Large reinforced component semi-closed local loading precision forming die and application

Abstract

A semi-closed, locally loaded precision forming mold for large ribbed components and its application are disclosed. The mold includes: an upper template, a front floating blank holder module, a forming punch, and a rear floating blank holder module sequentially arranged on the upper template, a sequence of split punches arranged opposite each other below the upper template, a punch template, a die, and a lower template. The blank is placed between the split punch sequence and the die. The die and the lower template are slidably connected, with each punch in the split punch sequence facing the front floating blank holder module, the forming punch, or the rear floating blank holder module, collectively constructing a structural feature conforming to the cross-sectional morphology of the ribbed component. This invention, by employing a floating blank holder, establishes sufficient constraints on both sides of the forming area, effectively suppressing the transverse flow of material across regions during forming, eliminating forming defects such as folding, and significantly reducing the overall forming load of the component. This is expected to enable labor-saving manufacturing of large ribbed components.

Description

Technical Field

[0001] This invention relates to a technology in the field of metal plastic processing, specifically a semi-closed local loading precision forming mold for large ribbed components and its application. Background Technology

[0002] Local loading technology offers the combined advantages of labor saving and precise forming, and is considered one of the most promising technologies for low-cost manufacturing of large, ribbed components. However, in existing technologies, when the die applies local pressure to the blank, the necessary constraints are lacking on both sides of the deformation zone. This makes the material prone to transverse flow across the region, causing defects such as warping and folding, which limits the widespread application of this technology. Summary of the Invention

[0003] This invention addresses the limitations of existing local loading forming techniques in resolving issues such as transverse material flow across regions, folding, and warping. It proposes a semi-closed local loading precision forming mold for large ribbed components and its application. By employing a floating pressure plate method, sufficient constraints are established on both sides of the forming area, effectively suppressing transverse material flow across regions during the forming process, eliminating forming defects such as folding, and significantly reducing the overall forming load of the component. This invention holds promise for achieving labor-saving manufacturing of large ribbed components.

[0004] This invention is achieved through the following technical solution:

[0005] This invention relates to a semi-closed, locally loaded precision forming mold for large ribbed components, comprising: an upper template, a front floating blank holder module, a forming punch and a rear floating blank holder module sequentially arranged thereon, a sequence of split punches arranged opposite to each other under the upper template, a punch template, a die, and a lower template, wherein: the blank is arranged between the sequence of split punches and the die, the die and the lower template are slidably connected such that each punch in the sequence of split punches is sequentially aligned with the front floating blank holder module, the forming punch or the rear floating blank holder module, together constructing a structural feature that conforms to the cross-sectional shape of the ribbed component.

[0006] The convex template is provided with stepped through holes for installing a sequence of split convex dies. Each convex die is sequentially and movably installed in the convex template through the stepped through holes.

[0007] The upper template is provided with a recessed groove for mounting the front floating blank holder module, the forming punch, and the rear floating blank holder module, so that the assembly height of the rear floating blank holder module is greater than that of the front floating blank holder module, and the difference in assembly height between the two is consistent with the single pressing amount of the forming punch; the assembly height of the front floating blank holder module is slightly higher than that of the forming punch, and the difference in assembly height ensures that the forming process is carried out under sufficient boundary constraints.

[0008] This invention relates to a method for precision forming of large ribbed components using semi-closed local loading based on the aforementioned device, comprising:

[0009] Step 1: Install the molds: Assemble the molds in sequence according to the mating relationships between different molds;

[0010] Step 2: Turn on the heating system to heat the billet and the mold separately;

[0011] Step 3: Start the feeding device to push the die cavity and accurately position the first area to be formed in the split punch sequence directly below the forming punch.

[0012] Step 4: Start the press. The upper die platen moves downwards until the front floating blank holder module contacts the second area to be formed in the split punch sequence (corresponding to the undeformed area of ​​the blank). Since there is no corresponding die below the rear floating blank holder module at this time, the rear floating blank holder module does not contact the split punch sequence. The press continues to move downwards until the forming punch contacts the first area to be formed in the split punch sequence (corresponding to the area to be formed in the blank). During this process, the hydraulic cylinder of the front floating blank holder module retracts under pressure, and the front floating blank holder module continuously applies blank holder force to the second area to be formed in the split punch sequence. The press moves downwards again, and the forming punch drives the first area to be formed in the split punch sequence to locally load the blank, completing the first step of blank forming. During this loading stage, the front floating blank holder module continuously retracts and stably outputs blank holder force.

[0013] Step 5: Press return stroke;

[0014] Step Six: The press descends again, and the rear floating blank holder module descends accordingly, contacting the first formed area of ​​the split punch sequence. Simultaneously, the front floating blank holder module contacts the third unformed area of ​​the split punch sequence. The press continues to descend until the forming punch contacts the second unformed area of ​​the split punch sequence. During this process, the front and rear floating blank holder modules are continuously compressed and retract, continuously outputting blank holder force to the third unformed area (corresponding to the undeformed area of ​​the blank) and the first deformed area (corresponding to the formed area of ​​the blank) of the split punch sequence, respectively. The press continues to descend, and the forming punch drives the second unformed area of ​​the split punch sequence to locally load the blank, causing the material to undergo plastic deformation, completing the second forming step.

[0015] Step 7: Repeat steps 5 and 6 above, loading in sequence, until all the ribs on the large ribbed component are formed. The number of repetitions is the same as the number of the split punch sequence.

[0016] Technical effect

[0017] This invention employs a combination of "floating blank holder" and "local loading" to ensure that the material within the deformation zone is under high hydrostatic stress during local loading. Compared to existing technologies, this completely eliminates the constraint gaps introduced by rigid pads in traditional local loading processes, preventing unwanted transverse material flow across regions and controlling forming defects such as folding and warping. By establishing a localized high hydrostatic stress horizontal stress state, this invention significantly improves the plastic filling effect of the material, enabling large ribbed components to achieve a dense microstructure and precise macroscopic dimensions, realizing the "fabrication of large components with small equipment." Furthermore, through the decoupling distribution of the main forming force and blank holder force, a rational distribution of kinetic energy is achieved. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the large reinforced component of the present invention;

[0020] Figure 3 This is a schematic diagram of the concave mold structure of the present invention;

[0021] Figure 4 This is a schematic diagram of the split punch sequence structure of the present invention;

[0022] Figure 5 This is a schematic diagram of the front floating edge pressing module and the rear floating edge pressing module of the present invention;

[0023] Figure 6 This is a schematic diagram of the convex template structure of the present invention;

[0024] Figure 7 This is a schematic diagram of the semi-closed local loading precision forming process of the present invention;

[0025] Figure 8 The results show the comparison of forming forces between the semi-closed local loading precision forming of this invention and other forming processes (taking a component size of 500mm as an example).

[0026] Figure 9 This is a comparison chart of simulation results of the semi-closed local loading precision forming of the present invention with other forming processes (taking a component size of 500mm as an example);

[0027] In the diagram: 1. Separate punch sequence, 2. Punch template, 3. Die, 4. Lower template, 5. Feeding device, 6. Forming punch, 7. Upper template, 8. Front floating edge pressing module, 9. Rear floating edge pressing module, 10. Guide post, 11. Blank. Detailed Implementation

[0028] like Figure 1As shown in the figure, this embodiment relates to a semi-closed partial loading precision forming mold for a large ribbed component, including: an upper template 7, a front floating pressure plate module 8, a forming punch 6 and a rear floating pressure plate module 9 sequentially arranged on it, and a split punch sequence 1, a punch template 2, a die 3 and a lower template 4 sequentially arranged opposite to each other under the upper template 7, wherein: the blank 11 is arranged between the split punch sequence 1 and the die 3, the die 3 and the lower template 4 are slidably connected such that each punch in the split punch sequence 1 is sequentially facing the front floating pressure plate module 8, the forming punch 6 or the rear floating pressure plate module 9, together constructing a structural feature that conforms to the cross-sectional shape of the ribbed component.

[0029] The convex template 2 is provided with stepped through holes for installing the split convex die sequence 1. Each convex die is sequentially and movably installed in the convex template 2 through the stepped through holes.

[0030] The front ends of the die 3 and the lower template 4 are both provided with threaded holes and connected to the feeding device 5. The feeding device 5 drives the die 3 to move smoothly back and forth linearly on the lower template 4.

[0031] The lower template 4 is provided with heating holes for installing heating rods to achieve overall preheating and temperature control of the mold system.

[0032] Both the concave mold 3 and the convex mold 2 are provided with corresponding guide post holes, and the concave mold 3 and the convex mold 2 are precisely aligned and guided by the guide post 10.

[0033] The upper template 7 is provided with a receiving groove for installing the front floating edge pressing module 8, the forming punch 6 and the rear floating edge pressing module 9, with the forming punch 6 located between the front floating edge pressing module 8 and the rear floating edge pressing module 9.

[0034] The assembly height of the rear floating blank holder module 9 is greater than that of the front floating blank holder module 8, and the difference in assembly height between the two is consistent with the single pressing amount of the forming punch 6; the assembly height of the front floating blank holder module 8 is slightly higher than that of the forming punch 6, and the difference in assembly height ensures that the forming process is carried out under sufficient boundary constraints.

[0035] The front floating pressure plate module 8 and the rear floating pressure plate module 9 are driven by independent hydraulic cylinders. These hydraulic cylinders have the functions of retracting under pressure and springing back after unloading, and their maximum retraction stroke is much greater than the sum of the single pressing amount of the forming punch 6 and the height difference between the front floating pressure plate module 8 and the forming punch 6.

[0036] This embodiment relates to a forming method for large ribbed aluminum alloy components of the 7xxx series based on the above-mentioned device, including:

[0037] Step 1: Mold Installation: First, securely fix the lower template 4 on the press worktable. Place heating rods in the heating holes of the lower template 4 and connect the temperature control power supply. Then, hoist and fix the die 3 onto the lower template 4. Precisely position and assemble the feeding device 5 with the die 3 and lower template 4 through the threaded hole at the front end. Adjust the feeding device 5 to ensure that the die 3 can slide freely and smoothly on the lower template 4 in the front-back direction. Next, press each of the separate punch sequences 1 into the stepped through holes of the punch template 2. Use guide pillars 10 inserted into the corresponding guide pillar holes of the punch template 2 and the die 3 to achieve precise alignment of the punch and die system, so that the separate punch sequences 1 and the die 3 are precisely combined to form a forming cavity that conforms to the cross-sectional shape of the ribbed component. Fix the upper template 7 onto the press slide. Then, sequentially embed the front floating pressure plate module 8, the forming punch 6, and the rear floating pressure plate module 9 into the receiving groove of the upper template 7. During this process, the initial assembly height of each module must be strictly adjusted to ensure that the height difference between the rear floating blank holder module 9 and the front floating blank holder module 8 is consistent with the single pressing amount of the forming punch 6, and to ensure that the assembly height of the front floating blank holder module 8 is slightly higher than that of the forming punch 6. Finally, the front 8 and the rear floating blank holder module 9 are fastened to their respective independent hydraulic cylinder drive systems, and the retraction stroke of the hydraulic cylinders is tested to ensure that it meets the design requirements.

[0038] Step 2: Turn on the heating system and use heating rods to heat the lower template 4, the die 3, the split punch sequence 1, and the punch template 2. Use corresponding temperature sensors to monitor the temperature of the split punch sequence 1 and the die 3 in real time. Simultaneously, place the blank 11 to be formed into the heating furnace for preheating. When the blank 11, the die 3, and the split punch sequence 1 are all close to the target forming temperature, remove the preheated blank 11 from the heating furnace and place it stably into the cavity of the die 3.

[0039] The heating temperature of the mold is 450°C, and the preheating temperature of the blank 11 is 450°C.

[0040] Step 3: Start the feeding device 5 to push the die 3 and accurately position the first area to be formed in the split punch sequence 1 directly below the forming punch 6.

[0041] Step 4: Start the press. The upper die plate 7 moves downward until the front floating blank holder module 8 contacts the second area to be formed in the split punch sequence 1 (corresponding to the undeformed area of ​​the blank). Since there is no corresponding die below the rear floating blank holder module 9 at this time, the rear floating blank holder module 9 does not contact the split punch sequence 1. The press continues to move downward until the forming punch 6 contacts the first area to be formed in the split punch sequence 1 (corresponding to the area to be formed in the blank). During this process, the hydraulic cylinder of the front floating blank holder module 8 is compressed and retracts, and the front floating blank holder module 8 continuously applies blank holder force to the second area to be formed in the split punch sequence 1. The press moves downward again, and the forming punch 6 drives the first area to be formed in the split punch sequence 1 to locally load the blank, completing the first step of blank forming. During this loading stage, the front floating blank holder module 8 continuously retracts and stably outputs blank holder force.

[0042] Step 5: Press return. During this process, the front floating pressure module 8 is continuously ejected and reset under the action of the hydraulic cylinder. Then, the feeding device 5 is started, driving the die 3 to move the second area to be formed in the split punch sequence 1 to directly below the forming punch 6. The moving distance is set according to the spacing of the split punch sequence 1.

[0043] Step Six: The press descends again, and the rear floating blank holder module 9 descends accordingly, contacting the first formed area of ​​the split punch sequence 1. Simultaneously, the front floating blank holder module 8 contacts the third area to be formed in the split punch sequence 1. The press continues to descend until the forming punch 6 contacts the second area to be formed in the split punch sequence 1. During this process, the front 8 and rear floating blank holder modules 9 are continuously compressed and retract, continuously outputting blank holder force to the third area to be formed in the split punch sequence 1 (corresponding to the undeformed area of ​​the blank) and the first deformed area (corresponding to the formed area of ​​the blank), respectively. The press continues to descend, and the forming punch 6 drives the second area to be formed in the split punch sequence 1 to locally load the blank, causing the material to undergo plastic deformation, completing the second forming step.

[0044] Step 7: Repeat steps 5 and 6 above, loading in sequence until all ribs on the large ribbed component are formed. The number of repetitions is the same as the number of times the split punch sequence 1 is executed.

[0045] In steps four through seven, the press descends at a speed of 3 mm / s, the return distance of the front floating edge pressing module 8 and the rear floating edge pressing module 9 is 15 mm, and the pressing force is 150 kN.

[0046] Through actual finite element simulation experiments, the above process was carried out in an isothermal environment of 450℃. The formed large ribbed components showed no obvious folding or warping defects, demonstrating good defect control capabilities. Compared to overall loading, the forming load of this invention is reduced by 76%. Figure 7The diagram illustrates the loading process for semi-closed local loading precision forming of a large ribbed component. (a) shows the forming process of the first loading step, (b) shows the forming process of the second loading step, and (c) shows the forming process of the final loading step. This invention employs a sequential local loading method from front to back to reduce the forming load on the component and avoid filling defects in this complex component. The front floating edge clamping module 8 and the rear floating edge clamping module 9 provide clamping force during the forming process, restricting the transverse flow of material across regions and preventing defects such as rib penetration and folding.

[0047] like Figure 8 The figure shows a comparison of forming loads between semi-closed local loading precision forming and other forming processes. Because all the separate punches in sequence 1 compress the blank simultaneously during the overall loading process, the total forming tonnage is the highest, approximately 13544 kN. In the traditional local loading forming process, only a local punch contacts the blank in the early stage of deformation, resulting in a lower forming load of approximately 2325 kN, achieving labor-saving forming. However, in the later stage of forming, the undeformed and formed areas lack mold constraints, making it easy for material to flow laterally across regions. This causes the mold in the undeformed and formed areas to contact the blank, resulting in a sudden increase in the maximum forming load to 11912 kN, only about 12% lower than the overall loading load, failing to achieve the expected labor-saving forming advantage. The semi-closed local loading precision forming technology in this invention establishes sufficient constraints by setting floating pressure plates on both sides of the forming area, greatly limiting the lateral flow of material across regions, with a maximum forming load of approximately 2900 kN. Compared to traditional local loading, the semi-closed local loading load is reduced by approximately 76%, truly achieving labor-saving forming. Therefore, the semi-closed local loading precision forming technology of the present invention has significant labor-saving forming advantages in forming large ribbed components.

[0048] like Figure 9 The figure shows a comparison of simulation results between semi-closed local loading precision forming and other forming processes. The equivalent strain distribution of large ribbed components formed by overall loading is relatively uniform, and no obvious forming defects such as folding were found. In contrast, the equivalent strain distribution of large ribbed components formed by traditional local loading is significantly uneven. Lateral material flow across regions causes the rib height in the later formed region to be higher than that in the earlier formed region, resulting in folding at the root of the lateral ribs and a significant increase in equivalent strain in the folded area. The semi-closed local loading precision forming of this invention, by setting sufficient constraints on both sides of the forming area, restricts the lateral material flow across regions, avoiding defects such as folding. The structure of the formed large ribbed component is largely consistent with that of the large ribbed component formed by overall loading. Therefore, the semi-closed local loading precision forming process of this invention can constrain the lateral material flow across regions, avoid forming defects, and achieve precision forming of large ribbed components.

[0049] In summary, compared with the prior art, the present invention achieves the following performance improvements:

[0050] 1) Eliminating constraint gaps effectively suppresses forming defects and achieves labor-saving forming. This invention constructs sufficient and dynamic boundary constraint conditions on both sides of the forming area by setting front and rear floating pressure modules. This structure effectively overcomes the problem of constraint gaps introduced by the use of hard pads to set height differences in traditional local loading forming, which leads to lateral flow of material across regions. It fundamentally suppresses defects such as folding and warping of material during the forming process, and truly leverages the labor-saving forming advantages of local loading technology.

[0051] 2) Achieving localized closed-die forging significantly improves shape and property control. All forming steps in this invention are based on fully constrained boundary conditions, essentially transforming the traditional "overall closed-die forging" into "multiple localized closed-die forging." This forming method with localized high hydrostatic stress levels greatly improves the plastic filling fluidity of the material, which is beneficial for achieving excellent shape and property control for large, ribbed components.

[0052] 3) Rational power distribution and optimized equipment load. Based on the difference between the blank holder force and the forming force, this invention scientifically configures the drive source. The larger main forming force is provided by the press, while the smaller blank holder force is provided independently by the hydraulic cylinder. This design achieves rational distribution and efficient utilization of system kinetic energy and load, reducing reliance on a single ultra-large tonnage press.

[0053] 4) Modular design ensures high equipment flexibility and wide applicability. Both the front and rear floating edge-pressing modules of this invention adopt independent modular designs. In actual production, the specific installation positions of the front and rear floating edge-pressing modules can be flexibly adjusted according to the specific structural characteristics of different forming components (such as rib spacing). This design significantly improves the versatility of the mold, meeting the forming requirements of various different components and effectively avoiding the cost of repeatedly developing dedicated equipment for new products.

[0054] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.

Claims

1. A semi-closed, locally loaded precision forming mold for large ribbed components, characterized in that, include: The upper template, the front floating blank holder module, the forming punch and the rear floating blank holder module are sequentially set on it, the split punch sequence, the punch template, the die and the lower template are sequentially set opposite to each other under the upper template, wherein: the blank is set between the split punch sequence and the die, the die and the lower template are slidably connected and each punch in the split punch sequence is sequentially facing the front floating blank holder module, the forming punch or the rear floating blank holder module, together constructing a structural feature that conforms to the cross-sectional shape of the ribbed component.

2. The large-scale ribbed component semi-closed local loading precision forming mold according to claim 1, characterized in that, The convex template is provided with stepped through holes for installing a sequence of split convex dies. Each convex die is sequentially and movably installed in the convex template through the stepped through holes.

3. The large-scale ribbed component semi-closed local loading precision forming mold according to claim 1, characterized in that, The upper template is provided with a recessed groove for mounting the front floating blank holder module, the forming punch, and the rear floating blank holder module, so that the assembly height of the rear floating blank holder module is greater than that of the front floating blank holder module, and the difference in assembly height between the two is consistent with the single pressing amount of the forming punch; the assembly height of the front floating blank holder module is slightly higher than that of the forming punch, and the difference in assembly height ensures that the forming process is carried out under sufficient boundary constraints.

4. The large-scale ribbed component semi-closed local loading precision forming mold according to claim 1, characterized in that, The lower template is provided with heating holes for installing heating rods to achieve overall preheating and temperature control of the mold system.

5. The large-scale ribbed component semi-closed local loading precision forming mold according to claim 1, characterized in that, The front ends of both the die cavity and the lower template are provided with threaded holes and connected to a feeding device, which drives the die cavity to move smoothly back and forth linearly on the lower template.

6. The large-scale ribbed component semi-closed local loading precision forming mold according to claim 1, characterized in that, Both the die cavity and the die plate are provided with corresponding guide post holes, and the die cavity and the die plate are precisely aligned and guided by the guide posts.

7. The large-scale ribbed component semi-closed local loading precision forming mold according to claim 1 or 3, characterized in that, The front floating blank holder module and the rear floating blank holder module are driven by independent hydraulic cylinders. The hydraulic cylinders have the functions of retracting under pressure and springing back after unloading. Moreover, their maximum retraction stroke is much greater than the sum of the single pressing amount of the forming punch and the height difference between the front floating blank holder module and the forming punch.

8. A method for precision forming of large ribbed components under semi-closed local loading based on the device described in any one of claims 1-7, characterized in that, include: Step 1: Install the molds: Assemble the molds in sequence according to the mating relationships between different molds; Step 2: Turn on the heating system to heat the billet and the mold separately; Step 3: Start the feeding device to push the die cavity and accurately position the first area to be formed in the split punch sequence directly below the forming punch; Step 4: Start the press. The upper die plate moves downward until the front floating blank holder module contacts the second area to be formed in the split punch sequence. Since there is no corresponding mold below the rear floating blank holder module at this time, the rear floating blank holder module does not contact the split punch sequence. The press continues to move downward until the forming punch contacts the first area to be formed in the split punch sequence. During this process, the hydraulic cylinder of the front floating blank holder module is compressed and retracts. The front floating blank holder module continuously applies blank holder force to the second area to be formed in the split punch sequence. The press descends again, and the forming punch drives the first area of ​​the split punch sequence to locally load the blank, completing the first step of blank forming. During this loading stage, the front floating blank holder module continues to retract and stably outputs blank holder force. Step 5: Press return stroke; Step Six: The press descends again, and the rear floating blank holder module descends accordingly and contacts the first formed area of ​​the split punch sequence. At the same time, the front floating blank holder module contacts the third area to be formed of the split punch sequence. The press continues to descend until the forming punch contacts the second area to be formed of the split punch sequence. During this process, the front and rear floating blank holder modules are continuously compressed and retract, and continuously output blank holder force to the third area to be formed and the first deformed area of ​​the split punch sequence, respectively. As the press continues to descend, the forming punch drives the second forming area of ​​the split punch sequence to locally load the blank, causing the material to undergo plastic deformation and completing the second forming step. Step 7: Repeat steps 5 and 6 above, loading in sequence, until all the ribs on the large ribbed component are formed. The number of repetitions is the same as the number of the split punch sequence.

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