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

Abstract

The invention discloses a design method of a precision die forging forming die for a large curved window frame, which comprises the following steps of: designing reasonable machining allowance, pattern draft and flash for a specified large curved window frame part along the characteristics of ribs to obtain a large curved window frame forged piece structure; the method comprises the following steps of: designing mold cores, mold cavities, flash bridge parts and bin parts of an upper die and a lower die for die forging by taking the normal direction of a maximum area projection plane of a large window frame forging as a die splitting direction and taking a neutral surface of the forging along the die splitting direction as a die splitting surface; cutting blanks with approximately same appearance along the middle position of the flash by taking the maximum inner and outer contours of the forge piece as a reference; analog simulation is carried out on die forging forming of the large curved window frame forge piece, the machining allowance size of the forge piece and the bridge portion and bin portion size of a die flash are adjusted according to the die filling condition and the load change, and finally the shape and size of a die forging forming die cavity are obtained. By adopting the method, the material utilization rate and the forging deformation can be obviously improved, and meanwhile, the machining difficulty is effectively reduced.

Description

Technical Field

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

[0002] In the prior art, the forging processing method of large curved window frame forgings is usually a simple large hexahedron that envelops the parts. The die forging process is to press the rectangular blank into a curved hexahedron with a certain curvature, and then perform mechanical processing on it to obtain the required parts. However, the material utilization rate of this method is often less than 5%, and the forming time is difficult and long; at the same time, the formed forging does not have certain part shape characteristics, which makes the subsequent mechanical processing tools difficult.

[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 object 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 high processing difficulty and low material utilization rate in the existing large curved window frame forging forming methods.

[0005] To achieve the above purpose, the present invention adopts the following technical solution: A method for designing a precision forging die for a large curved window frame, characterized in that it comprises the following steps: Step 1: Based on the forging design standard, a reasonable machining allowance, draft angle and flash are designed for the features of the specified large curved window frame parts along the ribs to obtain the large curved window frame forging structure; Step 2: Take the normal direction of the largest area projection surface of the large window frame forging as the parting direction, take the neutral surface of the forging along the parting direction as the parting surface, and 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 a blank with roughly the same shape along the middle of the flash; Step 4: Simulate the die forging of large curved window frame forgings, 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, and finally obtain the shape and size of the die forging die cavity.

[0006] Furthermore, the large curved window frame forging in step 1 should have a similar curved surface curvature to the large curved window frame part, with an error not exceeding ±5°.

[0007] Furthermore, the single-side machining allowance in step 1 is 5-20 mm, including 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 in step 2. The neutral surface in step 2 is the curved parting surface in the area where the mold core and cavity are located, and the parting surface in the area where the mold base is located is the plane where the maximum area projection surface of the neutral surface is located.

[0008] 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.

[0009] Furthermore, the flash of step 3 should include both inner flash and outer flash, and both the upper mold and the lower mold 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, the bin range is 20-200 mm, and the error does not exceed ±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.

[0010] In step 3, according to the simulation results, the height of the burr bridge is appropriately increased when the load is too large; when the filling is poor, the height of the burr bridge is appropriately reduced until the best simulation result is achieved.

[0011] 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 mechanical processing.

[0012] 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.

[0013] 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; finally, the plate is used for die forging.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention creatively proposes a design method for a precision die forging die for large curved window frames, and a special die obtained by the design method. By designing the die structure of curved parting, internal and external flash, combined with numerical simulation analysis, the forging processing allowance, draft angle, bridge and bin height dimensions of the flash are adjusted to optimize the low material utilization rate and high mechanical processing difficulty of die forging of large curved window frames, so that the material utilization rate is increased from less than 5% to about 10%, and the mechanical processing can be processed along the rib routing, reducing the processing difficulty by nearly 30%, and making the rib have a certain degree of uniform deformation, which significantly improves the convenience of processing large curved window frame forgings and improves the material utilization rate.

[0015] 2. The present invention designs a mold structure with curved parting and internal and external flash to make the forging have certain shape characteristics of the rib area of ​​the part after die forging, so that the subsequent mechanical processing can be processed along the line of the rib, which significantly reduces the difficulty of mechanical processing. At the same time, forging the rib can effectively reduce the volume of the blank, significantly improve the material utilization rate, and make the forging have a certain degree of deformation to ensure the mechanical performance requirements of the forging. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the forging design of Example 1 of the present invention.

[0017] Figure 2 Schematic diagram of the upper mold and lower mold design of Example 1 of the present invention.

[0018] Figure 3 This is a diagram of the numerical simulation load distribution and optimization results of Example 1 of the present invention.

[0019] Figure 4 It is a comparison chart of material utilization and deformation between Example 1 of the present invention and the traditional design method.

[0020] Specific implementation measures The technical solution of the present invention is clearly and completely described below in conjunction with specific embodiments and drawings. Obviously, the embodiments are only representative of 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 creative work are within the scope of protection of the present invention.

[0021] It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. The terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the figures, or the positions or positional relationships in which the invented product is usually placed when used. 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 orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] The present invention provides a method for designing a precision forging die for a large curved window frame, comprising the following steps: 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 single-side machining allowance of the curved window frame forging is 5-20 mm, the draft angle is 5-7°, and it is symmetrically distributed along the parting surface, and the forging and the curved window frame part have a similar surface curvature, and the error does not exceed ±5°; Step 2, taking the normal direction of the maximum area projection surface of the curved window frame forging as the parting direction, taking the neutral surface of the forging along the parting direction as the curved parting surface, designing the core on the upper die, designing the cavity on the lower die, designing the flash bridge and the bin to be symmetrically distributed along the curved parting surface, the bridge range is 5-30 mm, the bin range is 20-200 mm, and the error does not exceed ±1 mm. The flash includes an inner flash and an outer flash, and its height can be set to different sizes, and the same curvature as the curved parting surface is maintained; 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; 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 condition and load changes, and finally obtain the shape and size of the die forging die cavity.

[0023] The neutral surface is the curved parting surface where the mold core and cavity are located, and the mold base is located on the plane where the maximum projection surface of the curved parting surface is located. This can ensure the maximum utilization of the blank and facilitate demolding of the forging.

[0024] The single-side machining allowance is 5-20 mm, including both sides of the ribs and the upper and lower surfaces; the draft angle is 5-7° and is symmetrically distributed along the parting surface. Such symmetrical distribution allows the ribs to be filled in two directions at the same time, reducing the difficulty of filling.

[0025] The core should be on the concave side of the forging and designed in the upper die, and the cavity should be on the convex side of the forging and designed in the lower die. In this way, the blank can be placed in the cavity, which is convenient for positioning the blank.

[0026] Example 1 like Figure 1 The figure shows a three-dimensional diagram of a forging designed along the rib alignment of a part, where the orange area is the forging, the red area is the flash bridge, and the blue area is the inner flash warehouse. The parting direction of the forging is the direction of the arrow, that is, the normal direction of the maximum surface area projection. The single-sided machining allowance on both sides of the forging is 20 mm at the thin ribs and 10 mm at the thick ribs, and the single-sided machining allowance on the upper and lower surfaces is 10 mm. The height dimensions of the flash bridge of the forging in the parting direction are the same, the inner flash bridge is 25 mm, and the outer flash bridge is 10 mm, and it has the same surface curvature as the parting surface.

[0027] See also Figure 2 Based on the design method of the die forging forming die of the present invention, the upper die and the lower die of this embodiment are obtained. Among them, the core is located in the upper die, the cavity is located in the lower die, and the red area is the flash bin of the die, which has the same height dimension in the parting direction, the inner flash bin is 120 mm, the outer flash bin is 100 mm, and has the same surface curvature as the parting surface. At the same time, due to the particularity of this embodiment, the green area in the figure is a flash bin that relieves the filling pressure.

[0028] See also Figure 3 ,based on Figure 2 The die forging die is used to forge the flat blank through a press. From the filling analysis, it can be seen that the forging area shown in the shaded part has been completely filled, the inner flash bin is still full, and the outer flash bin also has excess overflow, which proves that the blank flows in this area during forming, and proves that the forming possibility is good.

[0029] like Figure 4 The figure shows a comparison between the present embodiment and the conventional large curved window frame forging die forging method and product. By comparison, it can be seen 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.

[0030] 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.

[0031] Figure 4 b is a die forging die obtained by using the embodiment of the present invention. The flat blank is die forged by a press, and the forming load is 49,000 tons. The large curved window frame forging obtained is then formed by wire cutting. After using the method of the present invention, V 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.

[0032] 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.

[0033] 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 the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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 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 standard, a reasonable machining allowance, draft angle and flash are designed for the features of the specified large curved window frame parts along the ribs to obtain the large curved window frame forging structure; Step 2: Take the normal direction of the largest area projection surface of the large window frame forging as the parting direction, take the neutral surface of the forging along the parting direction as the parting surface, and 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 a blank with roughly the same shape along the middle of the flash; Step 4: Simulate the die forging of large curved window frame forgings, 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, and finally obtain the shape and size of the die forging die cavity.

2. The design method of the precision forging die for large curved window frames according to claim 1 is characterized by: The large curved window frame forging in step 1 should have a similar curved surface curvature to the large curved window frame parts, with an error of no more than ±5°.

3. The design method of the precision forging die for large curved window frames according to claim 1 is characterized by: 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 design method of the precision forging die for large curved window frames according to claim 1 is characterized by: The neutral surface in step 2 is the curved parting surface in the area where the mold core and cavity are located, and the parting surface in the area where the mold base is located is the plane where the maximum area projection surface of the neutral surface is located.

5. The design method of the precision forging die for large curved window frames according to claim 4 is characterized by: 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 design method of the precision forging die for large curved window frames according to claim 1 is characterized by: The flash described in step 3 should include both inner and outer flash. 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. The error does not exceed ±1 mm. The heights of the bridge and the bin of the inner and outer flash can be 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, characterized in that: In step 3, according to the simulation results, the height of the burr bridge is appropriately increased when the load is too large; when the filling is poor, the height of the burr bridge is appropriately reduced until the best simulation result is achieved.

8. According to the design method of the precision forging die for large curved window frames as described in claim 1, the optimization goal is to improve the material utilization rate of large curved window frame forgings, increase the deformation of forgings, and reduce the difficulty of subsequent machining.

9. 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 8.

10. A die forging method for large curved window frame precision forgings, characterized in that: The method comprises the following steps: firstly, designing the forging structure by adopting step 1 of claim 1; then, designing the die by adopting any design method described in claims 1-8; and finally, performing die forging by adopting the plate.

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