阅读说明：本技术 一种拓扑结构壁板增材热压气胀复合成形方法 (Additive hot-pressing and air-bulging composite forming method for topological structure wall plate ) 是由 秦中环 李保永 姚为 韩维群 刘奇 刘伟 肖瑞 徐柄桐 张天麟 丁科迪 于 2020-06-30 设计创作，主要内容包括：本发明公开了一种拓扑结构壁板增材热压气胀复合成形方法,属于精密钣金加工技术领域,解决了现有技术加工的零件整体性差、外形精度控制困难或成本较高的缺点。本发明成形方法,包括以下步骤：步骤1.确定出热压成形所需的拓扑结构壁板坯料的加强筋和拓扑结构位置；步骤2.通过增材制备出拓扑结构壁板坯料；步骤3.制作拓扑结构壁板热压成形模具；步骤4.拓扑结构壁板坯料放于热压成形模具的型腔内,拓扑结构壁板坯料热压成形；步骤5.拓扑结构壁板坯料与上模之间形成一个密闭型腔,通过通气孔将密闭型腔与外界气源连通,向密闭型腔通气加压校形,使拓扑结构壁板加强筋之间的曲面部位形成光滑曲面。本发明改善了零件的表面质量。(The invention discloses a material-adding, hot-pressing and air-bulging composite forming method for a topological structure wall plate, belongs to the technical field of precision sheet metal machining, and solves the defects of poor part integrity, difficult appearance precision control or higher cost in the prior art. The forming method comprises the following steps: step 1, determining reinforcing ribs and topological structure positions of a topological structure wall plate blank required by hot press forming; step 2, preparing a topological structure wallboard blank through material increase; step 3, manufacturing a hot-press forming die for the topological structure wall plate; step 4, placing the topological structure wallboard blank into a cavity of a hot-press forming die, and hot-press forming the topological structure wallboard blank; and 5, forming a closed cavity between the topological structure wall plate blank and the upper die, communicating the closed cavity with an external air source through a vent hole, ventilating, pressurizing and correcting the closed cavity, and forming a smooth curved surface at the curved surface part between the topological structure wall plate reinforcing ribs. The invention improves the surface quality of the part.)

1. A material-adding, hot-pressing and air-bulging composite forming method for a topological structure wallboard is characterized by comprising the following steps of:

step 1, determining reinforcing ribs and topological structure positions of a topological structure wall plate blank required by hot press forming according to the external dimension, the reinforcing rib positions and the topological structure form of the topological structure wall plate to be formed;

step 2, preparing a topological structure wall plate blank through additive manufacturing according to the reinforcing ribs and the topological structure positions of the topological structure wall plate blank determined in the step 1;

step 3, manufacturing a hot press forming die for the topological structure wall plate according to the external dimension of the topological structure wall plate to be formed;

step 4, after the hot-press forming die manufactured in the step 3 is heated to the hot-press forming temperature, the topological structure wallboard blank manufactured in the step 2 is placed in a cavity of the hot-press forming die, the upper die gradually moves towards the lower die, the topological structure wallboard blank gradually deforms in the cavity of the hot-press forming die until the upper die and the lower die are closed, namely the die assembly is complete, and the hot-press forming of the topological structure wallboard blank is finished;

and 5, forming a closed cavity between the topological structure wall plate blank and the upper die after hot press forming in the step 4, wherein the upper die is provided with a vent hole, the closed cavity is communicated with an external air source through the vent hole, and the closed cavity is ventilated, pressurized and corrected to form a smooth curved surface at the curved surface part between the topological structure wall plate reinforcing ribs.

2. The method according to claim 1, wherein the topological structure in step 1 is in the form of a tetrahedron structure, a pyramid structure or a diamond structure.

3. The additive hot-pressing and air-bulging composite forming method for the topological structure wall plate according to claim 1, wherein the topological structure wall plate is made of aluminum alloy or titanium alloy.

4. The additive hot-pressing and air-bulging composite forming method for the topological structure wall plate according to claim 1, wherein the additive forming method in the step 2 is a selective melting method, a direct melting deposition method or an electric arc additive forming method.

5. The additive hot-pressing and air-bulging composite forming method for the topological structure wall plate according to claim 3, wherein in the step 3, the cavity of the hot-pressing forming die of the aluminum alloy topological structure wall plate blank is subjected to proper amplification processing, so that the size of the cavity of the hot-pressing forming die is properly amplified to be 3-7% of the external dimension of the topological structure wall plate to be formed.

6. The additive hot-pressing and air-bulging composite forming method for the topological structure wallboard as claimed in claim 3, wherein in the step 3, the cavity of the hot-pressing forming die of the titanium alloy topological structure wallboard blank is subjected to proper reduction processing, so that the size of the cavity of the hot-pressing forming die is properly reduced by 3-7 per mill of the external dimension of the topological structure wallboard to be formed.

7. The additive hot-pressing and air-bulging composite forming method for the topological structure wall plate according to claim 5, wherein in the step 4, the hot-pressing forming temperature of the aluminum alloy topological structure wall plate blank is 420-520 ℃, and the moving speed of an upper die to a lower die is 1-10 mm/s.

8. The additive hot-pressing and air-bulging composite forming method for the topological structure wallboard according to claim 1, wherein in the step 4, the hot-pressing forming temperature of the titanium alloy topological structure wallboard blank is 880-930 ℃, and the moving speed of an upper die to a lower die is 1-10 mm/s.

9. The additive hot-pressing and air-bulging composite forming method for the topological structure wallboard according to claims 1-8, wherein in the step 5, the final gas pressure of the pressurization and shape correction is 0.1-3 MPa, and the pressure is maintained for 10-30 min.

10. The additive hot-pressing and air-bulging composite forming method for the topological structure wallboard according to claim 7, wherein the hot-pressing forming temperature of the aluminum alloy topological structure wallboard blank is 420-460 ℃.

Technical Field

The invention belongs to the technical field of precision sheet metal machining, and particularly relates to a material-adding, hot-pressing and air-bulging composite forming method for a topological structure wall plate.

Background

The titanium alloy and the aluminum alloy have excellent use performance, and are widely applied in the fields of aerospace, rail transit, weaponry and the like. In the field of aerospace, the integration and lightweight degree of a topological structure wall plate type part product is higher and higher, and the requirement on manufacturing precision is higher and higher. In the field of sheet forming, common manufacturing methods for topological structure wall plates mainly comprise cold press forming, casting forming and direct additive forming. The cold press forming has the defects that the dimensional accuracy is difficult to meet the requirement, the profile accuracy is difficult to control, a large amount of manual correction is required in the subsequent process, the forming period is long, and the defects of springback, wrinkling, cracking and the like are easy to generate. In addition, non-uniform wall thickness can cause sagging of the thin wall portions between ribs during cold forming. The casting forming method is limited by the types of materials, the topological structure wall plate parts are difficult to cast, a large amount of mechanical processing is still needed in the subsequent process, the processing cost is high, and the preparation period is long. The direct additive forming can manufacture a complex topological structure, but has low forming efficiency, difficult profile control and high processing cost.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a method for additive hot-pressing and air-bulging composite forming of a topological structure wall plate, so as to solve the defects of poor part integrity, difficult shape precision control or high cost in the prior art.

The purpose of the invention is mainly realized by the following technical scheme:

a material-adding, hot-pressing and air-bulging composite forming method for a topological structure wallboard comprises the following steps:

step 1, determining reinforcing ribs and topological structure positions of a topological structure wall plate blank required by hot press forming according to the external dimension, the reinforcing rib positions and the topological structure form of the topological structure wall plate to be formed;

step 2, preparing a topological structure wall plate blank through additive manufacturing according to the reinforcing ribs and the topological structure positions of the topological structure wall plate blank determined in the step 1;

step 3, manufacturing a hot press forming die for the topological structure wall plate according to the external dimension of the topological structure wall plate to be formed;

step 4, after the hot-press forming die manufactured in the step 3 is heated to the hot-press forming temperature, the topological structure wallboard blank manufactured in the step 2 is placed in a cavity of the hot-press forming die, the upper die gradually moves towards the lower die, the topological structure wallboard blank gradually deforms in the cavity of the hot-press forming die until the upper die and the lower die are closed, namely the die assembly is complete, and the hot-press forming of the topological structure wallboard blank is finished;

and 5, forming a closed cavity between the topological structure wall plate blank and the upper die after hot press forming in the step 4, wherein the upper die is provided with a vent hole, the closed cavity is communicated with an external air source through the vent hole, and the closed cavity is ventilated, pressurized and corrected to form a smooth curved surface at the curved surface part between the topological structure wall plate reinforcing ribs.

Further, the topological structure in step 1 is in a tetrahedral structure, a pyramid structure or a diamond structure.

Further, the topological structure wall plate is made of aluminum alloy or titanium alloy.

Further, the additive method in the step 2 is a selective melting method, a direct fused deposition method or an arc additive method.

Further, in the step 3, a cavity of the hot-press forming die for the aluminum alloy topological structure wall plate blank is subjected to proper amplification processing, so that the size of the cavity of the hot-press forming die is properly amplified to be 3-7 per mill of the external dimension of the topological structure wall plate to be formed.

Further, in step 3, the cavity of the titanium alloy topological structure wall plate blank hot-press forming die is properly reduced, so that the size of the cavity of the hot-press forming die is properly reduced to 3-7 per mill of the external dimension of the topological structure wall plate to be formed.

Further, in the step 4, the hot press forming temperature of the aluminum alloy topological structure wall plate blank is 420-520 ℃, and the moving speed of the upper die to the lower die is 1-10 mm/s.

Further, in the step 4, the hot press forming temperature of the titanium alloy topological structure wall plate blank is 880-930 ℃, and the moving speed of the upper die to the lower die is 1-10 mm/s.

Further, in the step 5, the final gas pressure of the pressurization and shape correction is 0.1-3 MPa, and the pressure is maintained for 10-30 min.

Further, the hot press forming temperature of the aluminum alloy topological structure wall plate blank is 420-460 ℃.

Compared with the prior art, the invention can at least realize one of the following technical effects:

1) the topological structure wallboard formed by the invention has good integrity, the size precision of parts reaches GB/T1804-m, the profile precision reaches +/-0.2 mm, and the surface quality is higher. The invention adopts the combined process of material increase, hot press forming and gas bulging correction to form the topological structure wall plate, solves the problem that the size precision and the profile precision of the parts are difficult to control in the conventional cold stamping or mechanical processing, improves the surface quality of the parts and avoids the overweight problem in the casting processing.

2) The invention adopts hot press forming, and can effectively avoid the defects of springback, wrinkling, cracking and the like in the cold forming process.

3) The near-net forming of the part can be realized by adopting the inflatable shape correction, the subsequent processing amount can be effectively reduced, the subsequent manual shape correction is avoided, the efficiency is improved by more than 20%, the cost is reduced by more than 10%, and the requirements of the size precision, the profile precision and the surface quality of the part are ensured.

4) Compared with direct additive manufacturing, the invention improves the processing efficiency by more than 20 percent, the profile precision is easy to control, and the residual stress is low.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

FIG. 1 is a schematic view of a topological wall panel;

FIG. 2 is a schematic view of a thermoformed topology wall blank;

FIG. 3 is a schematic view of a thermoforming mold for a topological structure panel;

fig. 4 is a schematic view of the hot pressing and inflation process of the topological structure wall plate.

Reference numerals:

1-upper mould; 2-a vent hole; 3-topological structure wall plate blank; 4-lower mould; a 5-tetrahedral structure; 6-a pyramid structure; 7-diamond structure.

Detailed Description

A method for additive, hot-pressing, and air-inflation composite forming of a topological wall panel is described in further detail below with reference to specific examples, which are provided for purposes of comparison and explanation only and to which the present invention is not limited.

A material-adding, hot-pressing and air-bulging composite forming method for a topological structure wallboard comprises the following steps:

step 1, determining reinforcing ribs and topological structure positions of a topological structure wall plate blank required by hot press forming according to the external dimension, the reinforcing rib positions and the topological structure form of the topological structure wall plate to be formed;

step 2, preparing a topological structure wall plate blank through additive manufacturing according to the reinforcing ribs and the topological structure positions of the topological structure wall plate blank determined in the step 1;

step 3, manufacturing a hot press forming die for the topological structure wall plate according to the external dimension of the topological structure wall plate to be formed;

step 4, after the hot-press forming die manufactured in the step 3 is heated to the hot-press forming temperature, the topological structure wallboard blank manufactured in the step 2 is placed in a cavity of the hot-press forming die, the upper die gradually moves towards the lower die, the topological structure wallboard blank gradually deforms in the cavity of the hot-press forming die until the upper die and the lower die are closed, namely the die assembly is complete, and the hot-press forming of the topological structure wallboard blank is finished; keeping the pressure for 10-30min after the die assembly is completed, wherein the rebound can occur when the pressure keeping time is too short, and the performance of the material can be reduced when the pressure keeping time is too long;

and 5, forming a closed cavity between the topological structure wall plate blank and the upper die after hot press forming in the step 4, wherein the upper die is provided with vent holes, the vent holes are connected with the inside of the cavity and the outside, the closed cavity is communicated with an outside air source through the vent holes of the upper die, and the closed cavity is ventilated, pressurized and corrected, so that the curved surface part between the topological structure wall plate reinforcing ribs forms a smooth curved surface.

According to the invention, the topological structure wall plate is formed by adopting a combined process of material increase, hot press forming and gas bulging correction, so that the problem that the size precision and the profile precision of the parts are difficult to control in conventional cold stamping or machining is solved, the surface quality of the parts is improved, and the overweight problem in casting is avoided; by manufacturing a topological structure wall plate flat plate in an additive mode, hot press forming is adopted firstly, so that the defects of springback, wrinkling, cracking and the like in a cold forming process can be effectively avoided; the inflatable shape correction is adopted, so that the requirements on the size precision, the profile precision and the surface quality of the part are met; compared with direct additive manufacturing, the machining efficiency is high, the profile precision is easy to control, and the residual stress is low.

The topological structure in step 1 may be, but is not limited to, a tetrahedral structure 5, a pyramidal structure 6 or a diamond structure 7.

The additive process in step 2 may be, but is not limited to, a selective melting process, a direct fused deposition process, or an arc additive process.

The topological wall plate material can be, but is not limited to, an aluminum alloy or a titanium alloy.

When the material of the topological structure wall plate is aluminum alloy, in the step 3, the cavity of the aluminum alloy topological structure wall plate blank hot-press forming die is subjected to proper amplification processing, so that the size of the cavity of the hot-press forming die is properly amplified to be 3-7 per mill of the external dimension of the topological structure wall plate to be formed, and the accuracy of the oversize or undersize size cannot meet the requirement of +/-0.3 mm. In the step 4, the hot press forming temperature of the aluminum alloy topological structure wall plate blank is 420-520 ℃, the aluminum alloy topological structure wall plate blank can rebound when the temperature is too low, the performance of the material is reduced when the temperature is too high, the moving speed of the upper die to the lower die is 1-10 mm/s, the speed is too high, parts are easy to crack, the speed is too low, the processing efficiency is low, and the preferable speed is 1-5 mm/s.

When the material of the topological structure wall plate is titanium alloy, in the step 3, the cavity of the hot-press forming die of the titanium alloy topological structure wall plate blank is properly reduced, so that the size of the cavity of the hot-press forming die is properly reduced to 3-7 per mill of the external dimension of the topological structure wall plate to be formed, and the excessive or insufficient size precision can not reach the requirement of +/-0.3 mm. In the step 4, the hot-press forming temperature of the titanium alloy topological structure wallboard blank is 880-930 ℃, the temperature is too low, the material performance is reduced due to too high temperature, the moving speed of the upper die to the lower die is 1-10 mm/s, the speed is too high, parts are easy to crack, the speed is too low, the processing efficiency is low, and the preferable speed is 1-5 mm/s.

In the step 5, the rate of loading gas during ventilation is 0.01-1 MPa/min, the efficiency is too low due to too low loading rate, and local fracture is caused due to too high loading rate. And keeping the final gas pressure at 0.1-3 MPa for 10-30 min.

The aluminum alloy topological structure wall plate prepared by the method has the size precision of +/-0.3 mm, the profile precision of +/-0.5 mm and the surface roughness of Ra3.2 or less, reduces the manufacturing cost by more than 10 percent compared with the existing method, and improves the processing efficiency by more than 20 percent.

Preferably, the hot press forming temperature of the aluminum alloy topological structure wall plate blank is 420-460 ℃, the forming temperature is low, and the required heating time is shortened, so that the cost is reduced. The forming cost of the aluminum alloy topological structure wall plate can be reduced by more than 20 percent compared with the prior art.

According to the invention, a preferable scheme is provided, the pressure of the loaded gas in the step 5 is 1-3 MPa, the pressure is higher, the die attaching effect is good, the precision is improved, the precision of the forming size of the aluminum alloy topological structure wall plate can be improved to be more than +/-0.2 mm, the aerospace craft has a more excellent aerodynamic appearance, and the attitude control of the aerospace craft is facilitated.