Adhesive solid state and viscous flow state bonding process method and process determination method

Abstract

The invention relates to an adhesive solid-state and viscous-flow-state bonding process method and a process determination method, which can ensure that the product order difference index meets the use requirement and meet the requirements of high-quality and high-reliability bonding assembly of a thermal protection system. Comprising the following steps: 1) for a matched thermal protection component of the out-of-tolerance product, measuring the height from the thermal protection of the end surface of the out-of-tolerance product to the surface of a bearing structure by using a depth gauge before bonding so as to determine the brushing thickness of an adhesive of the matched bonded thermal protection component; (2) solid glue solution bonding is conducted, specifically, a solid glue layer with the required thickness is brushed and manufactured in advance within the range of 10-20 mm away from the thermal protection edge, the upper surface and the periphery of the solid glue layer are brushed and coated with sufficient liquid glue during bonding, and it is ensured that the prepared solid glue layer is completely wrapped and covered; and (3) viscous-state glue solution bonding is conducted, specifically, the thermal protection edge area is coated with a liquid glue solution with the set thickness in a brushing mode, and after the glue solution is cured for 12 h at the normal temperature, the viscous-state glue solution is coated with the liquid glue solution in a brushing mode to ensure that the glue solution is full.

Description

Technical Field

[0001] The invention belongs to the field of bonding and assembling of thermal protection systems of high-speed flight products, and in particular relates to a solid-state and viscous-flow bonding process method of an adhesive and a process determination method. Background Art

[0002] The large-area thermal protection assembled by bonding on the outer surface of high-speed aircraft prevents the high-speed aircraft from being affected by the heat generated by air friction. At the same time, the assembly between adjacent thermal protections satisfies the airflow assembly with the axis being low in front and high in the back, and high in the bottom and low in the top, so that the flight posture is not affected by adverse airflow during flight. However, the thermal protection components on the surface of the aircraft, especially the characteristic areas such as the mouth cover frame and edges, are affected by the thickness of the bonding adhesive, resulting in the contour of the thermal protection in the characteristic area being out of tolerance. As a result, the matching mouth cover thermal protection products cannot be used normally. Bonding by solid-state and viscous-flow processes of adhesives can ensure that when the contour of the thermal protection in the characteristic area is out of tolerance, it will not affect the key indicators of the thermal protection system of the flight product, such as the bonding strength and effective bonding area, thereby ensuring that the aircraft step difference indicators meet the use requirements and meet the requirements of high-quality and high-reliability bonding assembly of the thermal protection system. Summary of the invention

[0003] The present invention proposes a solid-state and viscous-flow bonding process method and a process determination method of an adhesive, which can ensure that when the thermal protection has contour deviations, the key indicators of the bonding strength and effective bonding area of ​​the thermal protection system of the flight product are not affected, and the product step difference indicators meet the use requirements, thereby meeting the requirements of high-quality and high-reliability bonding assembly of the thermal protection system.

[0004] The present invention is achieved by the following technical solutions:

[0005] An adhesive solid-state and viscous-flow bonding process method, comprising:

[0006] 1) For the supporting thermal protection components of out-of-tolerance products, use a depth gauge to measure the height from the end surface thermal protection of the out-of-tolerance product to the surface of the bearing structure before bonding, so as to determine the brushing thickness of the adhesive for the supporting thermal protection components;

[0007] 2) Solid glue liquid bonding is to brush in advance to prepare a solid glue layer of required thickness within the range of 10 to 20 mm from the edge of the heat protection. During bonding, brush a sufficient amount of liquid adhesive on the upper surface and around the solid glue layer to ensure that the prepared solid glue layer is completely covered;

[0008] Preparation method of solid adhesive layer: Use tooling to assemble the frame, use double-sided tape to bond the bottom of the frame to the load-bearing structure, brush the adhesive inside the frame and use a scraper to scrape it flat, and after the adhesive is completely cured, use a foot knife to cut a slope on the edge of the solid adhesive layer. In order to avoid bubbles in the adhesive that cannot be discharged during the bonding process, the solid adhesive layer is made into a diamond shape according to the product direction;

[0009] 3) Viscous glue bonding is to brush a predetermined thickness of liquid glue on the edge area of ​​the heat protection, wait for the glue to cure at room temperature for 12 hours, and then brush liquid glue on the viscous glue to ensure that the glue is full;

[0010] The preparation method of the viscous glue layer is the same as that of the solid glue layer, but no slope treatment is performed when the glue liquid is not completely solidified.

[0011] A method for determining the solid-state and viscous-flow bonding process of an adhesive, the process is as follows:

[0012] 1) Prepare the shear test pieces of solid and viscous adhesive layers respectively to verify the process before bonding. Compare the shear strength after shearing with the shear data of normal adhesive liquid to confirm whether there is a large difference in the data and whether the process method can be applied to formal products;

[0013] 2) Prepare a large area of ​​solid glue layer to support thermal protection, apply glue liquid around the solid glue layer to completely wrap the glue layer, and solidify it under vacuum loading. After solidification, perform CT detection and check the CT slices to find a small amount of debonding defects near the glue layer;

[0014] 3) Analysis shows that the debonding positions are all located at the rear end of the solid glue layer. It is judged that the large area of ​​solid glue layer blocks the surrounding glue liquid from converging to the center of the solid glue layer. The second solid glue layer is prepared, and the glue layer is made into a size of 10×10mm. After curing, CT detection is performed. Checking the CT slices, it is found that there are a small amount of debonding defects near the glue layer;

[0015] 4) Analysis shows that the debonding positions are all located on both sides of the solid glue layer. It is judged that the gas in the glue liquid gathers around the solid glue layer during vacuum loading, causing debonding. In order to avoid gas aggregation, the solid glue layer is prepared for the third time and cut into diamonds along the heading. At the same time, the glue layer is sloped. After curing, CT detection is performed. No debonding defects are found in the glue layer after checking the CT slices, which proves that the measures are effective.

[0016] 5) Clarify the preparation method of the cured adhesive layer, prefabricate a solid adhesive layer with a width of 20×20mm, cut it into diamond-shaped solid adhesive layers after the adhesive layer is cured, and bond the thermal protection components according to the optimized process method. After the curing is completed, test whether the flight product bonding effective area, contour, and step difference technical indicators are met;

[0017] 6) Prepare a viscous adhesive layer at the edge of the load-bearing structure, and after curing for 12 hours, bond the thermal protection components according to the optimized process method. After curing, check whether the flight product meets the technical indicators such as effective bonding area, contour, and step difference;

[0018] 7) After checking the CT slices after bonding, it was found that there were a lot of bubbles in the CT slices of the semi-cured glue layer with a thickness of 0.6mm, but no large amount of bubbles were found in the CT slices of the 0.3mm glue layer. The construction process of curing the semi-cured glue layer was to prepare a semi-cured glue layer with a thickness greater than 0.3mm by brushing the glue liquid in several times. The glue liquid was cured for 4 hours, and the coating thickness of each brushing was not more than 0.3mm, and finally a cured glue layer was obtained.

[0019] The present invention proposes a solid-state and viscous-flow bonding process method of an adhesive and a process determination method, which can solve the problem that when the profile of a large-area thermal protection is out of tolerance after bonding, an adverse airflow step difference occurs after the matching thermal protection is assembled, which affects the flight risk. The bonding method is optimized, and two bonding process forms, solid-state and viscous-flow, are proposed. Bonding according to the process method of the present invention does not affect the key indicators of the bonding strength and effective bonding area of ​​the thermal protection system of the flight product, thereby ensuring that the product step difference indicators meet the use requirements and meet the requirements of high-quality and high-reliability bonding assembly of the thermal protection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Process verification to produce solid tensile shear test pieces, where Figure 1-1 Solid glue layer tensile shear test piece, Figure 1-2 Viscous fluid adhesive layer tensile shear test piece;

[0021] Figure 2: Preparation and testing of the first solid glue layer, where Figure 2-1 The effect after the first solid glue layer preparation, Figure 2-2 CT detection of debonding areas;

[0022] Figure 3 Second solid glue layer preparation and testing, where Figure 3-1 The effect after the first solid glue layer preparation, Figure 3-2 CT detection of debonding areas;

[0023] Figure 4 solid glue layer shaping, where Figure 4-1 Solid glue layer preparation, Figure 4-2 Effect after solid glue layer preparation, Figure 4-3 Solid glue layer cuts the slope. In the figure, 1 is the frame for preparing the tooling to be spliced, 2 is the glue layer to be applied by brush, and 3 is the bearing structure;

[0024] Figure 5 Preparation of viscous fluid adhesive layer, where Figure 5-1 Preparation process of viscous fluid adhesive layer, Figure 5-2 The effect after the viscous fluid adhesive layer is prepared. In the figure, 1 is the prepared tooling splicing frame, 2 is the brushed adhesive layer, and 3 is the bearing structure. DETAILED DESCRIPTION

[0025] The adhesive solid state and viscous flow bonding process of the present invention comprises:

[0026] 1) For the supporting thermal protection components of out-of-tolerance products, use a depth gauge to measure the height from the end face thermal protection of the out-of-tolerance product to the surface of the bearing structure before bonding, so as to determine the brushing thickness of the adhesive for the supporting thermal protection components.

[0027] 2) Solid glue liquid bonding means that a solid glue layer of required thickness is brushed in advance within 10 to 20 mm from the edge of the heat protection. During bonding, a sufficient amount of liquid adhesive is brushed on the upper surface and around the solid glue layer to ensure that the prepared solid glue layer is completely wrapped and covered.

[0028] 3) Preparation of solid adhesive layer: For adhesive layers of different thicknesses, tooling is used to prepare them. The tooling is used to assemble the frame 1 (the size of the frame is adjusted according to the actual situation). The bottom of the frame is bonded to the bearing structure 3 with double-sided tape. The adhesive is brushed inside the frame and scraped flat with a scraper. After the adhesive is completely cured, a slope is cut out of the edge of the solid adhesive layer with a foot knife. In order to avoid bubbles in the adhesive that cannot be discharged during the bonding process, the solid adhesive layer is made into a diamond shape according to the product direction.

[0029] 4) Viscous glue bonding is to brush a predetermined thickness of liquid glue on the edge area of ​​the heat protection. After the glue is cured at room temperature for 12 hours, liquid glue is brushed on the viscous glue to ensure that the glue is full.

[0030] 5) Preparation of viscous glue layer: the method is the same as that of solid glue layer, but the slope treatment is not performed until the glue liquid is completely solidified.

[0031] The present invention is further described in detail with reference to Figures 1 to 3 and implementation examples.

[0032] Figure 1 shows the process of process verification, during which the process plan is tested to verify its feasibility.

[0033] FIG2 shows the first solid adhesive layer preparation process in the present technical invention to achieve overall adhesive layer thickness control for large-area thermal protection, but the CT detection quality after bonding does not meet the requirements.

[0034] FIG3 shows that the size of the solid adhesive layer is changed based on the first bonding verification to ensure that the bonding quality meets the requirements.

[0035] Figure 4 shows that the direction and angle of the solid glue layer were changed based on the second bonding verification. After CT testing, the bonding quality met the requirements. The final preparation form of the solid glue layer was fixed to make a diamond glue layer along the heading, with a slope cut on the edge of the glue layer and a size of no more than 10mm×10mm.

[0036] FIG5 shows the process of preparing the viscous flow adhesive layer to achieve control of the thickness of the adhesive layer in the edge area.

[0037] Example:

[0038] 1) Prepare shear test pieces of solid and viscous adhesive layers respectively to verify the process before bonding. Compare the shear strength after shearing with the shear data of normal adhesive liquid to confirm whether there is a large difference in the data and determine whether the process method can be applied to formal products.

[0039] 2) Prepare a large area of ​​solid glue layer to support thermal protection, brush glue liquid around the solid glue layer to completely wrap the glue layer, and solidify it under vacuum loading. After solidification, CT inspection is performed, and a small amount of debonding defects are found near the glue layer after checking the CT slices.

[0040] 3) Analysis shows that the debonding positions are all located at the rear end of the solid glue layer. It is judged that the large area of ​​solid glue layer blocks the surrounding glue liquid from converging to the center of the solid glue layer. The second solid glue layer is prepared and the glue layer is made into a size of 10×10mm. After curing, CT detection is performed and a small amount of debonding defects are found near the glue layer after checking the CT slices.

[0041] 4) Analysis shows that the debonding positions are all located on both sides of the solid glue layer. It is judged that the gas in the glue liquid gathers around the solid glue layer during vacuum loading, causing debonding. In order to avoid gas aggregation, the solid glue layer was prepared for the third time, cut into diamonds along the heading, and the glue layer was sloped. After curing, CT detection was performed, and no debonding defects were found in the glue layer after checking the CT slices, proving that the measures are effective.

[0042] 5) Clarify the preparation method of the cured adhesive layer, prefabricate a solid adhesive layer with a width of 20×20mm, cut it into diamond-shaped solid adhesive layers after the adhesive layer is cured, and bond the thermal protection components according to the optimized process method. After the curing is completed, check whether the technical indicators such as the effective bonding area, contour, and step difference of the flight product are met.

[0043] 6) Prepare a viscous adhesive layer at the edge of the load-bearing structure, and after curing for 12 hours, bond the thermal protection components according to the optimized process method. After curing, check whether the flight product meets the technical indicators such as effective bonding area, contour, and step difference.

[0044] 7) After checking the CT slices after bonding, it was found that there were a lot of bubbles in the CT slices of the semi-cured adhesive layer with a thickness of 0.6mm, but no large amount of bubbles were found in the CT slices of the 0.3mm adhesive layer. The construction process of curing the semi-cured adhesive layer is to prepare a semi-cured adhesive layer with a thickness greater than 0.3mm. The adhesive liquid needs to be brushed in several times. The adhesive liquid is cured for about 4 hours. The thickness of each brushing is not more than 0.3mm, and finally a cured adhesive layer is obtained.

Claims

1. A solid-state and viscous-flow bonding process of an adhesive, characterized in that: include: 1) For the supporting thermal protection components of out-of-tolerance products, use a depth gauge to measure the height from the end surface thermal protection of the out-of-tolerance product to the surface of the bearing structure before bonding, so as to determine the brushing thickness of the adhesive for the supporting thermal protection components; 2) Solid glue liquid bonding is to brush in advance to prepare a solid glue layer of required thickness within the range of 10 to 20 mm from the edge of the heat protection. During bonding, brush a sufficient amount of liquid adhesive on the upper surface and around the solid glue layer to ensure that the prepared solid glue layer is completely covered; Preparation method of solid adhesive layer: Use tooling to assemble the frame, use double-sided tape to bond the bottom of the frame to the load-bearing structure, brush the adhesive inside the frame and use a scraper to scrape it flat, and after the adhesive is completely cured, use a foot knife to cut a slope on the edge of the solid adhesive layer. In order to avoid bubbles in the adhesive that cannot be discharged during the bonding process, the solid adhesive layer is made into a diamond shape according to the product direction; 3) Viscous glue bonding is to brush a predetermined thickness of liquid glue on the edge area of ​​the heat protection, wait for the glue to cure at room temperature for 12 hours, and then brush liquid glue on the viscous glue to ensure that the glue is full; The preparation method of the viscous glue layer is the same as that of the solid glue layer, but no slope treatment is performed when the glue liquid is not completely solidified.

2. A method for determining the bonding process of an adhesive in a solid state or a viscous flow state, characterized in that: as follows: 1) Prepare the shear test pieces of solid and viscous adhesive layers respectively to verify the process before bonding. Compare the shear strength after shearing with the shear data of normal adhesive liquid to confirm whether there is a large difference in the data and whether the process method can be applied to formal products; 2) Prepare a large area of ​​solid glue layer to support thermal protection, apply glue liquid around the solid glue layer to completely wrap the glue layer, and solidify it under vacuum loading. After solidification, perform CT detection and check the CT slices to find a small amount of debonding defects near the glue layer; 3) Analysis shows that the debonding positions are all located at the rear end of the solid glue layer. It is judged that the large area of ​​solid glue layer blocks the surrounding glue liquid from converging to the center of the solid glue layer. The second solid glue layer is prepared, and the glue layer is made into a size of 10×10mm. After curing, CT detection is performed. Checking the CT slices, it is found that there are a small amount of debonding defects near the glue layer; 4) Analysis shows that the debonding positions are all located on both sides of the solid glue layer. It is judged that the gas in the glue liquid gathers around the solid glue layer during vacuum loading, causing debonding. In order to avoid gas aggregation, the solid glue layer is prepared for the third time and cut into diamonds along the heading. At the same time, the glue layer is sloped. After curing, CT detection is performed. No debonding defects are found in the glue layer after checking the CT slices, which proves that the measures are effective. 5) Clarify the preparation method of the cured adhesive layer, prefabricate a solid adhesive layer with a width of 20×20mm, cut it into diamond-shaped solid adhesive layers after the adhesive layer is cured, and bond the thermal protection components according to the optimized process method. After the curing is completed, test whether the flight product bonding effective area, contour, and step difference technical indicators are met; 6) Prepare a viscous adhesive layer at the edge of the load-bearing structure, and after curing for 12 hours, bond the thermal protection components according to the optimized process method. After curing, check whether the flight product meets the technical indicators such as effective bonding area, contour, and step difference; 7) After checking the CT slices after bonding, it was found that there were a lot of bubbles in the CT slices of the semi-cured glue layer with a thickness of 0.6mm, but no large amount of bubbles were found in the CT slices of the 0.3mm glue layer. The construction process of curing the semi-cured glue layer was to prepare a semi-cured glue layer with a thickness greater than 0.3mm by brushing the glue liquid in several times. The glue liquid was cured for 4 hours, and the coating thickness of each brushing was not more than 0.3mm, and finally a cured glue layer was obtained.

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