A manufacturing device and manufacturing method for a porosity specimen

Abstract

The present invention discloses a manufacturing device and a manufacturing method for a porosity specimen. By using a large-sized uniform pressing plate in combination with thickness control blocks of different thicknesses and structures, and in conjunction with a resin-absorbing material, the stress state of the resin in the prepreg is adjusted during curing, and the physical state of small-molecule substances such as water dissolved in the resin is controlled, thereby achieving the goal of adjusting the porosity. This device does not use any additional solvents or materials, so no new substances are introduced into the specimen or the content of a certain component is increased. Its measurement results are closer to the true state of composite parts. This device is safe, reliable, and has strong repeatability.

Description

Technical Field

[0001] The present invention relates to the field of manufacturing composite components, and particularly to a manufacturing device and method for a porosity specimen. Background Art

[0002] Porosity refers to the volume percentage of pores inside a composite part. Porosity is an important index for measuring the comprehensive performance of composite parts.

[0003] The ultrasonic comparison method is a common method for obtaining the porosity of composite parts. By using ultrasonic equipment to detect composite parts and comparing with the detection results of porosity specimens, the actual porosity of composite parts can be obtained.

[0004] Existing methods for manufacturing porosity specimens include the pre-embedding method and the solvent method, etc. In the pre-embedding method, a medium is placed between plies to form interply pores, thereby obtaining a porosity specimen. Chinese Patent Publication No. CN10447060A (A method for manufacturing a composite material porosity comparison specimen) discloses a method for manufacturing a porosity specimen. By pre-embedding microbeads between plies to form gaps and simulate pores, a porosity specimen is obtained. In the solvent method, a volatile solvent is sprayed on the surface of the ply. During curing, the solvent volatilizes to form pores, thereby obtaining a porosity specimen. Chinese Patent Publication No. CN103552255A (A method for manufacturing a composite material porosity detection and comparison sample block) discloses a method for manufacturing a porosity specimen. By spraying a specific amount of alcohol (acetone) on the surface of the ply, during the curing process, the alcohol (acetone) volatilizes into gas to form pores.

[0005] Although both of these methods can obtain porosity specimens, new substances are introduced into the specimens, or the content of a certain component in the specimens is increased. The actual composition of the porosity specimen is different from that of the composite part, which affects the accuracy of the final result judgment and may lead to misjudgment. Moreover, when using functional materials, the microbead medium or solvent may be part of the functional material, or may affect or change the composition or performance of the functional material. Therefore, it is impossible to manufacture a porosity specimen that meets the requirements.

[0006] Therefore, there is an urgent need for a manufacturing device and method for a porosity specimen, which can truly simulate the pore state during the curing process of a part and form uniform pores without introducing new substances, increasing the content of a certain component, or affecting the functionality of the product. Summary of the Invention

[0007] To solve the above problems, the present invention provides a manufacturing device and method for a porosity specimen, which adjusts the stress state of fibers and resin in the prepreg during the curing process through a large-size uniform pressure plate in cooperation with thickness control blocks of different thicknesses and structures.

[0008] A manufacturing device for a porosity specimen, comprising a tooling main body, thickness control blocks, and a uniform pressing plate. The specimen is laid on the tooling main body, the thickness control blocks are placed adjacent to the periphery of the specimen blank, and the uniform pressing plate is placed on the specimen blank and the thickness control blocks. The outer dimension of the uniform pressing plate is larger than that of the specimen blank, and the outer dimension of the uniform pressing plate is smaller than the overall outer dimension of the specimen blank plus the thickness control blocks around it. The height and structure of the thickness control blocks are set according to the target porosity. When the target porosity < 1%, the height of the thickness control blocks is 2 - 3 layer laying theoretical thicknesses smaller than the theoretical thickness of the specimen. When the target porosity is 1% - 2%, the height of the thickness control blocks is 0 - 2 layer laying theoretical thicknesses smaller than the theoretical thickness of the specimen. And an overflow glue groove is provided at the bottom of the thickness control blocks. When the target porosity > 2%, the height of the thickness control blocks is at least 1 layer laying theoretical thickness larger than the theoretical thickness of the specimen. And an overflow glue groove is provided at the bottom of the thickness control blocks, and a glue absorbing material is placed in the overflow glue groove. The glue absorbing material can be dry glass cloth or breathable fabric.

[0009] A manufacturing method for a porosity specimen, characterized by comprising the following steps:

[0010] 1 Lay the specimen blank on the upper surface of the tooling main body;

[0011] 2 Cut the four sides of the specimen blank to be flush;

[0012] 3 Determine the height and structure of the thickness control blocks according to the target porosity, and place them around the specimen blank;

[0013] 4 Check the fitting condition between the specimen blank and the thickness control blocks, and fill the gaps with the same material as the specimen blank;

[0014] 5 When the target porosity > 2%, place a glue absorbing material in the overflow glue groove at the bottom of the thickness control blocks;

[0015] 6 Place the uniform pressing plate, and place the four sides of the uniform pressing plate on the thickness control blocks around the specimen blank;

[0016] 7 Make a bag and cure.

[0017] 8 Calibrate the actual porosity of the specimen.

[0018] The manufacturing device and manufacturing method of the present invention have the following advantages: 1) No additional solvents or media are used, so no new substances are introduced or the content of a certain component is increased. The composition of the specimen is exactly the same as that of the composite material part, eliminating the possibility of misjudgment; 2) Strong versatility, not affected by the composition and compatibility of raw materials, applicable to various resins, fibers, and functional materials; 3) Adjust the resin compression state by using the device, without safety hazards, and good repeatability. Description of the Drawings

[0019] Figure 1 Schematic Diagram of the Porosity Specimen Manufacturing Device

[0020] Figure 2 Cross-sectional view of the porosity sample manufacturing device

[0021] Explanation of the numbers in the figure: 1 - Tooling body, 2 - Thickness control block, 3 - Sample blank, 4 - Uniform pressing plate, 5 - Glue overflow groove, 6 - Glue absorption material. Specific implementation manner

[0022] The composite material is composed of fibers and resin. The resin dissolves small molecule substances such as water, solvents used in the prepreg manufacturing process, and by-products generated by the prepreg curing reaction. During the manufacturing process of composite parts, the resin and fibers jointly bear the curing pressure. When the pressure borne by the resin is large, the small molecule substances remain in the dissolved state in the resin and the volatilization amount is small. When the pressure borne by the resin is small, some small molecule substances volatilize from the dissolved state into gas, and the volatilization amount increases, forming micropores inside the composite part. Therefore, the actual curing pressure borne by the resin affects the physical state of the small molecule substances dissolved in the resin, and further affects the porosity of the composite part.

[0023] During curing, if the resin completely fills and wraps the fibers, the fibers and the resin jointly bear the curing pressure, and the small molecule substances mainly remain in the dissolved state in the resin, with a small volatilization amount, and the porosity of the composite part is low.

[0024] During curing, if the resin cannot completely fill and wrap the fibers, the fibers mainly bear the curing pressure, the resin bears less pressure, and some small molecule substances dissolved in the resin volatilize from the dissolved state into gas, forming micropores, and the porosity of the composite part increases.

[0025] This application uses the height and structure of the thickness control block, as well as the glue absorption material, to adjust the force-bearing state of the resin during the curing process and control the state of the small molecule substances dissolved in the resin, so as to achieve the goal of adjusting the porosity.

[0026] When the height of the thickness control block is 2 - 3 layer ply theoretical thickness smaller than the theoretical thickness of the sample, the uniform pressing plate fully compacts on the blank. During the curing process, the resin is oppressed and cannot flow out. The resin fills and wraps the fibers. The resin and the fibers jointly bear the pressure, and the small molecule substances mainly remain in the dissolved state in the resin, with less volatilization, and the porosity is low.

[0027] When the height of the thickness control block is 0 - 2 layer ply theoretical thickness smaller than the theoretical thickness of the sample, and there is a glue overflow groove at the bottom of the thickness control block. During curing, part of the resin flows out from the glue overflow groove, the total amount of resin in the sample blank decreases, and the resin cannot completely fill and wrap the fibers. The uniform pressing plate mainly compacts on the fibers, and the resin bears less pressure. Some small molecule substances volatilize from the resin into gas, causing micropores, and the porosity of the sample increases.

[0028] When the height of the thickness control block is at least one layer of prepreg theoretical thickness greater than the theoretical thickness of the specimen, and absorbent material is placed in the overflow groove at the bottom of the thickness control block. During curing, the absorbent material induces a large amount of resin to flow out, and the resin cannot fill and wrap the fibers. The uniform pressing plate mainly compacts the fibers, the pressure on the resin is further reduced, small molecule substances further volatilize from the dissolved state in the resin and become gases, and the micropores further increase, and the porosity of the specimen further increases.

[0029] This device breaks through the convention in the industry that the outer contour size of the uniform pressing plate should be smaller than the blank of the specimen. By using a large-size uniform pressing plate in combination with thickness control blocks of different thicknesses and structures, the stress states of the fibers and resin in the prepreg during the curing process are adjusted.

[0030] Example 1, a specimen with a porosity < 1%.

[0031] As Figures 1 to 2 shown, taking the production of a specimen with a target porosity < 1% as an example, a manufacturing device for a specimen with a certain porosity includes a tooling main body 1, a thickness control block 2, and a uniform pressing plate 4. The specimen is laid on the tooling main body 1, and the thickness control block 2 is placed around the specimen blank 3. It is characterized in that the uniform pressing plate 4 is placed on the specimen blank 3 and the thickness control block 2. The outer dimension of the specimen blank is 500mm × 500mm, the overall outer dimension of the specimen blank plus the surrounding thickness control blocks is 600mm × 600mm, and the outer dimension of the uniform pressing plate is 600mm × 600mm. The specimen is 2mm thick, the single layer thickness of the prepreg is 0.2mm, and the height of the thickness control block is 1.6mm.

[0032] A manufacturing method for a specimen with a certain porosity is characterized by including the following steps:

[0033] 1 Lay the specimen blank 3 on the upper surface of the tooling main body 1;

[0034] 2 Cut the four sides of the specimen blank 3 to be flush;

[0035] 3 Place the thickness control block 2 around the specimen blank 3;

[0036] 4 Check the fitting condition between the specimen blank 3 and the thickness control block 2, and fill the gap with the same material as the specimen blank 3;

[0037] 5 Place the uniform pressing plate, and place the four sides of the uniform pressing plate on the thickness control blocks around the specimen blank;

[0038] 6 Make a bag and cure;

[0039] 7 Calibrate the actual porosity.

[0040] Example 2, a specimen with a porosity of 1% - 2%.

[0041] As Figures 1 to 2As shown, taking the production of a specimen with a target porosity of 1% - 2% as an example, a manufacturing device for a porosity specimen includes a tooling main body 1, a thickness control block 2, and a uniform pressing plate 4. The specimen is laid on the tooling main body 1, and the thickness control block 2 is placed closely around the specimen blank 3. It is characterized in that the uniform pressing plate 4 is placed on the specimen blank 3 and the thickness control block 2. The outer dimension of the specimen blank is 500 mm × 500 mm, the overall outer dimension of the specimen blank plus the surrounding thickness control blocks is 600 mm × 600 mm, and the outer dimension of the uniform pressing plate is 550 mm × 550 mm. The specimen is 2 mm thick, the thickness of a single layer of prepreg is 0.1 mm, and the height of the thickness control block is 1.9 mm. A glue overflow groove 5 is provided at the bottom of the thickness control block 2.

[0042] A manufacturing method for a porosity specimen is characterized by comprising the following steps:

[0043] 1 Lay the specimen blank 3 on the upper surface of the tooling main body 1;

[0044] 2 Cut the four sides of the specimen blank 3 to be flush;

[0045] 3 Place the thickness control blocks 2 around the specimen blank 3;

[0046] 4 Check the fitting condition between the specimen blank 3 and the thickness control blocks 2, and fill the gaps with the same material as the specimen blank 3;

[0047] 5 Place the uniform pressing plate, and place the four sides of the uniform pressing plate on the thickness control blocks around the specimen blank;

[0048] 6 Make a bag and cure;

[0049] 7 Calibrate the actual porosity.

[0050] Example 3, a specimen with a porosity > 2%.

[0051] As Figures 1 to 2 As shown, taking the production of a specimen with a target porosity > 2% as an example, a manufacturing device for a porosity specimen includes a tooling main body 1, a thickness control block 2, and a uniform pressing plate 4. The specimen is laid on the tooling main body 1, and the thickness control block 2 is placed closely around the specimen blank 3. It is characterized in that the uniform pressing plate 4 is placed on the specimen blank 3 and the thickness control block 2. The outer dimension of the specimen blank is 500 mm × 500 mm, the overall outer dimension of the specimen blank plus the surrounding thickness control blocks is 600 mm × 600 mm, and the outer dimension of the uniform pressing plate is 520 mm × 520 mm. The specimen is 2 mm thick, the thickness of a single layer of prepreg is 0.1 mm, and the height of the thickness control block is 2.1 mm. A glue overflow groove 5 is provided at the bottom of the thickness control block 2, and a glue absorption material 6 is placed in the glue overflow groove 5. The glue absorption material 6 can be dry glass cloth or breathable fabric.

[0052] A manufacturing method for a porosity specimen is characterized by comprising the following steps:

[0053] 1 Lay the sample blank 3 on the upper surface of the tooling body 1;

[0054] 2 Cut the four sides of the sample blank 3 to be flush;

[0055] 3 Place the thickness control blocks 2 around the sample blank 3;

[0056] 4 Check the fitting condition between the sample blank 3 and the thickness control blocks 2. At the gaps, fill with the same material as the sample blank 3;

[0057] 5 Place the glue absorption material 6 in the glue overflow groove 5 at the bottom of the thickness control blocks 2;

[0058] 6 Place the even pressure plate. The four sides of the even pressure plate are placed on the thickness control blocks around the sample blank;

[0059] 7 Make a bag and cure;

[0060] 8 Calibrate the actual porosity.

Claims

1. A manufacturing device for a porosity specimen, comprising a tooling main body, a thickness control block, and a uniform pressing plate. The specimen is laid on the tooling main body, and the thickness control block is placed adjacent to the periphery of the specimen blank. It is characterized in that The uniform pressure plate is placed on the sample blank and the thickness control blocks. The outer dimensions of the uniform pressure plate are larger than those of the sample blank, and the outer dimensions of the uniform pressure plate are smaller than the overall outer dimensions of the sample blank plus the surrounding thickness control blocks. The height and structure of the thickness control blocks are set according to the target porosity. When the target porosity < 1%, the height of the thickness control blocks is 2 - 3 layers of the theoretical thickness of the ply smaller than the theoretical thickness of the sample. When the target porosity is 1% - 2%, the height of the thickness control blocks is 0 - 2 layers of the theoretical thickness of the ply smaller than the theoretical thickness of the sample and an overflow groove is provided at the bottom of the thickness control blocks. When the target porosity > 2%, the height of the thickness control blocks is at least 1 layer of the theoretical thickness of the ply larger than the theoretical thickness of the sample and an overflow groove is provided at the bottom of the thickness control blocks. An absorbent material is placed in the overflow groove. The absorbent material is dry glass cloth or breathable fabric. During curing, the absorbent material induces a large amount of resin to flow out.

2. A method for manufacturing a porosity specimen using the manufacturing apparatus for a porosity specimen according to claim 1, characterized in that It includes the following steps: 2 - 1 Lay the sample blank on the upper surface of the tooling body; 2 - 2 Cut the four sides of the sample blank to be flush; 2 - 3 Determine the height and structure of the thickness control blocks according to the target porosity and place them around the sample blank; 2 - 4 Check the fitting condition between the sample blank and the thickness control blocks. At the gaps, fill with the same material as the sample blank; 2 - 5 When the target porosity > 2%, the height of the thickness control blocks is at least 1 layer of the theoretical thickness of the ply larger than the theoretical thickness of the sample and an overflow groove is provided at the bottom of the thickness control blocks. An absorbent material is placed in the overflow groove. The absorbent material is dry glass cloth or breathable fabric. During curing, the absorbent material induces a large amount of resin to flow out; 2 - 6 Place the uniform pressure plate. The four sides of the uniform pressure plate are placed on the thickness control blocks around the sample blank; 2 - 7 Make a bag and cure; 2 - 8 Calibrate the actual porosity of the sample.

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