Design method of precision forging die for large curved window frame forgings

Abstract

The present invention discloses a design method for a precision die forging die for a large curved window frame. The method includes designing a reasonable machining allowance, draft angle, and flash along the rib features of a specified large curved window frame part to obtain a large curved window frame forging structure. The method uses the normal direction of the maximum projected surface of the large window frame forging as the parting direction, and the neutral surface of the forging along the parting direction as the parting surface to design the core, cavity, flash bridge, and chamber of the upper and lower die forging dies. Based on the maximum inner and outer contours of the forging, a blank with a substantially identical shape is cut along the middle of the flash. The die forging of the large curved window frame forging is simulated, and the machining allowance size of the forging and the bridge and chamber sizes of the die flash are adjusted according to the die filling condition and load changes. Finally, the shape and size of the die forging die cavity are obtained. The present invention can significantly improve material utilization and deformation of forgings, while effectively reducing machining difficulty.

Description

Technical Field

[0001] The invention relates to a design method for a precision die forging die for a large curved window frame, and belongs to the technical field of die forging. Background Art

[0002] Existing forging methods for large curved window frame forgings typically involve die-forging a simple large hexahedron that envelops the part. The die-forging process involves pressing a rectangular blank into a curved hexahedron with a defined radius, which is then machined to create the desired part. However, this method often results in a material utilization rate of less than 5%, and the forming process is complex and time-consuming. Furthermore, the resulting forging lacks the desired shape characteristics, making subsequent machining challenging.

[0003] Therefore, how to provide a design method for a precision forging die for large curved window frames to provide a special die to simplify the processing method of large curved window frame forgings, reduce the processing difficulty, and improve material utilization is a technical problem to be solved by technical personnel in this field. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a precision die forging method for large curved window frames and its die, so as to solve the problems of the existing large curved window frame forging forming methods such as high processing difficulty and low material utilization rate.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A method for designing a precision forging die for a large curved window frame, characterized by comprising the following steps:

[0007] Step 1: Based on the forging design standards, reasonable machining allowance, draft angle, and flash are designed along the rib features of the specified large curved window frame part to obtain the large curved window frame forging structure;

[0008] Step 2: Taking the normal direction of the largest projected surface of the large window frame forging as the parting direction and the neutral surface of the forging along the parting direction as the parting surface, design the core, cavity, flash bridge and chamber of the upper and lower die forging;

[0009] Step 3: Based on the maximum inner and outer contours of the forging, cut out blanks with roughly the same shape along the middle of the flash;

[0010] Step 4: Simulate the die forging of the large curved window frame forging. Adjust the machining allowance size of the forging and the bridge and bin sizes of the die flash according to the die filling conditions and load changes. Finally, obtain the shape and size of the die forging die cavity.

[0011] Furthermore, the large curved window frame forging in step 1 should have a similar surface curvature to that of the large curved window frame part, with an error not exceeding ±5°.

[0012] Furthermore, the single-side machining allowance in step 1 is 5-20 mm, including both sides and the upper and lower surfaces of the ribs; the draft angle is 5-7° and is symmetrically distributed along the parting surface described in step 2. The neutral surface in step 2 is the curved parting surface in the mold core and cavity areas, and the parting surface in the mold base area is the plane with the largest area projection of the neutral surface.

[0013] Furthermore, the core should be the concave side of the forging and should be designed in the upper die, and the cavity should be the convex side of the forging and should be designed in the lower die.

[0014] Furthermore, the flash of step 3 should include both inner and outer flash, and both the upper and lower molds have a flash bridge and a bin. The bridge and the bin should have the same height dimension in the parting direction, the bridge range is 5~30 mm, and the bin range is 20-200 mm, with an error of no more than ±1 mm. The heights of the bridge and the bin of the inner and outer flash can be set to different sizes, and the bridge and the bin of the flash should maintain the same surface curvature as the parting surface.

[0015] In step 3, based on the simulation results, the height of the fin bridge portion is appropriately increased when the load is too large; and the height of the fin bridge portion is appropriately reduced when the filling is poor, until the best simulation result is achieved.

[0016] The optimization goal of the present invention is to improve the material utilization rate of large curved window frame forgings, increase the deformation of the forgings, and reduce the difficulty of subsequent machining.

[0017] The present invention also provides a precision forging die for a large curved window frame, which is obtained by adopting the above-mentioned design method.

[0018] The present invention also provides a die forging method for a large curved window frame precision forging. First, the forging structure is designed; then, the die is designed using the design method; and finally, the plate is used for die forging.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention creatively proposes a design method for a precision die forging die for large curved window frames, as well as a special die obtained by using the design method. By designing the die structure of the curved parting die and the internal and external flash, combined with numerical simulation analysis, the forging processing allowance, draft angle, and the height dimensions of the bridge and bin of the flash are regulated, thereby optimizing the low material utilization rate and high mechanical processing difficulty of the die forging of large curved window frames, thereby increasing the material utilization rate from less than 5% to about 10%, and enabling mechanical processing along the rib line, reducing the processing difficulty by nearly 30%, and allowing the rib to have a certain degree of uniform deformation, thereby significantly improving the convenience of processing large curved window frame forgings and improving material utilization rate.

[0021] 2. By designing a die structure with curved parting and internal and external flash, this invention ensures that the forged part has a specific shape characteristic of the rib area after die forging. This allows subsequent machining to follow the alignment of the ribs, significantly reducing the machining difficulty. Furthermore, forging the ribs effectively reduces the volume of the blank, significantly improving material utilization, and allowing the forging to have a certain degree of deformation, ensuring the forging's mechanical performance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the forging design of Example 1 of the present invention.

[0023] Figure 2 Schematic diagram of the upper mold and lower mold design of Example 1 of the present invention.

[0024] Figure 3 This is a diagram of the numerical simulation load distribution and optimization results of Example 1 of the present invention.

[0025] Figure 4 1 is a comparison chart of material utilization and deformation between Example 1 of the present invention and the traditional design method. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solutions of the present invention in conjunction with specific embodiments and drawings. Obviously, the embodiments are only representative of the embodiments of the present invention and are not limited to the described embodiments. Therefore, the following detailed description of the embodiments provided in the drawings is not intended to limit the scope of the invention claimed for protection. 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.

[0027] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures. The terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the figures, or the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limiting the present invention. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The present invention provides a method for designing a precision forging die for a large curved window frame, comprising the following steps:

[0029] Step 1: Based on the structure of the large curved window frame part, a curved window frame forging is designed along the rib area of ​​the large curved window frame part. The curved window frame forging has a single-side machining allowance of 5-20 mm, a draft angle of 5-7°, and is symmetrically distributed along the parting plane. The forging has a similar surface curvature to the curved window frame part, with an error of no more than ±5°.

[0030] Step 2: Using the normal direction of the maximum projected surface of the curved window frame forging as the parting direction and the neutral surface of the forging along the parting direction as the curved parting surface, design the core in the upper die, design the cavity in the lower die, and design the flash bridge and the chamber to be symmetrically distributed along the curved parting surface. The bridge range is 5-30 mm, and the chamber range is 20-200 mm, with an error of no more than ±1 mm. The flash includes inner flash and outer flash, and its height can be set to different sizes while maintaining the same surface curvature as the curved parting surface.

[0031] Step 3, based on the maximum inner and outer contours of the forging, cutting the sheet material along the middle of the flash to design a blank;

[0032] Step 4: simulate the die forging of the large curved window frame forging. Adjust the machining allowance size of the forging and the bridge and bin sizes of the die flash according to the die filling situation and load changes. Finally, obtain the shape and size of the die forging die cavity.

[0033] The neutral plane is the curved parting surface where the mold core and cavity are located, and the mold base is the plane where the maximum projection of the curved parting surface is located. This ensures maximum utilization of the blank and facilitates demolding of forgings.

[0034] The single-side machining allowance is 5-20 mm, including both sides and the upper and lower surfaces of the ribs. The draft angle is 5-7° and is symmetrically distributed along the parting plane. This symmetrical distribution allows the ribs to be filled in two directions simultaneously, reducing the filling difficulty.

[0035] The core should be located on the concave side of the forging and designed in the upper die, while the cavity should be located on the convex side of the forging and designed in the lower die. This allows the blank to be placed in the cavity, making it easier to position the blank.

[0036] Example 1

[0037] like Figure 1 The figure shows a 3D image of a forging designed along the rib alignment of a part. The orange area represents the forging, the red area represents the flash bridge, and the blue area represents the inner flash pocket. The parting direction of the forging is the direction of the arrow, which is the normal to the maximum surface area projection. The single-sided machining allowance on both sides of the forging is 20 mm for thin ribs and 10 mm for thick ribs. The single-sided machining allowance on both surfaces is 10 mm. The flash bridge height dimensions of the forging are identical in the parting direction: 25 mm for the inner flash bridge and 10 mm for the outer flash bridge. The curvature of the surface is the same as that of the parting surface.

[0038] See also Figure 2 Based on the die forging die design method of the present invention, the upper and lower dies of this embodiment are obtained. The core is located in the upper die, and the cavity is located in the lower die. The red area represents the flash pocket of the die. Its height dimensions along the parting direction are identical: the inner flash pocket is 120 mm, and the outer flash pocket is 100 mm. They also have the same curvature as the parting surface. Furthermore, due to the unique characteristics of this embodiment, the green area in the figure represents a flash-like pocket that relieves filling pressure.

[0039] See also Figure 3 ,based on Figure 2 The die forging die is used to forge a flat sheet of material using a press. Analysis of the filling situation shows that the shaded area of ​​the forging is completely filled, with some excess material remaining in the inner flash pocket and some excess material in the outer flash-like pocket. This demonstrates that material flow occurs in this area during forming, indicating good forming potential.

[0040] like Figure 4 The figure shows a comparison between this embodiment and the conventional large curved window frame forging die forging method and product. The comparison shows that the material utilization rate of the method of the present invention is increased from 3.8% to 6.9% compared with the conventional method.

[0041] Figure 4 a is the traditional processing method, that is, the die forging process is to press the rectangular blank into a curved hexahedron with a certain curvature, and then machine it to obtain the required parts, V 零件=0.027m 3 , V 传统 =0.702m 3 , after calculation, the material utilization rate is 3.8%. Figure 4 As can be seen from c, the strain in the forging area is less than 0.2, indicating that almost no deformation has occurred.

[0042] Figure 4 b is a die forging die obtained by using an embodiment of the present invention. A flat sheet is die forged by a press with a forming load of 49,000 tons. The obtained large curved window frame forging is then formed by wire cutting. 优化 =0.389m 3 , after calculation, the material utilization rate is 6.9%. Figure 4 d shows that the strain range of the forging area is mainly 0.75-1.5, which shows that its uniform deformation is good and its deformation amount is significantly increased.

[0043] In summary, the present invention creatively designs a mold structure with curved parting and internal and external flash to give the forging the shape characteristics of the part rib area, significantly improves material utilization, increases the deformation of the forging, and at the same time enables machining to be carried out along the alignment of the ribs, reducing the difficulty of machining.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A design method for a precision forging die for a large curved window frame, characterized in that: The steps include: Step 1: Based on the forging design standards, reasonable machining allowance, draft angle and flash are designed along the rib features of the specified large curved window frame part to obtain the large curved window frame forging structure; Step 2: Taking the normal direction of the largest projected surface of the large window frame forging as the parting direction and the neutral surface of the forging along the parting direction as the parting surface, design the core, cavity, flash bridge and chamber of the upper and lower die forging; Step 3: Based on the maximum inner and outer contours of the forging, cut out blanks with roughly the same shape along the middle of the flash; Step 4: Simulate the die forging of the large curved window frame forging. Adjust the machining allowance size of the forging and the bridge and bin sizes of the die flash according to the die filling conditions and load changes. Finally, obtain the shape and size of the die forging die cavity.

2. The method for designing a precision forging die for a large curved window frame according to claim 1, characterized in that: The large curved window frame forging in step 1 should have a similar surface curvature to the large curved window frame part, with an error not exceeding ±5°.

3. The method for designing a precision forging die for a large curved window frame according to claim 1 is characterized in that: The single-side machining allowance in step 1 is 5-20 mm, which includes both sides of the rib and the upper and lower surfaces; the draft angle is 5-7° and is symmetrically distributed along the parting surface described in step 2.

4. The method for designing a precision forging die for a large curved window frame according to claim 1 is characterized in that: The neutral surface in step 2 is the curved parting surface of the mold core and cavity area, and the parting surface of the mold base area is the plane where the maximum area projection surface of the neutral surface is located.

5. The method for designing a precision forging die for a large curved window frame according to claim 4 is characterized in that: The core should be the concave side of the forging and should be designed in the upper die, and the cavity should be the convex side of the forging and should be designed in the lower die.

6. The method for designing a precision forging die for a large curved window frame according to claim 1 is characterized in that: The flash described in step 3 should include both inner and outer flash. The upper and lower molds also have a flash bridge and a bin. The bridge and the bin should have the same height dimension in the parting direction. The bridge range is 5~30 mm, and the bin range is 20-200 mm. The error does not exceed ±1 mm. The heights of the bridge and the bin of the inner and outer flash are set to different sizes. The bridge and the bin of the flash should maintain the same surface curvature as the parting surface.

7. The method for designing a precision forging die for a large curved window frame according to claim 1 is characterized in that: In step 3, based on the simulation results, the height of the fin bridge portion is appropriately increased when the load is too large; and the height of the fin bridge portion is appropriately reduced when the filling is poor, until the best simulation result is achieved.

8. A precision forging die for a large curved window frame, characterized in that it is obtained by adopting the design method described in any one of claims 1 to 7.

9. A die forging method for large curved window frame precision forgings, characterized in that: The method comprises the following steps: first, designing a forging structure by adopting step 1 of claim 1; then, designing a die by adopting any design method described in claims 1-7; and finally, performing die forging by using a plate.

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