Rib structure automatic fiber placement forming tool and forming method

Abstract

The invention discloses a rib structure automatic fiber placement forming tool and a forming method, and belongs to the field of composite material forming. The forming tool comprises a T-shaped groove mold, a rubber strip, a rubber strip baffle and a curing baffle. According to the forming method, prepreg is laid on a rubber strip baffle through an automatic fiber laying machine, and after laying is completed, a curing baffle is fixed to a groove opening of a T-shaped groove; the rib structure automatic fiber placement forming tool is heated, when the rubber strip is heated to expand and ejects the rubber strip baffle towards the direction of the notch, the prepreg is pressed under the combined action of the rubber strip and the curing baffle, and curing is completed. The problem that solidification is difficult when the rib structure uses an automatic fiber placement process can be effectively avoided, the usable placement pressure upper limit of the rib structure during placement is effectively improved, rubber strip damage caused by too large placement pressure is avoided, and the molding quality of the rib structure is improved.

Description

Technical Field

[0001] The invention belongs to the field of composite material forming, and in particular relates to an automatic wire-laying forming tool for a rib structure and a forming method. Background Art

[0002] Fiber reinforced composites are high-performance composites made of reinforcing fibers and resin-based matrices. They have many characteristics such as high specific strength, high specific modulus, good fatigue resistance and corrosion resistance, and strong designability. Automated Fibre Placement (AFP) is a new type of composite digital manufacturing technology with a high degree of automation developed on the basis of Automated Filament Winding (AFW) and Automated Tap Laying (FTL). It not only has the strong adaptability of traditional hand lay-up composite manufacturing technology to complex surfaces and the high reliability, high molding efficiency and high molding precision of digital manufacturing technology, but also effectively avoids the shortcomings of both, improves the consistency of large-scale composite production, and ensures the yield rate. As the last step in the product production process, the molding process is the key to ensuring the quality of product molding.

[0003] Automatic fiber placement molding of composite materials has been widely used in the field of aerospace, especially in the field of skin reinforcement structures. In the existing automatic fiber placement molding process, the laying of rib structures is generally done by autoclave or rubber mold curing, but both methods have obvious defects: autoclave curing is only suitable for structures with relatively low rib heights and is powerless for high rib structures; rubber mold molding cannot use high pressure during the automatic laying process, causing the fibers to loosen and affecting the final molding quality. Therefore, improving the automatic fiber placement molding process for rib structures is of great significance for improving the efficiency and quality of rib molding. Summary of the invention

[0004] The purpose of the present invention is to provide an automatic wire placement forming tool and a forming method for a rib structure, which is used to produce rib structure components made of composite materials. The problem of difficult solidification of the rib structure when using the automatic wire placement process can be effectively avoided, and the upper limit of the laying pressure that can be used for the rib structure during laying can be effectively increased, thereby avoiding damage to the rubber strip due to excessive laying pressure and improving the forming quality of the rib structure.

[0005] The technical solution adopted by the present invention to achieve its purpose is as follows:

[0006] A rib structure automatic wire laying forming tool comprises a T-slot die, a rubber strip, a rubber strip baffle and a curing baffle, wherein the T-slot die comprises a T-slot, which is composed of a wide slot, a narrow slot and a step therebetween; the rubber strip is placed in the narrow slot of the T-slot, the rubber strip baffle is placed at the step of the T-slot, and the wide slot area on the rubber strip baffle is used for laying prepreg; the curing baffle is detachably fixed on the notch of the T-slot.

[0007] Furthermore, the wide groove of the T-slot has a draft angle.

[0008] Furthermore, the shape and size of the rubber strip are adapted to the shape and size of the narrow groove of the T-slot.

[0009] Furthermore, the width of the rubber strip baffle is the same as the bottom width of the wide groove of the T-shaped groove.

[0010] Furthermore, a longitudinal guide groove and a transverse guide groove are provided on the solidification baffle.

[0011] Furthermore, the cross section of the longitudinal guide groove of the solidification baffle is T-shaped, the cross section of the transverse guide groove of the solidification baffle is rectangular, and the longitudinal guide groove and the transverse guide groove are interconnected.

[0012] A method for automatic wire laying and forming of a rib structure is implemented based on the above-mentioned automatic wire laying and forming tooling for the rib structure, and comprises the following steps:

[0013] Place the rubber strip in the narrow groove of the T-slot;

[0014] Place the rubber strip baffle on the step of the T-slot;

[0015] The prepreg is laid on the rubber strip baffle by an automatic fiber laying machine, and after the laying is completed, the cured baffle is fixed on the notch of the T-slot;

[0016] The automatic wire laying and forming tooling of the rib structure is heated. When the rubber strip expands due to the heat and pushes the rubber strip baffle toward the notch, the prepreg is compressed under the joint action of the rubber strip and the curing baffle to complete the curing.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1) The present invention adopts rubber mold thermal expansion molding, and the fiber placement machine can use a larger pressure to lay the ribs, thereby avoiding fiber wrinkles and improving the rib molding quality.

[0019] 2) The rubber strip baffle makes the prepreg more evenly compressed during curing.

[0020] 3) Excess resin can flow out through the guide groove to avoid the formation of resin-rich areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a three-dimensional diagram of an automatic wire-laying forming tool for a rib structure.

[0022] Figure 2 It is a top view of the T-slot die.

[0023] Figure 3 It is a top view of a cross-sectional view of an automatic wire-laying forming tool for a rib structure.

[0024] Figure 4 It is a structural diagram of the curing baffle.

[0025] Figure 5 It is a side sectional view of an automatic wire-laying forming tool for a rib structure.

[0026] Description of reference numerals:

[0027] 1: T-slot mold;

[0028] 2: wide slot;

[0029] 3: Narrow slot;

[0030] 4: steps;

[0031] 5: Rubber strip;

[0032] 6: Rubber strip baffle

[0033] 7: Curing baffle;

[0034] 8: Longitudinal guide groove;

[0035] 9: Horizontal guide groove. DETAILED DESCRIPTION

[0036] In order to make the various technical features and advantages or technical effects in the above technical solutions of the present invention more obvious and easy to understand, they are described in detail below with reference to the accompanying drawings.

[0037] This embodiment discloses an automatic wire laying and forming tool for a rib structure, such as Figure 1 As shown, it includes a T-slot mold 1, a rubber strip 5, a rubber strip baffle 6 and a curing baffle 7.

[0038] The structure of the T-slot die 1 is as follows Figure 2 As shown, it includes a T-shaped groove, which is divided into a wide groove 2 in the upper part and a narrow groove 3 in the lower part, and there is a step 4 at the junction of the upper and lower parts. The wide groove 2 has a draft angle, which is convenient for excess resin to flow out during curing and for smooth demoulding after curing.

[0039] like Figure 3As shown, the rubber strip 5 is placed in the narrow groove 3 of the T-slot, the rubber strip baffle 6 is placed at the step 4, and the prepreg is laid on the rubber strip baffle 6. After laying, the curing baffle 7 is fixed to the top notch of the wide groove 2 of the T-slot. The shape and size of the rubber strip 5 are adapted to the shape and size of the narrow groove 3 of the T-slot. In order to facilitate installation and ensure that the rubber strip just contacts the rubber strip baffle 6 at the maximum expansion force, the rubber strip 5 should be slightly lower than the narrow groove 3 of the T-slot. And in order to ensure the molding quality, the rubber strip 5 should be guaranteed to be a whole and should not be divided. The width of the rubber strip baffle 6 is the same as the bottom width of the wide groove 2 of the T-slot. It can be placed at the step 4 of the T-slot. It can withstand the large laying pressure when laid by the wire laying machine, and can move upward freely during curing to transfer the pressure of the rubber strip 5 to the prepreg.

[0040] The structure of the curing baffle 7 is as follows Figure 4 As shown, a longitudinal guide groove 8 and a transverse guide groove 9 are provided. The cross section of the longitudinal guide groove 8 is T-shaped, and while ensuring the molding accuracy of the ribs, the excess resin can flow out smoothly through the longitudinal guide groove 8. The cross section of the transverse guide groove 9 of the curing baffle is rectangular, and the transverse guide groove 9 is interconnected with the longitudinal guide groove 8 to ensure that the resin in the longitudinal guide groove 8 can flow out smoothly through the transverse guide groove 9. Figure 5 The positional relationship of the main structures of the rib structure automatic wire laying forming tooling is shown. It can be seen that the longitudinal guide groove 8 is perpendicular to the length direction of the rubber strip baffle 6, and can also be seen to be perpendicular to the length direction of the T-shaped groove.

[0041] This embodiment also discloses a method for automatic wire placement and forming of a rib structure, which is implemented based on the automatic wire placement and forming tooling of the rib structure, and includes the following steps:

[0042] 1) Place the rubber strip 5 in the narrow groove 3 of the T-slot.

[0043] 2) Place the rubber strip baffle 6 on the step 4 of the T-slot.

[0044] 3) The prepreg is laid on the rubber strip baffle 6 by an automatic fiber laying machine, and after the laying is completed, the curing baffle 7 is fixed on the notch of the T-slot. When the automatic fiber laying machine lays with a large pressure, the pressure cannot be transmitted to the rubber strip 5 due to the presence of the step 4 and the rubber strip baffle 6, thereby avoiding damage to the rubber strip 5 and wrinkling of the prepreg fibers.

[0045] 4) When the laying is completed and enters the oven for curing, the rubber strip 5 expands due to heat. Since the three sides of the rubber strip 5 are molds, it can only expand upward. At this time, the rubber strip baffle 6 moves upward due to the pressure from the rubber strip 5, and the prepreg is subjected to the pressure from the rubber strip baffle 6 below and the curing baffle 7 above, thereby completing the curing process. During the curing process, the excess resin flows out along the draft angle of the wide groove 2 of the T-slot and the longitudinal guide groove 8 and the transverse guide groove 9 on the curing baffle 7 to avoid resin enrichment.

[0046] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Appropriate modifications or equivalent substitutions of the technical solutions of the present invention made by ordinary technicians in the field should all be included in the protection scope of the present invention. The protection scope of the present invention shall be based on what is defined in the claims.

Claims

1. A rib structure automatic wire laying forming tool, characterized in that: It includes a T-slot mold, a rubber strip, a rubber strip baffle and a curing baffle. The T-slot mold contains a T-slot, which is composed of a wide slot, a narrow slot and a step between the two; the rubber strip is used to be placed in the narrow slot of the T-slot, the rubber strip baffle is used to be placed at the step of the T-slot, and the wide slot area on the rubber strip baffle is used to lay prepreg; the curing baffle can be detachably fixed on the notch of the T-slot.

2. The rib structure automatic wire laying forming tool as claimed in claim 1, characterized in that: The wide groove of the T-slot has a draft angle.

3. The rib structure automatic wire laying forming tool as claimed in claim 1, characterized in that: The shape and size of the rubber strip are adapted to the shape and size of the narrow groove of the T-slot.

4. The rib structure automatic wire laying forming tool as claimed in claim 1, characterized in that: The width of the rubber strip baffle is the same as the bottom width of the wide groove of the T-slot.

5. The rib structure automatic wire laying forming tool as claimed in claim 1, characterized in that: A longitudinal guide groove and a transverse guide groove are arranged on the curing baffle.

6. The rib structure automatic wire laying forming tool as claimed in claim 5, characterized in that: The longitudinal guide groove and the transverse guide groove are communicated with each other.

7. The rib structure automatic wire laying forming tool as claimed in claim 5, characterized in that: The cross section of the longitudinal guide groove of the curing baffle is T-shaped.

8. The rib structure automatic wire laying forming tool as claimed in claim 5, characterized in that: The cross section of the transverse guide groove of the curing baffle is rectangular.

9. A method for automatic wire placement and forming of a rib structure, implemented based on the automatic wire placement and forming tooling for a rib structure according to any one of claims 1 to 8, comprising the following steps: Place the rubber strip in the narrow groove of the T-slot; Place the rubber strip baffle on the step of the T-slot; The prepreg is laid on the rubber strip baffle by an automatic fiber laying machine, and after the laying is completed, the cured baffle is fixed on the notch of the T-slot; The automatic wire laying and forming tooling of the rib structure is heated. When the rubber strip expands due to the heat and pushes the rubber strip baffle toward the notch, the prepreg is compressed under the joint action of the rubber strip and the curing baffle to complete the curing.

Images