CN116674231A - Method for improving internal quality of non-autoclave molded part and application thereof - Google Patents
Method for improving internal quality of non-autoclave molded part and application thereof Download PDFInfo
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- CN116674231A CN116674231A CN202310860020.5A CN202310860020A CN116674231A CN 116674231 A CN116674231 A CN 116674231A CN 202310860020 A CN202310860020 A CN 202310860020A CN 116674231 A CN116674231 A CN 116674231A
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- 238000000034 method Methods 0.000 title claims abstract description 57
- 239000004744 fabric Substances 0.000 claims abstract description 61
- 230000008569 process Effects 0.000 claims abstract description 25
- 238000000926 separation method Methods 0.000 claims abstract description 7
- 239000002131 composite material Substances 0.000 claims abstract description 6
- 230000001681 protective effect Effects 0.000 claims abstract description 6
- 238000005086 pumping Methods 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 11
- 238000005056 compaction Methods 0.000 claims description 9
- 239000004820 Pressure-sensitive adhesive Substances 0.000 claims description 6
- 239000003365 glass fiber Substances 0.000 claims description 5
- 210000001503 joint Anatomy 0.000 claims description 5
- 238000004806 packaging method and process Methods 0.000 claims description 5
- 230000002093 peripheral effect Effects 0.000 claims description 5
- 238000002360 preparation method Methods 0.000 claims description 2
- 239000010410 layer Substances 0.000 description 21
- 230000000052 comparative effect Effects 0.000 description 13
- 238000007789 sealing Methods 0.000 description 12
- 238000000465 moulding Methods 0.000 description 7
- 238000003825 pressing Methods 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 6
- 238000007689 inspection Methods 0.000 description 5
- 239000011324 bead Substances 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000005470 impregnation Methods 0.000 description 3
- 238000007373 indentation Methods 0.000 description 3
- 238000002955 isolation Methods 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 230000004888 barrier function Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 150000003384 small molecules Chemical class 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 238000012858 packaging process Methods 0.000 description 1
- 238000010587 phase diagram Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/30—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
- B29C70/38—Automated lay-up, e.g. using robots, laying filaments according to predetermined patterns
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
- B29C33/68—Release sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/30—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
- B29C70/34—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core and shaping or impregnating by compression, i.e. combined with compressing after the lay-up operation
- B29C70/342—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core and shaping or impregnating by compression, i.e. combined with compressing after the lay-up operation using isostatic pressure
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/40—Weight reduction
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Composite Materials (AREA)
- Robotics (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
The application provides a method for improving the internal quality of a non-autoclave molded part and application thereof, and relates to the technical field of composite materials. The method comprises the following steps: an embossed film is used as a protective film on both sides of the prepreg, and an exhaust channel is formed on the surface of the prepreg by the embossed film; tearing off the embossed film, paving a plurality of layers of prepregs on a die with a first release cloth, paving 2-8 layers of prepregs in the paving process, placing an air guide piece at the edge of the plurality of layers of prepregs, and then continuously paving the prepregs to form a prefabricated member; and a second demolding cloth, a separation film and an airfelt are sequentially paved on the surface of the prefabricated member, the size of the second demolding cloth is larger than that of the prefabricated member, the size of the separation film is equal to that of the prefabricated member, and the airfelt is connected with the second demolding cloth. The application increases the gas exhaust channel and path; realize the omnidirectional air guide, can effectively improve the discharge of gas and micromolecule in the paving and curing process, improve the internal quality of the finished piece.
Description
Technical Field
The application relates to the technical field of composite materials, in particular to a method for improving the internal quality of a non-autoclave molded part and application thereof.
Background
As the composite materials are increasingly used in the aerospace field, the control of cost is also increasingly focused, and the curing cost is effectively reduced on the basis of maximally maintaining the advantages of the autoclave molding part by the non-autoclave molding, so that the research on the non-autoclave molding process is also increasingly conducted.
However, compared with autoclave molding, the non-autoclave molding product has mainly difference in internal quality, such as higher porosity, and may have macroscopic layering, loosening and other defects for complex or larger-sized products.
Analysis from its principle, to improve the internal quality of non-autoclave molded parts, it is necessary to reduce the gas inside the preform. The gas comprises two parts, namely, the gas existing in the prepreg due to the low impregnation degree of the prepreg; and secondly, in the paving process, the prepreg layer and the interlayer are wrapped with air. The gas present in the prepreg itself is not the vent path of the autoclave molding during curing, and from the golden phase diagram of the article, the voids of the article exist between the prepreg layers, mainly formed by the gas remaining from the second case. Through optimizing the operation method of paving, can reduce the wrapping up in of gas, but in order to keep inside exhaust passage, the impregnation degree of prepreg is low, and the viscidity is generally bigger, and the gas of wrapping up in the paving process can't discharge completely. The method provides a channel for discharging the gas between the prepreg layers, and is an important direction for solving the internal quality of the non-autoclave molded part.
In view of this, the present application has been made.
Disclosure of Invention
The application aims to provide a method for improving the internal quality of a non-autoclave molded part and application thereof.
The application is realized in the following way:
in a first aspect, the present application provides a method of improving the internal quality of a non-autoclave molded article comprising:
preparing a prepreg: an embossed film is used as a protective film on both sides of the prepreg, and the embossed film forms an exhaust passage on the surface of the prepreg;
laying up the prepreg: tearing off the embossed film, paving a plurality of layers of prepregs on a die with a first release cloth, paving 2-8 layers of prepregs in the paving process, placing air guide pieces at the edges of the plurality of layers of prepregs, and then continuously paving the prepregs to form a prefabricated part;
and (3) packaging: and a second demolding cloth, a separation film and an airfelt are sequentially paved on the surface of the prefabricated member, the size of the second demolding cloth is larger than that of the prefabricated member, the size of the separation film is equal to that of the prefabricated member, and the airfelt is connected with the second demolding cloth.
In an alternative embodiment, the exhaust channel is in the shape of a strip or a grid.
In an alternative embodiment, the air guide piece is a strip air guide material with the width of 4-5 cm, and the air guide material is laid on the periphery edge of the prepreg in a circle;
preferably, the air guide material is glass fiber mesh cloth;
preferably, the air guide material is lapped on the peripheral edge of the plurality of layers of the prepreg by one circle, the lapping width is 4-6mm, and the lapping position is located outside the net size of the product.
In an alternative embodiment, the second release cloth is broken at the inside corners of the prepreg and the broken second release cloth is connected in a lap joint manner while the second release cloth is laid.
In an alternative embodiment, when the isolating film is paved, the isolating film and the second release cloth are fixed by using a pressure-sensitive adhesive tape at the edge of the isolating film, and a uniform pressing strip is placed at the internal corner of the prepreg;
preferably, the separator is a perforated separator.
In an alternative embodiment, the airfelt is broken at the inside corners of the prepreg and the broken airfelt is connected by butt joint;
in an alternative embodiment, the end of the air guide remote from the prepreg extends beyond the second release sheet and is directly connected to the airfelt.
In an alternative embodiment, during the process of laying up the prepreg, vacuum pumping pre-compaction is carried out once for every 1-4 layers, the vacuum pumping pressure is not lower than 800mbar, and the vacuum pumping time is not lower than 10min;
preferably, at pre-compaction, a balancing bar is placed at the inside corners of the prepreg.
In a second aspect, the present application provides the use of a method of improving the internal quality of a non-autoclave shaped article according to any of the preceding embodiments for the preparation of a composite material.
The application has the following beneficial effects:
according to the method for improving the internal quality of the non-autoclave molded part, provided by the application, the two sides of the prepreg are protected by the embossed film, so that the gas can be effectively prevented from being wrapped in the paving process, and the gas exhaust channel is increased; meanwhile, an air guide piece is arranged at the edge of the preform, and a gas exhaust path is provided; the porous isolating film is used, and the demolding cloth is directly connected with the air-permeable felt, so that omnibearing air guide is realized, the discharge of air and small molecules in the paving and curing processes can be effectively improved, and the internal quality of a finished product is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a process flow diagram of a method for improving the internal quality of a non-autoclave molded article according to an embodiment of the present application;
FIG. 2 is a schematic illustration of the structure of an embossed film used in a method for improving the internal quality of a non-autoclave molded article according to an embodiment of the present application;
FIG. 3 is a schematic view of a method for improving the internal quality of a non-autoclave molded part according to an embodiment of the present application, wherein the method is directed to a method for placing a uniform pressing bar at a reentrant corner;
FIG. 4 is a schematic illustration of a specific lay-up in a method for improving the internal quality of a non-autoclave molded article according to an embodiment of the present application;
FIG. 5 is a schematic illustration of a specific lay-up of air guides and prepregs in a method for improving the internal quality of non-autoclave molded parts according to an embodiment of the application;
FIG. 6 is an ultrasonic inspection of a non-autoclave molded article according to example 1 of the present application;
FIG. 7 is an ultrasonic inspection of a non-autoclave molded article according to example 2 of the present application;
FIG. 8 is an ultrasonic inspection of a non-autoclave molded article provided in comparative example 1 of the present application;
FIG. 9 is an ultrasonic inspection of a non-autoclave molded article provided in comparative example 2 of the present application;
fig. 10 is an ultrasonic inspection of a non-autoclave molded article provided in comparative example 3 of the present application.
Icon: 101-a mold; 102-prepreg; 103-uniformly pressing the strips; 104-a first release cloth; 105-an air guide; 106-a second release cloth; 107-isolating film; 108-airfelt; 109-vacuum bag; 110-seals.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
The application provides a method for improving the internal quality of a non-autoclave molded part, referring to fig. 1, comprising the following steps:
s1, preparing the prepreg 102.
An embossed film (see fig. 2) is used as a protective film on both sides of the prepreg 102, and the embossed film forms an exhaust passage on the surface of the prepreg 102.
According to the application, a double-sided embossed film is adopted to replace a traditional flat film PE film, and a release paper is adopted, so that a gap exists between the embossed film (PE film) and the prepreg 102, the prepreg 102 can be directly contacted with air, the viscosity of the prepreg 102 can be reduced under the condition that the impregnation degree of the prepreg 102 is not improved, and the release of gas wrapped in the paving process is facilitated; meanwhile, since the embossed film has protruding patterns, the prepreg 102 is formed with "ravines", which may form exhaust passages on the surface of the prepreg 102, as exhaust passages during the laying, pre-compacting and curing processes.
In the present application, the shape of the exhaust passage includes, but is not limited to, a stripe shape or a mesh shape, as long as the internal gas of the prepreg 102 can be exhausted.
S2, paving the prepreg 102.
The embossed film was peeled off and a plurality of layers of prepregs 102 were laid up on the mold 101 with the first release cloth 104.
Referring to fig. 1 and 4 in combination, in the process of laying up the prepreg 102, vacuum pumping pre-compaction is performed once for each 1-4 layers, the vacuum pumping pressure is not lower than 800mbar, and the vacuum pumping time is 10-15 min; in prepressing, a uniform pressing strip 103 is placed at the internal corner of the prepreg 102 (refer to fig. 3), fig. 3 shows the position of the internal corner and the arrangement mode of the uniform pressing strip 103, and the internal corner can be better laid by using the uniform pressing strip 103, so that the situation that the prepreg 102 at the internal corner is arched or layered is avoided.
Referring to fig. 4 and 5, each 2-8 layers of prepreg 102 are laid during lay-up, and air guides 105 are placed around the peripheral edges of the layers of prepreg 102, and then the lay-up of the prepreg 102 is continued to form a preform. The air guide 105 is a strip air guide material, and the width (D in FIG. 5) of the air guide material is 4-5 cm; preferably, the air guide material is glass fiber mesh cloth; preferably, the air guide 105 is lapped over the peripheral edge of the multi-layer prepreg 102 by a lap width (d in fig. 5) of 4-6mm, and the lap position is outside the net size of the article.
In the application, the air guide 105 is arranged at the edge of the prepreg 102, so that the air wrapped in the prepreg 102 can be directly discharged through the exhaust channel and the air guide 105, and the air guide effect is better.
S3, packaging.
Referring to fig. 1 and 4 in combination, a second release cloth 106, a separator 107 and an airfelt 108 are sequentially laid on the surface of the preform. The second release cloth 106 has a size greater than the size of the preform and the release film 107 has a size equal to the size of the preform, and the airfelt 108 generally covers the area enclosed by the vacuum bag, sometimes double-layered or more at the edges, in order to achieve a better air guiding and ventilation effect.
When the second release cloth 106 is laid, the second release cloth 106 is broken at the inside corner of the prepreg 102, and the broken second release cloth 106 is connected in a lap joint manner. In the present application, by breaking the second release cloth 106 at the inside corners, the phenomenon of bulging at the inside corners during the packaging process can be avoided.
When the isolating film 107 is paved, the edge of the isolating film 107 adopts a pressure sensitive adhesive tape to fix the isolating film 107 and the second release cloth 106, and the uniform pressing strip 103 is placed at the internal corner of the prepreg 102; the isolation film 107 in this embodiment is a porous isolation film 107. In the application, the size of the isolating film 107 is smaller than that of the second demolding cloth 106, at this time, the isolating film 107 is fixed by the pressure-sensitive adhesive tape, so that the displacement of the isolating film 107 is effectively prevented, and the isolating film 107 can effectively prevent the resin in the prefabricated member from seeping out to the airfelt 108. Since the size of the release cloth is substantially identical to the size of the preform in the conventional case, and the size of the release film 107 is larger than the size of the preform, unlike the conventional case in which the size of the second release cloth 106 is larger than the size of the preform, the size of the release film 107 is equal to the size of the preform, and at this time, since the size of the release film 107 becomes smaller, the ventilation effect of the preform is better.
Further, while laying airfelt 108, airfelt 108 is broken at the inside corner of prepreg 102 and the broken airfelt 108 is connected by butt joint. The end of the air guide 105 remote from the prepreg 102 extends beyond the second release cloth 106 and is directly connected to the airfelt 108. In the present application, by connecting the air guide 105 to the airfelt 108, the air in the prepreg 102 can be guided out to the airfelt 108 effectively. In the present application, the airfelt 108 has a smaller weight per unit area, and the provision of airfelt 108 facilitates the pressurization during the curing process.
In this embodiment, the edges of the pressure equalizing strip 103 placed at the inside corners should be as thin as possible to achieve uniform transition, otherwise uneven indentations are easily formed on the surface of the product after curing.
S4, solidifying.
The vacuum bag 109 is used for sealing, the vacuum bag 109 and the mold 101 are connected in a sealing way by a sealing element 110 (such as a sealing rubber strip), the vacuum degree is detected, and after the vacuum degree meets the requirement, the vacuum bag is cured according to a conventional curing procedure, and the internal pressure of the vacuum bag 109 is not lower than 900mbar in the curing process. Fig. 4 of the present application only lists one half of the schematic diagram of non-autoclave molding, the other side being identical to that shown.
The method for improving the internal quality of the non-autoclave molded part can be widely applied to preparing composite materials.
The features and capabilities of the present application are described in further detail below in connection with the examples.
Example 1
The embodiment provides a method for improving the internal quality of a non-autoclave molded part, which comprises the following steps:
s1, preparing the prepreg 102.
An embossed film is used as a protective film on both sides of the prepreg 102, and the embossed film forms a mesh-like exhaust passage on the surface of the prepreg 102.
S2, paving the prepreg 102.
The embossed film was peeled off and a plurality of layers of prepregs 102 were laid up on the mold 101 with the first release cloth 104. In the process of laying the prepreg 102, each 2 layers are subjected to vacuum pumping pre-compaction once, the vacuum pumping pressure is 900mbar, and the vacuum pumping time is 15min; at pre-compaction time, a bead 103 is placed at the inside corner of the prepreg 102. In the laying process, 6 layers of prepregs 102 are laid, a circle of strip-shaped air guide pieces 105 (glass fiber mesh cloth) with the width of 5cm are placed at the edges of the layers of prepregs 102, the lap joint width is 5mm, and the lap joint positions are located outside the net size of the product. The prepreg 102 is then laid up continuously to form a preform.
S3, packaging.
A second release cloth 106, a barrier film 107 and an airfelt 108 are sequentially laid on the surface of the prefabricated member.
Wherein, when the second release cloth 106 is laid, the size of the second release cloth 106 is larger than the size of the preform, the second release cloth 106 is broken at the internal corner of the prepreg 102, and the broken second release cloth 106 is connected in a lap joint manner.
When the release film 107 (porous release film 107) is laid, the size of the release film 107 is equal to the size of the preform, the release film 107 is fixed to the second release cloth 106 by the edge of the release film 107 with a pressure-sensitive adhesive tape, and the leveling bars 103 are placed at the inside corners of the prepreg 102. The edges of the uniform bead 103 need to be as thin as possible to achieve a uniform transition, otherwise uneven indentations are easily formed on the surface of the part after curing.
When laying the airfelt 108, the airfelt 108 is larger in size than the second release cloth 106, the airfelt 108 is broken at the inside corner of the prepreg 102, and the broken airfelt 108 is connected by butt joint. The end of the air guide 105 remote from the prepreg 102 extends beyond the second release cloth 106 and is directly connected to the airfelt 108.
S4, solidifying.
Sealing is performed by using a vacuum bag 109, the vacuum bag 109 and the mold 101 are in sealing connection by using a sealing member 110 (for example, a sealing rubber strip), vacuum degree is detected, and after the requirements are met, a curing program is set: heating to 80 ℃ at a heating rate of 2 ℃/min, preserving heat for 1h, heating to 125 ℃ and preserving heat for 2h, curing, wherein the internal pressure of the vacuum bag 109 is more than 900mbar in the curing process, and obtaining the finished product after curing.
Example 2
The embodiment provides a method for improving the internal quality of a non-autoclave molded part, which comprises the following steps:
s1, preparing the prepreg 102.
An embossed film is used as a protective film on both sides of the prepreg 102, and the embossed film forms a mesh-like exhaust passage on the surface of the prepreg 102.
S2, paving the prepreg 102.
The embossed film was peeled off and a plurality of layers of prepregs 102 were laid up on the mold 101 with the first release cloth 104. In the process of laying the prepreg 102, vacuum pre-compaction is carried out once for 4 layers, the vacuum pressure is 850mbar, and the vacuum time is 10min; at pre-compaction time, a bead 103 is placed at the inside corner of the prepreg 102. In the laying process, 8 layers of prepreg 102 are laid, a circle of strip-shaped air guide pieces 105 (glass fiber grid cloth) with the width of 4cm are placed at the edges of the layers of prepreg 102, the lap joint width is 6mm, and the lap joint positions are located outside the net size of the product. The prepreg 102 is then laid up continuously to form a preform.
S3, packaging.
A second release cloth 106, a barrier film 107 and an airfelt 108 are sequentially laid on the surface of the prefabricated member.
Wherein, when the second release cloth 106 is laid, the size of the second release cloth 106 is larger than the size of the preform, the second release cloth 106 is broken at the internal corner of the prepreg 102, and the broken second release cloth 106 is connected in a lap joint manner.
When the release film 107 (porous release film 107) is laid, the size of the release film 107 is equal to the size of the preform, the release film 107 is fixed to the second release cloth 106 by the edge of the release film 107 with a pressure-sensitive adhesive tape, and the leveling bars 103 are placed at the inside corners of the prepreg 102. The edges of the uniform bead 103 need to be as thin as possible to achieve a uniform transition, otherwise uneven indentations are easily formed on the surface of the part after curing.
When laying the airfelt 108, the airfelt 108 is larger in size than the second release cloth 106, the airfelt 108 is broken at the inside corner of the prepreg 102, and the broken airfelt 108 is connected by butt joint. The end of the air guide 105 remote from the prepreg 102 extends beyond the second release cloth 106 and is directly connected to the airfelt 108.
S4, solidifying.
Sealing is performed by using a vacuum bag 109, the vacuum bag 109 and the mold 101 are in sealing connection by using a sealing member 110 (for example, a sealing rubber strip), vacuum degree is detected, and after the requirements are met, a curing program is set: heating to 80 ℃ at a heating rate of 2 ℃/min, preserving heat for 1h, heating to 125 ℃ and preserving heat for 2h, curing, wherein the internal pressure of the vacuum bag 109 is not lower than 900mbar in the curing process, and obtaining the finished product after curing.
Comparative example 1
This comparative example is substantially the same as example 1 except that in this comparative example, the prepreg 102 in step S1 is protected with a release paper while using a flat film PE film.
Comparative example 2
The present comparative example is substantially the same as example 1 except that in the present comparative example, the strip-shaped air guide 105 is placed between the second separation film 107 and the pressure equalizing pad in step S2.
Comparative example 3
This comparative example is substantially the same as example 1, except that:
in the step S1, the prepreg 102 adopts a flat film PE film and is protected by release paper;
in step S2, the strip-shaped air guide 105 is placed between the second isolation film 107 and the pressure equalizing pad;
the second release cloth 106 in step S3 has a size consistent with the preform, the size of the release film 107 is larger than the size of the preform, and the size of the airfelt 108 is larger than the size of the release film 107.
Experimental example
The articles provided in examples 1-2 and comparative examples 1-3 above were inspected for internal quality using an Olympus ultrasonic phased array flaw detector, with typical internal quality being shown in fig. 6, 7, 8, 9 and 10.
As can be seen from fig. 6 and 7, the position echo of the probe at the moment is obvious and not reduced in the embodiment 1 and the embodiment 2 from the scan a and the scan B, and the color is uniform and consistent on the whole test piece from the scan C, so that no obvious defect is generated; as can be seen from the A scanning image and the B scanning image of the comparative examples 1-3, the bottom wave of the probe is obviously reduced, the defect wave is obvious between the bottom wave and the initial wave, and a plurality of areas with deepened colors exist on the whole test piece, namely a plurality of defects exist on the C scanning image.
In summary, according to the method for improving the internal quality of the non-autoclave molded part provided by the application, the double sides of the prepreg 102 are protected by the embossed film, so that the gas is effectively prevented from being wrapped in during the laying process, and the gas exhaust channel is increased; meanwhile, the application places the air guide 105 at the edge of the preform to provide a path for discharging air; the porous isolating film 107 is used, and the release cloth is directly connected with the airfelt 108, so that omnibearing air guide is realized, the discharge of air and small molecules in the paving and curing processes can be effectively improved, and the internal quality of a finished product is improved.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (8)
1. A method of improving the internal quality of a non-autoclave molded article comprising:
preparing a prepreg: an embossed film is used as a protective film on both sides of the prepreg, and the embossed film forms an exhaust passage on the surface of the prepreg;
laying up the prepreg: tearing off the embossed film, paving a plurality of layers of prepregs on a die with a first release cloth, paving 2-8 layers of prepregs in the paving process, placing air guide pieces at the edges of the plurality of layers of prepregs, and then continuously paving the prepregs to form a prefabricated part;
and (3) packaging: and a second demolding cloth, a separation film and an airfelt are sequentially paved on the surface of the prefabricated member, the size of the second demolding cloth is larger than that of the prefabricated member, the size of the separation film is equal to that of the prefabricated member, and the airfelt is connected with the second demolding cloth.
2. The method of claim 1, wherein the vent channels are in the form of strips or grids.
3. The method for improving the internal quality of a non-autoclave molded part according to claim 1, wherein the air guide member is a strip-shaped air guide material with the width of 4-5 cm, and the air guide material is paved on a circle of the peripheral edges of the plurality of layers of prepregs;
preferably, the air guide material is glass fiber mesh cloth;
preferably, the air guide material is lapped on the peripheral edge of the plurality of layers of the prepreg by one circle, the lapping width is 4-6mm, and the lapping position is located outside the net size of the product.
4. The method of improving the internal quality of a non-autoclave molded article according to claim 1, wherein the second release cloth is broken at the inside corner of the prepreg and the broken second release cloth is connected in a lap joint manner while the second release cloth is laid.
5. The method of improving the internal quality of a non-autoclave molded article according to claim 1, wherein the edge of the release film is fixed with the second release cloth by a pressure-sensitive adhesive tape at the time of laying the release film, and a leveling bar is placed at the inside corner of the prepreg;
preferably, the separator is a perforated separator.
6. The method of improving the internal quality of a non-autoclave molded article according to claim 1, wherein the airfelt is broken at the inside corner of the prepreg and the broken airfelt is connected by butt joint;
preferably, the end of the air guide away from the prepreg extends beyond the second release cloth and is directly connected with the airfelt.
7. The method for improving the internal quality of a non-autoclave molded article according to any one of claims 1 to 6, wherein, in the process of laying up the prepreg, vacuum-pumping pre-compaction is performed once for every 1 to 4 layers, the vacuum-pumping pressure is not lower than 800mbar, and the vacuum-pumping time is not lower than 10min;
preferably, at pre-compaction, a balancing bar is placed at the inside corners of the prepreg.
8. Use of the method of improving the internal quality of a non-autoclave molded article as claimed in any one of claims 1 to 7 for the preparation of a composite material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310860020.5A CN116674231A (en) | 2023-07-12 | 2023-07-12 | Method for improving internal quality of non-autoclave molded part and application thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310860020.5A CN116674231A (en) | 2023-07-12 | 2023-07-12 | Method for improving internal quality of non-autoclave molded part and application thereof |
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| CN116674231A true CN116674231A (en) | 2023-09-01 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117484909A (en) * | 2023-11-02 | 2024-02-02 | 哈尔滨远驰航空装备有限公司 | Composite material airborne component, forming method and forming die thereof |
-
2023
- 2023-07-12 CN CN202310860020.5A patent/CN116674231A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117484909A (en) * | 2023-11-02 | 2024-02-02 | 哈尔滨远驰航空装备有限公司 | Composite material airborne component, forming method and forming die thereof |
| CN117484909B (en) * | 2023-11-02 | 2024-04-19 | 哈尔滨远驰航空装备有限公司 | Composite material airborne component, forming method and forming die thereof |
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