Large-curvature T-shaped rib paving mold for autoclave-vacuum bag method forming, preparation method and preparation method of large-curvature T-shaped rib

Abstract

The invention discloses a large-curvature T-shaped rib paving mold for forming by an autoclave-vacuum bag method in the technical field of composite products, which comprises a first L mold, a second L mold and a bottom mold, L-shaped paving surfaces are arranged on the surfaces of the first L mold and the second L mold, and a T-shaped paving surface is formed after the first L mold, the second L mold and the bottom mold are assembled. The T-shaped paving surface comprises a vertical paving surface and a horizontal paving surface, and is characterized in that the first L mold, the second L mold and the bottom mold comprise large-curvature bent sections connected with the two straight sections in the length direction of the first L mold, the second L mold and the bottom mold, a notch is machined in the position, located on the horizontal paving surface, of the large-curvature bent section of the first L mold, and the notch is filled with a shape follow-up soft mold. The problems of wrinkles, abnormal model attaching degree and abnormal internal quality are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material preparation, in particular to a paving mould. Background Art

[0002] The large curvature T-shaped ribs in the prior art are as follows Figure 6-7 As shown, it includes the web surface A and the edge surface B. The existing large curvature T-shaped rib forming tooling is composed of a double L mold + base plate tooling. If these three are used to combine and enter the tank for curing at the same time, there will be expansion interference on both sides of the base plate R zone during the curing process, resulting in insufficient pressure or no pressure in the R zone, and the R zone of the molded part is rich in resin or wrinkled in the R zone, resulting in defects both inside and outside, and the part is scrapped; if the L mold + base plate + soft mold is used to enter the tank for curing, for parts with conventional curvature or large curvature, it can be regarded as the most in line with the technical requirements of the parts, and it is also the molding method that can best meet the internal and external quality of the parts. However, for parts with large curvature, the combination of these three will cause the bottom plate to be damaged during the curing process. Expansion interference occurs between the plate and the two sides of the R zone, resulting in uneven pressure on the R zone or an inability to bear pressure, defects in the internal and external quality of the part, and scrapping of the part; if a double L-die is used without a base plate, the double L-die expands and the R zone has no base plate support, resulting in abnormal mold fit of the formed part, resulting in scrapping, and the part cannot be used in secondary bonding; the above three methods are tooling made of conventional ordinary steel Q235 material. In the process, tooling made of Yingwa steel 4J36 with smaller deformation is used, and the above problems still occur. The structure of the part determines that the conventional tooling design method can no longer meet the production requirements of parts with complex curvatures. To this end, this patent proposes a more cost-effective tooling production method that can meet the production requirements with ordinary steel materials, solving the pain points of forming T-shaped ribs with large curvature. Summary of the Invention

[0003] In response to the deficiencies in the prior art, the present invention provides a large-curvature T-shaped rib paving mold, a preparation method, and a large-curvature T-shaped rib preparation method for autoclave-vacuum bag molding, which solves the problem that the R zone molding of the existing large-curvature T-shaped rib does not meet the requirements.

[0004] The object of the present invention is achieved as follows: a large curvature T-shaped rib paving mold for autoclave-vacuum bag molding, comprising a first L-mold, a second L-mold and a bottom mold, wherein the surfaces of the first L-mold and the second L-mold are provided with an L-shaped paving surface, and a T-shaped paving surface is formed between the first L-mold, the second L-mold and the bottom mold after the mold is closed, and the T-shaped paving surface includes a vertical paving surface and a horizontal paving surface, and is characterized in that the first L-mold, the second L-mold and the bottom mold include a large curvature bent section connecting two straight sections along their length direction, wherein a notch is processed in the large curvature bent section of the first L-mold at the position of the horizontal paving surface, and the notch is filled with a conformable soft mold.

[0005] Furthermore, the cross section of the bottom mold is L-shaped, including a stacking bottom surface and a sliding side surface, the sliding side surface is provided with a sliding groove, and a sliding rail is provided in the sliding groove.

[0006] A method for manufacturing a large-curvature T-shaped rib paving mold for autoclave-vacuum bag molding, comprising the following steps: Step 1) making a conformable stopper, wherein the surface of the conformable stopper is processed into a curved surface corresponding to the notch of the large curvature bend; Step 2) Place the conformal stopper in the notch of the first L-mold and lay a rubber sheet in the notch, with the height of the rubber sheet slightly higher than the tooling surface; Step 3) Assemble with non-porous isolation film + porous isolation film + breathable felt + vacuum bag; send into autoclave for curing; Step 4) Remove the conformal stopper and auxiliary materials, retain the soft mold on the tooling, and remove surface residues to ensure that the soft mold surface is smooth and flat, thus obtaining the first L mold with the soft mold.

[0007] A method for preparing a large curvature T-shaped rib, using the above-mentioned paving mold, comprises the following steps: 1) Preparation: Clean the mold, prepare carbon fiber prepreg, and lay out and cut according to the cutting drawing; 2) Laying: Start laying from the edge strip surface to ensure that no fracture occurs on the edge strip surface. Lay according to the laying angle, from the center to both sides, from the edge strip surface to the web area, compact and squeeze out the laying gas. Perform vacuum pre-compaction every 1-4 layers; 3) Twisting: Cut out the sheet that meets the core material size according to the requirements, coil the wire, press the two sides into shape on the tooling, and heat seal and press; 4) Mold closing: Close the first L-shaped mold and the second L-shaped mold, fill the R area with filaments to ensure that the top of the R area is completely filled, then place the core material in the R area. After placing the core material, make sure that the core material is slightly higher than the double L-shaped blank. Then place a non-porous isolation film slightly wider than the core material in the core material area and perform heat sealing and pressing. 5) Floor laying: Check the core material condition after it comes out of the can, trim it until the core material is flush with the blank, lay the bottom plate sheets, and vacuum compact them; 6) Mold closing and assembly: Check the soft mold, twist the soft mold, and check whether the R area can be pressed. Use rubber strips to block the glue during assembly, and use pressure-sensitive tape to connect the block strips and the blank. The pressure-sensitive tape slightly overlaps the blank, and the bottom mold is placed. During installation, operate the bottom mold to slide in with the slide rail to complete the bottom mold closing and assembly; 7) Curing and demoulding: Send it into the autoclave for curing. After curing, demould it to obtain T-shaped ribs with large curvature.

[0008] Compared with the prior art, the present invention has the following beneficial effects: the present invention effectively solves the problems of resin-rich R zone, wrinkles, abnormal mold adhesion and abnormal internal quality after molding, and improves the product qualification rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0010] Figure 1 Schematic diagram of the paving mold structure in the present invention Figure 1 .

[0011] Figure 2 Schematic diagram of the paving mold structure in the present invention Figure 2 .

[0012] Figure 3 Schematic diagram of the cooperation between the first L-mold and the conformal stopper in the present invention.

[0013] Figure 4 Schematic diagram of the second L-mode structure in the present invention.

[0014] Figure 5 This is a schematic diagram of the cooperation between the bottom mold and the slide rail in the present invention.

[0015] Figure 6 Schematic diagram of a large curvature T-shaped rib in the prior art Figure 1 .

[0016] Figure 7 Schematic diagram of a large curvature T-shaped rib in the prior art Figure 2 .

[0017] Figure 8 Schematic diagram of the deformation trend of the bottom mold relative to the first L mold during curing of the present invention Figure 1 .

[0018] Figure 9 Schematic diagram of the deformation trend of the bottom mold relative to the first L mold during curing of the present invention Figure 2 .

[0019] Among them, 100 is the first L mold, 101 is the notch, 200 is the second L mold, 300 is the bottom mold, 301 is the slide groove, 400 is the slide rail, 500 is the form-fitting soft mold, and 600 is the form-fitting stopper. DETAILED DESCRIPTION

[0020] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Example 1 like Figure 1-5 The shown embodiment shows a large curvature T-shaped rib paving mold for autoclave-vacuum bag molding, comprising a first L-mold, a second L-mold and a bottom mold. The surfaces of the first L-mold and the second L-mold are provided with L-shaped paving surfaces. After the first L-mold, the second L-mold and the bottom mold are combined, a T-shaped paving surface is formed between them. The T-shaped paving surface includes a vertical paving surface and a horizontal paving surface. The first L-mold, the second L-mold and the bottom mold include a large curvature curved section connecting two straight sections along their length direction. A notch is processed in the large curvature curved section of the first L-mold at the position of the horizontal paving surface, and the notch is filled with a conformable soft mold made of rubber.

[0022] Specifically, the first L mold, the second L mold and the bottom mold are all metal molds. L-shaped blanks can be obtained by stacking along the L-shaped paving surface, and a T-shaped paving surface will be formed after the mold is closed; the vertical paving surface and the horizontal paving surface are defined horizontally and vertically based on the T-shape.

[0023] The principle of using a conformal soft mold to remove the gap is explained below.

[0024] First, the existing mold adopts an integral structure, and the R area with large curvature is not replaced by a conformable soft mold. After the sheet is laid, it is sent to the autoclave for curing. During the curing process, the sheet and the mold will expand due to the temperature increase. Under the same heating conditions, the deformation trend of the large curvature R area is the most obvious, squeezing the bottom mold, causing it to shift outward. The gap in the R area will be larger than that in the two side areas, resulting in a larger gap between the bottom mold in the R area and the first L mold relative to the two sides, which leads to problems such as fat enrichment and wrinkles. Figure 8-9 As shown, Figure 8 Before deformation, Figure 9 After deformation, it should be noted that, in order to illustrate the deformation trend, the deformation during actual operation will not be as large as the trend in the figure; the present invention solves the existing problem by cutting off the original R area and replacing it with a conformable soft mold. Due to the soft and elastic properties of the conformable soft mold itself, the R area of the bottom mold will not be over-extruded when expansion occurs, and the deformation effect is small.

[0025] Furthermore, the cross section of the bottom mold is L-shaped, including a stacking bottom surface and a sliding side surface, a sliding groove is provided on the sliding side surface, and a sliding rail is provided in the sliding groove.

[0026] Specifically, the slide rail is fixed on the profile, and the bottom mold is slidably arranged through the slide groove.

[0027] It should be noted that such a design can make the sliding operation of the bottom mold more stable, thereby ensuring that the pressure exerted by the bottom mold when in contact with the blank is more balanced.

[0028] Example 2 A method for manufacturing a large-curvature T-shaped rib paving mold for autoclave-vacuum bag molding, comprising the following steps: Step 1) making a conformable stopper, wherein the surface of the conformable insert is processed into a curved surface corresponding to the notch of the large curvature bend; Step 2) Place the follow-up block in the notch of the first L-mold, refer to Figure 3 , cut the appropriate number of layers of rubber sheets according to the size of the gap in the soft mold of the forming mold, and fill the gap with rubber sheets layer by layer. The height of the rubber sheets should be slightly higher than the tooling surface by 3-5mm; Step 3) Assemble the film using a non-porous separator, a porous separator, a breathable felt, and a vacuum bag; place the film in an autoclave for curing, using curing parameters similar to those of existing rubber sheet molding processes. Step 4) Remove the conformal stopper and auxiliary materials, retain the soft mold on the tooling, and remove surface residues to ensure that the soft mold surface is smooth and flat, thus obtaining the first L mold with the soft mold.

[0029] Example 3 A method for preparing a large curvature T-shaped rib, using the above-mentioned paving mold, comprises the following steps: Step 1) Preparation: Before layup, clean the mold's paving surface with absorbent cotton (or paper) dipped in acetone until the gauze is completely discolored. Allow to air-dry at room temperature for at least 15 minutes. Then, treat the paving surface with a release agent at least three times. Once dry, lay the material. Obtain qualified carbon fiber prepreg, etc., remove it from the cold storage in advance and allow it to sit at room temperature for at least 12 hours. Before use, inspect the material's certificate of conformity, re-verification certificate, and validity period. Ensure the bag is free of moisture before opening. Lay out the material according to the cutting diagram, and arrange the pieces to ensure the angle and quantity meet the layup requirements.

[0030] Step 2) Laying: Start laying from the edge strip surface, ensuring that no fracture appears on the edge strip surface. Lay according to the laying angle, from the middle to both sides, from the edge strip surface to the web area, compact, squeeze out the stacking gas, and perform vacuum pre-compaction every 1-4 layers.

[0031] Step 3) Twisting: Cut out the sheet that meets the core material size as required, coil the wire, press out the two-sided shape on the core material tooling, assemble it, use the cover plate + porous isolation film + breathable felt + vacuum bag, and execute according to the core material heat sealing and pressing parameters.

[0032] Step 4) Mold closing and assembly: Close the first L mold and the second L mold, making sure there is no offset and the bottom surfaces are on the same horizontal plane. Then fill the R area with 2mm, 3mm, 5mm, 7mm, and 10mm wire to ensure that the top of the R area is completely filled. Then place the core material in the R area. The core material is slightly higher than the blank, with a slight shake. Use an iron to flatten it. The core material is slightly higher than the blank by 1-2mm. Place the bottom plate tooling and use two layers of porous isolation film + breathable felt + vacuum bag for assembly. Execute according to the existing core material heat sealing and pressing parameters.

[0033] Step 5) Bottom plate laying: Check the core material condition after taking out the can, trim it until the core material is flush with the blank, lay the bottom plate sheet, and vacuum compact it.

[0034] Step 6) Mold assembly: Check the soft mold, twist the soft mold, and check whether the R area can be pressed (if the R area is too hard, the soft mold needs to be remade). Use rubber strips to block the glue during assembly, and use pressure-sensitive tape to connect the block strips and the blank. The pressure-sensitive tape overlaps the blank by 0.5-1mm. Place the bottom plate tooling and use two layers of porous isolation film + breathable felt + vacuum bag for assembly.

[0035] Step 7) Autoclave curing: Check the vacuum bag for air leakage, execute the autoclave curing procedure according to the material parameters, remove the auxiliary materials after curing, and mark the parts with the drawing number.

[0036] Step 8) Follow the corresponding process files and perform cutting and tolerance control according to the part line.

[0037] Step 9) Non-destructive testing: Acceptance is carried out according to the corresponding technical conditions.

[0038] Step 10) Inspection: Use qualified instruments and compliant operations to measure thickness and weigh parts, check the appearance quality of parts, organize documents and fill in part notes.

[0039] Step 11) Inspection of furnace parts: Conduct mechanical property tests on furnace parts according to corresponding technical conditions to determine the eligibility of furnace parts.

[0040] Step 12) Final Inspection: The production process of the parts is recorded completely and clearly, and the appearance is checked according to the technical requirements; non-destructive testing; performance testing of the furnace parts; weighing; thickness measurement. The surface quality and appearance meet the acceptance standards and manufacturing outline requirements.

[0041] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A large curvature T-shaped rib paving mold for autoclave-vacuum bag molding, comprising a first L-mold, a second L-mold, and a bottom mold, wherein the surfaces of the first L-mold and the second L-mold are provided with L-shaped paving surfaces, and a T-shaped paving surface is formed between the first L-mold, the second L-mold, and the bottom mold after being combined, wherein the T-shaped paving surface comprises a vertical paving surface and a horizontal paving surface, characterized in that: The first L mold, the second L mold and the bottom mold include a large curvature curved section connecting two straight sections along their length direction, wherein the large curvature curved section of the first L mold is processed with a notch at the horizontal paving surface position, and the notch is filled with a conformable soft mold.

2. The large curvature T-shaped rib laying mold for autoclave-vacuum bag molding according to claim 1, characterized in that: The cross section of the bottom mold is L-shaped, comprising a stacking bottom surface and a sliding side surface. The sliding side surface is provided with a sliding groove, and a sliding rail is provided in the sliding groove.

3. A method for manufacturing a large curvature T-shaped rib paving mold for autoclave-vacuum bag molding according to claim 1 or 2, characterized in that: The following steps are involved: Step 1) making a conformable stopper, wherein the surface of the conformable stopper is processed into a curved surface corresponding to the notch of the large curvature bend; Step 2) Place the conformal stopper in the notch of the first L-mold and lay a rubber sheet in the notch, with the height of the rubber sheet slightly higher than the tooling surface; Step 3) Assemble with non-porous isolation film + porous isolation film + breathable felt + vacuum bag; send into autoclave for curing; Step 4) Remove the conformal stopper and auxiliary materials, retain the soft mold on the tooling, and remove surface residues to ensure that the soft mold surface is smooth and flat, thus obtaining the first L mold with the soft mold.

4. A method for preparing a large curvature T-shaped rib, characterized in that: The paving mold according to any one of claims 1 to 3 is used, comprising the following steps: 1) Preparation: Clean the mold, prepare carbon fiber prepreg, and lay out and cut according to the cutting drawing; 2) Laying: Start laying from the edge strip surface to ensure that no fracture occurs on the edge strip surface. Lay according to the laying angle, from the center to both sides, from the edge strip surface to the web area, compact and squeeze out the laying gas. Perform vacuum pre-compaction every 1-4 layers; 3) Twisting: Cut out the sheet that meets the core material size according to the requirements, coil the wire, press the two sides into shape on the tooling, and heat seal and press; 4) Mold closing: Close the first L-shaped mold and the second L-shaped mold, fill the R area with filaments to ensure that the top of the R area is completely filled, then place the core material in the R area. After placing the core material, make sure that the core material is slightly higher than the double L-shaped blank. Then place a non-porous isolation film slightly wider than the core material in the core material area and perform heat sealing and pressing. 5) Floor laying: Check the core material condition after it comes out of the can, trim it until the core material is flush with the blank, lay the bottom plate sheets, and vacuum compact them; 6) Mold closing and assembly: Check the soft mold, twist the soft mold, and check whether the R area can be pressed. Use rubber strips to block the glue during assembly, and use pressure-sensitive tape to connect the block strips and the blank. The pressure-sensitive tape slightly overlaps the blank, and the bottom mold is placed. During installation, operate the bottom mold to slide in with the slide rail to complete the bottom mold closing and assembly; 7) Curing and demoulding: Send it into the autoclave for curing. After curing, demould it to obtain T-shaped ribs with large curvature.

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