CN110640009A - An electric field-assisted deep drawing device for hard-to-deform sheet metal - Google Patents

Abstract

The invention discloses an electric field-assisted deep drawing device for hard-to-deform metal sheets, which belongs to the technical field of solid particle forming molds under the action of an electric field. A concave die with an inner hole, an insulating layer is provided on the upper surface of the concave die and the side wall of the inner hole of the concave die, the upper end of the concave die is provided with a blank holder for pressing the sheet material on the concave die, and the bottom of the inner hole of the concave die is provided with elastic The lower end of the blank holder is provided with a positive electrode that is in contact with the sheet metal and connected to the power supply live wire, the inner side wall of the female die is provided with a female die electrode connected to the power supply zero line, and the top of the elastic block is provided with a power supply zero line. The electrode of the invention has the advantages of simple structure, high forming efficiency, less labor and time-consuming, and stable product quality.

Description

An electric field-assisted deep drawing device for hard-to-deform sheet metal

technical field

The invention relates to a deep drawing die under the action of an electric field, in particular to an electric field assisted deep drawing device for a hard-to-deform metal sheet, which is used in the technical field of solid particle forming die under the action of an electric field.

Background technique

Deep drawing is a processing method that uses a drawing die to make a flat blank or a hollow process part into an open hollow part under the pressure of a press. It is one of the basic stamping processes. It can process rotating body parts, box-shaped parts and other thin-walled parts with complex shapes. The size of the deep-drawn parts can range from a few mm in diameter to 2 to 3 m, and the thickness is 0.2 to 300 mm. It is widely used in automobiles, tractors, airplanes, clocks, electrical appliances, instruments, light industry and civil products. The traditional rigid convex-concave die drawing process requires multiple deep drawing for parts with a large drawing ratio, and the quality of the parts will not meet the standard, and some difficult-to-deform, high-strength, low-plastic parts cannot even be formed. A half-mold forming process is proposed. In the sheet metal half-die forming process, the half-die forming with oil or water (emulsion) as the force-transmitting medium is characterized by uniform pressure distribution. However, the uniform pressure distribution is not conducive to the control of the thickness of the formed parts. Once local thinning occurs, it will be very easy to rupture, and there will be difficulties in sealing control, leakage, and oil splashing endangering operators. Therefore, hydroforming is limited. The solid particle medium forming process is a newly developed half-mold forming process in recent years. The Solid Granules Medium Forming (SGMF) process disclosed in Patent ZL 200510007167.1 is a process in which solid particles are used instead of rigid punches or concave dies (or elastomers, liquids) to form soft-molded plates. The internal pressure of solid particle medium has non-uniform distribution characteristics, so different pressures can be generated in different parts of the blank, and the deformation of different parts of the plate can be controlled, which is beneficial to improve the forming limit of the material. Zhao Changcai et al. used solid particles to replace the role of punches to form half-moulds for sheets, which overcomes the defects of hydroforming. However, there are difficult-to-deform metal deep-drawings that are easy to break, parts cannot be automatically ejected after forming, and particles are filled with punches and molds. Die clearance and manual removal become very difficult, and the ejector mechanism is unclear and cannot be used in progressive dies and other problems.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an electric field-assisted deep drawing device for hard-to-deform metal sheets.

For solving the above-mentioned technical problems, the technical scheme adopted in the present invention is:

An electric field assisted deep drawing device for hard-to-deform sheet metal, comprising a punch 1 fixed on the lower part of a press for insulation treatment with the press and a concave die 8 provided with an inner hole on the upper part of the lower die base, characterized in that the concave die 8. An insulating layer is provided on the upper surface of the die 8 and the side wall of the inner hole of the die 8. The upper end of the die 8 is provided with a blank holder 2 that presses the sheet material 4 on the die 8. The bottom of the inner hole of the die 8 is provided with an elastic block 11. , the lower end of the blank holder 2 is provided with a positive electrode 3 that is in contact with the sheet material 4 and is connected to the power supply live wire, the inner wall of the female die 8 is provided with a female die electrode 6 that is connected to the power supply zero line, and the top of the elastic block 11 is provided with a power supply Negative electrode 10 connected to the neutral line.

A further improvement of the technical solution of the present invention lies in that: above the elastic block 11, a backing plate 9 is arranged to cooperate with the inner hole of the die 8; There are rigid particles 7.

A further improvement of the technical solution of the present invention is that the rigid particles 7 are particles made of stainless steel balls, steel balls or other pressure-resistant conductive rigid materials.

A further improvement of the technical solution of the present invention is that the insulating layer 5 on the upper surface of the die 8 is insulating paper, the insulating layer on the side wall of the inner hole of the die 8 is an insulating sleeve 13, and the insulating sleeve 13 is connected to the die. 8 is a transition fit.

A further improvement of the technical solution of the present invention is that a plurality of openings are arranged along the side wall of the die 8 and the height direction of the insulating sleeve 13 , and a die electrode 6 is arranged in each opening.

A further improvement of the technical solution of the present invention is that the concave die electrode 6 is an annular electrode, and the outer periphery of the concave die electrode 6 is covered with an insulating sleeve to ensure the insulation between the annular electrode and the concave die 8 .

A further improvement of the technical solution of the present invention is that: the elastic block 11 is a rubber block, the center of the elastic block 11 is provided with a mounting hole for mounting the negative electrode 10, an insulating sleeve is provided between the negative electrode 10 and the mounting hole of the elastic block 11, and the negative electrode 10 Use an interference fit with the insulating sleeve.

A further improvement of the technical solution of the present invention is that: the positive electrode 3 is a ring electrode, a mounting hole is arranged in the blank holder ring 2, and an insulating sleeve is provided on the periphery of the positive electrode 3 to ensure the insulation between the electrode and the blank holder ring 2.

A further improvement of the technical solution of the present invention is that: the center of the punch 1 is provided with an air hole for separating the sheet material 4 from the punch 1 after the drawing is completed.

Owing to having adopted the above-mentioned technical scheme, the technical progress that the present invention obtains is:

An electric field-assisted deep drawing device for hard-to-deform metal sheets, which utilizes an existing press to insulate a punch 1 to insulate between the press and the punch 1, and facilitates processing of the sheet 4 by using an external electric field; 1. The outer side blank holder 2 fixes the sheet material 4 to prevent the sheet material 4 from wrinkling. The positive electrode 3 in the opening of the blank holder ring 2 contacts the sheet material 4, so that the current flows through the sheet material 4, and the sheet material 4 is electrically treated. The positive electrode 3 is protected. When the blank holder 2 leaves the sheet 4, the electrode is far away from the sheet 4, which protects the safety of the staff when picking and placing the sheet 4; Outflow creates a safety hazard. An insulating sleeve 13 is placed in the center hole of the die 8 to accommodate the rigid particles 7 and improve the forming effect; a backing plate 9 is arranged in the insulating sleeve 13, and the backing plate 9 is supported by the spring 12, which is convenient for the completion of the deep drawing work. Afterwards, the top of the spring 12 pushes the sheet 5 out of the die 8, and the finished product is easily taken out; the insulating sleeve 13 prevents the current from flowing to the die 8 and protects the die 8; the holes on the die 8 penetrate the electrodes, and electrodes of different heights The sheet material 4 in different deep drawing states can form a current loop through the concave die electrode 7 to generate Joule resistance heat and improve the state of the sheet material 4; the concave die electrode 6 is a ring electrode, and an insulating sleeve is provided outside the electrode to prevent electrode leakage and increase safety. The insulating sleeve 13 and the die 8 are transition fit, which is convenient for replacing the insulating sleeve 13; when the sheet material 4 is drawn to the extent that the elastic block 11 is squeezed, the elastic block 11 gives the sheet material 4 a back-drawing force, and the elastic block 11 is made of rubber It can avoid the influence of the leakage of the negative electrode 10 on the spring 12 and effectively protect the service life of the spring 12. The negative electrode 10 has an insulating sleeve to prevent the current of the negative electrode 10 from damaging the elastic block 11; the positive electrode 3 has an insulating sleeve to protect the blank holder. 2. Avoid electric leakage of the positive electrode 3; There is a hole in the center of the punch 1 to prevent the sheet 4 from being adsorbed on the punch 1 and difficult to remove; the insulating sleeve 13 is made of ceramic material, with good insulation and low price; the rigid particles 7 use steel balls , the pressure bearing effect is good, and the service life is long; the insulating layer 5 uses insulating paper, the insulating effect is good, and the cost is reasonable.

The invention mainly improves the deep drawing forming of the existing plate, changes the corresponding structure on the basis of the existing stamping die, and combines it with the external electric field and the rigid particle forming technology, and can be applied to the progressive die at the same time, using the current to flow through the plate The Joule resistance heat generated by the material 4 directly heats the billet itself, and keeps its temperature within the forming temperature range, so that it undergoes plastic deformation in the mold, so that the temperature distribution inside the billet is very uniform, and multiple electrodes are provided to make the workpiece The current distribution is stable and uniform, which is beneficial to the plastic forming of the blank and improves the quality of the product; it solves the problems of difficulty in deep drawing, cracking and residual stress in the process of low plasticity, high strength and difficult deformation during the drawing process, and improves the difficulty in deformation. Sheet metal forming limit; in addition, the invention also has the characteristics of strong insulation, simple structure and processing, high forming efficiency, less labor time and stable product quality.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is the schematic diagram when the present invention performs deep drawing and contacts with the first height electrode;

Fig. 3 is the schematic diagram when the present invention performs deep drawing and contacts with the second height electrode;

Fig. 4 is the schematic diagram when the deep drawing of the present invention reaches the forming limit;

Among them, 1, punch, 2, blank holder, 3, positive electrode, 4, sheet, 5, insulating layer, 6, die electrode, 7, rigid particle, 8, die, 9, backing plate, 10 , Negative electrode, 11, elastic block, 12, spring, 13, insulating sleeve.

Detailed ways

The technical solutions 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. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

An electric field-assisted deep drawing device for hard-to-deform sheet metal, comprising a press with a punch 1 fixed at the bottom, a blank holder 2 fixed on the press on the outside of the punch 1, and a female die 8 on the upper part of the lower die base, The female die 8 is provided with an inner hole matched with the male die. Insulation treatment is carried out between the press and punch 1 to prevent the current from damaging the press through punch 1, the side wall of the blank holder 2 is opened to place the positive electrode 3, and the bottom surface of the blank holder is opened to expose the positive electrode 3. 3. Place 4 electrodes at an angle of 90° with the center of the blank holder as the center, or place 3 electrodes at an angle of 120°, or place electrodes at other suitable angles to ensure that the current flows evenly on the sheet 4. The positive electrode 3 is a ring electrode. The insulating sleeve 4 is isolated from the crimp ring 2 , and the annular electrode and the insulating sleeve 4 are in an interference fit. When the blank holder 2 descends with the punch 1 of the press to fix the sheet 4, the positive electrode 3 is in contact with the sheet 4, the positive electrode 3 is connected to the power live wire, and the sheet 4 is placed on the die 8. The concave die 8 is fixed on the upper part of the lower die base, and an insulating layer 5 is provided at the upper part of the concave die 8 in contact with the sheet material 4 to prevent the current from passing through the concave die. The insulating layer is an insulating device to protect the die, and the elastic block 11 is arranged at the bottom of the inner hole of the die 8 . When the sheet material 4 is drawn until the elastic block 11 is squeezed, the elastic block 11 gives the sheet material 4 a back-drawing force. A negative electrode 10 is arranged in the upper opening of the elastic block 11, and the negative electrode 10 is connected to the neutral line of the power supply. The hole is opened, the insulating device is an insulating sleeve 13, the die electrode 6 is in contact with the drawn sheet 4 through the hole of the same height of the die 8 and the insulating device, and the die electrode 6 is centered on the center of the inner hole of the die Evenly placed, the concave mold electrodes 6 are placed at an angle of 90°, an angle of 120°, or other suitable angles to place multiple electrodes.

A preferred embodiment is shown in FIG. 1 . In this embodiment, the female die 8 has holes at a preset height. The insulating device is an insulating sleeve 13 . The insulating sleeve 13 has holes corresponding to the opening positions of the female die 8 , and the ring electrode passes through the hollow. The die 8 and the insulating sleeve 13 are respectively provided with annular electrodes in the holes of different heights of the die 8 . An insulating sleeve is arranged outside the annular electrode, and an elastic member supporting pad 9 is arranged on the lower die base in the insulating sleeve 13 , and the elastic member is a spring 12 . The backing plate 9 is matched with the inner hole of the die 8, and the insulating sleeve 13 above the backing plate 9 is filled with rigid particles 7 such as stainless steel balls, steel balls or other pressure-resistant and conductive material particles. The specific particles are used according to the temperature of sheet forming. , internal pressure and other conditions, the rigid particles 7 can be used repeatedly without affecting the forming effect. The elastic block 11 is covered with a spring 12. The elastic block is a rubber block. A negative electrode 10 is installed at the top of the rubber block. The negative electrode 10 is provided with an insulating sleeve.

In a preferred embodiment, the insulating layer 5 where the upper surface of the die 8 is in contact with the sheet material 4 is insulating paper.

In a preferred embodiment, the insulating sleeve 13 uses a ceramic sleeve.

In the preferred embodiment, the rigid particles 7 use stainless steel beads.

In the preferred embodiment, the center of the punch 1 is provided with an air hole, and the air hole is connected with the air jet device. The air jet device sprays compressed air or nitrogen through the air hole to eject the parts adsorbed on the punch mold 1, so as to facilitate the deep drawing after the deep drawing is completed. The sheet 4 is separated from the punch 1 to prevent the sheet 4 from being adsorbed on the punch 1.

The working process is as follows:

As shown in Figure 1, place the sheet 4 on the die 8, turn on the press, and the press drives the punch 1 and the blank holder 2 downward, and the blank holder 2 contacts and presses the blank 4 to fix the blank 4 , the positive electrode 3 contacts the sheet 4, at this time the current flows from the positive electrode 3 through the sheet 4, the rigid particles 7 and the die electrode 6 to form a loop, and the Joule resistance heat generated by the current flowing through the sheet 4 directly heats the sheet 4 itself , and keep its temperature within the molding temperature range, and the pressure exerted by the press on the sheet material 4 causes the sheet material 4 to undergo plastic deformation in the mold. As shown in Figures 2 and 3, the punch 1 continues to descend, and the sheet material 4 is deep-drawn. The current flows from the positive electrode 3 through the sheet material 4, the rigid particles 7 and the two die electrodes 6 to form a loop, and the punch 1 Descending to the lowest point, as shown in FIG. 4 , the backing plate 9 descends to contact the negative electrode 10 , the current flows from the positive electrode 3 through the sheet material 4 and the negative electrode 10 to form a loop, and the spring 12 reversely pulls the sheet material 4 through the backing plate 9 Deep force, relieve the stress state of sheet 4 at the fillet of punch 1, the drawing is completed, punch 1 rises, the spring 12 pushes out sheet 4, and at the same time the air hole at the punch will blow out the parts, a deep drawing operation Finish.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "inside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for convenience The invention is described and simplified without indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation and therefore should not be construed as limiting the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed to indicate or imply relative importance.

Specific examples are used in the present invention to illustrate the principles and implementations of the present invention, and the descriptions of the above examples are used to help understand the method and core idea of the present invention; There will be changes in the specific implementation manner and application scope of the idea of the invention. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (9)

1. The utility model provides a supplementary deep-drawing device of difficult deformation sheet metal electric field, is including fixing terrace die (1) that carries out insulation treatment with the press in the press lower part and setting up die (8) that set up the hole on die holder upper portion, its characterized in that: insulating layers are arranged on the upper surface of the female die (8) and the side wall of an inner hole of the female die (8), a blank holder (2) for pressing the plate (4) on the female die (8) is arranged at the upper end of the female die (8), an elastic block (11) is arranged at the bottom of the inner hole of the female die (8), a positive electrode (3) which is in contact with the plate (4) and connected with a live wire of a power supply is arranged at the lower end of the blank holder (2), a female die electrode (6) connected with a zero line of the power supply is arranged on the inner side wall of the female die (8), and a negative electrode (10).

2. The electric field assisted drawing device for the difficultly deformed metal plates according to claim 1 is characterized in that: a backing plate (9) matched with an inner hole of the female die (8) is arranged above the elastic block (11), an elastic piece for supporting the backing plate (9) is arranged outside the elastic block (11), and rigid particles (7) are arranged between the plate material (4) and the backing plate (9).

3. The electric field assisted drawing device for the difficultly deformed metal plates as claimed in claim 2 is characterized in that: the rigid particles (7) are particles made of stainless steel balls, steel balls or other pressure-resistant conductive rigid materials.

4. The electric field assisted drawing device for the metal plates difficult to deform according to any one of claims 1 to 3, is characterized in that: insulating layer (5) of die (8) upper surface are insulating paper, the insulating layer on die (8) hole lateral wall is insulating sleeve (13), is transition fit between insulating sleeve (13) and die (8).

5. The electric field assisted deep drawing device for the difficultly deformed metal plates as claimed in claim 4, is characterized in that: a plurality of openings are formed in the height direction of the side wall of the female die (8) and the insulating sleeve (13), and a female die electrode (6) is arranged in each opening.

6. The electric field assisted deep drawing device for the difficultly deformed metal plates as claimed in claim 4, is characterized in that: the female die electrode (6) is an annular electrode, and an insulating sleeve for ensuring the insulation of the annular electrode and the female die (8) is sleeved on the periphery of the female die electrode (6).

7. The electric field assisted deep drawing device for the difficultly deformed metal plates as claimed in claim 4, is characterized in that: the elastic block (11) is a rubber block, a mounting hole for mounting the negative electrode (10) is formed in the center of the elastic block (11), an insulating sleeve is arranged between the negative electrode (10) and the mounting hole of the elastic block (11), and the negative electrode (10) and the insulating sleeve are in interference fit.

8. The electric field assisted deep drawing device for the difficultly deformed metal plates as claimed in claim 4, is characterized in that: the positive electrode (3) is an annular electrode, a mounting hole is formed in the blank holder (2), and an insulating sleeve for ensuring the insulation of the electrode and the blank holder (2) is sleeved on the periphery of the positive electrode (3).

9. The electric field assisted deep drawing device for the difficultly deformed metal plates as claimed in claim 4, is characterized in that: the center of the male die (1) is provided with an air hole which is convenient for separating the plate (4) from the male die (1) after drawing is finished.

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