the product quality is difficult to control in the prior art; according to the embodiment of the application, the combination die is adopted, the female die comprises the first half female die and the second half female die, the first half female die and the second half female die are combined to form the die cavity, the prepreg is paved to form a composite material product, and meanwhile, the demolding is convenient; in addition, the radius of the fillet at the inner chamfer of the inner part of the model cavity is equal to 1.5mm, compared with the radius of the fillet of the existing female die, the method is small, so that the composite material obtained by processing has small fillet, meanwhile, the prepreg is paved in the inner part of the model cavity, the structure with unequal thickness of the fillet area is conveniently formed by controlling the quality requirement of paving the prepreg, the radius of curvature of the inner fillet and the outer fillet of the composite material product is different, the composite material with unequal thickness and small fillet is obtained, the forming quality of the composite material with unequal thickness and small fillet is ensured, the operation is simple, and the realization is easy; wherein unequal thicknesses means that the radius of curvature of the fillet and the radius of curvature of the bullnose are different.

The curve edge in the embodiment of the application is beneficial to ensuring that the outer surface of the prepared composite material product is a curved surface, the curved surface structure has good local hydrodynamic property, and meanwhile, the phenomenon of stress concentration formed on the composite material product can be avoided, so that the composite material product prepared by the female die of the embodiment of the application is very suitable for aviation equipment.

As an achievable mode, the female die further comprises an auxiliary die assembly, the auxiliary die assembly at least comprises a sealing strip, a vacuum bag and a vacuum pump, wherein the vacuum bag is sleeved outside the female die and is sealed through the sealing strip, the vacuum bag is connected with the vacuum pump, and vacuum is extracted, so that the prepreg inside the die cavity 13 is compacted and solidified. In the embodiment, through vacuum pre-pressing and solidification, the quality of a formed product is guaranteed, volatile components in a high polymer material on the prepreg are easy to escape, the porosity of the inside of the prepared composite material product is reduced, and the mechanical property of the composite material product is improved.

As shown in fig. 4-6, an embodiment of the present invention provides a low radius composite outer liner 200, the outer liner 200 comprising a base 210, the base 210 having a mounting cavity, the base 210 comprising an inner surface 211 and an outer surface 212, the inner surface 211 for providing a mounting surface for mating with an external workpiece, the outer surface 212 for providing a contoured surface; the inner surface 211 is provided with a first circular chamfer 213 and the outer surface 212 is provided with a second circular chamfer 214, the radius of curvature of the first circular chamfer 213 being larger than the radius of curvature of the second circular chamfer 214.

In this embodiment, the base 210 includes a side wall 30, and a first flat wall 40 and a second flat wall 50 disposed at two ends of the side wall 30, where the side wall 30 includes a first flat wall 31 and a second flat wall 32 disposed in parallel, and an arc-shaped connecting wall 33 disposed between the first flat wall 31 and the second flat wall 32; the edges of the first flat wall 40, the second flat wall 50, the first side flat wall 31 and the second side flat wall 32 are surrounded to form an opening 60, and a plurality of mounting holes 80 are provided on the first side flat wall 31 and the second side flat wall 32.

The outer liner 200 may be secured to the workpiece by the side walls 30 and the first and second flat walls 40, 50 surrounding a mounting cavity 70 having an opening 60, the mounting cavity 70 and the mounting hole 80. In this embodiment, the workpiece has the same shape as the mounting cavity 70. The outer liner 200 is also provided with rounded corners between adjacent surfaces, the rounded corners having the same dimensions as the first rounded corners 213 of the inner surface 211.

In this embodiment of the application, the radius of curvature of first round chamfer 213 is greater than the radius of curvature of second round chamfer 214 and sets up the mode, satisfies aviation appearance needs through the design of the little fillet of first round chamfer 213, satisfies the installation needs through the design of the big fillet of second round chamfer 214 for outer liner 200 is laminated more with the work piece, improves the cooperation installation effect of outer liner 200 and outside work piece, prevents that outer liner 200 from concentrating at chamfer position department internal stress.

It should be noted that, in the prior art molding technology, in order to ensure product performance, it is particularly difficult to meet the dimensions of the molded structure in a manner that some small round corners are encountered, due to the aeronautical lamination manner. For example, it is more difficult for the female die to form a small round chamfer in the hot pressing process, and the male die (punch) to form a round chamfer: r is more than or equal to 2mm, and a female die (female die) is formed: r is more than or equal to 2+t mm.

In this embodiment, in the manner of forming the outer liner 200, the female die 100 is preferably adopted to form the outer liner 200 with a good outer surface 212, and the heating layer 220 is formed on the substrate 210 of the outer liner 200 conveniently, and the size of the round chamfer that can be formed in the manner of the female die 100 adopted in this application may be less than 2mm. Illustratively, the radius of curvature of the first circular chamfer 213 is 4mm, 4.5mm, 5mm, and the radius of curvature of the second circular chamfer 214 is 1mm, 1.5mm, 2mm.

The outer liner 200 has an arcuate surface, for example, the generatrix of the arcuate connecting wall 33 is disposed at an angle to the first and second planar walls 40, 50; the included angle may be any angle between 0 ° and 180 °, for example, may be 40 °, 90 °, 120 °, and the like.

The arcuate connecting wall 33 has equal circumferences at a first arcuate edge adjacent to the first flat wall 40 and a second arcuate edge adjacent to the second flat wall 50, and the arcuate connecting wall 33 has equal radii of curvature in a direction along the first flat wall 40 to the second flat wall 50.

Optionally, the first flat wall 40 includes a first curved edge 41 that interfaces with the side wall 30, and the second flat wall 50 includes a second curved edge 51 that interfaces with the side wall 30, the perimeter of the first curved edge 41 being smaller than the perimeter of the second curved edge 51. In this embodiment, the first flat wall 40 is parallel to the second flat wall 50, and the area of the first flat wall 40 is smaller than that of the second flat wall 50, and the first curved edge 41 and the second curved edge 51 correspond to two end edges of the side wall 30. The arcuate connecting wall 33 mates with the arcuate configuration of the workpiece by the outer liner 200 being sleeved around the forming box configuration on the workpiece.

It will be appreciated that in embodiments of the present application, the first rounded chamfer 213 may be disposed at any angular position between adjacent faces on the inner surface 211 of the outer liner 200, and likewise, the second rounded chamfer 214 may be disposed at any angular position between adjacent faces on the outer surface 212 of the outer liner 200.

Optionally, the first rounded chamfer 213 comprises a first inner rounded chamfer provided on the first curved edge 41 and a second inner rounded chamfer provided on the second curved edge 51; the curvature radius of the first inner circular chamfer is more than or equal to 4mm, and the curvature radius of the second inner circular chamfer is more than or equal to 4mm; illustratively, the first inner circular chamfer has a radius of curvature of 4mm, 4.5mm, 5mm, and the second inner circular chamfer has a radius of curvature of 4mm, 4.5mm, 5mm.

The second rounded corner 214 includes a first outer rounded corner disposed on the first curvilinear edge 41 and a second outer rounded corner disposed on the second curvilinear edge 51; the curvature radius of the first outer circular chamfer is smaller than or equal to 2mm, and the curvature radius of the second outer circular chamfer is smaller than or equal to 2mm. By way of example, the radius of curvature of the first outer circular chamfer may be 1mm, 1.5mm, 2mm and the radius of curvature of the second outer circular chamfer 1mm, 1.5mm, 2mm.

It should be further noted that, the aviation structure used in the application has the appearance of a small round angle (R is less than or equal to 2 mm), and in the embodiment of the application, for convenient installation, the structure of the aviation workpiece is preferentially improved, so that the aviation workpiece has a larger round angle (R is more than or equal to 4 mm). The outer liner 200 in the embodiment of the present application is correspondingly adjusted in structure, so that the outer shape of the outer liner 200 meets the requirement of small round corners, and the inner chamfer 14 is more convenient to install with a workpiece.

In addition, in the embodiment of the present application, the applicable aeronautical structure may have a more complex curved surface or other shape surface with a changed size, and in the embodiment of the present application, when the shape of the workpiece has a certain curved surface or a size change area by adjusting the installation matching manner of the outer liner 200 and the workpiece, in order to improve the installation matching degree of the outer liner 200, the shapes of the outer liner 200 and the workpiece are adjusted in the present application, so that the installation cavity 70 of the outer liner 200 and the workpiece is a regular surface, the outer surface 212 of the outer liner 200 is a required shape surface, the shape of the inner surface 211 and the shape of the shape surface are not matched, and the shape of the inner surface 211 is more regular, so as to overcome the installation difficulty caused by some size change areas. It is understood that in the embodiment of the present application, the shape of the workpiece to be mounted matches the shape of the inner surface 211, and is a regular shape.

As shown in fig. 7, the present application illustrates a constant width dimension of the inner surface 211 of the outer liner 200 along a first direction and a certain dimensional transformation of the width of the outer surface 212 along the first direction. This dimensional change is described as an example in the embodiments of the present application.

In this embodiment, at a position near the first flat wall 40, in a first direction along the first flat wall 40 pointing toward the center of the opening 60, a part of the mounting profile width (H1) corresponding to the outer surface 212 gradually increases, and the mounting cavity 70 width (W1) corresponding to the inner surface 211 is unchanged; at a position near the second flat wall 50, in a first direction along the second flat wall 50 toward the center of the opening 60, a portion of the mounting profile width (H2) corresponding to the outer surface 212 is unchanged, and a portion of the mounting cavity 70 width (W2) corresponding to the inner surface 211 is unchanged. Wherein the mounting profile width (H1, H2) is the distance of the outer surface 212 in the second direction, and the mounting cavity 70 width (W1, W2) is the distance of the inner surface 211 in the second direction.

The embodiment of the application also provides a forming method of the small-fillet composite material outer lining, which comprises the following steps:

s100, preforming a prepreg block 20, wherein the cross-sectional shape of the prepreg block 20 is approximate to a triangle, the prepreg block 20 comprises a round tip 21 and an arc surface 22, the arc surface 22 is matched with the shape of the first round chamfer 213, and the curvature radius of the arc surface 22 is equal to the curvature radius of the first round chamfer 213; the rounded tip 21 matches the shape of the second rounded corner 214 and the radius of curvature of the rounded tip 21 is equal to the radius of curvature of the second rounded corner 214.

In this embodiment, the material of the prepreg 20 may be the same as that of the prepreg, and the prepreg 20 may be formed by molding the female mold 100 matching the shape thereof, or by cutting, which is not limited in this application.

The prepreg block 20 further comprises a first plane 23 and a second plane 24, and an included angle is formed between the first plane 23 and the second plane 24 to form the toe 21. The two ends of the arc surface 22 are respectively connected with the first plane 23 and the second plane 24. Illustratively, the rounded tip 21 mates with a second rounded corner 214.

In this embodiment of the present application, through the mode of preforming the prepreg 20, can avoid collapsing or bridging etc. at the position of the small round chamfer in the shaping process, reduce the stress concentration in the shaping process, improve the shaping quality of the outer liner 200, the mode of preforming through the prepreg 20 in this application is convenient to shape the small round chamfer on the outer liner 200.

S200, providing a female die 100 and forming an outer lining in the female die 100, wherein the female die 100 comprises a first half female die 11 and a second half female die 12, the first half female die 11 and the second half female die 12 are detachably combined and define a die cavity 13, the die cavity 13 is used for forming the outer lining 200, the die cavity 13 is provided with an inner chamfer, the shape of the inner chamfer is matched with that of a second round chamfer, and the curvature radius of the inner chamfer is equal to that of the second round chamfer;

It will be appreciated that in step S200, a release agent needs to be brushed on the inner wall surface of the mold cavity 13 before the outer liner is molded in the female mold 100, which is advantageous for facilitating the release after the molding of the composite product.

Wherein, the forming of the outer liner 200 in the female die 100 includes:

s300, at least one layer of first prepreg 300 is paved in the die cavity 13, and the at least one layer of first prepreg 300 is shaped layer by layer and then covers the inner chamfer 14 in a follow-up mode.

Specifically, the method comprises the steps of lay-up at least one layer of the first prepreg 300 in a conformal manner, wherein: the first prepregs 300 are shaped layer by layer, paved, pre-pressed, the radius of curvature of each first prepreg 300 with a certain layer number at intervals is detected, and the rest of the first prepregs 300 are continuously paved until the paving is completed. In the embodiment of the application, the inner chamfer 14 area is ensured to be smooth in a mode of shaping, paving, prepressing and detecting the curvature radius layer by layer, and wrinkles are avoided, so that the bridging problem in the process of forming a composite material product is avoided, and the final forming quality is influenced.

Specifically, as shown in fig. 9 and 10, two layers of first prepregs 300 are sequentially laid, and then vacuum pre-pressing is performed for 15 minutes, so that the prepregs of the two layers are compacted, the radius of curvature of a fillet is detected by using an R gauge, and the radius of curvature of the fillet reaches a preset value; the prepreg block 20 is laid again and then compacted, and the radius of curvature of the fillet is checked again using an R gauge and the quality of the layup at the fillet is checked.

The number of layers is determined according to actual processing requirements and product quality requirements, and can be two layers, three layers or four layers, and the embodiment of the application is not limited to the two layers; the pre-pressing of the first prepregs 300 after shaping and paving layer by layer is performed, which means that the prepregs of each layer are compacted, so that the problems of bulge or bridging and the like between the first prepregs 300 of two adjacent layers are avoided, and the quality of the formed product is improved; wherein the fact that bridging does not occur at the fillet means that prepregs at the fillet cannot be compacted to form caking due to accumulation, and the molding quality of the product is further improved. For example, the precompaction can be carried out by means of vacuum suction, ensuring the compaction at the corners.

The radius of curvature of the fillet can be detected by the R gauge, and according to the process requirement, whether the radius of curvature of the fillet meets the requirement or not is required to be detected when the prepreg with a certain layer number is paved, wherein the radius of curvature of the fillet meets the requirement that the radius of curvature of the fillet is smaller than or equal to a preset value.

S400, paving the prepreg 20 on the at least one layer of first prepreg 300, wherein the rounded tip 21 of the prepreg 20 is attached to the at least one layer of first prepreg 300 at a position corresponding to the inner chamfer 14, and the first plane 23 and the second plane 24 of the prepreg 20 are attached to the surface of the first prepreg 300 respectively.

Optionally, as shown in fig. 11, the prepreg 20 includes a first prepreg 201 and a second prepreg 202, where the first prepreg 201 is used to form the first rounded chamfer 213 and the second rounded chamfer 214 of the first chamfer area on the first curved edge 41, and the second prepreg 202 is used to form the first rounded chamfer 213 and the second rounded chamfer 214 of the second chamfer area on the second curved edge 51;

a prepreg block 20 is laid on at least one layer of a first prepreg 300, the method comprising: on the same layer of the first prepreg 300, a first prepreg 201 is laid on the corresponding first curved edge 41 and a second prepreg 202 is laid on the corresponding second curved edge 51, the first prepreg 201 extending from one side to the other side of the mold cavity 13, and the second prepreg 202 extending from one side to the other side of the mold cavity 13.

S500, paving at least one layer of second prepreg 400 on the at least one layer of first prepreg 300 and the prepreg 20, and covering the arc surface 22 of the prepreg 20 in a follow-up mode after shaping the at least one layer of second prepreg 400 layer by layer.

Wherein the at least one layer of second prepreg 400 is laid down in a conformal manner, the method comprising: the second prepreg 400 is shaped layer by layer, paved and pre-pressed, the second prepreg 400 with a certain layer number at intervals detects the curvature radius, and the rest of the second prepregs 400 are continuously paved until the paving is completed.

The laying manner of the second prepreg 400 may refer to the laying manner of the first prepreg 300, and will not be described herein.

In this embodiment of the present application, the first prepreg 300 and the second prepreg 400 may be continuous prepregs, or may be discontinuous prepregs, which is not limited in this application. In addition, in the embodiment of the present application, the number of layers of the first prepreg 300 and the second prepreg 400 is as thin as possible, the first prepreg 300 may be one layer or two layers, and the prepreg block 20 is as close to the outer surface 212 of the outer liner 200 as possible; the second prepreg 400 is determined according to the thickness of the outer liner 200, and for example, the second prepreg 400 may have more than 10 layers.

It should be noted that, in the embodiment of the present application, on a cross section perpendicular to the plane direction in which the opening 60 is located, the first prepreg 300 is continuously disposed at a position corresponding to the first curved edge 41 to facilitate the placement and shaping of the first prepreg strip 201, and similarly, the first prepreg 300 is continuously disposed at a position corresponding to the second curved edge 51 to facilitate the placement and shaping of the second prepreg strip 202. That is, the first prepreg 300 extends from a position corresponding to the first flat wall 40 over the first curved edge 41 onto the side wall 30, and the first prepreg 300 extends from a position corresponding to the second flat wall 50 over the second curved edge 51 onto the side wall 30. The method is beneficial to avoiding influencing the curvature radius of the round angle and improving the forming quality of the round chamfer position.

As shown in fig. 12, in the embodiment of the present application, a partial prepreg is disposed between two adjacent second prepregs 400, and a plurality of layers of the partial prepregs are disposed at positions of the side walls 30 away from the first flat wall 40, so as to form the mounting cavity 70 with a constant width of the mounting cavity 70, corresponding to the manner in which the mounting profile width (H1) is changed.

In one embodiment, the second prepreg 400 is formed by splicing, and the splicing position of the second prepreg 400 is located at the position of the first side flat wall 31 or the second side flat wall 32; for example, the second prepreg includes a first prepreg portion 410 for forming the first flat wall 40 and a second prepreg portion 420 for forming the second flat wall 50, the first prepreg portion 410 covering at least the first curved edge 41 and extending onto a portion of the side wall 30, and the second prepreg portion 420 covering at least the second curved edge 51 and extending onto a portion of the side wall 30.

In the present embodiment, the number of layers of the first prepreg 410 for forming the first flat wall 40 is smaller than the number of layers of the second prepreg 420 for forming the second flat wall 50; the second prepreg portion 420 for forming the second flat wall 50 extends from the position of the second flat wall 50 to the position of the first flat wall 40 to form the partial prepreg.

In a direction parallel to the opening 60, the second prepreg 400 has a certain length, and in this embodiment, the first prepreg 410 covers at least the first flat wall 40 and extends to the side walls 30 on both sides in a direction parallel to the opening 60, and the second prepreg 420 covers at least the second flat wall 50 and extends to the side walls 30 on both sides in a direction parallel to the opening 60.

In this embodiment, the number of layers of the second prepreg portion 420 is greater than that of the first prepreg portions 410, the second prepreg portion 420 extends between two adjacent first prepreg portions 410 to form the partial prepreg portion, in order to form the H1 variation, the length of the second prepreg portion 420 gradually increases along the direction from the outer surface 212 to the inner surface 211, and the distance from the end of the second prepreg portion 420 to the first flat wall 40 gradually decreases.

It is understood that the second prepreg portion 420 may extend between the first prepreg portions 410 with a partial layer number, and may extend between the first prepreg portions 410 with a complete layer number, which is not limited in this application. By extending the second prepreg portion 420, the molding quality of the outer liner 200 can be improved.

In the embodiment of the present application, the first prepreg portion 410 and the second prepreg portion 420 that are disposed near the inner surface 211 of the outer liner 200 may be disposed continuously, which is not limited in this application, and in different embodiments, each prepreg may be tailored according to the shape of the outer liner 200 to achieve better fit.

In addition, in the present application, the first prepreg 300 and the second prepreg 400 may be the same material, each layer of the first prepreg 300 and each layer of the second prepreg 400 may be one piece of cloth, two pieces of cloth or more than two different pieces of cloth, which is not limited in this embodiment of the present application, and specifically determined according to an actual operation process, so long as it can be ensured that the prepregs of each layer are flatly laid on the inner wall surface of the mold cavity 13.

As shown in fig. 13, at least one cutting opening 310 may be preset on the first prepreg 300 and the second prepreg 400, where the cutting opening 310 is formed in order to ensure flatness in the inner chamfer 14 area during the prepreg layering process, so that no wrinkles occur, and thus, the bridging problem occurring during the composite material product molding process is avoided, and the final molding quality is affected. The number of the cutting openings 310 may be one, two or more, and the plurality of cutting openings 310 on the same layer of prepreg may be distributed at different positions, and the plurality of cutting openings 310 may be distributed on the same side of the prepreg or on different sides of the prepreg.

In the process of paving each layer of the first prepreg 300 and the second prepreg 400, the positions of the cutting openings 310 on the first prepreg 300 and the second prepreg 400 are ensured to be positioned on the first flat wall 40, the second flat wall 50, the first side flat wall 31 or the second side flat wall 32 as far as possible, and the cutting openings 310 cannot be placed on the inner chamfer area or the arc-shaped connecting wall 33, so that the influence on the curvature radius of the round corners is avoided, and meanwhile, the processing quality of the round corners is ensured; and the cutting openings 310 of the prepregs of two adjacent layers are arranged in a staggered manner, so that the thickness uniformity of the composite material is guaranteed, the structural strength is consistent, and the molding quality of the composite product is improved.

And, each layer of the first prepreg 300 and the second prepreg 400 forms a first extension area and a second extension area at both sides of the cutting opening 310, and the first extension area and the second extension area are overlapped at the area except for the inner chamfer of the inner wall surface of the mold cavity 13, so that the first prepreg 300 and the second prepreg 400 are flatly attached to the mold cavity 13 and between the adjacent two layers of prepregs.

The shearing opening 310 of this embodiment is favorable to guaranteeing that the fillet area does not produce the fold, guarantees to level, and in the layering process, can be used for leveling first prepreg 300 and second prepreg 400 through adjusting first extension district and second extension district, guarantees each regional laminating to after each regional laminating that levels, first extension district and second extension district overlap joint each other, be favorable to the quality of the combined material product after the shaping.

S600, pasting a vacuum bag on the female die 100, and forming the outer liner 200 by a hot press molding mode.

It will be appreciated that the female die and the preform are placed together in an autoclave for thermal curing, and during the thermal curing process, the first prepreg and the polymeric material on the prepreg are melted and bonded together to obtain the composite material outer liner product.

Specifically, a rubberized fabric, a separation film, an airfelt, a vacuum bag and an air guide tool are sequentially paved or placed on the female die 100, and the vacuum bag and the model cavity are packaged and communicated with the air guide tool; connecting the outer vacuum bag with a first vacuum pump to tightly adhere the outer vacuum bag to the air guide tool; the inner vacuum bag is connected with the second vacuum pump, so that the inner vacuum bag expands under the action of pressure difference, and compaction is realized.

After the outer vacuum bag is connected with the first vacuum pump, the outer vacuum bag is pumped to the pressure of 0.09 Mpa-0.1 Mpa by the first vacuum pump, and at this time, the outer vacuum bag is tightly adhered to the air guide tool under the action of atmospheric pressure.

After the inner vacuum bag is connected with the second vacuum pump, the inner vacuum bag is pumped to the pressure of 0.06-0.09 MPa by the second vacuum pump, and the inner vacuum bag expands under the action of the pressure difference, so that the laid prepreg is under the vacuum condition but does not bear any compaction acting force.

In this embodiment, the method for pressing and forming the double vacuum bags is to seal two layers of vacuum bags on the prepreg, an inner vacuum bag and an outer vacuum bag, an air guide tool is placed between the two layers of vacuum bags, and the two layers of vacuum bags are respectively connected with two independent vacuum pumps through two vacuum switches. When the prepreg is in the pre-curing stage, the removal of pores and compaction of the prepreg are performed in two steps, firstly, the prepreg layering is exposed in vacuum but does not bear any compaction force at the same time, the pores in the prepreg blank and volatile matters in the resin are enabled to escape easily, and finally, the prepreg is compacted in the curing stage of the prepreg, so that the internal porosity of the material is reduced, and the mechanical property is improved.

In addition, the air guide tool can be replaced according to the difference of using the female die, and the rigidity of the air guide tool is required to be up to the extent that the air guide tool can bear one atmosphere.

The embodiment of the application solves the problems that the traditional single vacuum bag pressing technology can pump most of air during pre-compaction operation and solidification in paving, but the prepreg or the adhesive tape is usually sticky and can be locally bonded together, the vacuum has a compaction effect on the paved prepreg, so that a pore discharging channel is closed to a certain extent, the pressure gradient of the internal pores and the external parts of the prepreg is reduced, the driving force of pore movement is reduced, and therefore, part of pores in the prepreg are difficult to discharge and remain in the resin matrix composite material to form defects. The embodiment of the application is beneficial to improving the molding quality of products through the arrangement of the double vacuum bags.

The following describes, by way of example, a method for processing a composite material according to an embodiment of the present application, specifically as follows:

before layering, firstly, the female die is assembled, a mold release agent is brushed on a die-attaching surface, when layering, a cutting opening 310 is cut in advance on the prepreg, and when layering, a first extension area and a second extension area at the cutting opening 310 are in lap joint, so that the product mounting size is ensured, and the cutting opening 310 should be uniformly distributed on the plane of the product as much as possible to avoid the lap joint at the round angle. As shown in fig. 10 and 11, the laying of the whole cloth of the two layers of the first prepreg 300 is completed firstly, then vacuum pre-suction is performed for 15min, then the stacking of the chopped fibers is performed, at this time, the stacking amount of the chopped fibers is strictly controlled, the stacking is stopped after the R angle reaches 4mm, the laying of the whole cloth of the layer of the second prepreg is performed after the stacking of the chopped fibers is completed, then the inspection of the R angle and the quality of the R angle is performed, the excessive R angle or bridging is avoided, the laying of the two layers of the second prepreg after the inspection is qualified, the inspection of the size of the R angle and the quality of the R angle is performed after the laying is completed, then vacuum pre-suction is performed after the vacuum pre-suction is performed, in order to ensure the compaction of the R angle, the stacking of the vacuum bag at the R angle is required, the laying of the layer by layer of the second prepreg is continued after the pre-suction is completed, the vacuum pre-suction is performed once every 3 layers, and the size of the R angle and the quality of the vacuum bag are required to be inspected before the pre-suction is ensured, and the size of the R angle is not greater than 4mm.

As shown in fig. 14, the present invention provides a small rounded composite material outer liner product prepared by the processing method of the first aspect. It is clear from this that the small fillet composite material outer lining product has all the features and advantages of the processing method described above, and will not be described in detail herein.

Illustratively, in the embodiment of the present application, there is further provided an application manner of the outer liner, including a composite material heating outer liner 200, as shown in fig. 14, the outer liner 200 includes:

a substrate 210, wherein the substrate 210 is made of a polymer material;

a heating layer 220 disposed on the substrate 210, where the heating layer 220 includes a metal trace 223, and a first organic insulating layer 221 and a second organic insulating layer 222 disposed on two sides of the metal trace 223, the first organic insulating layer 221 is disposed on the outer surface 212, and the second organic insulating layer 222 is disposed on a side attached to the substrate 210; the heating layer 220 and the substrate 210 are integrally formed by laying a material on the die 100 and by hot pressing.

As shown in fig. 15, the matrix 210 and the heating layer 220 in the embodiment of the present application are integrally formed by a hot pressing method, which means that materials for forming the heating layer 220 and the matrix 210 are laid in the cavity 100 in a conformal manner and formed into a whole by a vacuum hot pressing method.

In this embodiment, the metal wire 223 is made of a material with good conductivity, and the material of the metal wire 223 may be nichrome, iron-chromium-aluminum alloy, stainless steel, copper, aluminum, etc. The metal trace 223 may be a metal strip.

The first organic insulating layer 221 and the second organic insulating layer 222 are made of organic polymer materials with good insulation property, so that the metal wire 223 is sealed between the first organic insulating layer 221 and the second organic insulating layer 222, packaging of the metal wire 223 is achieved, and insulation property of the heating layer 220 is improved. For example, the first organic insulating layer 221 and the second organic insulating layer 222 are polyimide films (PI films), which are high-performance, high-temperature, and high-strength polymer materials having excellent thermal stability, chemical stability, abrasion resistance, oxidation resistance, radiation resistance, electrical insulation, high temperature resistance, and the like.

The matrix 210 may be various resin-based fiber composite materials, and the resin-based fiber composite materials have excellent characteristics such as high specific strength, high specific modulus, good fatigue resistance, unique materials and structural designability, so that the resin-based fiber composite materials are increasingly widely applied to aviation aircrafts. Illustratively, the substrate 210 may be a resin-impregnated glass fiber composite or a resin-impregnated carbon fiber composite. In this embodiment, the substrate 210 is made of a non-conductive material, and the polyimide film has better electrical insulation property than the substrate 210.

In the application, the substrate 210 and the heating layer 220 are integrally formed by hot pressing, so that the bonding degree and strength between the polymer substrate 210 and the heating layer 220 can be increased, and delamination between the heating layer 220 and the substrate 210 is prevented. The outer liner 200 is made of a resin-based fiber composite material suitable for aerospace applications, and improves the strength of the workpiece.

In this embodiment, the heating layer 220 is disposed on the side wall 30, and the metal trace 223 at least covers the arc-shaped connection wall 33. In this embodiment of the present application, the position of the heating layer 220 is not limited, the heating layer 220 may be disposed on the entire side wall 30, may only cover the arc-shaped connecting wall 33, may also extend from the arc-shaped connecting wall 33 to the position of the first side flat wall 31 or the second side flat wall 32, in this embodiment of the present application, the first organic insulating layer 221 and the second organic insulating layer 222 at least cover the area where the metal trace 223 is located, and may extend from the area to two sides, so as to improve the insulating effect, in this embodiment of the present application, the first organic insulating layer 221 and the second organic insulating layer 222 may extend to the first side flat wall 31 or the second side flat wall 32, which is not limited in this embodiment of the present application.

Combining in this application first round chamfer 213 on the internal surface and second round chamfer 214 on the external surface makes the arc-shaped connecting wall 33 more easily fit with the arc-shaped surface of the workpiece, improves the arrangement effect of the heating layer 220.

The aviation structure with the heating function is provided with the appearance of a small round angle (R is less than or equal to 2 mm), and in the embodiment of the application, the structure of the aviation workpiece is improved for the convenience of the arrangement of the heating layer 220, so that the aviation workpiece is provided with a large round angle (R is more than or equal to 4 mm). The outer liner 200 in the embodiment of the present application is correspondingly adjusted in structure, so that the outer shape of the outer liner 200 meets the requirement of small round corners, and the inner chamfer 14 is more convenient to install with a workpiece.

Based on the same conception, the present invention provides a method of forming a composite heated outer liner 200, optionally for forming a composite heated outer liner 200 as described in any of the above, the method comprising: S100-S500 described above.

Wherein the outer liner 200 is molded in the female die 100, the method further comprises, prior to S300:

s30, paving materials for forming the heating layer 220 in the female die, wherein the materials comprise: a first organic insulating layer 221, a metal trace 223, and a second organic insulating layer 222 are sequentially laid in the mold cavity 13 along with the shape.

Considering that polyimide films on two sides are thin, smooth and airtight, the whole film is paved in a die cavity to easily generate wrinkles, in addition, the adhesion between the film and the prepreg of the forming matrix 210 is poor, bubbles easily exist in the product, the bonding strength is low, layering and other problems easily occur, and the rejection rate of the product is high.

In this embodiment, before the material for forming the heating layer 220 is laid in the die in S30, as shown in fig. 16, the method further includes:

s031, respectively presetting a notch 224 and a through hole 225 on the first organic insulating layer 221 and the second organic insulating layer 222 at the position corresponding to the arc-shaped connecting wall 33, wherein the through hole 225 penetrates through the first organic insulating layer 221 and the second organic insulating layer 222, the notch 224 at least penetrates through a central bus of the arc-shaped connecting wall 33, and the through hole 225 penetrates through the first organic insulating layer 221 or the second organic insulating layer 222; and

s032, presetting a metal wire 223, wherein the metal wire 223 forms a broken line wire which avoids the cutting opening 224 and the through hole 225 according to the positions of the cutting opening 224 and the through hole 225 on the first organic insulating layer 221 and the second organic insulating layer 222.

In this embodiment, the organic insulating layer may be a PI film, and no transformation of material morphology is performed in the hot press forming, so that the laying quality of the first organic insulating layer 221 and the second organic insulating layer 222 in the mold cavity 13 is directly related to the forming quality of the outer liner 200, and in order to avoid the PI film from forming wrinkles at the position of the arc structure, in this embodiment, the PI film is preprocessed before the first organic insulating layer 221 and the second organic insulating layer 222 are laid.

In the application, by forming the shearing openings 224 at the preset positions, the first organic insulating layer 221 and the second organic insulating layer 222 can be prevented from being wrinkled, so that the paving surface is good; in the process of hot-pressing the substrate 210 and the heating layer 220 into a whole, the glue material in the substrate 210 melts and penetrates through the cut 224 on the first organic insulating layer 221, so that the viscosity of the substrate 210 and the heating layer 220 is increased, and the strength of the electric heating composite material structure is improved.

It can be understood that, a person skilled in the art can set the curved surface shape of the cavity of the female die according to actual requirements, and can correspondingly adjust the positions, lengths and variation trends of the cutouts 224 on the first organic insulating layer 221 and the second organic insulating layer 222 by changing the shape and the size of the curved surface of the female die, and also can adjust the shape and the size of the final formed electric heating composite structure.

In this embodiment, after the first organic insulating layer 221 and the second organic insulating layer 222 are laid on the mold cavity 13, the position of the notch 224 may be parallel to the directions of the first flat wall 40 and the second flat wall 50, the notch 224 is located in the area of the arc-shaped connecting wall 33, and the notch 224 points from the first side flat wall 31 to the direction of the second side flat wall 32. In this application, the notch 224 and at least one side edge of the first organic insulating layer 221 and the second organic insulating layer 222 are both provided with a reserved area (i.e. the notch 224 keeps a certain distance from one side edge of the first organic insulating layer 221 and one side edge of the second organic insulating layer 222 respectively), so that the notch 224 is prevented from shearing off the first organic insulating layer 221 and the second organic insulating layer 222.

The metal wire 223 avoids the corresponding notch 224 at the wire position between the first organic insulating layer 221 and the second organic insulating layer 222, and prevents the metal wire 223 from penetrating out of the corresponding first organic insulating layer 221 and second organic insulating layer 222 from the notch 224.

In some embodiments, the metal trace 223 is in a continuous folded line shape, the metal trace 223 at least includes two straight line segments arranged in parallel, the cutting opening 224 is located between two adjacent straight line segments, and the position of the straight line segment is determined according to the preset position of the cutting opening 224.

Specifically, as shown in fig. 4 and fig. 9, the metal wires 223 include a plurality of metal wires 223, the plurality of metal wires 223 are in an S-shaped folded line shape, and the cutouts 224 of the first organic insulating layer 221 and the second organic insulating layer 222 are opened between two parallel straight line segments of the metal wires 223, so as to avoid the metal wires 223 contacting with an external material at the cutouts 224.

For example, as shown in fig. 16, the two metal wires 223 are in an S-shaped folded line shape, the positions of the metal wires 223 at the positions of the plurality of cuts 224 are designed firstly, then the positions of the metal wires 223 at other positions are designed, and finally the layout of the metal wires 223 is completed, namely, according to the positions of the plurality of cuts 224, two parallel vertical straight-line section metal wires 223 are respectively arranged at two sides of the corresponding cuts 224, the distance between the two straight-line section metal wires 223 is adjusted within a preset range corresponding to the cuts 224, a transverse straight-line section metal wire 223 surrounding the cuts 224 is arranged, the two vertical straight-line section metal wires 223 and the transverse straight-line section metal wire 223 are arranged as one metal wire 223, and then the positions of the metal wires 223 at other positions are designed. It is understood that the distances between each two adjacent vertical straight metal traces 223 are not necessarily equal, and may be within a predetermined range of the cutouts 224.

In some embodiments, as shown in fig. 17, the first organic insulating layer 221 is provided with a plurality of first cutouts 224-1, and the second organic insulating layer 222 is provided with a plurality of second cutouts 224-2. The projection positions of the first cutouts 224-1 and the second cutouts 224-2 of the first organic insulating layer 221 and the second organic insulating layer 222 at the corresponding positions on the same plane are different and coincide.

In the embodiment of the application, the number of the cutting openings 224 can be reduced on the basis of ensuring the attaching flatness by arranging the cutting openings 224 at different positions on different organic insulating layers; avoiding overlapping of the positions of the cutting openings 224 can prevent the situation that the positions of the cutting openings 224 deviate and the like due to the fact that the sizing material flows between two layers in the direction perpendicular to the surface at the overlapping positions of the cutting openings 224, and the forming quality of the heating layer 220 is affected.

In some embodiments, as shown in fig. 14, before the substrate 210 and the heating layer 220 are hot pressed, a plurality of through holes 225 penetrating through the first organic insulating layer 221 and the second organic insulating layer 222 are formed on the first organic insulating layer 221 and the second organic insulating layer 222, so as to prevent bubbles from being generated in the first organic insulating layer 221 and the second organic insulating layer 222, and solve the problem that the bubbles are difficult to be discharged; in the hot pressing process, the glue in the substrate 210 can penetrate through the through holes 225 on the first organic insulating layer 221 and the second organic insulating layer 222 in a heating and melting state, so that the bonding degree of the substrate 210 and the heating layer 220 is further increased, the heating layer 220 cannot be in a position after being paved on the substrate 210, and the bonding strength of the electric heating composite material structure is improved. In this embodiment, the positions of the through holes 225 on the first organic insulating layer 221 and the second organic insulating layer 222 are coincident, and the through holes 225 penetrate through the first organic insulating layer 221 and the second organic insulating layer 222 at the same time.

The glue stock is heated to be in a molten state in the hot pressing process, the glue stock in the molten state can flow from the inside of the substrate 210 to one side of the first organic insulating layer 221 and fill the through holes 225 of the first organic insulating layer 221, the bonding degree of the substrate 210 and the heating layer 220 is increased, the strength of the electric heating composite structure is improved, and the through holes 225 are filled with the glue stock.

It can be understood that in the embodiment of the present application, S300 is laid on the second organic insulating layer 222, where the specific operations of S300-S500 are not described herein.

The foregoing description is only of the preferred embodiments of the present application and is presented as a description of the principles of the technology being utilized. It will be appreciated by persons skilled in the art that the scope of the invention referred to in this application is not limited to the specific combinations of features described above, but it is intended to cover other embodiments in which any combination of features described above or equivalents thereof is possible without departing from the spirit of the invention. Such as the above-described features and technical features having similar functions (but not limited to) disclosed in the present application are replaced with each other.

Claims

1. A method of forming a small fillet composite outer liner, wherein the outer liner has a mounting cavity, the outer liner comprising an inner surface for providing a mounting surface for mating with an external workpiece and an outer surface for providing a profile surface; the inner surface is provided with a first round chamfer, the outer surface is provided with a second round chamfer, the outer liner comprises a side wall, a first flat wall and a second flat wall which are arranged at two ends of the side wall, the side wall comprises a first flat side wall and a second flat side wall which are arranged in parallel, and an arc-shaped connecting wall which is arranged between the first flat side wall and the second flat side wall, edges of the first flat wall, the second flat side wall, the first flat side wall and the second flat side wall surround an opening, the first flat wall comprises a first curve edge connected with the side wall, the second flat wall comprises a second curve edge connected with the side wall, and the circumference of the first curve edge is smaller than that of the second curve edge; the first round chamfer comprises a first inner round chamfer arranged on the first curve edge and a second inner round chamfer arranged on the second curve edge, and the second round chamfer comprises a first outer round chamfer arranged on the first curve edge and a second outer round chamfer arranged on the second curve edge; the radius of curvature of the first circular chamfer is greater than the radius of curvature of the second circular chamfer, the method comprising:

The method comprises the steps of preforming a prepreg, wherein the cross section of the prepreg is approximately triangular, the prepreg comprises a circular tip part and a circular arc surface, the circular arc surface is matched with the shape of the first circular chamfer, and the curvature radius of the circular arc surface is equal to that of the first circular chamfer; the shape of the round tip part is matched with that of the second round chamfer, and the curvature radius of the round tip part is equal to that of the second round chamfer;

providing a female die and forming the outer liner in the female die, wherein the female die comprises a first half female die and a second half female die, the first half female die and the second half female die are detachably combined and define a die cavity, the die cavity is used for forming the outer liner, the die cavity is provided with an inner chamfer, the shape of the inner chamfer is matched with that of the second round chamfer, and the curvature radius of the inner chamfer is equal to that of the second round chamfer; wherein forming the outer liner within the female die comprises:

paving at least one layer of first prepreg in the model cavity, and covering the inner chamfer after shaping the at least one layer of first prepreg layer by layer;

paving the prepreg on the at least one layer of first prepreg, wherein the round tip of the prepreg is attached to the position of the at least one layer of first prepreg corresponding to the inner chamfer;

At least one layer of second prepreg is paved on the at least one layer of first prepreg and the prepreg, and the at least one layer of second prepreg is shaped layer by layer and then covered on the arc surface of the prepreg in a conformal manner;

2. The method of claim 1, wherein the at least one layer of the first prepreg layer-by-layer shaping comprises:

the first prepregs are shaped layer by layer, paved, pre-pressed, the curvature radius of each first prepreg with a certain layer number at intervals is detected, and the rest first prepregs are continuously paved until the paving is completed;

the layer-by-layer shaping of the at least one layer of the second prepreg comprises:

3. The method of claim 1, wherein the opening is disposed at an angle to the first planar wall and the second planar wall; mounting holes are formed in the first side flat wall and the second side flat wall;

and an included angle is formed between the bus of the arc-shaped connecting wall and the first flat wall as well as between the bus of the arc-shaped connecting wall and the second flat wall.

4. The method of claim 1, wherein the first curvilinear edge has a first chamfer region disposed thereon and the second curvilinear edge has a second chamfer region disposed thereon;

the prepreg comprises a first prepreg strip and a second prepreg strip, wherein the first prepreg strip is used for forming the first round chamfer and the second round chamfer on the first chamfer area, and the second prepreg strip is used for forming the first round chamfer and the second round chamfer on the second chamfer area.

5. The method of claim 1, wherein a portion of the outer surface corresponds to a mounting profile width in a first direction along the first planar wall toward the center of the opening that is progressively increasing, and the inner surface corresponds to a mounting cavity width that is constant, wherein the mounting profile width is a distance of the outer surface in a second direction, the mounting cavity width is a distance of the inner surface in the second direction, the second direction being perpendicular to the first direction;

along the first direction that the second flat wall points to the center of the opening, the width of the installation appearance corresponding to part of the outer surface is unchanged, and the width of the installation cavity corresponding to the inner surface is unchanged.

6. A method according to claim 1, wherein a partial prepreg is provided between two adjacent second prepregs, a plurality of layers of the partial prepregs being provided at positions of the side walls remote from the first flat wall for forming the mounting cavity with a constant width.

7. The method of claim 6, wherein the second prepreg comprises a first prepreg for forming the first planar wall and a second prepreg for forming the second planar wall, the first prepreg covering at least the first curvilinear edge and extending onto a portion of the sidewall, the second prepreg covering at least the second curvilinear edge and extending onto a portion of the sidewall;

8. The method of claim 1, wherein the radius of curvature of the first circular chamfer is 4mm or greater and the radius of curvature of the second circular chamfer is 2mm or less.

9. A small radius composite outer liner, characterized in that the small radius composite outer liner is formed by a method according to any one of claims 1-8.