阅读说明：本技术 采用双线圈的金属板件吸引式成形方法及成形装置 (Metal plate attraction type forming method and forming device adopting double coils ) 是由 熊奇 杨猛 刘馨 闫佳颖 宋先祺 李哲 邱立 江进波 余坤 于 2019-12-17 设计创作，主要内容包括：本发明公开了采用双线圈组的金属板件吸引式成形方法,对成形金属板件边缘施加压力将金属板件固定,控制第一脉冲发生电路,在成形区域产生背景磁场,确定成形过程需要的金属板件中的感应涡流大小,控制第二脉冲发生电路,在第二线圈组中产生短脉宽电流,使得金属板件中产生成形需要的感应涡流,受到向上的洛伦兹力,成形区域向上变形。本发明还公开了一种金属板件成形装置。通过两组线圈组对金属板件的成形进行控制,第一线圈组在成形区域形成背景磁场,第二线圈组在金属板件中产生成形需要的感应涡流,通过第一线圈组、第二线圈组分别对背景磁场、感应涡流进行控制,实现金属板件的高效、精确成形。(The invention discloses a sheet metal suction type forming method adopting a double-coil group, which comprises the steps of applying pressure to the edge of a formed sheet metal to fix the sheet metal, controlling a first pulse generating circuit to generate a background magnetic field in a forming area, determining the size of induced eddy current in the sheet metal required in the forming process, controlling a second pulse generating circuit to generate short-pulse-width current in a second coil group, so that the induced eddy current required by forming is generated in the sheet metal and is subjected to upward Lorentz force, and the forming area is deformed upwards. The invention also discloses a metal plate forming device. The forming of the metal plate is controlled through the two groups of coil groups, the first coil group forms a background magnetic field in a forming area, the second coil group generates induction eddy currents required by forming in the metal plate, and the background magnetic field and the induction eddy currents are controlled through the first coil group and the second coil group respectively, so that the efficient and accurate forming of the metal plate is realized.)

1. The attracted forming method of the sheet metal by adopting the double coil group is characterized in that a first coil group and a second coil group are respectively adopted to generate a background magnetic field and an induced eddy current in a forming area of the formed sheet metal, the forming area of the sheet metal is subjected to an upward Lorentz force to deform the forming area upwards, the forming method of the sheet metal comprises the following steps,

step 1: applying pressure to the edge of the metal plate to fix the metal plate, placing a first coil group above the metal plate, and arranging a second coil group above a forming area of the metal plate;

step 2: connecting the first coil group to a first pulse generating circuit, controlling the first pulse generating circuit, generating a long pulse width current in the first coil group, and generating a background magnetic field in a forming area;

and step 3: determining the size of the induced eddy current in the metal plate required in the forming process according to the size of the background magnetic field and the forming specification of the metal plate;

and 4, step 4: connecting the second coil group to a second pulse generating circuit, controlling the second pulse generating circuit, generating short-pulse-width current in the second coil group, generating induced eddy current required by forming in the metal plate, and enabling a forming area of the metal plate generating the induced eddy current to be subjected to upward Lorentz force under the action of a background magnetic field, so that the forming area is deformed upwards;

and 5: judging whether the forming of the metal plate in the step 4 reaches the forming specification of the metal plate;

step 5.1: if the molding specification is not met, executing the step 2;

step 5.2: if the molding specification is reached, the process is terminated.

2. The sheet-attractive forming method using double coils as claimed in claim 1, further comprising an annealing pretreatment of the sheet metal member before step 1.

3. The panel attraction forming method using a double coil as claimed in claim 1, wherein the formed sheet metal member is an alloy sheet member for automobile skin.

4. The plate attraction type forming method adopting double coils as claimed in claim 1, wherein the first pulse generating circuit is a capacitor bank, and the capacitance is 2880-3200μF。

5. The plate attraction type forming method adopting double coils as claimed in claim 1, wherein the second pulse generation circuit is a capacitor bank, and the capacitance is 40-160%μF。

6. The forming device using the plate suction forming method with the double coils as claimed in any one of claims 1 to 5, comprising a first coil group, a second coil group, a first pulse generating circuit, a second pulse generating circuit, and a binder device, wherein the first coil group is connected with the first pulse generating circuit through a switching tube VT1, the second coil group is connected with the second pulse generating circuit through a switching tube VT2, and the binder device is used for fixing the edge of the metal plate.

7. The forming apparatus as claimed in claim 6, wherein the first coil group is connected in parallel with a freewheel diode VD 1.

8. The forming device according to claim 6, wherein a freewheeling diode VD2 is connected in parallel to the second coil group.

Technical Field

The invention belongs to the field of metal forming and manufacturing, and particularly relates to a metal plate attraction type forming method and a metal plate attraction type forming device adopting double coils.

Background

The light alloy is widely applied to the manufacturing of various high-precision products such as airplanes, rockets, automobiles and the like, so the light alloy has great purpose and significance for the dent repair of the light alloy. The existing methods for forming the attraction type plate include gradient magnetic field force method, metal screen method and hot forming method. As shown in the literature, "Pulsed electromagnetic absorption of sheet metals-metals and passive applications", the gradient magnetic field force method adopts a metal plate made of a coil magnetized magnetic material based on low-frequency current, and generates stronger gradient magnetic field force between the coil and a workpiece so as to realize plate attraction forming; as shown in the document "Pulsed electromagnetic absorption of non-magnetic sheet metals", the metal screen method adds a good metal conductor between the coil and the metal plate, and pulse current is introduced into the coil to generate induced eddy currents in the same direction in the metal conductor and the plate, so as to realize attractive force shaping; the thermoforming method is to heat the plate by using high-temperature gas or liquid and then perform drawing forming by using a specific tool, such as drawing forming and top warping forming mainly in the automobile dent repairing technology.

Disclosure of Invention

The technical problem of the invention is that the existing forming method of the metal plate comprises a gradient magnetic field force method, a metal screen method and a hot forming method, which have the disadvantages of undesirable effect, low efficiency and uncontrollable forming quality.

The present invention is directed to solve the above problems, and an object of the present invention is to provide a method and an apparatus for forming a sheet metal member by attraction using a dual coil, in which a background magnetic field is generated in a sheet metal member forming area by a first coil group, and an induced eddy current is generated in the sheet metal member forming area by a second coil group, so that the sheet metal member forming area is deformed by an upward lorentz force, thereby achieving the sheet metal member forming specification.

The technical scheme of the invention is that a double-coil metal plate attraction type forming method is adopted, a first coil group and a second coil group are respectively adopted to generate a background magnetic field and an induced eddy current in a forming area of a formed metal plate, the forming area of the metal plate is subjected to an upward Lorentz force to enable the forming area to deform upwards, the forming method of the metal plate comprises the following steps,

step 1: applying pressure to the edge of the metal plate to fix the metal plate, placing a first coil group above the metal plate, and arranging a second coil group above a forming area of the metal plate;

step 2: connecting the first coil group to a first pulse generating circuit, controlling the first pulse generating circuit, generating a long pulse width current in the first coil group, and generating a background magnetic field in a forming area;

and step 3: determining the size of the induced eddy current in the metal plate required in the forming process according to the size of the background magnetic field and the forming specification of the formed metal plate;

and 4, step 4: connecting the second coil group to a second pulse generating circuit, controlling the second pulse generating circuit, and generating short-pulse-width current in the second coil group to generate induced eddy current required by forming in the metal plate, wherein the forming area of the metal plate generating the induced eddy current is subjected to upward Lorentz force under the action of a background magnetic field, and the forming area is deformed upwards;

and 5: judging whether the forming of the formed metal plate in the step 4 reaches the forming specification of the metal plate or not;

step 5.1: if the molding specification is not met, executing the step 2;

step 5.2: if the molding specification is reached, the process is terminated.

The attraction forming method for the metal plate adopting the double coils further comprises the step of annealing pretreatment on the metal plate before the step 1.

Further, the formed sheet metal piece is an alloy sheet piece for automobile skins.

Preferably, the first pulse generating circuit is a capacitor bank, and the capacitance is 2880-3200 muF.

Preferably, the second pulse generating circuit is a capacitor bank, and the capacitance is 40-160 muF.

The metal plate forming device comprises a first coil group, a second coil group, a first pulse generating circuit, a second pulse generating circuit and a blank pressing device, wherein the first coil group is connected with the first pulse generating circuit through a switch tube VT1, the second coil group is connected with the second pulse generating circuit through a switch tube VT2, and the blank pressing device is used for fixing the edge of a metal plate.

Preferably, the first coil set is connected with a freewheeling diode VD1 in parallel.

Preferably, the second coil group is connected with a freewheeling diode VD2 in parallel.

Compared with the prior art, the invention has the beneficial effects that:

1) the forming of the metal plate is controlled through two groups of coil groups, a background magnetic field is formed in a forming area by a first coil group, induced eddy current required by forming is generated in the formed metal plate by a second coil group, the forming area of the formed metal plate is subjected to upward Lorentz force under the action of the background magnetic field, the forming area is deformed upwards, and the background magnetic field and the induced eddy current are respectively controlled through the first coil group and the second coil group, so that the efficient and accurate forming of the metal plate is realized;

2) controlling the pulse current of the second coil group by controlling the voltage and the capacitance of the capacitor group connected with the second coil group, and further controlling the forming quality of the metal plate;

3) controlling the pulse current of the first coil group by controlling the voltage and the capacitance of the capacitor group connected with the first coil group, and controlling the background magnetic field formed by the metal plate;

4) the method of the invention realizes the accurate control of the forming effect of the metal plate, and can repeatedly carry out forming adjustment on the forming area of the metal plate for many times.

Drawings

The invention is further illustrated by the following figures and examples.

Fig. 1 is a flowchart of a metal plate suction type forming method using a double coil.

Fig. 2 is a schematic view of a sheet metal member forming apparatus of the present invention.

Fig. 3 is a schematic structural diagram of the coil assembly of the embodiment.

Fig. 4 is a waveform diagram of currents in the first coil assembly and the second coil assembly.

Fig. 5 is a schematic diagram of magnetic induction lines of the first coil assembly and the second coil assembly.

FIG. 6 is a schematic illustration of induced eddy currents and Lorentz forces generated on a sheet metal piece.

Fig. 7 is a diagram showing simulation results of the forming of the metal plate member.

Description of reference numerals: the device comprises a first coil group 1, a second coil group 2, a first pulse generation circuit 3, a second pulse generation circuit 4, a blank pressing device 5 and a metal plate 6.

Detailed Description

As shown in fig. 1, a double-coil plate suction type forming method is adopted, after annealing pretreatment is carried out on an alloy plate for automobile skin, a hydraulic mechanism of a blank holder is utilized to fix a metal plate from the edge, a first coil group and a second coil group are adopted to respectively generate a background magnetic field and an induced eddy current in a forming area of the formed metal plate, the forming area of the metal plate is subjected to an upward lorentz force to enable the forming area to deform upward, the forming method comprises the following steps,

step 1: applying pressure to the edge of the formed metal plate to fix the metal plate, placing a first coil group above the formed metal plate, and arranging a second coil group above a forming area of the formed metal plate;

step 2: connecting the first coil group to a first pulse generating circuit, controlling the first pulse generating circuit, generating a long pulse width current in the first coil group, and generating a background magnetic field in a forming area;

and step 3: determining the size of the induced eddy current in the formed metal plate required in the forming process according to the size of the background magnetic field and the forming specification of the formed metal plate;

and 4, step 4: connecting the second coil group to a second pulse generating circuit, controlling the second pulse generating circuit, and generating short-pulse-width current in the second coil group to generate induced eddy current required by forming in the formed sheet metal part, wherein the forming area of the formed sheet metal part generating the induced eddy current is subjected to upward Lorentz force under the action of a background magnetic field, and the forming area is deformed upwards;

and 5: judging whether the forming of the formed metal plate in the step 4 reaches the forming specification of the formed metal plate;

step 5.1: if the molding specification is not met, executing the step 2;

step 5.2: if the molding specification is reached, the process is terminated.