Molding tool and molding method for easy-to-wear layer of engine fan casing

Abstract

The invention discloses an engine fan casing easy-to-wear layer forming tool and method, the forming tool comprises an upper die body and a lower die body, the upper die body and the lower die body are both of a frame type structure and form a closed cavity with the same thickness after being assembled, air guide holes are evenly formed in the area, located in the closed cavity, of the bottom face of the upper die body, and air guide holes are formed in the bottom face of the lower die body. The upper die body and the lower die body are locked through a fastener, and the thickness of the formed closed cavity is adjustable. The forming method for the forming tool specifically comprises the steps of material consumption calculation, easy-to-wear layer material blanking, pre-paving, auxiliary material placement, tool preheating, oven curing, numerical control machining and the like. According to the forming method, the heating uniformity of the material can be guaranteed in the preparation process, meanwhile, the problem that the density of a product is inconsistent after the variable-thickness easy-to-wear layer is foamed is solved, and the forming quality of the product is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, in particular to an engine fan case easy-wear layer forming tool and forming method. BACKGROUND

[0002] In order to improve the working efficiency of the engine, maintain the minimum air gap of the engine flow passage surface, and protect the fan blades and the case from damage caused by scraping and colliding during high-speed operation, an easy-wear layer that can be abraded is often added between the case and the fan blades. In order to ensure the aerodynamic effect, the profile of the easy-wear layer is often designed as a variable-thickness double-curvature structure, and the thickness and curvature change gradually.

[0003] The abradable material is an epoxy resin material filled with hollow microspheres (glass beads) (US20140367920A1) or a silicone rubber material (CN102432225A, US20150198056A1).

[0004] In the method for preparing an easy-wear ring from a foamed epoxy resin easy-wear layer material in CN114055805, first, an expandable modified epoxy resin film is prepared, the thickness of the tool is selected according to the use requirements, and the number of film layers is calculated. For the easy-wear layer with variable thickness, based on the different thicknesses, the number of layers of the easy-wear layer material is set to be different in different regions to realize the layer number requirement of the easy-wear layer with different thicknesses. Further, a hot mold pressing forming process is used for part forming, and the net size is obtained by mechanical processing. The forming process of the epoxy resin easy-wear ring has some obvious disadvantages: (1) the profile of the easy-wear layer is a double-curvature structure with gradually changing thickness, and it is difficult to ensure the uniformity of the density of the thickness gradually changing region using the layer dropping method; (2) the heat transfer source of the hot mold pressing process is the heat source surface of the upper and lower presses, and the heat is transferred from the upper and lower heat source surfaces to the material in the middle through the easy-wear layer forming tool, and the heat transfer direction is single; in order to ensure heat transfer, for the easy-wear layer with variable curvature, the forming tool is often designed as a solid tool, and the thickness of the forming tool is not uniform, which further affects the temperature uniformity of the internal material and the density uniformity of the foamed easy-wear layer material.

[0005] In addition, the easy-wear layer material forming often produces a skin-core structure (the surface state and the internal state are inconsistent), and the core cause is the difference in cooling rate of the melt in the tool. The surface layer is quickly cooled by contacting the low-temperature tool wall, and the core layer is slowly cooled in a high-temperature environment. The different cooling histories of the two lead to structural differentiation. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides an engine fan case easy-wear layer forming tool and forming method. The forming method can ensure uniformity of material heating during preparation, avoid inconsistent product density after foaming of the variable-thickness easy-wear layer, and effectively improve the product forming quality.

[0007] An engine fan case easy-to-wear layer forming tool, comprising an upper die body and a lower die body, both of which adopt a frame structure and form a closed cavity with equal thickness after assembly, the bottom surface of the upper die body is uniformly provided with air guide holes in the area of the closed cavity, and the thickness of the closed cavity formed by locking the upper die body and the lower die body through fasteners is adjustable.

[0008] As a preferred embodiment of the above technical solution, the upper die body and the lower die body are provided with positioning mechanisms on the periphery of the locking edge, and the upper die body and the lower die body are aligned and positioned through the positioning mechanisms.

[0009] As a preferred embodiment of the above technical solution, the upper die body is symmetrically provided with a support leg on the side surface.

[0010] As a preferred embodiment of the above technical solution, the lower die body is provided with a forklift hole.

[0011] As a preferred embodiment of the above technical solution, the upper die body and the lower die body are symmetrically provided with lifting rings on the side surfaces.

[0012] A forming method applied to the engine fan case easy-to-wear layer forming tool of any one of the above technical solutions, and the specific forming process is as follows: S1, material quantity calculation, according to the target density and thickness requirement of the easy-to-wear layer product, combined with the machining allowance thickness requirement of the two sides of the easy-to-wear layer product, the required number of layers of the easy-to-wear layer raw material is calculated; S2, easy-to-wear layer material blanking, the material sheet of the required shape is cut by a blanking machine, and the isolation film is used for protection after cutting; S3, pre-laying, the prepared easy-to-wear layer raw material in S2 is laid on the lower die body layer by layer, and during the laying process, after each layer of easy-to-wear layer raw material is laid, vacuum pre-compaction treatment is carried out, and after laying is completed, it is taken out for standby; S4, auxiliary material placement, a layer of air-permeable felt and a layer of PTFE cloth are sequentially positioned from inside to outside in the area of the closed cavity between the upper die body and the lower die body; S5, tool preheating, the lower die body and the upper die body with the auxiliary material placed in S4 are put into an oven for preheating; S6, oven curing, the prepared easy-to-wear layer raw material in S3 is put into the preheated lower die body, and after the assembly of the tool is completed, it is sent to an oven for foaming and curing of the easy-to-wear layer raw material, so as to obtain an easy-to-wear layer blank; S7, numerical control machining, the prepared easy-to-wear layer blank in S6 is machined according to the required profile die, and a net size easy-to-wear layer product is obtained.

[0013] As the preferred technical scheme, in S1, when the closed cavity height of the tooling cannot meet the target thickness requirement of the easy-to-abrade layer product, the adjustment is made by installing a sealing heightening pad on the edge of the upper die body and the lower die body used for sealing.

[0014] As the preferred technical scheme, in S3, the vacuum degree during the vacuum pre-compaction treatment is not less than 0.08 MPa, and the time is not less than 10 min.

[0015] As the preferred technical scheme, in S5, the temperature rising rate during the tooling preheating is controlled to be 1-3 ℃ / min, and the tooling is kept at 60±5 ℃ for 30-40 min after the temperature rising.

[0016] As the preferred technical scheme, in S6, the specific temperature control environment of the oven curing is as follows: S61, the temperature is raised to 80±5 ℃, kept for 20-30 min, and the temperature rising rate is 1-3 ℃ / min, so that the heating in the closed cavity of the tooling is uniform; S62, the temperature is further raised to 130±5 ℃, kept for 120-130 min, and the temperature rising rate is 1-3 ℃ / min.

[0017] After the easy-to-abrade layer blank is prepared, the temperature is lowered to below 60 ℃, the demolding is performed, and the temperature lowering rate is lower than 3 ℃ / min.

[0018] Compared with the prior art, the present application has the following beneficial effects: 1. The manufacturing quality of the easy-to-abrade layer material is improved by the structure design and the forming process design of the easy-to-abrade layer forming tooling.

[0019] 2. The frame type uniform thickness closed cavity forming tooling design is adopted to ensure the uniformity of the material heating, and to avoid the problem of inconsistent product density after the variable thickness easy-to-abrade layer foaming.

[0020] 3. The "in-plane + out-of-plane" collaborative air guiding layout of the air permeable felt + upper die body air guiding hole can make the easy-to-abrade layer raw material discharge the gas in time during the foaming process, and improve the forming quality of the easy-to-abrade layer surface and interior.

[0021] 4. The layout of the upper and lower die bodies placed with PTFE cloth + air permeable felt auxiliary material avoids the direct contact between the raw material and the tooling, improves the "skin-core" effect problem, and facilitates the demolding.

[0022] 5. The tooling preheating + step temperature rising process is adopted to further improve the uniformity of the material heating and the product forming quality. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The figure is a structure diagram of the tooling of the present application.

[0024] Figure 2A sectional view of the tooling of the present application.

[0025] Figure 3 A bottom view of the upper die body.

[0026] Figure 4 A sectional view of the closed cavity before oven curing.

[0027] The reference signs are as follows: 1-upper die body, 2-lower die body, 3-closed cavity, 4-air guide hole, 5-positioning mechanism, 6-supporting leg, 7-forklift hole, 8-lifting ring, 9-wear layer, 10-air-permeable felt, 11-tetrafluoro cloth. DETAILED DESCRIPTION

[0028] To make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0029] The present application will be described in further detail below with reference to the drawings: As Figures 1 to 3 shown in the drawings, the tooling for forming the wear layer of an engine fan case includes an upper die body 1 and a lower die body 2. The upper die body 1 and the lower die body 2 are both of frame type structure and form a closed cavity 3 of equal thickness after assembly. The bottom surface of the upper die body 1 is uniformly provided with air guide holes 4 in the area of the closed cavity 3. The upper die body 1 and the lower die body 2 are locked by fasteners and the thickness of the closed cavity 3 formed thereby is adjustable.

[0030] In the present embodiment, the upper die body 1 and the lower die body 2 are circumferentially provided with a positioning mechanism 5 at the edges for locking. The upper die body 1 and the lower die body 2 are aligned and positioned by the positioning mechanism 5. The specific positioning mechanism 5 can use a protrusion and a groove in cooperation.

[0031] In the present embodiment, the upper die body 1 is symmetrically provided with a supporting leg 6 on the side surface.

[0032] In the present embodiment, the lower die body 2 is provided with a forklift hole 7.

[0033] In the present embodiment, the upper die body 1 and the lower die body 2 are symmetrically provided with a lifting ring 8 on the side surface.

[0034] Specifically, the tooling is of steel material and has the function of not deforming under high temperature and high pressure.

[0035] The upper die body 1 and the lower die body 2 are designed in a frame type closed cavity forming tool with equal thickness, which ensures the uniformity of material heating and avoids the problem of inconsistent product density after foaming of the variable-thickness easy-wearing layer.

[0036] The lower die body 2 is provided with a forklift hole for transferring the tool.

[0037] The upper die body 1 and the lower die body 2 are both provided with lifting rings 8 for integral or split lifting.

[0038] The upper die body 1 is provided with support legs 6 for supporting the upper die body 1 to avoid damage to the tool profile.

[0039] The upper die body 1 and the lower die body 2 form a closed cavity 3 with equal thickness after combination, which can solve the problem of uneven density of variable-thickness products, and at the same time, equal-thickness padding can be added to the edge of the cavity for adjusting the thickness of the cavity for forming products with different thicknesses.

[0040] The upper die body panel has hexagonally arranged air guide holes for discharging gas from the closed cavity during forming.

[0041] A forming method applied to the engine fan case easy-wearing layer forming tool of any one of the above-mentioned embodiments, the specific forming process is as follows: S1, material quantity calculation, according to the target density and thickness requirement of the easy-wearing layer 1 product, combined with the machining allowance thickness requirement on both sides of the easy-wearing layer 1 product, the required number of layers of easy-wearing layer 1 raw materials is calculated; S2, easy-wearing layer 1 material blanking, the required shape of the easy-wearing layer 1 material is cut by a blanking machine, and the cutting is protected by using a separation film; S3, pre-laying, the prepared easy-wearing layer 1 raw material in S2 is laid on the lower die body 2 layer by layer, and during the laying process, after each layer of easy-wearing layer 1 raw material is laid, vacuum pre-compaction treatment is carried out, and after laying is completed, it is taken out for standby; S4, auxiliary material placement, a layer of air-permeable felt 10 and a layer of Teflon cloth 11 are positioned from inside to outside in the area of the closed cavity 3 between the upper die body 1 and the lower die body 2; S5, tool preheating, the lower die body 2 and the upper die body 1 with auxiliary materials placed in S4 are put into an oven for preheating; S6, oven curing, the prepared easy-wearing layer 9 raw material in S3 is put into the preheated lower die body 2, as shown in Figure 4 , after the assembly of the tool is completed, it is sent to the oven for foaming and curing of the easy-wearing layer 9 raw material, and the easy-wearing layer 9 blank is prepared; S7, numerical control machining, the prepared easy-wearing layer 9 blank in S6 is machined according to the required profile die, and the net size easy-wearing layer product is obtained.

[0042] In the embodiment, in S1, when the closed cavity height of the tooling cannot meet the target thickness requirement of the easy-to-wear layer 9 product, the height of the sealing pad is adjusted by installing the sealing heightening pad on the edge of the upper die body and the lower die body used for sealing.

[0043] In the embodiment, in S3, the vacuum degree during the vacuum pre-compaction process is not less than 0.08 MPa, and the time is not less than 10 min.

[0044] In the embodiment, in S5, the temperature rising rate during the tooling preheating is controlled to be 1-3 ℃ / min, and the tooling is kept at 60±5 ℃ for 30-40 min after being heated to 60±5 ℃.

[0045] In the embodiment, in S6, the specific temperature control environment of the oven curing is as follows: S61, heated to 80±5 ℃, kept for 20-30 min, and the temperature rising rate is 1-3 ℃ / min, so that the heat in the closed cavity of the tooling is uniform; S62, further heated to 130±5 ℃, kept for 120-130 min, and the temperature rising rate is 1-3 ℃ / min. Specifically, the easy-to-wear layer 9 raw material is a fibrous reinforced resin sheet-shaped adhesive film material with a certain viscosity, or a medium-temperature curing epoxy resin material containing a foaming agent and having easy-to-wear and corrosion-resistant functions.

[0046] The "in-plane+out-of-plane" collaborative air guiding layout of the air-permeable felt 10+air guiding hole 4 of the upper die body 1 can make the easy-to-wear layer 9 raw material timely discharge gas during the foaming process, and improve the forming quality of the surface and the interior of the easy-to-wear layer 9.

[0047] The upper die body 1 and the lower die body 2 are both placed with the auxiliary material layout of the polytetrafluoroethylene cloth 11+air-permeable felt 10, which avoids the direct contact between the raw material and the tooling, improves the "skin-core" effect problem, and facilitates demolding.

[0048] The tooling preheating+stepwise heating process is adopted, which further improves the heat uniformity of the material and improves the product forming quality.

[0049] The above is only a preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A tooling for forming the wear-prone layer of an engine fan casing, characterized in that: It includes an upper mold body and a lower mold body. Both the upper mold body and the lower mold body adopt a frame structure. After assembly, they form a closed cavity of equal thickness. The bottom surface of the upper mold body is provided with air guide holes evenly in the area of ​​the closed cavity. The upper mold body and the lower mold body are locked together by fasteners, and the thickness of the closed cavity formed is adjustable.

2. The tooling for forming the wear-prone layer of an engine fan casing according to claim 1, characterized in that: The upper and lower mold bodies are provided with positioning mechanisms along their circumferential edges for locking, and the upper and lower mold bodies are aligned and positioned by the positioning mechanisms.

3. The tooling for forming the wear-prone layer of an engine fan casing according to claim 1, characterized in that: Support legs are symmetrically installed on the sides of the upper mold body.

4. The tooling for forming the wear-prone layer of an engine fan casing according to claim 1, characterized in that: The lower mold body is provided with forklift holes.

5. The tooling for forming the wear-prone layer of an engine fan casing according to claim 1, characterized in that: Lifting rings are symmetrically installed on the sides of both the upper and lower mold bodies.

6. A forming method for a tooling used in forming the wear-prone layer of an engine fan casing as described in any one of claims 1-5, characterized in that: The specific molding process is as follows: S1, Material usage calculation: Based on the target density and thickness requirements of the wear-resistant layer product, and combined with the machining allowance thickness requirements on both sides of the wear-resistant layer product, calculate the required number of wear-resistant layer raw material layers. S2, Abrasion layer material cutting: The abrasion layer material of the required shape is cut into sheets by a cutting machine, and then protected with a release film after cutting. S3, Pre-laying: The wear-resistant layer material prepared in S2 is laid layer by layer on the lower mold body. During the laying process, after each layer of wear-resistant layer material is laid, vacuum pre-compacting treatment is performed. After laying, it is taken out for use. S4, Auxiliary material placement: In the area of ​​the upper and lower mold bodies located in the closed cavity, a layer of breathable felt and a layer of PTFE cloth are positioned sequentially from the inside to the outside. S5, tooling preheating: put the lower mold body and the upper mold body with auxiliary materials placed in S4 into the oven for preheating; S6, Oven curing: Place the easy-wear layer material prepared in S3 into the preheated lower mold body, and after the tooling is assembled, send it to the oven to foam and cure the easy-wear layer material to obtain the easy-wear layer blank. S7, CNC machining, machining the easy-wear layer blank prepared in S6 according to the required surface model, to obtain the easy-wear layer product with net dimensions.

7. The molding method according to claim 6, characterized in that: In S1, when the height of the tooling cavity cannot meet the target thickness requirement of the wear-resistant layer product, it is adjusted by installing sealing height-increasing pads on the sealing edges of the upper and lower mold bodies.

8. The molding method according to claim 6, characterized in that: In S3, the vacuum degree during vacuum pre-compaction treatment shall not be less than 0.08 MPa and the time shall not be less than 10 min.

9. The molding method according to claim 6, characterized in that: In S5, the heating rate during tooling preheating is controlled at 1~3℃ / min, and the tooling is heated to 60±5℃ and then held for 30~40min.

10. The molding method according to claim 6, characterized in that: In S6, the specific temperature control environment for oven curing is as follows: S61, heat to 80±5℃, hold for 20~30min, heating rate 1~3℃ / min, so that the tooling cavity is heated evenly; S62, further heat up to 130±5℃, hold for 120~130min, heating rate 1~3℃ / min.

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