Thermal forming tool and thermal forming method for thin-wall structural part and composite material

Abstract

The invention relates to a thermal forming tool and method for a thin-wall structural part and a composite material, in particular to the field of thermal forming, and the thermal forming tool for the thin-wall structural part and the composite material comprises a female die and a sub die which are matched in a nested mode; a thermal conversion material is arranged between the female die and the workpiece to be formed; the thermal conversion material is converted from a flexible material to a rigid material along with temperature rise. According to the thermal forming tool provided by the invention, hard contact between the to-be-formed workpiece and the female die in the thermal forming process is avoided by virtue of the specific thermal conversion material, and a certain buffering and supporting effect is achieved, so that the defects of large deformation and damage of the thin-wall structural part in the thermal forming process are avoided, and a product subjected to thermal forming can still be reasonably used.

Description

Technical Field

[0001] The present invention relates to the field of thermoforming, and in particular to a thermoforming tool and a thermoforming method for thin-walled structural parts and composite materials, and in particular to a thermoforming tool and a thermoforming method for special-shaped thin-walled structural parts and composite materials. Background Art

[0002] With the development of aerospace technology, the requirements for lightweight thermal stability, mechanical properties and other aspects of related components in aircraft are becoming higher and higher. At present, high-performance materials such as resin, carbon fiber and other materials are used to replace some metal parts to ensure the performance of related components, thereby achieving the purpose of lightweighting, such as the molding of the insulation layer of the engine head.

[0003] For example, CN112497587A discloses a method for forming a fiber-wound engine head insulation layer, in which the bottom layer is individually molded and formed as a whole, the bottom layer is placed in a molding mold, and then adhesive is brushed on the bottom layer and in the area above the crack stop point, i.e., the bonding area with the cover layer, and allowed to dry, and an insulation layer film is pasted on the adhesive-coated area of ​​the bottom layer according to the thickness and profile of the cover layer. Before pasting, an adhesive is brushed on the surface of the insulation layer film and allowed to dry, and after the covering layer insulation layer film is pasted, the whole is molded, and then the molding mold is placed on a flat vulcanizer for vulcanization.

[0004] However, currently, special-shaped thin-walled structural parts need to withstand large axial and radial loads during the process of integrated thermoforming with composite materials, which causes the special-shaped thin-walled structural parts to be prone to large deformation and damage during the forming process, rendering the product unusable. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a hot forming tool for thin-walled structural parts and composite materials, so as to solve the problem that special-shaped thin-walled structural parts need to bear large axial and radial loads during the hot forming process with composite materials, which causes the special-shaped thin-walled structural parts to be prone to large deformation and damage during the forming process.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a thermoforming tool for thin-walled structural parts and composite materials, the thermoforming tool for thin-walled structural parts and composite materials comprising:

[0008] Nested master and daughter molds;

[0009] A thermal transition material is disposed between the master mold and the workpiece to be formed;

[0010] The thermal transition material includes: a flexible material that changes into a rigid material as the temperature increases.

[0011] The thermoforming tooling provided by the present invention avoids hard contact between the workpiece to be formed and the mother mold during the thermoforming process by using specific heat transition materials, plays a certain buffering and supporting role, thereby ensuring that thin-walled structural parts do not have defects of large deformation and damage during the thermoforming process, and ensuring that the products after thermoforming can still be used reasonably.

[0012] As a preferred technical solution of the present invention, the mother mold and the daughter mold are connected by a connecting piece.

[0013] As a preferred technical solution of the present invention, the master mold includes an upper mold and a lower mold.

[0014] As a preferred technical solution of the present invention, the upper die and the lower die are provided with a positioning matching structure and are connected via a guide positioning shaft.

[0015] As a preferred technical solution of the present invention, the transformation temperature of the thermal transition material from a flexible material to a rigid material is 80-120°C.

[0016] As a preferred technical solution of the present invention, the material of the master mold includes high-strength steel or mold steel.

[0017] As a preferred technical solution of the present invention, the material of the sub-mold includes high-strength steel or mold steel.

[0018] As a preferred technical solution of the present invention, the material of the thermal transition material includes foam material or rubber material.

[0019] As a preferred technical solution of the present invention, the thickness of the thermal transition material is ≤1 mm.

[0020] In a second aspect, the present invention provides a method for thermoforming a thin-walled structural part and a composite material, the method comprising: assembling a workpiece to be formed with a thermoforming tool and then performing thermoforming;

[0021] A heat-transforming material is arranged between the workpiece to be formed and the mother mold of the thermoforming tooling;

[0022] The thermal transition material includes: a flexible material that changes into a rigid material as the temperature increases.

[0023] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0024] The present invention provides a thermoforming tool for thin-walled structural parts and composite materials. By configuring a specific thermal transition material in the thermoforming tool, the thin-walled structural parts can be matched with the pressure of the hot pressing process as the temperature changes during the thermoforming process, thereby avoiding deformation of the thin-walled structural parts during the forming process. The radial deformation of the thin-walled structural parts after thermoforming is less than 0.5 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of a thermoforming tooling for thin-walled structural parts and composite materials provided by an embodiment of the present invention.

[0026] In the figure: 110 - upper die, 120 - lower die, 130 - guide and positioning shaft, 200 - sub-die, 300 - thermal transition material, 400 - thin-walled structural part.

[0027] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0028] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0029] This embodiment provides a thermoforming tool for thin-walled structural parts and composite materials, such as Figure 1 As shown, the hot forming tooling of the thin-walled structural parts and composite materials includes:

[0030] Nested matching mother mold and daughter mold 200;

[0031] A thermal transition material 300 is disposed between the master mold and the workpiece to be molded;

[0032] The thermal transition material 300 includes a flexible material that changes into a rigid material as the temperature increases.

[0033] In the present invention, the thin-walled structural member 400 refers to a member with a wall thickness of less than 2.5 mm.

[0034] In the present invention, the composite material refers to composite materials commonly used in the art such as phenolic prepreg and rubber-based composite materials connected with metals.

[0035] In the present invention, hot forming refers to diffusion bonding the thin-walled structural member 400 and the composite material.

[0036] In the present invention, the workpiece to be formed is arranged between the mother mold and the sub-mold 200 during the thermoforming process, and then the thermal transition material 300 is arranged between the mother mold and the workpiece to be formed.

[0037] In the present invention, the mother mold refers to the mold that contacts the outer wall of the product to be molded, or is responsible for forming the outer contour of the product, or the outer frame or cavity of the mold.

[0038] In the present invention, the sub-mold 200 refers to a mold that contacts the inner wall of the product to be molded, or is responsible for shaping the internal shape of the product, or is the inner cavity or core of the mold.

[0039] In the present invention, the shapes of the sub-mold 200 and the mother mold can be reasonably designed according to the requirements of the molded product.

[0040] Wherein, the mother mold and the daughter mold 200 are connected via a connecting piece.

[0041] In the present invention, the connection between the mother mold and the sub-mold 200 is positioned and fixedly connected by connecting members such as bolts, pins and the like to ensure efficient and stable connection between the mother mold and the sub-mold 200.

[0042] The mother mold includes an upper mold 110 and a lower mold 120 .

[0043] The upper die 110 and the lower die 120 are provided with a positioning and matching structure and are connected via a guide positioning shaft 130 .

[0044] In the present invention, the positioning and matching structure used refers to a structure that can position and connect the upper mold 110 and the lower mold 120 to avoid unreasonable assembly due to misalignment, such as using a concave-convex matching structure to achieve positioning and matching, or using positioning parts and other components to achieve positioning and matching. For example, the positioning parts have different matching structures with the upper mold 110 and the lower mold 120, and positioning and matching is achieved through a specific matching structure.

[0045] The conversion temperature of the thermal transition material 300 from a flexible material to a rigid material is 80-120°C, for example, 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, 92°C, 94°C, 96°C, 98°C, 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C or 120°C, etc., but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0046] Wherein, the material of the master mold includes high-strength steel or mold steel.

[0047] The material of the sub-mold 200 includes high-strength steel or mold steel.

[0048] Exemplarily, the high-strength steel used includes: 30CrMnSiA, D406 and other steel materials commonly used as raw materials for molds in the art.

[0049] Exemplarily, the mold steel used includes: 40Cr, 42Cr, 42CrMo and the like which are used as steel materials for mold raw materials.

[0050] The thermal conversion material 300 is made of foam material or rubber material.

[0051] For example, the thermal conversion material 300 may be a commercially available polymethacrylimide foam material, or a polymethacrylimide foam material prepared according to the prior art and meeting the definition of the present invention.

[0052] Exemplarily, the thermal transition material 300 used can be selected from commercially available nitrile rubber and chloroprene rubber materials, or modified nitrile rubber and modified chloroprene rubber materials prepared according to the prior art and meeting the requirements of the present invention.

[0053] The thickness of the thermal transition material 300 is ≤1 mm, for example, it can be 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm or 0.1 mm, but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0054] In the present invention, the thermoforming tooling and the thin-walled structural member 400 may be positioned and connected by bolts, pins, etc., so as to ensure that the cavities between the two are evenly distributed, and further ensure that the thermal transition material 300 is evenly distributed between the two.

[0055] Furthermore, the present embodiment provides a method for thermoforming thin-walled structural parts and composite materials, which can be implemented based on the aforementioned thermoforming tooling, and specifically includes: assembling the workpiece to be formed with the thermoforming tooling and then thermoforming;

[0056] A thermal transition material 300 is provided between the workpiece to be formed and the mother mold of the thermoforming tooling;

[0057] The thermal transition material 300 includes a flexible material that changes into a rigid material as the temperature increases.

[0058] In the present invention, the parameters such as pressure and temperature that need to be controlled during the hot forming process are designed based on the conventional requirements in the field and the requirements of the workpiece to be formed, and have no necessary connection with the tooling structure of the present invention.

[0059] Further, in order to illustrate the good forming effect that can be achieved by the thermoforming tooling of thin-walled structural parts and composite materials provided by the present invention, the following actual examples are used for illustration, as follows:

[0060] Example 1

[0061] This embodiment provides a thermoforming tool for thin-walled structural parts and composite materials, including:

[0062] Nested master and daughter molds;

[0063] A thermal transition material is disposed between the master mold and the workpiece to be molded (with a wall thickness of 2 mm);

[0064] The thermal transition material includes: a flexible material that changes into a rigid material as the temperature increases;

[0065] The master mold and the daughter mold are connected by a connecting piece;

[0066] The master mold comprises an upper mold and a lower mold;

[0067] The upper die and the lower die are provided with a positioning matching structure and are connected via a guide positioning shaft;

[0068] The transformation temperature of the thermal transition material from a flexible material to a rigid material is 90°C; the thickness of the thermal transition material is 0.5 mm; the material of the thermal transition material is polymethacrylimide foaming material;

[0069] The material of the master mold is 30CrMnSiA; the material of the sub-mold is 30CrMnSiA.

[0070] Example 2

[0071] This embodiment provides a thermoforming tool for thin-walled structural parts and composite materials, including:

[0072] Nested master and daughter molds;

[0073] A thermal transition material is arranged between the master mold and the workpiece to be molded (with a wall thickness of 1 mm);

[0074] The thermal transition material includes: a flexible material that changes into a rigid material as the temperature increases;

[0075] The master mold and the daughter mold are connected by a connecting piece;

[0076] The master mold comprises an upper mold and a lower mold;

[0077] The upper die and the lower die are provided with a positioning matching structure and are connected via a guide positioning shaft;

[0078] The transformation temperature of the thermal transition material from a flexible material to a rigid material is 120°C; the thickness of the thermal transition material is 0.11mm; the material of the thermal transition material is nitrile rubber material;

[0079] The material of the master mold is 42CrMo; the material of the sub-mold is 42CrMo.

[0080] Application Example 1

[0081] This embodiment provides a method for thermoforming thin-walled structural parts and composite materials, which is performed using the thermoforming tooling for thin-walled structural parts and composite materials provided in Embodiment 1, as follows:

[0082] Assemble the workpiece to be formed with the thermoforming tooling and then perform thermoforming.

[0083] Application Example 2

[0084] This embodiment provides a method for thermoforming thin-walled structural parts and composite materials, which is performed using the thermoforming tooling for thin-walled structural parts and composite materials provided in Embodiment 2, as follows:

[0085] Assemble the workpiece to be formed with the thermoforming tooling and then perform thermoforming.

[0086] Furthermore, the following comparative examples are used to illustrate the effects that can be achieved by the thermoforming tooling of thin-walled structural parts and composite materials provided by the present invention, as follows:

[0087] Comparative Example 1

[0088] The only difference from Example 1 is that no thermal transition material is arranged between the master mold and the workpiece to be molded.

[0089] Comparative Example 2

[0090] The only difference from Example 1 is that a PVC layer is arranged between the master mold and the workpiece to be molded.

[0091] Comparison Example 3

[0092] The only difference from Example 1 is that a polyurethane layer is arranged between the master mold and the workpiece to be molded.

[0093] Comparison Example 4

[0094] The only difference from Example 2 is that no thermal transition material is arranged between the master mold and the workpiece to be molded.

[0095] Comparative Example 5

[0096] The only difference from Example 2 is that a PVC layer is arranged between the master mold and the workpiece to be molded.

[0097] Comparative Example 6

[0098] The only difference from Example 2 is that a polyurethane layer is arranged between the master mold and the workpiece to be molded.

[0099] The deformation of the thin-walled structural parts of the above-mentioned formed products was detected and analyzed, and the results are shown in Table 1 below.

[0100] Table 1

[0101] Radial deformation of thin-walled structural parts Application Example 1 0.1mm Application Example 2 0.3mm Comparative Example 1 1.5mm Comparative Example 2 0.8mm Comparison Example 3 0.9mm Comparison Example 4 1.4mm Comparative Example 5 0.9mm Comparative Example 6 1.1mm

[0102] As can be seen from Table 1, the thermoforming tooling provided by the present invention avoids the hard contact between the workpiece to be formed and the mother mold during the thermoforming process by means of a specific thermal transition material, and plays a certain buffering and supporting role, thereby ensuring that the thin-walled structural parts do not have defects of large deformation and damage during the thermoforming process, and ensuring that the products after thermoforming can still be used reasonably.

[0103] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0104] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0105] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A thermoforming tool for thin-walled structural parts and composite materials, characterized in that: The thermoforming tooling for thin-walled structural parts and composite materials comprises: Nested master and daughter molds; A thermal transition material is disposed between the master mold and the workpiece to be formed; The thermal transition material includes: a flexible material that changes into a rigid material as the temperature increases.

2. The thermoforming tooling for thin-walled structural parts and composite materials according to claim 1, characterized in that: The mother mold and the daughter mold are connected via a connecting piece.

3. The thermoforming tooling for thin-walled structural parts and composite materials according to claim 1, characterized in that: The master mold includes an upper mold and a lower mold.

4. The thermoforming tooling for thin-walled structural parts and composite materials according to claim 3, characterized in that: The upper die and the lower die are provided with a positioning matching structure and are connected via a guide positioning shaft.

5. The thermoforming tooling for thin-walled structural parts and composite materials according to claim 1, characterized in that: The transformation temperature of the thermal transition material from a flexible material to a rigid material is 80-120°C.

6. The thermoforming tooling for thin-walled structural parts and composite materials according to claim 1, characterized in that: The material of the master mold includes high-strength steel or mold steel.

7. The thermoforming tooling for thin-walled structural parts and composite materials according to claim 1, characterized in that: The material of the sub-mold includes high-strength steel or mold steel.

8. The thermoforming tooling for thin-walled structural parts and composite materials according to claim 1, characterized in that: The material of the thermal conversion material includes foam material or rubber material.

9. The thermoforming tooling for thin-walled structural parts and composite materials according to claim 1, characterized in that: The thickness of the thermal transition material is ≤1 mm.

10. A method for thermoforming thin-walled structural parts and composite materials, characterized in that: The thermoforming method comprises: assembling a workpiece to be formed with a thermoforming tool and then performing thermoforming; A heat-transforming material is arranged between the workpiece to be formed and the mother mold of the thermoforming tooling; The thermal transition material includes: a flexible material that changes into a rigid material as the temperature increases.

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