CN112642930B

CN112642930B - Electromagnetic composite forming method for oblique flange box-shaped part

Info

Publication number: CN112642930B
Application number: CN202011459284.2A
Authority: CN
Inventors: 刘维; 周海波; 孟正华; 黄尚宇
Original assignee: Wuhan University of Technology WUT
Current assignee: Wuhan University of Technology WUT
Priority date: 2020-12-11
Filing date: 2020-12-11
Publication date: 2021-12-03
Anticipated expiration: 2040-12-11
Also published as: CN112642930A

Abstract

The invention discloses a method for electromagnetic composite forming of inclined flange box-shaped parts. The external circuit is connected, and the metal blank is attached to the flat rectangular spiral coil placed horizontally, and the flat rectangular spiral coil is charged or discharged through the external circuit, so that a pulse magnetic field is generated in the space around the flat rectangular spiral coil, which is then subjected to the action of electromagnetic force. , judge whether the metal blank after preliminary forming has reached the predetermined height, if it reaches the predetermined height, place a rubber pad in the die assembly, the rubber pad is set under the metal blank, and continue to charge or discharge the flat rectangular spiral coil through an external circuit, and carry out For shape correction, the punch assembly is driven by the press to press down to complete the forming and form the inclined flange box-shaped part, which can greatly simplify the forming process of the inclined flange box-shaped part and effectively improve its forming quality and efficiency.

Description

Electromagnetic composite forming method for oblique flange box-shaped part

Technical Field

The invention relates to the technical field of material forming, in particular to an electromagnetic composite forming method for an oblique flange box-shaped part.

Background

Electromagnetic pulse forming is a method of high-speed machining of metal workpieces using pulsed electromagnetic force. The research shows that: different from the quasi-static deformation behavior of the traditional processing method, the material has a dynamic deformation behavior under high-speed impact, and the dynamic deformation behavior is specifically represented as the dynamic behaviors of crystal twinning, tissue phase change, adiabatic shearing and the like. Therefore, the forming limit of the aluminum magnesium alloy and the titanium alloy can be effectively improved, and the rebound is reduced.

The oblique flange aluminum alloy box-shaped part is a common non-axisymmetric part in the field of aircraft industry, and due to the fact that the geometric shape of the oblique flange aluminum alloy box-shaped part is complex, stress and strain distribution of a deformation area is very uneven due to a traditional deep drawing forming method, and forming is difficult. In view of this, researchers have proposed different forming schemes, specifically the following:

(1) the forming of the box-shaped part is completed by adopting multi-pass deep drawing forming, a finite element model is established to analyze the forming process of the box-shaped part, the optimal data of a plurality of influencing factors such as blank expansion size, multi-pass die structure, blank pressing force and the like are determined, and a set of feasible forming method is researched. But the forming process needs to be completed by combining a plurality of sets of dies, so that the production cost is increased, and the processing process is more complicated.

(2) The method is applied to the production of the parts, the influence of various parameters of the hydraulic forming on the forming process of the unequal-height flat-bottom box-shaped part is researched through numerical simulation and experiments, and the simulation result is well matched with the experiment result. However, the liquid filling and discharging process exists in the hydraulic forming, and the pre-expansion height and the pressure are difficult to determine for the box-shaped parts with different heights, so that the forming process is difficult.

(3) In addition, the drop forming can also realize the processing of the special-shaped box-shaped part, but the processed surface of the finished part of the special-shaped box-shaped part has wrinkles which are difficult to eliminate, and the surface quality of the part is poor.

Disclosure of Invention

According to the defects of the prior art, the invention aims to provide the electromagnetic composite forming method of the oblique flange box-shaped part, which can greatly simplify the forming process of the oblique flange box-shaped part, does not need multiple sets of dies, has a simpler processing process and is easy to control, folds are not easy to appear on the surface of a processed part, and the forming quality and efficiency of the part are effectively improved.

In order to solve the technical problems, the invention adopts the technical scheme that:

an electromagnetic composite forming method for a beveled flange box-shaped part comprises the following steps:

step 1, assembling a die, namely placing a metal blank on a female die assembly, embedding a planar rectangular spiral coil at the bottom of a male die assembly, connecting external circuits at two ends of the planar rectangular spiral coil, and placing the male die assembly above the metal blank;

step 2, performing electromagnetic forming, namely enabling the metal blank to be tightly attached to the horizontally placed planar rectangular spiral coil, and charging or discharging the planar rectangular spiral coil through the external circuit to enable a space around the planar rectangular spiral coil to generate a pulse magnetic field, wherein the metal blank in the pulse magnetic field induces current to form a charged body, and then the charged body is subjected to the action of electromagnetic force to perform primary forming;

step 3, correcting the shape of a rubber pad, namely judging whether the preliminarily formed metal blank reaches a preset height, if so, placing the rubber pad in the female die assembly, wherein the rubber pad is arranged below the metal blank, continuously charging or discharging the planar rectangular spiral coil through the external circuit to correct the shape, and if not, moving the male die assembly downwards to reduce the distance between the planar rectangular spiral coil and the metal blank, and repeating the step 2;

and 4, forming a steel die, driving the male die assembly to press downwards through a press machine, and finishing forming to form the inclined flange box-shaped part.

Furthermore, the male die assembly comprises an upper die plate, a base plate, a male die and a male die fixing plate, the upper die plate is installed on the press machine, the base plate is fixed between the upper die plate and the male die, and the male die fixing plate is sleeved on the outer side of the male die and fixed to the bottom of the base plate.

Further, the female die assembly comprises a lower die plate and a female die, and the female die is fixed on the upper side of the lower die plate.

Further, the external circuit comprises a capacitor, a power switch and a resistor, and the planar rectangular spiral coil is charged or discharged by charging or discharging the capacitor.

Further, the number of times the capacitor is charged or discharged depends on the final desired sidewall height of the beveled flange box and the discharge capacity of the electromagnetic device.

Further, the planar rectangular spiral coil is adjusted according to the structure of the desired inclined flange box to change the direction and magnitude of the electromagnetic force.

Further, if the deformation degree of a certain part of the metal blank needs to be increased, the deformation degree can be realized by reducing the turn pitch of the planar rectangular spiral coil at the part, and if the deformation degree of the certain part of the metal blank needs to be reduced, the deformation degree can be realized by increasing the turn pitch of the planar rectangular spiral coil at the part.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the electromagnetic composite forming method for the oblique flange box-shaped piece, disclosed by the invention, combines forming methods such as electromagnetic forming, soft die sizing, steel die forming and the like, can greatly simplify the forming process of the oblique flange box-shaped piece, does not need multiple sets of dies, is simpler in processing process and easy to control, and can effectively improve the forming quality and efficiency of the piece, and wrinkles are not easy to appear on the surface of the processed piece.

2. According to the electromagnetic composite forming method for the inclined flange box-shaped part, disclosed by the invention, the metal blank is preformed by utilizing the advantage that electromagnetic force has non-contact, so that the problem of stress concentration in the traditional punch stamping process is avoided. Meanwhile, the electromagnetic forming is a high-energy forming technology, so that the forming limit of the metal blank is effectively increased, and the resilience is reduced.

3. According to the electromagnetic composite forming method for the oblique flange box-shaped part, the adopted planar rectangular spiral coil is changeable, the planar rectangular spiral coil can be adjusted according to the needed box-shaped part, and the application direction and the size of electromagnetic force can be flexibly changed.

Drawings

FIG. 1 is a schematic diagram of electromagnetic forming in accordance with the present invention.

Fig. 2 is a schematic view of the construction of the beveled flange box of the present invention.

FIG. 3 is a schematic view of a forming apparatus of the present invention.

Fig. 4 is a schematic illustration of electromagnetic forming in accordance with the present invention.

FIG. 5 is a schematic view of the shape correction of the rubber mat according to the present invention.

FIG. 6 is a schematic illustration of the steel die forming of the present invention.

Fig. 7 is a schematic diagram of a planar rectangular spiral coil layout according to the present invention.

Fig. 8 is a schematic diagram of another planar rectangular spiral coil layout of the present invention.

FIG. 9 is a flow chart of the present invention.

Wherein: 1. a power switch; 2. a capacitor; 3. a resistance; 4. mounting a template; 5. a male die fixing plate; 6. a first line connector; 7. a blank holder; 8. a female die; 9. a rubber pad; 10. a lower template; 11. a metal blank; 12. a planar rectangular spiral coil; 13. a second line connector; 14. a male die; 15. a base plate; 16. a male die assembly; 17. a female die assembly; 18. a beveled flange box; 19. a coil; 20. and (5) a workpiece.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

Referring to fig. 1, the principle of electromagnetic forming can be explained by the law of electromagnetic induction, when the coil 19 is charged or discharged, a changing current is generated in the coil 19, as known from the law of electromagnetic induction, the changing current generates a changing magnetic field in the surrounding space, and as the coil is continuously charged or discharged, a pulse magnetic field is generated in the surrounding space of the coil 19, a current (eddy current) is induced in the workpiece 20 in the pulse magnetic field, the workpiece 20 becomes a charged body, and the charged body in the rapidly changing magnetic field is acted by the electromagnetic force, and when the electromagnetic force exceeds the yield limit of the material, the workpiece 20 is plastically deformed along with the die 14, so as to achieve the purpose of processing the part.

The invention provides an electromagnetic composite forming method of an oblique flange box-shaped part, which is shown in figure 9 and comprises the following steps:

step 1, assembling a die, namely referring to fig. 3, placing a metal blank 11 on a female die assembly 17 and limiting the metal blank by using a blank holder 7 to prevent the metal blank 11 from wrinkling during forming, embedding a planar rectangular spiral coil 12 at the bottom of a male die assembly 16, connecting two ends of the planar rectangular spiral coil 12 with external circuits through a first circuit connector 6 and a second circuit connector 13 respectively, and placing the male die assembly 16 above the metal blank 11;

step 2, performing electromagnetic forming, namely referring to fig. 4, enabling a metal blank 11 to be tightly attached to a horizontally-placed planar rectangular spiral coil 12, and charging or discharging the planar rectangular spiral coil 12 through an external circuit to enable a space around the planar rectangular spiral coil 12 to generate a pulse magnetic field, wherein the metal blank 11 in the pulse magnetic field induces current to form a charged body, and then the charged body is subjected to the action of electromagnetic force to perform primary forming;

step 3, correcting the shape of the rubber pad 9, referring to fig. 5, judging whether the preliminarily formed metal blank 11 reaches a preset height, if so, placing the rubber pad 9 in the female die assembly 17, arranging the rubber pad 9 below the metal blank 11, continuously charging or discharging the planar rectangular spiral coil 12 through an external circuit, correcting the shape, if not, moving the male die assembly 16 downwards, reducing the distance between the planar rectangular spiral coil 12 and the metal blank 11, and repeating the step 2;

and 4, forming the steel die, and driving the male die assembly 16 to press down through a press machine to finish forming and form the oblique flange box-shaped part 18 as shown in the figure 6.

The invention performs the preforming on the metal blank 11 by utilizing the non-contact advantage of the electromagnetic force, thereby avoiding the problem of stress concentration in the traditional punch stamping process. In addition, by embedding the planar rectangular spiral coil 12 at the bottom of the male die assembly 16, the process of discharging the planar rectangular spiral coil 12 and correcting the shape of the male die assembly 16 can be finished by only one set of die, the processing process is simple and easy to control, wrinkles are not easy to appear on the surface of a processed workpiece, and the forming quality and efficiency of the workpiece are effectively improved.

Because the electromagnetic force is uneven in the electromagnetic forming process, the bottom of the metal blank 11 is uneven, if the metal blank 11 is directly formed by a steel die at the moment, stress concentration can be caused, and the metal blank 11 is cracked, so that the rubber pad 9 is used for correction below, the metal blank 11 expands towards two sides, the bottom of the metal blank 11 can be more flat, the two sides are closer to the female die assembly 17, and the subsequent male die assembly 16 is in surface contact with the metal blank 11 instead of point contact, so that the stress concentration cannot be generated.

Specifically, the male die assembly 16 comprises an upper die plate 4, a backing plate 15, a male die 14 and a male die fixing plate 5, wherein the upper die plate 4 is installed on the press machine, the backing plate 15 is fixed between the upper die plate 4 and the male die 14, and the male die fixing plate 5 is sleeved on the outer side of the male die 14 and fixed at the bottom of the backing plate 15.

The female die assembly 17 comprises a lower die plate 10 and a female die 8, and the female die 8 is fixed on the upper side of the lower die plate 10.

The external circuit comprises a capacitor 2, a power switch 1 and a resistor 3, and the planar rectangular spiral coil 12 is charged or discharged by charging or discharging the capacitor 2.

The number of times the capacitor 2 is charged or discharged depends on the final desired sidewall height of the beveled flange box 18 and the discharge capacity of the electromagnetic device.

In the present invention, the higher the required sloping flange box 18 side wall, the more deformation is required and the voltage, if constant, the increased number of discharges of capacitor 2 is required.

Further, the larger the voltage, the larger the deformation degree of the metal material 11, and if the number of times the capacitor 2 is discharged is to be reduced, the voltage of the coil is increased.

The planar rectangular spiral coil 12 is adjusted according to the structure of the inclined flange box member 18 as required to change the direction and magnitude of the electromagnetic force application. Referring to fig. 7, in one embodiment, if the layout of the planar rectangular spiral coil 12 is as shown in the left drawing of fig. 7, the electromagnetic force is mainly concentrated at the black frame in the right drawing of fig. 7. Referring to fig. 8, in another embodiment, if the layout of the planar rectangular spiral coil 12 is as shown in the left drawing of fig. 8, the electromagnetic force is mainly concentrated at the black frame in the right drawing of fig. 8.

If the deformation degree of a certain part of the metal blank 11 needs to be increased, the deformation degree can be realized by reducing the turn pitch of the planar rectangular spiral coil 12 at the part, and if the deformation degree of the certain part of the metal blank 11 needs to be reduced, the deformation degree can be realized by increasing the turn pitch of the planar rectangular spiral coil 12 at the part.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.

Claims

1. a method for electromagnetic composite forming of inclined flange box-shaped part, is characterized in that, comprises:

Step 1, mold assembly, place the metal blank on the die assembly, embed a flat rectangular spiral coil at the bottom of the punch assembly, connect the two ends of the flat rectangular spiral coil to an external circuit, and connect the convex die assembly the piece is placed over the metal blank;

Step 2: Electromagnetic forming, the metal blank is pressed against the horizontally placed flat rectangular helical coil, and the flat rectangular helical coil is adjusted according to the required structure of the oblique flange box-shaped piece to change the direction of application of the electromagnetic force If it is necessary to increase the deformation degree of a certain part of the metal blank, it can be achieved by reducing the turn spacing of the plane rectangular spiral coil at this part. If the deformation degree of a certain part of the metal blank needs to be reduced, it can be achieved by increasing this part. It is realized by the turn spacing of the planar rectangular helical coil, and the planar rectangular helical coil is charged or discharged through the external circuit, so that a pulsed magnetic field is generated in the space around the planar rectangular helical coil, and the metal blank in the pulsed magnetic field induces The electric current forms a charged body, which is then subjected to the action of electromagnetic force to initially take shape;

Step 3: Correct the shape of the rubber pad, and judge whether the metal blank after preliminary forming reaches a predetermined height. If it reaches the predetermined height, place a rubber pad in the die assembly, and the rubber pad is arranged below the metal blank. , continue to charge or discharge the planar rectangular helical coil through the external circuit, and perform shape correction. If the predetermined height is not reached, move the punch assembly down to reduce the distance between the planar rectangular helical coil and the metal blank. distance, repeat step 2;

Step 4. The steel mold is formed, and the punch assembly is driven to press down by a press to complete the forming and form an oblique flange box-shaped part.

2 . The electromagnetic composite forming method of the inclined flange box-shaped part according to claim 1 , wherein the punch assembly comprises an upper template, a backing plate, a punch and a punch fixing plate, and the upper template is installed on the upper template. 3 . On the press, the backing plate is fixed between the upper template and the punch, and the punch fixing plate is sleeved on the outside of the punch and fixed on the bottom of the backing plate.

3 . The electromagnetic composite forming method for a box-shaped piece with inclined flanges according to claim 1 , wherein the die assembly comprises a lower template and a die, and the die is fixed on the upper side of the lower die. 4 .

4 . The electromagnetic composite forming method of the inclined flange box-shaped part according to claim 1 , wherein the external circuit comprises a capacitor, a power switch and a resistor, and the planar rectangular spiral is charged or discharged by charging or discharging the capacitor. 5 . The coil is charged or discharged.

5. The electromagnetic composite forming method of the inclined flange box-shaped piece according to claim 4, wherein the number of times of charging or discharging the capacitor depends on the side wall height of the finally required inclined flange box-shaped piece and the electromagnetic equipment. The discharge capacity is determined.