Mold repairing method and mold

Abstract

The invention discloses a mold repairing method and a mold, and belongs to the technical field of forming molds, the mold repairing method comprises the following steps: S1, comparing data of a to-be-repaired mold and a qualified mold, and performing Boolean operation to obtain a difference value to obtain a repairing structure; s2, the repairing structure is sliced from the direction close to the to-be-repaired mold to the direction away from the to-be-repaired mold or in the opposite direction according to the thickness of the prepreg, and a plurality of slices are obtained; s3, blanking is conducted on the prepreg according to the slices, and prepreg slices are obtained; s4, the prepreg sheets are laid on the to-be-repaired mold layer by layer in the direction from the position close to the to-be-repaired mold to the position away from the to-be-repaired mold; s5, curing the prepreg sheet to obtain a semi-finished mold; and S6, the semi-finished mold is treated, and a finished mold conforming to the qualified mold size is obtained. According to the method, the to-be-repaired mold is repaired through the prepreg, the advantage of short repairing time is achieved on the basis that the requirements for the size, the strength and the like are met, and the time cost and the material cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of forming molds, and particularly to a mold repair method and a mold. Background Art

[0002] In the composite material forming process, the manufacturing of C-shaped or U-shaped structures such as beam ribs usually relies on mold tooling. Due to the springback effect of the composite material after forming, a springback compensation angle (such as an opening increase of 5°) needs to be preset during mold design to ensure that the product size meets the design requirements after demolding. However, the actual springback amount in production is affected by multiple factors such as material properties and forming temperature, making it difficult to accurately match the design of the mold springback angle. If the springback angle design deviation requires rework, the prior art usually adopts the following methods:

[0003] 1. When the springback angle is too large: directly correct the mold surface by machining;

[0004] 2. When the springback angle is too small: first perform repair welding to increase the material, and then adjust the size by machining.

[0005] The traditional repair method combining repair welding and machining has obvious defects: long process cycle (requiring multiple processes), high cost (large consumption of welding and machining resources), and low error tolerance (repeated trimming is likely to affect the mold accuracy). Especially when the springback angle design is insufficient, repair welding may introduce problems such as thermal deformation or uneven material properties, further increasing the complexity of rework.

[0006] Therefore, how to develop an efficient, low-cost, and high-precision mold springback angle repair method has become an urgent technical problem to be solved in the current composite material forming field. Summary of the Invention

[0007] The purpose of the present invention is to provide a mold repair method and a mold to solve the problems existing in the above prior art. The pre-preg is used to repair the mold to be repaired, which has the advantage of short repair time on the basis of meeting the requirements such as size and strength, and can reduce the time cost and material cost.

[0008] To achieve the above purpose, the present invention provides the following solutions:

[0009] The present invention provides a mold repair method, including the following steps:

[0010] S1. Compare the data of the mold to be repaired and the qualified mold, perform a Boolean operation to take the difference, and obtain the repair structure;

[0011] S2. Slice the repair structure in the direction from near the mold to be repaired to far from the mold to be repaired or from far from the mold to be repaired to near the mold to be repaired according to the thickness of the pre-preg to obtain a number of slices;

[0012] S3. Cut the prepreg according to the slices to obtain prepreg sheets.

[0013] S4. Lay the prepreg sheets layer by layer on the mold to be repaired from a position close to the mold to be repaired to a position far from the mold to be repaired.

[0014] S5. Cure the prepreg sheets to obtain a semi-finished mold.

[0015] S6. Process the semi-finished mold to obtain a finished mold that meets the size requirements of a qualified mold.

[0016] In one embodiment, in step S2, the thickness of the slices is 0.1 mm to 0.4 mm.

[0017] In one embodiment, in step S2, when slicing, the size of the slices gradually decreases from a position close to the mold to be repaired to a position far from the mold to be repaired.

[0018] In one embodiment, in step S3, the prepreg is an epoxy quartz fiber prepreg, an epoxy glass fiber prepreg, or an epoxy carbon fiber prepreg.

[0019] In one embodiment, in step S4, after laying each layer of prepreg sheets, encapsulation and vacuum pumping are performed to compact the prepreg sheets and the mold to be repaired.

[0020] In one embodiment, in step S4, the degree of vacuum after vacuum pumping is not lower than -0.095 Mpa, and the vacuum holding time is 10 min to 20 min.

[0021] In one embodiment, in step S5, when curing the prepreg sheets, the curing temperature is 90°C to 180°C, and the pressure is -1 bar to -6 bar.

[0022] In one embodiment, in step S6, when processing the semi-finished mold, the surface of the cured prepreg sheets is initially polished, putty is scraped at the gaps between adjacent prepreg sheets, and after drying, it is polished flat.

[0023] In one embodiment, in step S6, after polishing flat, it is cleaned, and a layer of back glue release cloth is laid on the surface of the mold.

[0024] The present invention provides a mold, and the mold to be repaired is repaired by using the mold repair method described above to obtain a finished mold.

[0025] The present invention has achieved the following technical effects compared with the prior art:

[0026] The present invention uses prepreg to repair the mold to be repaired. During the repair, by comparing the mold to be repaired with the qualified mold, the repair structure to be repaired is obtained. Utilizing the thickness characteristics of the prepreg itself, the repair structure is sliced, so that the prepreg is cut according to the slices, and then the prepreg sheets obtained by cutting are laid on the mold to be repaired layer by layer. After curing and treatment, a qualified mold that can meet the requirements such as size and strength can be obtained. On this basis, compared with the traditional methods of repair welding and machining, it has the advantage of short repair time and can reduce the time cost and material cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0028] Figure 1 Schematic diagram of the mold to be repaired in the embodiment of the present invention;

[0029] Figure 2 Schematic diagram of the qualified mold in the embodiment of the present invention;

[0030] Figure 3 Schematic diagram of the repair structure in the embodiment of the present invention;

[0031] Figure 4 Schematic diagram of the semi-finished mold in the embodiment of the present invention;

[0032] Figure 5 For Figure 4 Enlarged view of part A in

[0033] Wherein, 1, mold to be repaired; 2, qualified mold; 3, repair structure; 4, semi-finished mold; 5, prepreg sheet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0035] The purpose of the present invention is to provide a mold repair method and a mold to solve the problems existing in the prior art. Using prepreg to repair the mold to be repaired, on the basis of meeting the requirements such as size and strength, it has the advantage of short repair time and can reduce the time cost and material cost.

[0036] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] As Figures 1 to 5 shown, the present invention provides a mold repair method, including the following steps:

[0038] S1. Compare the data of the mold 1 to be repaired and the qualified mold 2, perform a Boolean operation to take the difference, and obtain the repair structure 3. Among them, the mold 1 to be repaired generally uses a metal material. If the springback angle of the mold 1 to be repaired is designed too small, it is necessary to repair the surface of the mold 1 to be repaired so that the springback angle meets the requirements after expansion. The qualified mold 2 refers to a mold that can meet the springback angle. Since the qualified mold 2 needs to expand the springback angle on the basis of the mold 1 to be repaired, the volume of the qualified mold 2 will be larger than that of the mold 1 to be repaired, and the extra part is the repair structure 3 obtained by the Boolean operation.

[0039] It should be noted that: the repair structure 3 may be a relatively regular triangular or arc-shaped structure, or a curved surface type or other irregular graphics, which needs to be determined according to the result of the Boolean operation. When performing the Boolean operation, the mold 1 to be repaired can be three-dimensionally scanned to obtain corresponding virtual data, and then compared with the data of the qualified mold 2. In the traditional scheme, there is no process of data comparison, and only welding is performed on the surface of the metal material mold 1 to be repaired. Since the welding accuracy is not high, it needs to be combined with machining. If it cannot be repaired perfectly at one time, it needs to be performed multiple times, repeating the processes of welding and machining until the repair work of the mold 1 to be repaired is completed. This process is relatively long.

[0040] S2. Slice the repair structure 3 according to the thickness of the prepreg to obtain a number of slices. When slicing, it can be sliced from the direction close to the mold 1 to be repaired to the direction away from the mold 1 to be repaired, or from the direction away from the mold 1 to be repaired to the direction close to the mold 1 to be repaired. The prepreg used is a composition of a resin matrix impregnating continuous fibers or fabrics under strictly controlled conditions, so the prepreg is a sheet structure and has a certain thickness itself. When slicing, the slice matches the thickness of the prepreg used. Thus, there is no need to consider the trimming of the thickness. After cutting the slice to the required width, a prepreg sheet 5 with the same specification as the slice can be obtained. For the convenience of subsequent laying to restore the repair structure 3, the slices can be numbered in sequence. For example, they are denoted as slice 1, slice 2... slice n.

[0041] S3. Cut the prepreg according to the slices. During the cutting process, trim the width of the prepreg to obtain prepreg sheets 5. The width and thickness dimensions of the prepreg sheets 5 correspond to the slices one by one. However, the slices are generally virtual data, while the prepreg sheets 5 are physical prepregs. Similarly, the prepreg sheets 5 are recorded according to the slice numbers.

[0042] S4. Layer by layer, lay the prepreg sheets 5 on the damaged mold 1 from a position close to the damaged mold 1 to a position far from the damaged mold 1. In this way, the width of the prepreg sheets 5 is in contact and connected with the surface of the damaged mold 1, and the width of the prepreg sheets 5 is in contact and connected with the width of adjacent prepreg sheets 5, which can enhance the connection strength between the prepreg sheets 5 and the damaged mold 1 and between the prepreg sheets 5, ensuring that the repaired mold meets the strength requirements.

[0043] S5. Cure the prepreg sheets 5 to obtain a semi-finished mold 4. The curing parameters refer to the curing data of the selected prepreg. After the prepreg sheets 5 are cured, the laid prepreg sheets 5 can be connected to the damaged mold 1 as a whole.

[0044] S6. Process the semi-finished mold 4. The processing process includes trimming and cleaning the surface of the semi-finished mold 4, etc. After processing, a finished mold that meets the size of the qualified mold 2 is obtained. The finished mold can meet the designed size of the springback angle and can be used for the molding of composite materials.

[0045] In one embodiment, in step S2, the thickness of the slices is 0.1 mm to 0.4 mm. For example, if the thickness of the prepreg used is 0.2 mm, the thickness of the slices can be set to 0.2 mm. The same group of repair structures 3 can adopt the same thickness specification, that is, the same prepreg material is used, which is convenient for slicing and repair. At the same time, the connection of the same material can also ensure the connection strength.

[0046] In one embodiment, in step S2, when slicing, the size of the slices gradually decreases from a position close to the damaged mold 1 to a position far from the damaged mold 1 (refer to Figure 5 the prepreg sheets 5 shown). At this time, the repair structure 3 is in the shape of a relative specification (refer to Figure 3 the specific embodiment shown). By adopting the above slicing method, a relatively large connection area can be ensured between the slices and the damaged mold 1 and between the slices. Finally, after laying the prepreg sheets 5, sufficient connection strength can be ensured. If Figure 5On the contrary, in the slicing method, the size of the slices gradually increases from the vicinity of the die 1 to be repaired to away from the die 1 to be repaired. At this time, since the prepreg sheet 5 laid later is larger than the prepreg sheet 5 laid earlier, the prepreg sheet 5 can only be attached to the surface of the prepreg sheet 5 laid earlier or the die 1 to be repaired after being slightly bent. Compared with the method of gradually decreasing the slice size, the connection effect will be slightly worse. However, it can be understood that this connection method should also fall within the protection scope of the present invention.

[0047] In one embodiment, in step S3, the prepreg is an epoxy quartz fiber prepreg, an epoxy glass fiber prepreg or an epoxy carbon fiber prepreg. The above materials are all epoxy resin-based prepregs, and the repaired die has excellent mechanical properties, heat resistance and process adaptability. The difference is that the reinforcing fiber used in the epoxy quartz fiber prepreg is high-purity quartz fiber (SiO2 content ≥ 99.95%), the reinforcing fiber used in the epoxy glass fiber prepreg is E-glass or S-glass fiber, and the reinforcing fiber used in the epoxy carbon fiber prepreg is PAN-based or pitch-based carbon fiber (such as T300, T700, T800, etc.).

[0048] In one embodiment, in step S4, after laying each layer of prepreg sheet 5, encapsulation and vacuum pumping are carried out to compact the prepreg sheet 5 and the die 1 to be repaired. That is, through the method of encapsulation and vacuum pumping, the prepreg sheet 5 is made to fit more closely to the adjacent die 1 to be repaired or the adjacent prepreg sheet 5, ensuring that the prepreg sheet 5 is laid in place, and capable of discharging air bubbles and ensuring the connection tightness, and finally ensuring the dimensional accuracy and connection strength of the laid prepreg sheet 5.

[0049] In one embodiment, in step S4, the vacuum degree after vacuum pumping is not less than -0.095 Mpa, and the vacuum holding time is 10 min to 20 min. In this example, to ensure that the vacuum degree requirement can be met and the stripping can be carried out smoothly for re-laying the next layer of prepreg sheet 5, during the vacuum pumping process, the auxiliary materials used include peel ply, release film, breather felt and vacuum bag. After laying one layer of prepreg sheet 5, the peel ply, release film and breather felt are placed in sequence, and then the vacuum bag is sleeved and the vacuum bag is vacuum pumped.

[0050] In one embodiment, in step S5, when curing the prepreg sheet 5, the curing temperature is 90°C to 180°C, the pressure is -1 bar to -6 bar, and it lasts for a period of time, such as 60 min to 120 min, to ensure sufficient cross-linking of the resin.

[0051] In one embodiment, in step S6, when processing the semi-finished die 4, the surface of the cured prepreg sheet 5 is initially polished, and putty is scraped at the gaps between adjacent prepreg sheets 5 and polished flat after drying to meet the roughness requirement of the die surface.

[0052] In one embodiment, in step S6, after grinding and leveling, it is cleaned, and a layer of adhesive-backed release cloth is laid on the surface of the mold so as to be able to be demolded smoothly when forming the composite material. The adhesive-backed release cloth can be a polytetrafluoroethylene adhesive-backed release cloth.

[0053] Refer again to Figures 1 to 5 As shown, the present invention provides a mold, and the mold to be repaired 1 is repaired by using the mold repair method described above. After attaching the prepreg sheet 5 and curing, a semi-finished mold 4 is obtained, and the semi-finished mold 4 is processed to obtain a finished mold.

[0054] Taking the U-shaped beam as an example, refer to Figures 1 to 5 , the mold repair method provided by the present invention is as follows:

[0055] 1) Compare the mold to be repaired 1 (such as Figure 1 , the current mold state) with the qualified mold 2 (such as Figure 2 , the mold state after repair). After performing a Boolean operation on the data to take the difference, the required repair structure 3 (such as Figure 3 shown) is obtained.

[0056] 2) Cut the repair structure 3 into slices with a thickness of 0.2 mm to obtain a number of slices, denoted as slice 1, slice 2... slice n.

[0057] 3) Use slice 1, slice 2... slice n in step 2 to make a cutting plan, and cut the prepreg according to the cutting plan to obtain the prepreg sheet 5.

[0058] 4) Clean the mold to be repaired 1, and lay the prepreg sheet 5 on the mold to be repaired 1 in the order and position of the slices (such as Figure 4 shown).

[0059] 5) The curing temperature is 100°C to 180°C, and the pressure is -1 bar to -6 bar.

[0060] 6) Roughly grind the surface of the cured prepreg sheet 5, scrape putty at the gaps of the prepreg sheet 5, and grind it flat after drying; after cleaning, lay a layer of adhesive-backed release cloth on the surface.

[0061] In the present invention, specific examples are used to elaborate the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A mold repair method, characterized in that, It includes the following steps: S1. Compare the data of the mold to be repaired and the qualified mold, perform a Boolean operation to take the difference, and obtain the repair structure; S2. Slice the repair structure in the direction from near the mold to be repaired to far from the mold to be repaired or from far from the mold to be repaired to near the mold to be repaired according to the thickness of the prepreg, and obtain a number of slices; S3. Cut the prepreg according to the slices to obtain prepreg sheets; S4. Layer by layer, lay the prepreg sheets on the mold to be repaired in the direction from near the mold to be repaired to far from the mold to be repaired; S5. Cure the prepreg sheets to obtain a semi-finished mold; S6. Process the semi-finished mold to obtain a finished mold that meets the dimensions of the qualified mold.

2. The mold repair method according to claim 1, characterized in that: In step S2, the thickness of the slices is 0.1 mm to 0.4 mm.

3. The mold repair method according to claim 2, wherein: In step S2, when slicing, the size of the slices gradually decreases from near the mold to be repaired to far from the mold to be repaired.

4. The mold repair method according to claim 1, characterized in that: In step S3, the prepreg uses epoxy quartz fiber prepreg, epoxy glass fiber prepreg or epoxy carbon fiber prepreg.

5. The mold repair method according to claim 1, characterized in that: In step S4, after laying each layer of the prepreg sheet, perform encapsulation and vacuum pumping to compact the prepreg sheet and the mold to be repaired.

6. The mold repair method according to claim 5, characterized in that: In step S4, the vacuum degree after vacuum pumping is not less than -0.095 Mpa, and the vacuum holding time is 10 min to 20 min.

7. The mold repair method according to claim 1, characterized in that: In step S5, when curing the prepreg sheets, the curing temperature is 90 °C to 180 °C, and the pressure is -1 bar to -6 bar.

8. The mold repair method according to claim 1, characterized in that: In step S6, when processing the semi-finished mold, initially polish the surface of the cured prepreg sheet, scrape putty at the gaps between adjacent prepreg sheets, and polish it flat after drying.

9. The mold repair method according to claim 8, characterized in that: In step S6, after polishing flat, clean it, and lay a layer of back glue release cloth on the surface of the mold.

10. A mold, characterized in that: Use the mold repair method according to any one of claims 1-9 to repair the mold to be repaired to obtain a finished mold.

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