A packaging method for manufacturing large curvature composite material parts by co-bonding process

Abstract

The present invention discloses a packaging method for manufacturing large curvature composite parts by a co-bonding process. Sealing tape is respectively pasted on the edge margin area of ​​the cured skin and the bag-making area of ​​the forming mold according to the contour of the part, and then the breathable fabric and the vacuum bag are laid in sequence, and a vacuum guide connection port is set to complete the first step of packaging. After that, the pre-bonded structural layer is completed on the cured skin, and the parts are packaged as a whole using packaging materials together with the packaged area, and a second vacuum connection port is set at the same time, and finally vacuum cured and formed in an autoclave. This method can achieve that the cured skin is completely fitted with the forming mold in the entire cycle of subsequent manufacturing, ensure the accuracy of subsequent bonding positioning, avoid problems such as prepreg wrinkles and skin delamination in the parts, and improve product quality.

Description

Technical Field

[0001] The invention relates to the technical field of composite material molding, in particular to a packaging method for manufacturing large-curvature composite material parts by a co-bonding process. Background Art

[0002] After the composite parts undergo high-temperature curing and cooling processes, they will inevitably produce certain curing deformations after returning to room temperature due to the thermal expansion and contraction effects of the materials, the chemical reaction shrinkage effects of the matrix resin, and the difference in thermal expansion coefficients between the composite materials and the molding mold materials, resulting in the inability of the cured composite parts to fit the mold completely. Especially for some composite skins with complex curvature changes or with obvious turning surfaces, if the subsequent process requires gluing uncured long spars and core materials, or laying skin prepreg, it is necessary to make the cured skin fit the molding mold as closely as possible, and then perform the co-gluing operation. The usual process method is to use a release cloth or tape to fix the skin edge where it does not fit the tooling after curing. This method can only fix the edge of the solidified skin, but cannot ensure that the middle curvature change area is completely fitted with the tooling, affecting the positioning accuracy of the long stringer and causing the axis of the co-glued long stringer to deviate in dimension. Or, due to the inconsistent curvature of the outer skin before and after packaging, the skin on the sandwich part will have internal and external defects such as wrinkles, delamination, and pores at the curvature change.

[0003] Therefore, a packaging method for manufacturing large-curvature composite parts using a co-bonding process is needed to ensure that the cured skin, especially the large-curvature skin, is fully fitted with the molding mold during the entire subsequent manufacturing cycle, thereby ensuring the accuracy of subsequent bonding positioning and avoiding problems such as prepreg wrinkles and skin delamination in the process, which would affect product quality. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problems and propose a packaging method for manufacturing large curvature composite material parts by a co-bonding process.

[0005] A packaging method for manufacturing large curvature composite material parts by a co-bonding process comprises the following steps:

[0006] 1. Prepare all materials or components to be bonded, ensure that they meet the bonding conditions, remove the packaging materials on the cured skin, and clean the surface of the molding mold;

[0007] 2. A circle of sealing tape is respectively pasted on the edge margin area of ​​the cured skin and the bag-making area of ​​the forming mold according to the contour of the part, a first breathable fabric is placed inside the two circles of sealing tape, and a first vacuum bag is laid on the upper layer of the first breathable fabric. The first vacuum bag simultaneously covers the envelope range surrounded by the two circles of sealing tape and is tightly attached to the sealing tape. A first vacuum connection port is provided on the first breathable fabric to pass through the first vacuum bag. The first vacuum connection port is connected to a vacuuming device. The device is started to vacuum the space between the cured skin and the forming mold. The cured skin and the forming mold are completely attached to each other under the action of atmospheric pressure. At this time, the vacuum connection is disconnected and the first vacuum connection port is closed;

[0008] 3. Make a pre-bonded structural layer on the unencapsulated area of ​​the cured skin;

[0009] 4. Use a non-porous isolation film to completely cover the pre-bonded structural layer and the packaging area prepared in 1-2, lay a second breathable fabric on the non-porous isolation film, lay a second vacuum bag on the upper layer of the second breathable fabric, and provide a sealing tape between the edge of the second vacuum bag and the forming mold, open the non-porous isolation film, the second breathable fabric and the second vacuum bag, pass the first vacuum connection port through the above materials, and seal the edge of the first vacuum connection port with the opening of the second vacuum bag with a sealing tape, and set a second vacuum connection port on the outside of the first vacuum connection port. The second vacuum connection port is set on the second breathable fabric and passes through the second vacuum bag;

[0010] 5. Place the packaged parts into the autoclave, connect the first vacuum connection port and the second vacuum connection port to the vacuum system, vacuum and compact them to complete the curing.

[0011] Furthermore, the sealing tape pasted on the cured skin is located at 1 / 2 of the width of the edge margin area, and the width of the edge margin area of ​​the cured skin is not less than 40 mm.

[0012] Furthermore, after the first vacuum bag is bonded to the sealing strip, the width of the first vacuum bag extending outside the sealing strip is 10 mm to 20 mm.

[0013] Furthermore, the width of the bag-making area of ​​the molding die in step 1-2 should be no less than 100 mm.

[0014] The beneficial effects of the above packaging method are:

[0015] 1) The packaging method proposed by the present invention is simple and easy to operate. The large curvature skin margin area and the forming mold are separately packaged, so that the two can be completely fitted in the subsequent manufacturing cycle, ensuring the accuracy of subsequent gluing positioning, avoiding the problems of prepreg wrinkles and skin delamination in the process, which affect product quality;

[0016] 2) The packaging method proposed in the present invention has a wide range of applications, especially for composite skins with complex curvature changes or with obvious turning surfaces. If the subsequent process also requires gluing uncured long stringers and core materials, or laying skin prepreg, it has been proven to be effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the cured skin packaging method.

[0018] Figure 2 Schematic diagram of the co-bonding parts packaging method.

[0019] Explanation of numbers in the figure: 1-cured skin, 2-molding mold, 3-sealing tape, 4-first breathable fabric, 5-first vacuum bag, 6-first vacuum connection port, 7-pre-bonded structural layer, 8-non-porous isolation membrane, 9-second breathable fabric, 10-second vacuum bag, 11-sealing strip, 12-second vacuum connection port, 13-edge margin area. DETAILED DESCRIPTION

[0020] The large curvature composite honeycomb sandwich part manufactured by the co-bonding process in this example is composed of a cured skin 1 and a pre-bonded structural layer 7. The pre-bonded structural layer 7 is a glue film, a honeycomb core and an upper skin to be laid. For the packaging method, please refer to Figure 1-2 .

[0021] Prepare the honeycomb core, adhesive film and prepreg to ensure that they meet the bonding state. At the same time, remove the packaging material on the cured skin 1 and clean the surface of the surrounding molding mold 2.

[0022] A circle of sealing tape 3 is respectively pasted at 1 / 2 of the width of the edge margin area 13 of the cured skin 1 and the bag-making area of ​​the forming mold 2 according to the contour of the part. The width of the edge margin area 13 of the cured skin 1 is 45 mm, and the width of the bag-making area of ​​the forming mold 2 is 140 mm. A first breathable fabric 9 is placed inside the two circles of sealing tape 3, and a first vacuum bag 5 is laid on the upper layer of the first breathable fabric 4. The first vacuum bag 5 needs to cover the envelope range surrounded by the two circles of sealing tape 3 at the same time and be tightly attached to the sealing tape 3. The width of the first vacuum bag 5 extending outside the sealing tape 11 is 15 mm. A first vacuum connection port 6 passing through the first vacuum bag 5 is provided on the first breathable fabric 4. The first vacuum connection port 6 is connected to a vacuum pumping device. The device is started to evacuate the space between the cured skin 1 and the forming mold 2 to above 0.08 MPa. Under the action of atmospheric pressure, the cured skin 1 and the forming mold 2 are completely attached. At this time, the vacuum connection is disconnected and the first vacuum connection port 6 is closed.

[0023] Lay a layer of adhesive film on the entire unpackaged area of ​​the cured skin 1, glue the honeycomb core according to the position determined by laser projection, continue to lay a layer of adhesive film on the upper surface area of ​​the honeycomb core, and then lay the skin prepreg layer by layer to form a pre-bonded structural layer 7;

[0024] A non-porous isolation film 8 is used to entirely cover the pre-bonded structural layer 7 and the packaged area, a second breathable fabric 9 is laid on the non-porous isolation film 8, a second vacuum bag 10 is laid on the upper layer of the second breathable fabric 9, a sealing tape 3 is provided between the edge of the second vacuum bag 10 and the forming mold 2, the non-porous isolation film 8, the second breathable fabric 9 and the second vacuum bag 10 are opened, the first vacuum connection port 6 is passed through the above materials, and the edge of the first vacuum connection port 6 and the opening of the second vacuum bag 10 are sealed with a sealing tape 11, a second vacuum connection port 12 is provided on the outer side of the first vacuum connection port 6, and the second vacuum connection port 12 is provided on the second breathable fabric 9 and passes through the second vacuum bag 10;

[0025] The packaged parts are placed in an autoclave, and the first vacuum connection port 6 and the second vacuum connection port 12 are connected to the vacuum system, and vacuumed and compacted to complete the curing.

[0026] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A packaging method for manufacturing large curvature composite material parts by co-bonding process, characterized in that The following steps are involved: 1-1 Prepare all materials or components to be bonded, ensure that they meet the bonding conditions, remove the packaging materials on the cured skin, and clean the surface of the molding mold; 1-2 A circle of sealing tape is respectively pasted on the edge margin area of ​​the cured skin and the bag-making area of ​​the forming mold according to the contour of the part, a first breathable fabric is placed inside the two circles of sealing tape, and a first vacuum bag is laid on the upper layer of the first breathable fabric. The first vacuum bag simultaneously covers the envelope range surrounded by the two circles of sealing tape and is tightly attached to the sealing tape. A first vacuum connection port is provided on the first breathable fabric to pass through the first vacuum bag. The first vacuum connection port is connected to a vacuum pumping device. The device is started to vacuum the space between the cured skin and the forming mold. The cured skin and the forming mold are completely attached to each other under the action of atmospheric pressure. At this time, the vacuum connection is disconnected and the first vacuum connection port is closed; 1-3 Making a pre-bonded structural layer on the unencapsulated area of ​​the cured skin; 1-4: using a non-porous isolation film to completely cover the pre-bonded structural layer and the packaging area prepared in 1-2, laying a second breathable fabric on the non-porous isolation film, laying a second vacuum bag on the upper layer of the second breathable fabric, and providing a sealing tape between the edge of the second vacuum bag and the forming mold, opening the non-porous isolation film, the second breathable fabric and the second vacuum bag, allowing the first vacuum connection port to pass through the above materials, and sealing the edge of the first vacuum connection port with the opening of the second vacuum bag with a sealing tape, and providing a second vacuum connection port on the outside of the first vacuum connection port, and the second vacuum connection port is provided on the second breathable fabric and passes through the second vacuum bag; 1-5: Place the packaged parts into the autoclave, connect the first vacuum connection port and the second vacuum connection port to the vacuum system, vacuum and compact them to complete the curing.

2. The packaging method for manufacturing large curvature composite material parts by co-bonding process according to claim 1, characterized in that The sealing tape pasted on the solidified skin is located at 1 / 2 of the width of the edge margin area, and the width of the edge margin area of ​​the solidified skin is not less than 40 mm.

3. The packaging method for manufacturing large curvature composite material parts by co-bonding process according to claim 1, characterized in that After the first vacuum bag is bonded to the sealing strip, the width of the first vacuum bag extending outside the sealing strip is 10 mm to 20 mm.

4. The packaging method for manufacturing large curvature composite material parts by co-bonding process according to claim 1, characterized in that The width of the bag-making area of ​​the molding die in the steps 1-2 should be no less than 100 mm.

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