CN112846647B - Forming method of special-shaped curved surface structural part - Google Patents

Forming method of special-shaped curved surface structural part Download PDF

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Publication number
CN112846647B
CN112846647B CN202011506387.XA CN202011506387A CN112846647B CN 112846647 B CN112846647 B CN 112846647B CN 202011506387 A CN202011506387 A CN 202011506387A CN 112846647 B CN112846647 B CN 112846647B
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die
forming
wall thickness
blank
section
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CN112846647A (en
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周蕾蕾
刘奇
李妍华
李保永
秦中环
刘玉平
韩维群
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Beijing Hangxing Machinery Manufacturing Co Ltd
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Beijing Hangxing Machinery Manufacturing Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
    • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D37/00—Tools as parts of machines covered by this subclass
    • B21D37/10—Die sets; Pillar guides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D43/00—Feeding, positioning or storing devices combined with, or arranged in, or specially adapted for use in connection with, apparatus for working or processing sheet metal, metal tubes or metal profiles; Associations therewith of cutting devices
    • B21D43/003—Positioning devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D45/00—Ejecting or stripping-off devices arranged in machines or tools dealt with in this subclass
    • B21D45/02—Ejecting devices
    • B21D45/04—Ejecting devices interrelated with motion of tool

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  • Mechanical Engineering (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)

Abstract

The invention relates to a forming method of a special-shaped curved surface structural part, belongs to precision sheet metal machining, and solves the problems that a special-shaped curved surface product with non-equal wall thickness cannot be formed at one time, the surface quality of the product is poor, and the machining efficiency is low in the prior art. The forming method comprises the steps of manufacturing a blank; welding the blank; the welded blank is placed on a forming die, and a welding line corresponds to the step of the upper die; and (5) lowering the upper die and the top cylinder to finish the one-step forming of the special-shaped curved surface structural member with the non-equal wall thickness. The forming die comprises an upper die and a lower die; the upper surface of the lower die is provided with an opening, and the blank is contacted with the lower surface of the upper die and enters the lower die cavity through the opening; the side surface of the upper die is provided with a step, and the step corresponds to the non-flush surface of the blank with different thickness. The invention realizes the one-step forming of the special-shaped curved surface structural member with the non-equal wall thickness.

Description

Forming method of special-shaped curved surface structural part
Technical Field
The invention relates to the technical field of precision sheet metal machining, in particular to a forming method of a special-shaped curved surface structural member.
Background
The aerospace parts are increasingly developed in a direction of complexity, and a product with unequal wall thickness is widely applied to aerospace aircrafts as a typical component.
The cold stamping device and the processing technology can only process products with equal wall thickness, can not form products with unequal wall thickness at one time, and can only adopt the process of tailor welding after sectional forming.
The adoption of the process of sectional forming and then tailor welding has the following defects: firstly, the process of sectional forming and then tailor welding needs manual repair, shape correction and polishing, and the workload is large, so that the processing efficiency of products is extremely low. Secondly, many welding seams, large welding seam deformation and easy crack generation during shape correction, which leads to low one-time qualification rate of products. And thirdly, the surface quality of the product processed by the tailor-welding process is poor. Finally, the mechanical properties of the part are necessarily reduced by the presence of the weld.
Disclosure of Invention
In view of the above analysis, the present invention aims to provide a method for forming a special-shaped curved structural member, which can solve at least one of the following technical problems: (1) The prior art can not form a special-shaped curved surface product with non-equal wall thickness in one step; (2) The split welding process after the sectional forming leads to poor surface quality of products and reduces the mechanical property of the products; and (3) the process processing efficiency of tailor-welding after sectional forming is low.
The invention is mainly realized by the following technical scheme:
on one hand, the forming method of the special-shaped curved surface structural part provided by the invention comprises the following steps:
step 1: manufacturing a blank;
and 2, step: welding the blank;
and step 3: the welded blank is placed on a forming die, and a welding line corresponds to the step of the upper die;
and 4, step 4: and (5) lowering the upper die and the top cylinder to finish the one-step forming of the special-shaped curved surface structural part with the unequal wall thickness.
Based on the further improvement of the forming method, the step 1 specifically comprises the following steps: respectively calculating the external dimensions of blanks with different thicknesses according to product models to be formed, and then respectively blanking; during the calculation of the size, the shell drawing processing is carried out in design software, and then the shell is unfolded.
Based on a further improvement of the forming method, the step 2 comprises the following steps: when in welding, one surface of the blank at two sides of the welding seam is parallel and level, and the other surface is not parallel and level.
Based on the further improvement of the forming method, the step 3 specifically comprises the following steps: the welded blank is placed on the lower die of the forming die, the welding seam corresponds to the step of the upper die, the non-parallel and level surfaces of the blanks on the two sides of the welding seam face the upper die, and the parallel and level surfaces face the lower die.
Based on the further improvement of the forming method, the step 2 and the step 3 comprise the following steps: and operating the jacking cylinder to jack the ejection block in the lower mold cavity, wherein the upper surface of the ejection block is flush with the upper surface of the lower mold.
Based on the further improvement of the forming method, in the step 4: the lower tonnage of the upper die is 50-100T, and the pressure of the top cylinder is 10-40T; forming speed V 1 Is 0.2mm/s.
Based on the further improvement of the forming method, the step 4 is followed by a step 5: demolding; the demolding specifically comprises: simultaneously moving the top cylinder and the upper die, driving the ejection block and the structural part to move upwards by the top cylinder until the upper surface of the ejection block is flush with the upper surface of the lower die, taking out the structural part, and moving at a speed V 2 Is 0.3mm/s.
Based on the further improvement of the forming method, the forming method is completed by adopting a forming die of the special-shaped curved surface structural part with the non-equal wall thickness.
Based on the further improvement of the forming device, the forming die comprises an upper die and a lower die; the side of the upper die is provided with a step.
Based on the further improvement of the forming device, the upper surface of the lower die is provided with an opening, and the blank is contacted with the lower surface of the upper die and enters the lower die cavity through the opening; the side of going up the mould is equipped with the step, the step corresponds with the non-parallel and level face department of the blank of different thickness.
Based on the further improvement of the forming die, the forming die further comprises a die holder, the die holder is arranged between the lower die and the power equipment, and the die holder is fixed on the power equipment.
Based on the further improvement of the forming die, the die holder is fixed on the power equipment through a pressing plate and a bolt.
Based on the further improvement of the forming die, the upper end of the upper die is provided with a flange.
Based on the further improvement of the forming die, the side surface of the upper die is T-shaped.
Based on the further improvement of the forming die, the width of the lower surface of the upper die is gradually changed from one side to the other side.
Based on the further improvement of the forming die, the forming die comprises a front section, a contraction section and a tail section, wherein the contraction section is positioned between the front section and the tail section; the wall thickness of the leading section and the wall thickness of the trailing section are the same as the wall thickness of the leading section and the wall thickness of the converging section.
Based on the further improvement of the forming die, the wall thickness of the tail section is larger than that of the front section and the contraction section.
Based on the further improvement of the forming die, the special-shaped curved surface structural part has unequal wall thickness.
Based on the further improvement of the forming die, the special-shaped curved surface structural part comprises a front section, a contraction section and a tail section; the wall thickness of the front section and the wall thickness of the narrowing section are the same, and the wall thickness of the tail section is different from the wall thickness of the front section and the wall thickness of the narrowing section.
In a further development of the forming tool, the wall thickness of the rear section is greater than the wall thickness of the front section and the constriction section.
Based on the further improvement of the forming die, the special-shaped curved surface structural part is formed by gradually widening the bottom surface of the structural part from the front section to the tail section.
Based on the further improvement of the forming die, the bottom surface of the special-shaped curved surface structural member inclines upwards from the tail section to the front section.
Based on the further improvement of the forming die, the front section has a radian.
Based on the further improvement of the forming die, the forming die further comprises an ejection block, and the ejection block is arranged in the lower die cavity and can ascend and descend under the driving of an ejection cylinder.
Based on the further improvement of the forming die, the lower surface of the upper die is matched with the upper surface of the ejection block, and the blank is positioned between the lower surface of the upper die and the upper surface of the ejection block.
Based on the further improvement of the forming die, the lower surface of the upper die and the upper surface of the ejection block are both parallel to the horizontal plane.
Based on the further improvement of the forming die, the die holder is provided with a avoiding hole, and the jacking cylinder penetrates through the avoiding hole to ascend and descend.
Based on the further improvement of the forming die, the avoiding holes comprise different types so as to adapt to different power equipment.
Based on the further improvement of the forming die, the lower end of the ejection block is provided with a flange.
Based on the further improvement of the forming die, the side surface of the ejection block is in an inverted T shape.
Based on the further improvement of the forming die, the upper surface of the ejection block is provided with a protruding part.
In a further improvement of the forming mold, the opening includes a first opening portion and a second opening portion located at one end of the lower mold, the second opening portion has a width larger than that of the first opening portion, and an end surface of the first opening portion adjacent to the second opening portion is inclined downward.
Compared with the prior art, the invention can realize at least one of the following beneficial effects:
1. the conventional process for producing products with unequal wall thickness is to form the products in sections and then weld the sections together. A large amount of manual trimming, grinding and shape correction are needed, and the process is complex. The invention designs the steps on the upper die of the forming die, breaks through the limitation that the stamping forming can only process materials with equal wall thickness, and realizes the one-step forming of the special-shaped curved surface product with unequal wall thickness.
2. The lower surface of a product to be formed is inclined upwards, and according to the traditional design idea, the mould is also designed to be inclined upwards, namely the lower surface of the upper mould and the upper surface of the ejection block are designed to be inclined upwards, but the mould is inclined upwards, so that the front section of the formed product is piled, the front section of the product is wrinkled and cracked, and the performance of the product is reduced. The invention innovatively designs the lower surface of the upper die and the upper surface of the ejection block to be parallel to the horizontal plane, so that the product is changed from deep stretching (130.8 mm) to shallow stretching (66.5 mm) during forming, and the formed front section of the product is effectively prevented from being piled, thereby reducing the risk of wrinkling and cracking of the front section of the product and ensuring the product quality.
3. According to the invention, the flange is arranged at the lower end of the ejection block, so that the limit effect can be achieved in the lifting process of the ejection block, and the ejection of the ejection block out of the lower die cavity is prevented in the lifting process of the ejection block.
4. The flange is arranged at the upper end of the upper die, so that the upper die can play a role in limiting in the descending process of the upper die, and the upper die is prevented from being excessively pressed into the lower die cavity in the descending process of the upper die.
5. According to the invention, the protruding positioning pin is arranged on the upper surface of the ejection block, so that the blank can be preliminarily positioned when placed on the lower die.
6. The invention adopts an integral forming process, namely, the blanks with unequal wall thicknesses are welded together and then the forming process is carried out, thereby reducing the procedures of manual trimming, polishing and shape correction and greatly improving the processing efficiency. Particularly, the one-step forming process can improve the processing efficiency by 180 percent.
7. The conventional welding process for the welding of products with unequal wall thicknesses has the defects of more welding seams, welding seam deformation, easy generation of cracks during welding seam polishing and the like, and low product yield. The invention adopts the process of welding the blank firstly and then integrally forming, thereby reducing the operation difficulty and greatly increasing the product percent of pass to 100 percent.
8. The integral forming process greatly reduces the number of welding seams and obviously improves the surface quality of parts.
9. The invention adopts an integral forming process, reduces the influence of welding seam deformation on the dimensional precision of parts, and improves the mechanical property of products by 10 percent.
10. According to the invention, the opening on the upper surface of the lower die is set to comprise the first opening part and the second opening part, the width of the second opening part is set to be larger than that of the first opening part, the end surface of the first opening part close to the second opening part is inclined downwards, the accumulation of surplus materials can be effectively reduced while the product profile is ensured to be sufficient, and therefore, the scratches and even the cracks of the lower die during wrinkle smoothing are reduced.
In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. 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 practice of the invention.
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 the overall structure of a forming apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic view of a mold base according to an embodiment of the invention;
FIG. 3 is a schematic view of a lower mold structure according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of an exemplary embodiment of an ejector block;
FIG. 5 is a bottom view of the upper mold in accordance with an embodiment of the present invention;
FIG. 6 is a longitudinal sectional view of the mold closed;
FIG. 7 is a schematic view of a product formed using the forming apparatus of the present invention;
FIG. 8 (a) is a schematic view of a target product formed by using a conventional mold, and FIG. 8 (b) is a schematic view of a target product formed by using a forming mold according to the present invention;
FIG. 9 is a front view of the product as a whole;
FIG. 10 is a top view of the product as a whole;
FIG. 11 is a diagram of a target product formed by a conventional mold;
FIG. 12 is a schematic view of a target product formed by the forming mold of the present invention.
Reference numerals:
1-a die holder, 2-a lower die, 3-an ejection block, 4-an upper die, 5-a positioning pin, 6-a lifting ring screw and 7-an inner hexagonal socket head screw; 8-forepart; 9-a contraction section; 10-end section; 11-bolt positioning holes; 12-avoiding holes; 14-lower mold cavity; 15-step; 16-bolt; 17-a first opening; 18-a second opening; 19-the first opening portion is adjacent to the end surface of the second opening portion.
Detailed Description
The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention and not to limit its scope.
Example one
The invention discloses a method for forming a special-shaped curved surface structural member with unequal wall thickness, which is used for one-step forming of the special-shaped curved surface structural member with unequal wall thickness.
Fig. 8 (a) is a schematic view of a target product formed by a conventional mold, and fig. 8 (b) is a schematic view of a target product formed by a forming mold according to the present invention. The products of fig. 8 (a) and 8 (b) are identical, but the product of fig. 8 (a) is superficially seen with the upper surface parallel to the horizontal and the lower surface inclined upwards by an angle β; whereas the lower surface of the product of fig. 8 (b) is parallel to the horizontal plane and the upper surface is inclined downwardly at an angle.
The process of forming the product is described in detail below.
First, a preform for a part is produced. Specifically, the outer dimensions of blanks with different thicknesses are calculated according to product models to be formed, and then the blanks are blanked respectively.
In a possible embodiment, the blanking mode of the blank adopts a laser cutting mode, 1Cr18Ni9Ti stainless steel with the thickness of 1mm and 1Cr18Ni9Ti stainless steel with the thickness of 2mm are respectively blanked on a laser cutting machine tool, and the blank can also be blanked on a water cutting machine tool, a five-axis numerical control milling machine or a numerical control punch press by selecting a plate. In addition, other blanking methods such as additive manufacturing and surfacing can be adopted for blanking.
It should be noted that, the calculation of the size of the blank is performed in the design software, and in the calculation process, the shell needs to be drawn out and then unfolded in the design software.
It should be noted that, because the product to be formed is a product with an unequal wall thickness, the calculation of the developed material cannot be completed in the design software, and thus the simulation cannot be performed in the simulation software. The shell extraction operation is to extract the product with unequal wall thickness from the middle layer to form a sheet body, and the sheet body can be used for calculating the size of the spreading material and simulating.
Next, blanks of different thicknesses are welded together. It should be noted that, because the thicknesses of the blanks are different, it is necessary to pay attention to the fact that one side of the blank on both sides of the weld seam is flush and the other side is not flush during welding.
And then integrally forming the special-shaped curved surface product with the non-equal wall thickness. Fig. 9 and 10 show a front view and a plan view of the integral forming of the product, and the forming process specifically includes the following steps:
firstly, an upper die is fixed on an upper platform of a 400t oil press through a pressing plate and a bolt, and a lower die is fixed on a lower platform of the 400t oil press through the pressing plate and the bolt.
When the lower die is fixed, attention needs to be paid to correspondence between the top cylinder and the top cylinder avoiding hole; when the upper die is connected with the upper platform, the matching of the positioning pin and the positioning hole between the upper die and the lower die needs to be noticed.
And secondly, brushing lubricating oil on the die, and sticking a plastic film on the welded blank to reduce the occurrence of scratch marks.
Particularly, lubricating oil is needed to be brushed at places where the product is required to be contacted with during product forming, such as the lower surface of the upper die, the upper surface of the ejection block and the side surface of the cavity of the lower die.
And thirdly, jacking the ejection block in the cavity of the lower mold by controlling the jacking cylinder to enable the upper surface of the ejection block to be flush with the upper surface of the lower mold.
Fourthly, placing the preformed welded 1Cr18Ni9Ti stainless steel blank between the upper die and the lower die, preliminarily positioning by using a positioning pin, and determining the final position to be matched with the step of the upper die.
When the welding seam welding device is placed, the unequal heights of the two sides of the welding seam on the blank are required to be noticed to correspond to the steps on the upper die, the uneven surfaces of the two sides of the welding seam on the blank face the upper die, and the uneven surfaces of the two sides of the welding seam on the blank face the lower die.
Fifthly, slowly descending the upper die until the upper die is contacted with the blank, and then simultaneously descending the upper die and the jacking cylinder to realize the forming process of the part; wherein the lower tonnage of the upper die is (50-100) T, and the top cylinder pressure of the lower die is (10-40) T; forming speed V 1 0.2mm/s until the mold is closed.
And sixthly, performing the step of. And (5) demolding the part. With V 2 And simultaneously moving the ejection cylinder and the upper die at 0.3mm/s, driving the ejection block and the part to move upwards by the ejection cylinder until the upper surface of the ejection block is flush with the upper surface of the lower die, and taking out the part.
Finally, the excess is removed from the formed product. The method specifically comprises the steps of firstly scribing, then carrying out laser cutting to remove allowance, and obtaining a final product.
Example two
The invention further discloses a forming device, which is used for forming the special-shaped curved surface structural member with the non-equal wall thickness in the first embodiment.
The special-shaped curved surface structural part with the unequal wall thickness comprises a front section 8, a contraction section 9 and a tail section 10; the product material is: 1Cr18Ni9Ti stainless steel, the material thickness is 1mm and 2mm respectively, namely the front section and the contraction section are 1mm, the rear section is 2mm, the length multiplied by the width multiplied by the height is 1100mm multiplied by 130mm multiplied by 100mm, and the molded product model is shown in figure 7. The bottom surface of the formed special-shaped curved surface structural member inclines upwards from the tail section to the front section, and the included angle between the bottom surface and the horizontal plane is beta, as shown in fig. 8 (a) and 8 (b).
According to the conventional design, in order to form a structural member having the above structure, a designer usually designs the mold to be inclined upward by a certain angle α, that is, the lower surface of the upper mold and the upper surface of the ejector block are designed to be inclined upward, and the following relationship is satisfied;
α＝(0.8～1)β
wherein α and β are both in units.
However, the upward inclination of the mold may cause the front section of the formed product to be piled up, thereby causing the front section of the product to wrinkle and even crack, as shown in fig. 11, and reducing the performance of the product. In a preferred embodiment, the lower surface of the upper die and the upper surface of the ejector block are designed to be parallel to the horizontal plane, so that the deep extension of 130.8mm is changed into the shallow extension of 66.5mm when a product is formed, the front section of the formed product is effectively prevented from being piled, and the risk of wrinkling and cracking of the front section of the product is reduced, as shown in fig. 12, and the product quality is ensured.
As shown in fig. 1. The forming device comprises a die holder 1, a lower die 2, an ejection block 3, an upper die 4, a positioning pin 5, a lifting ring screw 6 and an inner hexagonal socket head screw 7.
The respective parts of the above-described forming apparatus will be described in detail below.
The die holder 1 includes a bolt positioning hole 11 for fixing and an avoidance hole 12 for moving the top cylinder up and down, as shown in fig. 2. The die holder 1 is fixed on a lower platform of the oil press through a pressing plate and a bolt.
It should be noted that the number of the avoiding holes 12 is plural, and the avoiding holes are divided into two types. The first type of avoidance holes are avoidance holes used on the oil press in cooperation with the top cylinder; the second type is a relief hole used in conjunction with a top cylinder on a thermoforming press.
In one possible embodiment, the number of the avoiding holes may be 7, where 3 are the first type of avoiding holes and the remaining 4 are the second type of avoiding holes. Illustratively, the dimensions of the relief holes are: phi 60mm.
The structure of the lower mold 2 will be described in detail with reference to fig. 3.
The lower die 2 includes an ejector block 3 and a lower die cavity 14. The ejection block 3 is placed in the lower mold cavity 14 and can be lifted and lowered by the ejection cylinder. The lower die 2 and the die holder 1 are connected through bolts.
The upper surface of the lower die 2 is provided with an opening through which the lower part of the upper die 4 can enter the lower die cavity 14.
Because the front end of a product to be formed is a special-shaped curved surface, the product is easy to wrinkle in the forming process, and the piled materials are easy to have serious scratches and even cracks when the wrinkles are flattened. In a possible embodiment, the opening of the upper surface of the lower mold 2 comprises a first opening portion 17 and a second opening portion 18 located at one end of the lower mold 2. The width of the second opening portion 18 is larger than the width of the first opening portion 17, and the end surface 19 of the first opening portion adjacent to the second opening portion is inclined downward, and as shown in fig. 3, the end surface of the second opening portion adjacent to the first opening portion and the inclined end surface of the second opening portion are engaged with each other. Through the design, the accumulation of the materials at the allowance part can be effectively reduced while the enough molded surface of the product is ensured, so that scratches and even cracking of the folds at ordinary times are reduced.
The upper surface of the ejection block 3 is provided with a protruding part, and the blank is provided with a through hole corresponding to the protruding part. The projection passes through a through hole in the blank when the blank is placed on the die, and serves to preliminarily position the blank on the lower die 2. For example, the protruding portion may be a positioning pin, or may be another protrusion, as long as the protruding portion can be matched with the through hole on the blank material to perform the function of primarily positioning the blank material.
In a possible embodiment, the lower end of the ejection block 3 has a flange, and the side surface of the ejection block 3 is inverted T-shaped, as shown in fig. 4, so as to play a limiting role during the lifting process of the ejection block 3, thereby preventing the ejection block from punching out of the lower mold cavity during the lifting process.
In another possible embodiment, in order to obtain the product shown in fig. 7, the upper surface of the front section of the ejection block 3 is inclined upwards, as shown in fig. 4.
The upper mold 4 will be described next with reference to fig. 5.
The upper die 4 comprises a step 15 used for being matched with the surface with unequal wall thickness in the blank, a pressing plate (not shown in the figure) used for being connected with an upper platform of the oil press, a screw hole used for being matched with a bolt for hoisting, and a hoisting hole used for adopting a steel wire for hoisting when the bolt is inconvenient to use.
It should be noted that the height of the step 15 and the size of the non-flush face of the blank need to satisfy a certain relationship, as shown in the following formula:
y＝x+Δd
Δd＝d1-d2
in the formula, y is the width of the upper plane of the step in the upper die and is mm; x is the width of the lower plane of the step in the upper die and is mm; d1 is the thickness of the thick blank; d2 is the thickness of the thin blank; Δ d is the thickness difference between thick and thin stock Is composed of 0～0.5mm。
It is noted that the lower plane of the upper mold 4 is parallel to the upper surface of the ejector block 3 in the lower mold 2.
In a preferred embodiment, the upper end of the upper mould 2 has a flange which can act as a stop during the lowering of the upper mould. The side surface of the upper die 2 is T-shaped, and the width of the lower surface of the upper die 2 gradually narrows along the length direction shown in fig. 1, as shown in fig. 5.
In another possible embodiment, the lower surface of the front section of the upper die 4 is inclined upwards, as shown in figure 6, in order to obtain the product shown in figure 7.
Compared with the prior art, the invention can realize at least one of the following beneficial effects:
1. the conventional process for producing products with unequal wall thickness is to form the products in sections and then weld the products together in a tailor-welded manner. A large amount of manual trimming, polishing and shape correction are needed, and the process is complex. The invention designs the steps on the upper die of the forming die, breaks through the limitation that the stamping forming can only process materials with equal wall thickness, and realizes the one-step forming of the special-shaped curved surface product with unequal wall thickness.
2. The lower surface of a product to be formed is inclined upwards, and according to the traditional design idea, the mould is also designed to be inclined upwards, namely the lower surface of the upper mould and the upper surface of the ejection block are designed to be inclined upwards, but the mould is inclined upwards, so that the front section of the formed product is piled, the front section of the product is wrinkled and cracked, and the performance of the product is reduced. The lower surface of the upper die and the upper surface of the ejection block are designed to be parallel to the horizontal plane innovatively, so that the deep extension (130.8 mm) is changed into the shallow extension (66.5 mm) during product forming, the front section of the formed product is effectively prevented from being piled, the risk of wrinkling and cracking of the front section of the product is reduced, and the product quality is ensured.
3. According to the invention, the flange is arranged at the lower end of the ejection block, so that the ejection block can play a limiting role in the ascending process, and the ejection block is prevented from rushing out of the lower mold cavity in the ascending process.
4. The flange is arranged at the upper end of the upper die, so that the upper die can play a role in limiting in the descending process of the upper die, and the upper die is prevented from being excessively pressed into the lower die cavity in the descending process of the upper die.
5. According to the invention, the protruding positioning pin is arranged on the upper surface of the ejection block, so that the blank can be preliminarily positioned when placed on the lower die.
6. The invention adopts an integral forming process, namely, the blanks with unequal wall thicknesses are welded together and then the forming process is carried out, thereby reducing the procedures of manual trimming, polishing and shape correction and greatly improving the processing efficiency. Specifically, the one-step forming process can improve the processing efficiency by 180%.
7. The conventional welding process for the welding of the products with unequal wall thicknesses has the defects of more welding lines, welding line deformation, easy generation of cracks during welding line grinding and the like, and low product yield. The invention adopts the process of welding the blank firstly and then integrally forming, thereby reducing the operation difficulty and greatly increasing the product percent of pass to 100 percent.
8. The integral forming process greatly reduces the number of welding seams and obviously improves the surface quality of parts.
9. The invention adopts an integral forming process, reduces the influence of welding seam deformation on the dimensional precision of parts, and improves the mechanical property of products by 10 percent.
10. According to the invention, the opening on the upper surface of the lower die is set to comprise the first opening part and the second opening part, the width of the second opening part is set to be larger than that of the first opening part, the end surface of the first opening part close to the second opening part is inclined downwards, the accumulation of surplus materials can be effectively reduced while the product profile is ensured to be sufficient, and therefore, the scratches and even the cracks of the lower die during wrinkle smoothing are reduced.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims (5)

1. A forming method of a structural member is characterized by being used for forming the structural member with the irregular curved surface and the unequal wall thickness, and comprising the following steps of:
step 1: manufacturing a blank;
step 2: welding the blank;
and step 3: the welded blank is placed on a forming die, and a welding line corresponds to the step of the upper die;
and 4, step 4: the upper die and the top cylinder are lowered to finish the one-step forming of the special-shaped curved surface structural part with the non-equal wall thickness;
the step 2 and the step 3 comprise the following steps: controlling the jacking cylinder to jack the jacking block in the lower mold cavity, wherein the upper surface of the jacking block is flush with the upper surface of the lower mold;
the forming method is completed by adopting a forming die of a special-shaped curved surface structural part with non-equal wall thickness;
the forming die comprises an upper die and a lower die; the side surface of the upper die is provided with a step;
the forming die also comprises an ejection block, and the ejection block is arranged in the lower die cavity and can be driven by an ejection cylinder to ascend and descend;
the lower surface of the upper die and the upper surface of the ejection block are both parallel to the horizontal plane;
the forming die further comprises a front section, a contraction section and a tail section, wherein the contraction section is positioned between the front section and the tail section; the wall thickness of the front section and the wall thickness of the contraction section are the same, and the wall thickness of the tail section is different from the wall thickness of the front section and the wall thickness of the contraction section;
the wall thickness of the tail section is greater than that of the front section and the contraction section;
from the front section to the tail section, the bottom surface of the special-shaped curved surface structural member gradually becomes wider;
the bottom surface of the special-shaped curved surface structural member inclines upwards from the tail section to the front section;
the upper surface of the lower die is provided with an opening, and the opening comprises a first opening part and a second opening part positioned at one end of the lower die; the width of the second opening part is larger than that of the first opening part, the end face, close to the second opening part, of the first opening part inclines downwards, and the end face, close to the first opening part, of the second opening part is matched with the inclined end face of the second opening part.
2. The forming method according to claim 1, characterized in that said step 1 comprises in particular: and respectively calculating the external dimensions of the blanks with different thicknesses according to the product models to be formed, and then respectively blanking.
3. The forming method according to claim 1, wherein the step 2 includes: when in welding, one surface of the blank at two sides of the welding seam is parallel and level, and the other surface is not parallel and level.
4. The forming method according to claim 1, wherein in the step 4: the lower tonnage of the upper die is 50-100T.
5. The forming method according to any one of claims 1 to 4, further comprising, after the step 4, a step 5 of: and (6) demolding.
CN202011506387.XA 2020-12-18 2020-12-18 Forming method of special-shaped curved surface structural part Active CN112846647B (en)

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Publication number Priority date Publication date Assignee Title
RU2192342C2 (en) * 1997-10-30 2002-11-10 Вольво Аэро Корпорэйшн Method for making articles symmetrical relative to rotation axis of sheet metal with surface of double curvature and variable thickness of material
RU2167733C2 (en) * 1999-08-04 2001-05-27 Общество с ограниченной ответственностью "Синхрон-Рус" Method for making hollow articles with variable thickness of their walls
JP5300275B2 (en) * 2008-01-25 2013-09-25 キヤノン株式会社 Method for manufacturing metal member having a plurality of protrusions
CN103286158B (en) * 2012-02-29 2016-06-22 宝山钢铁股份有限公司 Two one-step forming methods are utilized to prepare method and the device of not uniform thickness vertical masonry joint laser welding pipe
CN103753136B (en) * 2013-12-26 2016-08-31 南宁市南北动力有限公司 A kind of preparation method of rotary cultivator transmission box board
CN109606223A (en) * 2018-12-03 2019-04-12 广汽零部件有限公司 A kind of lightweight not uniform thickness and easily molded automobile chair frame leans on dorsal plate and its manufacturing method
CN110666457A (en) * 2019-10-09 2020-01-10 北京星航机电装备有限公司 Preparation method of titanium alloy thin-wall lightweight flap part
CN110625344B (en) * 2019-11-21 2020-03-17 中国航空制造技术研究院 Method for manufacturing curved surface component with unequal wall thickness

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