CN113478883B

CN113478883B - Electromagnetic stamping method and device

Info

Publication number: CN113478883B
Application number: CN202110765053.2A
Authority: CN
Inventors: 黄海鸿; 桑豪杰; 李磊; 吕清宇; 甘雷; 刘志峰
Original assignee: Hefei University of Technology
Current assignee: Hefei University of Technology
Priority date: 2021-07-06
Filing date: 2021-07-06
Publication date: 2022-05-24
Anticipated expiration: 2041-07-06
Also published as: CN113478883A

Abstract

The invention relates to an electromagnetic stamping method and device. The electromagnetic stamping method comprises the following steps: dividing a blank holder of the electromagnetic stamping device into a plurality of blank holder areas according to the profile characteristics of the to-be-stamped part; setting a blank pressing force function which changes along with time for each blank pressing area according to the shape characteristics of each blank pressing area; for each binder zone, every cycle period t₀Collecting blank holder force data, and calculating the error between the blank holder force data and the value of the blank holder force function at the current time; and controlling the edge pressing force of each edge pressing area according to the error, and stamping the sheet material under the edge pressing force to obtain the piece to be stamped. The invention controls the blank holder force in real time according to the fluidity characteristic of the sheet material in the stamping process, realizes the accurate loading of the dynamically-changed blank holder force, improves the loading precision and the forming quality of the blank holder force, reduces the energy consumption in the blank holder process, and weakens the influence of electromagnetic coupling among multiple magnetic fields and external interference.

Description

Electromagnetic stamping method and device

Technical Field

The invention relates to the field of stamping processes, in particular to an electromagnetic stamping method and device.

Background

The stamping forming processing method is one of the main processing methods of metal plastic deformation, has the advantages of high production efficiency, low surface roughness and the like, and can realize one-step forming of complex parts. The blank pressing force control plays an important role in the aspects of the forming quality of a stamping part, the stress strain state of a plate material in the stamping process, the energy consumption in the stamping process and the like.

The existing hydraulic and electromagnetic edge pressing technology has the phenomenon of serious energy waste in the edge pressing process, and although the electric control permanent magnet edge pressing technology can solve the energy problem to a certain extent, the existing electric control permanent magnet sucker is not accurate enough in the aspect of edge pressing force loading.

Disclosure of Invention

In order to overcome the problems in the related art, the invention provides an electromagnetic stamping method and an electromagnetic stamping device.

An embodiment of the present invention provides an electromagnetic stamping method, including: dividing a blank holder of a stamping device into a plurality of blank holder areas according to the profile characteristics of a workpiece to be stamped; setting a blank pressing force function which changes along with time for each blank pressing area according to the shape characteristics of each blank pressing area; for each binder zone, every cycle period t₀Acquiring blank holder force data G, and calculating an error e between the acquired blank holder force data G and a value F of the blank holder force function at the current time to be F-G; and controlling the blank pressing force of each blank pressing area according to the error, and stamping the plate material under the blank pressing force to obtain the to-be-stamped part.

This embodiment makes the variable blank holder power function that real-time blank holder power strictly agrees with the setting, can both exert suitable blank holder power at every stage of blank holder process, and accurate control blank holder power has improved the loading capacity of blank holder power, has reduced the energy consumption of blank holder process.

In an exemplary embodiment, the stamping device includes a plurality of distributed magnetizing and demagnetizing circuits corresponding to the plurality of binder zones one to one, and controlling the binder force of each binder zone according to the error includes: and outputting at least one of a switching value signal, a pulse signal and a PWM (pulse-width modulation) signal to the distributed magnetizing and demagnetizing circuit corresponding to each edge pressing area according to the error so as to control the edge pressing force.

In the embodiment, the control signal is output to the distributed magnetizing and demagnetizing circuit to dynamically monitor the blank holder force in real time, so that the loading precision of the blank holder force is improved, and the metal flow of the plate is accurately controlled.

In an exemplary embodiment, each distributed magnetizing and demagnetizing circuit comprises four solid-state relays K_iWhere i ∈ {1,2,3,4}, and K_iThe distributed magnetizing and demagnetizing circuit is in a disconnected state in an initial state of stamping the plate, and the distributed magnetizing and demagnetizing circuit corresponding to each edge pressing area is output by the aid of the errorAt least one of the quantity signal, the pulse signal and the PWM pulse width modulation signal includes: to solid state relay K₃Output pulse signal so that the solid-state relay K₃The PWM control circuit is circularly switched on and off at a fixed duty ratio, and the frequency of the pulse signal is more than 5 times of the frequency of the PWM signal; adjusting the duty ratio of the PWM signal according to the error to enable the solid-state relay K₄Cycling on and off at a variable duty cycle, wherein the absolute value of the error is proportional to the duty cycle of the PWM pulse width modulated signal; when the error is larger than zero, a solid-state relay K is started₁Output a positive switching value signal so that the solid-state relay K₁Closing to magnetize the distributed magnetizing and demagnetizing circuit; and when the error is less than or equal to zero, switching to the solid-state relay K₂Output a positive switching value signal so that the solid-state relay K₂And closing to demagnetize the distributed magnetizing and demagnetizing circuit.

In the embodiment, the real-time edge pressing force in the edge pressing process is used as a feedback value, and the influence of multi-magnetic field coupling and external interference is weakened by adjusting the loading of the pulse current through the distributed magnetizing and demagnetizing circuit, so that the control precision is improved.

In an exemplary embodiment, the current value F of the blank holder force function is P × S, where P is the pressure required to stamp the slab at the time, and S is the contact area between the slab and the blank holder area at the time; and when the edge of the panel is far away from the inner edge of the edge pressing area, the edge pressing force function value is zero.

In the scheme of this embodiment, to the parameter variation of blank pressing in-process, set up suitable blank pressing force function for when the sheet material leaves the blank pressing piece, can not receive the atress between the blank pressing piece and bump, reduce blank pressing process energy consumption simultaneously.

In an exemplary embodiment, the method further comprises: every other cycle period t₀And collecting deformation data of the plate, and sending an alarm instruction and stopping stamping when the deformation data is more than 1.5 times of the initial thickness of the plate.

The embodiment monitors the thickness of the plate by feeding back real-time deformation data, optimizes the forming quality and avoids the defects of cracking, wrinkling and rebounding of the formed piece.

An embodiment of the present invention provides an electromagnetic stamping device, including: the blank holder is provided with a plurality of blank holding areas which are divided according to the outline characteristics of the part to be stamped; a plurality of pressure sensors in one-to-one correspondence with the plurality of binder zones, each pressure sensor for every cycle period t₀Collecting blank holder force data G corresponding to the blank holder area; and the controller is used for calculating an error e between the blank pressing force data G and a value F of a blank pressing force function which is set for each blank pressing area and changes along with time and is in the current time, controlling the blank pressing force of each blank pressing area according to the error, and stamping the sheet material under the blank pressing force to obtain the to-be-stamped piece.

This embodiment makes the variable blank holder force function that real-time blank holder force strictly agrees with and sets up, can both apply suitable blank holder force in every stage of blank holder process, and accurate control blank holder force has improved the loading capacity of blank holder force, has reduced the energy consumption of blank holder process.

In an exemplary embodiment, the electromagnetic stamping apparatus further includes a plurality of distributed magnetization and demagnetization circuits in one-to-one correspondence with the plurality of binder zones, and the controller is further configured to: and outputting at least one of a switching value signal, a pulse signal and a PWM (pulse-width modulation) signal to the distributed magnetizing and demagnetizing circuit corresponding to each edge pressing area according to the error so as to control the edge pressing force.

In an exemplary embodiment, each distributed magnetizing and demagnetizing circuit comprises four solid-state relays K_iWhere i ∈ {1,2,3,4}, and K_iIn an initial state of stamping the sheet material in a disconnected state, the controller is further configured to: to solid state relay K₃Output pulse signal so that the solid-state relay K₃Cycling on and off at a fixed duty cycle; adjusting said PWM signal in dependence on said errorDuty ratio of solid state relay K₄The pulse signal is circularly switched on and off at a variable duty ratio, the frequency of the pulse signal is more than 5 times of the frequency of the PWM signal, and the absolute value of the error is in direct proportion to the duty ratio of the PWM signal; when the error is larger than zero, a solid-state relay K is started₁Output a positive switching value signal so that the solid-state relay K₁Closing to magnetize the distributed magnetizing and demagnetizing circuit; and when the error is less than or equal to zero, switching to the solid-state relay K₂Output a positive switching value signal so that the solid-state relay K₂And closing to demagnetize the distributed magnetizing and demagnetizing circuit.

In an exemplary embodiment, the current value F of the blank holder force function is P × S, where P is the pressure required to stamp the slab at the time, and S is the contact area between the slab and the blank holder area at the time; the hold-down force function value is zero when the sheet edge is away from the inner edge of the hold-down region.

In an exemplary embodiment, the apparatus further comprises a plurality of displacement sensors in one-to-one correspondence with the plurality of binder zones, each displacement sensor for every cycle period t₀Gather the deformation data of sheet material, the controller still is used for: and when the deformation data is more than 1.5 times of the initial thickness of the plate, sending an alarm instruction and stopping stamping.

The scheme of the invention has the following advantages and beneficial technical effects:

the method aims at forming areas with different characteristics and provides different edge pressing forces at different stamping stages, and meanwhile, a negative feedback mechanism is utilized to dynamically monitor the edge pressing force in real time, so that the edge pressing force loading precision is improved, the metal flow of the plate is accurately controlled, the forming quality is optimized, the energy consumption is reduced, and the defects of cracking, wrinkling and rebounding of a formed part are avoided.

In addition, by combining the electric permanent magnet edge pressing technology and the distributed edge pressing technology, the influence of the gradual reduction of the contact area of the plate and the edge pressing block on the edge pressing force control in the stamping process caused by the time change is comprehensively considered, the edge pressing force is controlled in real time according to the flowability of the plate in the stamping process, and the energy consumption in the edge pressing process is reduced; the controller is used for controlling the distributed magnetizing and demagnetizing circuits, so that the accurate loading of the dynamically-changed blank holder force can be realized, and the forming quality is improved; the data of the stamping process is monitored in real time by using a negative feedback mechanism, the blank holder force loading precision is improved, and the influence of electromagnetic coupling among multiple magnetic fields and the problem of external interference are reduced.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

FIG. 1 shows a schematic flow diagram of an electromagnetic stamping method according to an embodiment of the invention;

FIG. 2 shows a schematic flow diagram of an electromagnetic stamping method according to another embodiment of the invention;

FIG. 3 shows a schematic flow diagram of an electromagnetic stamping method according to yet another embodiment of the invention;

FIG. 4 shows a schematic flow diagram of an electromagnetic stamping method according to yet another embodiment of the invention;

FIG. 5 shows a schematic view of an electromagnetic stamping apparatus according to an embodiment of the invention;

FIG. 6 shows a schematic view of an electromagnetic stamping apparatus according to another embodiment of the invention;

fig. 7 is a block diagram showing an electromagnetic punching apparatus according to an embodiment of the present invention;

FIG. 8 shows a schematic illustration of a zonal division of the bead ring in the electromagnetic stamping apparatus of FIG. 7;

figure 9 shows a circuit diagram of a distributed magnetizing and demagnetizing circuit according to an embodiment of the present invention;

fig. 10 is a perspective view showing a structure of an electromagnetic punching apparatus according to an embodiment of the present invention; and

fig. 11 shows a schematic view of the division of the region of the blank holder in the electromagnetic stamping device of fig. 10.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.

The invention discloses an electromagnetic stamping method, an electromagnetic stamping device and a storage medium. Specifically, the invention relates to an electric permanent magnet distributed edge pressing method and an edge pressing device for a stamping process. The scheme of the invention provides different edge pressing forces in different stamping stages for forming areas with different characteristics, and simultaneously utilizes a negative feedback mechanism to carry out real-time and dynamic monitoring on the edge pressing force, thereby improving the loading precision of the edge pressing force, accurately controlling the metal flow of the plate, optimizing the forming quality, reducing the energy consumption and avoiding the defects of cracking, wrinkling and rebounding of a formed part.

An electromagnetic punching method, an electromagnetic punching apparatus, and a storage medium of the embodiments of the present disclosure are described below with reference to the drawings.

FIG. 1 shows a schematic flow diagram of a stamping method according to an embodiment of the invention. The disclosed embodiments are exemplified by the fact that the stamping method is configured in a stamping device, the stamping device can be applied to, but not limited to, an electro-permanent-magnet distributed stamping system, and a controller of the stamping device can execute a proportional-integral-derivative (PID) control program to make the stamping device execute a stamping process.

As shown in fig. 1, the punching method of the present invention includes the following steps.

In step S101, the blank holder of the stamping device is divided into a plurality of blank holder regions according to the contour characteristics of the part to be stamped.

In the embodiment of the disclosure, the to-be-stamped part may have any shape, the contour features of the to-be-stamped part include at least one of straight lines and curved lines, and a plurality of straight lines or curved lines are connected end to form a closed outer contour of the to-be-stamped part.

In the embodiment of the disclosure, the blank holder of the stamping device is divided into s regions along the circumferential direction, and the ith region is sequentially divided into k regions along the radial direction_iA binder region, any one of which is represented by A_ijWhere i ∈ {1,2, …, s }, j ∈ {1,2, …, k }, respectively_i}。

In step S102, a blank force function that varies with time is set for each blank region according to the shape characteristics of each blank region.

Because the shape of the blank holding region and the stage of the stamping process affect the control of the blank holding force and the quality of a formed part, the invention considers that the variable blank holding force which changes along with the time is loaded on each blank holding region. In order to accurately control the blank holding force of each blank holding region, a blank holding force function which changes along with time for each blank holding region is set for each blank holding region according to the shape characteristics of each blank holding region, such as whether the blank holding region has a right angle, a round angle, an arc line or a special shape formed by multiple linear combinations, considering the proceeding stage (embodied as a time parameter) of the stamping process.

It will be appreciated that different binder zones correspond differentlyAnd the values of the blank pressing force functions in the same region at different moments are different. The blank force function is expressed as F_ij＝f(t_ij)，F_ijAnd the edge pressing area A_ijCorresponds to, t_ijIs a time variable and represents the radial direction of the sheet from the area A during the stamping process_ijThe outer edge of (a) to the inner edge of (b). For the binder region A_ijCurrent value of the blank force function F_ijThe pressure required for pressing the edges of the plate at the moment is P multiplied by S, and S is the contact area between the plate and the edge pressing area at the moment; at time t_ijInner, plate material in area A_ijThe contact area on the plate is continuously reduced, the pressure required by the plate is continuously changed, F_ij＝f(t_ij) And is changed accordingly. The shape of the region is characterized by fixed parameters of the function, and the invention is not limited to specific values.

The current value F of the blank pressing force function is P multiplied by S, wherein P is the pressure intensity required by the stamping of the plate at the moment, and S is the contact area between the plate and the blank pressing area at the moment; when the edge of the sheet material is far away from the inner edge of the edge pressing area, the contact area of the sheet material and the edge pressing area is zero, namely the edge pressing force function value is zero. In other words, as the pressing process progresses and the time varies, the outer edge of the slab flows from the outer edge of a certain edge pressing region to the inner edge of the edge pressing region, the contact area between the slab and the edge pressing region decreases, and when the edge of the slab leaves the inner edge of the edge pressing region, the contact area is zero, i.e. F_ij＝f(t_ij) And the blank pressing force is zero, so that when the plate material leaves the blank pressing blocks, the blank pressing blocks cannot collide with each other due to the action of the blank pressing force.

In step S103, for each binder region, every cycle period t₀And collecting the blank holder force data G, and calculating the error e between the collected blank holder force data G and the value F of the blank holder force function at the current time to be F-G.

In the embodiment of the invention, in order to ensure that the actual edge pressing force change is strictly matched with the curve of the edge pressing force function, so that the proper edge pressing force can be applied at each stage of the stamping process, a counter N is arranged in the stamping device_ijIn particular, a counter is provided in the controller for the modulePseudo-time variation, each time a period t₀And adding 1 to the counter, and carrying out PID control once by the controller according to the new blank holder force set value. The current value of the counter is n, and when n reaches the set value of the counter, n is₀And the stamping process is finished.

For example, in the PID control program C_ijIn which a cycle interrupt program is built, the cycle interrupt program has a period t₀The controller of the stamping device can control the PID instruction to operate circularly, and aiming at each blank holding area, the controller can control the PID instruction to operate circularly at intervals of a cycle period t₀And collecting the blank holder force data G, and calculating the error e between the collected blank holder force data G and the value F of the blank holder force function at the current time to be F-G. By controlling the magnitude of the error, the actual blank holder force value can be controlled to approach the real-time value of the function.

In step S104, the blank holding force of each blank holding region is controlled according to the error, and the sheet is stamped under the blank holding force to obtain a piece to be stamped.

In the embodiment of the invention, for each edge pressing area, according to the edge pressing force data G collected this time and the error e between the edge pressing force function and the value F at the current moment, which is equal to F-G, the edge pressing force applied to the area is controlled, so that the actual edge pressing force approaches the value of the edge pressing force function at the moment of collecting the edge pressing force data G, and the plate is punched under the edge pressing force to obtain the part to be punched.

In an exemplary embodiment, the stamping method proposed by the present invention further comprises: every other cycle period t₀And (3) collecting deformation data of the plate, and sending an alarm instruction and stopping stamping when the deformation data is more than 1.5 times of the initial thickness of the plate.

It can be understood that the sheet material is deformed due to the forced flow in the stamping process, the deformation data of the sheet material can be the thickness of the sheet material, and the stamping device is provided with a displacement sensor for each edge pressing area, wherein the displacement sensor is arranged at intervals of a cycle period t₀And (3) collecting the thickness of the plate material in the area, and when the real-time thickness of the plate material is more than 1.5 times of the initial thickness of the plate material, indicating that the material is seriously wrinkled, and sending an alarm instruction and stopping stamping.

Alternatively, the deformation data of the sheet may be any data capable of indicating the deformation state of the sheet, such as the change rate of the thickness of the sheet or the fluidity of the sheet metal, and the invention is not limited herein.

The deformation data can also be used to assist in controlling the blank pressing process, for example, by feeding the deformation data back to a controller of the stamping device in real time for controlling the blank pressing force in real time. The deformation data may also be used for quality analysis of the stamping.

Therefore, according to the stamping method of the embodiment of the disclosure, the blank holder of the stamping device is divided into a plurality of blank holder areas according to the profile characteristics of the part to be stamped, the blank holder force function which changes along with time is set for each blank holder area according to the shape characteristics of each blank holder area, and for each blank holder area, the blank holder force function is set every other cycle period t₀The method comprises the steps of collecting blank holder force data G, calculating the error e between the collected blank holder force data G and a blank holder force function at the current time value F, wherein the error e is equal to F-G, controlling the blank holder force of each blank holder area according to the error, and stamping the plate under the blank holder force to obtain a to-be-stamped part, so that different blank holder forces are provided for forming areas with different characteristics at different stamping stages, and meanwhile, a negative feedback mechanism is utilized to carry out real-time and dynamic monitoring on the blank holder force, the blank holder force loading precision is improved, the metal flow of the plate is accurately controlled, the forming quality is optimized, the energy consumption is reduced, and the defects of cracking, wrinkling and rebounding of a formed part are avoided.

Fig. 2 shows a schematic flow diagram of a stamping method according to another embodiment of the invention. This embodiment specifically describes step S104 based on the embodiment corresponding to fig. 1. As shown in fig. 2, the punching method includes the following steps.

In step S201, the blank holder of the stamping device is divided into a plurality of blank holder regions according to the contour characteristics of the part to be stamped.

In step S202, a binder force function that varies with time is set for each binder region according to the shape characteristics of each binder region.

In step S203, for each binder region, every cycle period t₀Collecting blank holder force data G, and calculating the number of blank holder forcesThe error e between G and the value F of the hold-down force function at the current time is F-G.

The execution processes of steps S201 to S203 may refer to the execution processes of steps S101 to S103 in the above embodiments, which are not described herein again.

In step S204, at least one of the switching value signal, the pulse signal, and the PWM pulse width modulation signal is output to the distributed magnetizing and demagnetizing circuit corresponding to each edge pressing region according to the error, so as to control the edge pressing force.

In the embodiment of the invention, the stamping device comprises a plurality of distributed magnetizing and demagnetizing circuits U which are in one-to-one correspondence with a plurality of edge pressing areas_ijThe electric control permanent magnetic chuck, the force increasing plate and the pressure sensor corresponding to each edge pressing area form an edge pressing unit D_ijThe distributed magnetizing and demagnetizing circuit performs magnetizing and demagnetizing on the electric control permanent magnetic chuck by outputting pulse current, and the electric control permanent magnetic chuck is formed by the distributed magnetizing and demagnetizing circuit U_ijThe output pulse current is used for magnetizing and demagnetizing, and the force increasing plate is attracted to generate a blank holder force. The blank holder power that automatically controlled permanent magnetism sucking disc produced is stable and lasting, has improved the loading capacity of blank holder power, has reduced the energy consumption of blank holder process.

Particularly, because the area of each edge pressing area is limited, the direct action of the electric control permanent magnetic chuck on each edge pressing area can cause insufficient or unstable edge pressing force. The force increasing plate is connected with the edge pressing blocks corresponding to each edge pressing area through connecting rods, and the electric control permanent magnetic suction cups are arranged corresponding to the force increasing plate, so that the electric control permanent magnetic suction cups are magnetized and demagnetized by the distributed magnetizing and demagnetizing circuit U_ijThe output pulse current is used for magnetizing and demagnetizing, and the force-increasing plate is attracted to generate a blank-holding force, so that the loading capacity and the stability of the blank-holding force of each blank-holding block are improved.

Therefore, the stamping method of the embodiment of the disclosure, wherein the stamping device comprises a plurality of distributed magnetizing and demagnetizing circuits which are in one-to-one correspondence with the plurality of edge pressing areas, and the distributed magnetizing and demagnetizing circuits are arranged according to the positions to be stampedThe outline characteristic of a stamping part is that a blank holder of a stamping device is divided into a plurality of blank holder areas, a blank holder force function which changes along with time is set for each blank holder area according to the shape characteristic of each blank holder area, and for each blank holder area, a cycle period t is set every other₀Gather blank holder power data G, and calculate the blank holder power data G of gathering and the error e of blank holder power function between the value F of current time is equal to F-G, according to the error to the distributed magnetization and demagnetization circuit output switching value signal that every blank holder region corresponds, at least one in pulse signal and the PWM pulse width modulation signal, in order to control the blank holder power, thereby improve blank holder power control accuracy, weaken the influence of many magnetic field couplings and external disturbance, the blank holder power through the production of automatically controlled permanent magnetism sucking disc is stable and lasting, the loading capacity of blank holder power has been improved, the energy consumption of blank holder process has been reduced.

Fig. 3 shows a schematic flow diagram of a stamping method according to a further embodiment of the invention. This embodiment specifically describes step S204 based on the embodiment corresponding to fig. 2. As shown in fig. 3, the punching method includes the following steps.

In step S301, the blank holder of the stamping device is divided into a plurality of blank holder regions according to the contour characteristics of the workpiece to be stamped.

In step S302, a binder force function that varies with time is set for each binder region according to the shape characteristics of each binder region.

In step S303, for each binder region, every cycle period t₀And collecting the blank holder force data G, and calculating the error e between the collected blank holder force data G and the value F of the blank holder force function at the current time to be F-G.

The execution processes of steps S301 to S303 may refer to the execution processes of steps S101 to S103 in the above embodiments, which are not described herein again.

In the embodiment, each distributed magnetizing and demagnetizing circuit comprises four solid-state relays K_iWhere i ∈ {1,2,3,4}, and K_iIn the initial state of the pressing of the sheet material, it is in the broken state. Step S204 specifically includes the following steps.

In step S304, the relay K is turned to the solid state relay₃Output pulse signal to make solid-state relay K₃Cycled on and off at a fixed duty cycle. The frequency of the pulse signal is greater than 5 times the frequency of the PWM pulse width modulated signal.

In the embodiment of the invention, the controller charges and demagnetizes the circuit U to the distributed type_ijOutput signal to control solid relay K_iMake and break to make distributed magnetizing and demagnetizing circuit U_ijAnd outputting the pulse current.

Wherein, the solid state relay K₃And the circuit is circularly switched on and off at a fixed duty ratio, and the circuit outputs pulse current to carry out magnetization and demagnetization.

In step S305, the duty ratio of the PWM signal is adjusted according to the error, so that the solid-state relay K₄And cycling on and off at a variable duty cycle, wherein the absolute value of the error is proportional to the duty cycle of the PWM pulse width modulated signal.

In the embodiment of the invention, the solid-state relay K₄Controlled by PWM pulse width modulation signal, solid state relay K₄The duty ratio is changed to be switched on and off in a circulating mode, and the change is represented as the change of the magnetizing and demagnetizing rates of the circuit.

For example, the controller controls the program C by executing a PID_ijThe PID parameter can be adjusted according to the error e, and the duty ratio of the output PWM signal can be adjusted, so that the solid-state relay K₄In a cyclic on-off state of variable duty cycle. The absolute value of the error is in direct proportion to the duty ratio of the PWM signal, namely, if the absolute value of the error e is larger, the duty ratio of the PWM signal is larger; if the absolute value of the error e is smaller, the duty ratio of the PWM signal is smaller.

In step S306, when the error is larger than zero, the relay K is turned to the solid state relay K₁Output positive switching value signal to make solid-state relay K₁Closing to magnetize the distributed magnetizing and demagnetizing circuit; when the error is less than or equal to zero, the relay K is turned to a solid state relay₂Output positive switching value signal to make solid-state relay K₂And closing to demagnetize the distributed magnetizing and demagnetizing circuit.

In the embodiment of the invention, the distributed magnetizing and demagnetizing circuit U_ijSolid state relay K in₁And K₂Controlled by switching value signal, solid-state relay K₁Closed, indicating that the circuit is charged; solid state relay K₂Closed, indicating circuit demagnetization. For example, the controller is executing a PID control program C_ijIn the method, whether the error e is larger than zero is judged, if yes, the error is transferred to a solid-state relay K₁Output positive signal to make solid-state relay K₁Closing to charge the circuit, if not, then turning to the solid state relay K₂Output positive signal to make solid-state relay K₂Closed to demagnetize the circuit.

Therefore, in the stamping method of the embodiment of the disclosure, each distributed magnetizing and demagnetizing circuit comprises four solid-state relays K_iAnd i belongs to {1,2,3,4}, dividing the blank holder of the stamping device into a plurality of blank holder areas according to the contour characteristics of the to-be-stamped parts, setting a blank holder force function which changes along with time for each blank holder area according to the shape characteristics of each blank holder area, and setting a cycle period t for each blank holder area every other₀Collecting blank holder force data G, calculating the error e between the collected blank holder force data G and the blank holder force function value F at the current time to be F-G, and applying the error to a solid-state relay K₃Output pulse signal to make solid-state relay K₃The solid-state relay K is circularly switched on and off at a fixed duty ratio, and the duty ratio of the PWM signal is adjusted according to the error, so that the solid-state relay K₄The relay is switched on and off in a circulating mode with a variable duty ratio, wherein the absolute value of an error is in direct proportion to the duty ratio of a PWM (pulse width modulation) signal, and when the error is larger than zero, the relay is switched to a solid-state relay K₁Output positive switching value signal to make solid-state relay K₁Closed to magnetize the distributed magnetizing and demagnetizing circuit, and when the error is less than or equal to zero, the solid state relay K is switched on₂Output positive switching value signal to make solid-state relay K₂And closing to demagnetize the distributed magnetizing and demagnetizing circuit. Therefore, the distributed magnetizing and demagnetizing circuit is controlled by executing a PID control program, and the direction and the speed of the pulse current of the distributed magnetizing and demagnetizing circuit are adjusted, so that the electric control permanent magnetic chuck is magnetized and demagnetized, the force increasing plate is attracted to generate the blank holding force, the generated blank holding force is infinitely close to the value of a blank holding force function, and a proper blank holding force can be applied at each stage of the stamping process, thereby improving the quality of the productThe forming quality of the stamping part is improved. Real-time blank pressing force in the blank pressing process is used as a feedback value, and negative feedback control adjusts the loading of pulse current according to the feedback value so as to weaken the influence of multi-magnetic field coupling and external interference and improve the control precision. In addition, the stable and continuous blank holder force is obtained by magnetizing and demagnetizing the electric control permanent magnetic chuck, the loading capacity of the blank holder force is improved, and the energy consumption in the blank holder process is reduced.

Fig. 4 shows a schematic flow diagram of a stamping method according to a further embodiment of the invention. This embodiment specifically describes step S101 based on the embodiment corresponding to fig. 1. As shown in fig. 4, the punching method includes the following steps.

In step S401, contour features of a workpiece to be stamped are acquired.

In the embodiment of the disclosure, the part to be stamped may be a multi-feature curved surface stamped part, which may have any shape. On a two-dimensional plane, taking the outer contour of the part to be stamped as an example, the contour characteristics of the part to be stamped can include at least one of straight lines and curved lines, and the closed outer contour of the part to be stamped is formed by connecting a plurality of straight lines or curved lines end to end.

It is understood that the feature of obtaining the outer contour of the part to be stamped is only one example of the invention, and the relationship between the feature of the inner contour or a plurality of independent inner contours of the part to be stamped may also be obtained.

In step S402, the blank holder of the stamping device is divided into S regions along the circumferential direction according to the contour features of the part to be stamped, where S is an integer greater than 1.

For example, the outer contour of the part to be stamped is formed by connecting m straight lines and n curves end to end, and any straight line is L_i(i e {1,2, …, m), any curve being represented by C_j(j e {1,2, …, n) indicates that the connection type can be divided into any straight line connecting with any curve, any curve connecting with another curve, and any straight line connecting with another straight line. And dividing a blank holder of the stamping device into s areas along the circumferential direction according to the type of the connection relation formed by the profile characteristics of the parts to be stamped.

In an exemplary embodiment, dividing the blankholder of the stamping device circumferentially into s zones according to the profile characteristics of the part to be stamped comprises:

(1) when the straight line L_aAnd curve C_aWhen connected, will be in a straight line L_aThrough a straight line L_aA straight line L of one end point of_aFirst perpendicular line of (1), through straight line L_aAnd curve C_aIs a straight line L of the connection point of_aAnd a region formed by line segments between points where the first perpendicular line and the second perpendicular line intersect with the outer edge of the blank holder, respectively, is determined as a first region to be defined as a curve C_aBy curve C_aA second region is defined as a region formed by a curve between a third perpendicular line and a second perpendicular line of a tangent line of the point at one end point of (A) and a point where the second perpendicular line and the third perpendicular line intersect with the outer edge of the blank holder, respectively, and a straight line L_aAnd curve C_aThe curvature q at the connecting point of (1) is 0.

(2) When curve C_bAnd curve C_cConnected and curve C_bAnd curve C_cHas a curvature satisfying (q)_max-q_min)/q_maxWhen the curve is more than or equal to 0.05, the curve C is formed_bPassing curve C_bA fourth perpendicular to the tangent of the point at one end point of (A), through the curve C_bAnd curve C_cA third region is defined as a region formed by a curve between a fifth perpendicular line of the point tangent to the connecting point of (A) and points where the fourth and fifth perpendicular lines intersect with the outer edge of the blank holder, respectively, and a curve C is defined as a region of the third region_cPassing curve C_cA fourth region is defined as a region formed by a curve between a sixth perpendicular line and a fifth perpendicular line of the point tangent to the one end point of (a), and points where the fifth perpendicular line and the sixth perpendicular line intersect with the outer edge of the blank holder, respectively, wherein q is_maxRepresents curve C_bOr curve C_cMaximum value of curvature of any point above, q_minRepresents curve C_bOr curve C_cMinimum value of curvature of any point above, curve C_bAnd curve C_cThe rate of change of curvature is greatest at the point of connection.

Wherein, curve C_bAnd curve C_cCan be expressed in terms of the differential dq/dl, where q is the curvature and l is the length of the curve, then at Max { dq/dl } is the connection point of the two curves,herein will be C_bArea of curve and C_cThe curved region is divided into two independent binder regions.

(3) When curve C_bAnd curve C_cConnected and curve C_bAnd curve C_cDoes not satisfy (q)_max-q_min)/q_maxWhen the curve is more than or equal to 0.05, the curve C is used_bAnd curve C_cAnd the fourth perpendicular line, the sixth perpendicular line, and a region formed by a curve between points at which the fourth perpendicular line and the sixth perpendicular line intersect with the outer edge of the blank holder, respectively, are determined as a fifth region.

It can be understood that curve C_bAnd curve C_cHas a curvature satisfying (q)_max-q_min)/q_maxMore than or equal to 0.05 is the condition that two curves are divided into two edge pressing regions, if (q)_max-q_min)/q_maxIf < 0.05, no division is made, i.e. curve C is divided_bAnd curve C_cAnd an area formed by the whole curve, two vertical lines of tangent lines at two end points of the curve and a curve between the two vertical lines and the points of intersection of the two vertical lines and the outer edge of the blank holder respectively is used as a blank holder area.

It should be understood that in the actual stamping process, the stamping has rounded or chamfered corners, and therefore the present invention does not consider the case where a straight line is connected to a straight line.

In step S403, for the ith zone, i e {1,2, …, S), the ith zone is divided into k in the radial direction according to the width of the corresponding flange zone of the plate and the thread parameters of the pressure sensor_iA binder region where k_iEach edge pressing area corresponds to one pressure sensor and one edge pressing block which are connected through threads, and the number of the edge pressing areas is greater than or equal to 1.

In particular, the blankholder is divided in a two-dimensional plane into

A binder region, any binder region being designated A_ijWhere i ∈ {1,2, …, s }, j ∈ {1,2, …, k }, respectively_i}. In three-dimensional space, it is embodied in that the blank holder is divided into

Each edge-pressing block is represented as Y_ij，i∈{1,2,…,s},j∈{1,2,…,k_i}。

It can be understood that the part of the blank which is not completely drawn into the die is the flange area, when the width of the flange area corresponding to the sheet material is large, in order to meet the stamping requirement, a plurality of edge pressing blocks need to be arranged in the radial direction, and the purpose of providing different edge pressing forces for different edge pressing blocks is achieved by changing the time of the input pulse current of the edge pressing blocks corresponding to the magnetic pole blocks of the electric control permanent magnetic chuck. In other words, in order to realize multi-region distributed control of the blank pressing force, when the blank pressing region is divided, the width of the flange region corresponding to the plate material and the connection parameters between the blank pressing block and the pressure sensor need to be considered, and the problems of inaccurate blank pressing force control and the like caused by too large or too small blank pressing region are avoided.

In the exemplary embodiment, for the ith zone, i e {1,2, …, s), the width of the corresponding flange zone when the slab is in contact with the thread diameter d of the pressure sensor₀Is greater than 2 and less than 4, the ith area is divided into k along the radial direction_iA binder region where k_iThe width of the edge pressing area in the radial direction is equal to that of the ith area in the radial direction; when the width of the flange area corresponding to the plate material and the thread diameter d of the pressure sensor₀When the ratio of (a) to (b) is greater than or equal to 4, dividing the ith area into k areas along the radial direction_iA binder region where k_iK is not less than 2, the number k is_iThe total width of each edge pressing area in the radial direction is equal to the width of the ith area in the radial direction; wherein the width of any edge pressing area in the radial direction is more than 2d₀。

For example, the narrowest width w of the crimping block is the pressure sensor thread diameter d₀2 times of the pressure block, the edge of the inner side of the innermost side pressing block is tightly attached to the edge of the corresponding area of the inner side of the female die of the punching device when the innermost side pressing block works, and any straight line L_xOr curve C_xWhen the width h of a flange area corresponding to the plate material of the area is more than or equal to y (y is more than w), a y/w block blank holder block is required to be placed at the radial position, when y/w is more than 1 and less than 2,only the width of the first block edge pressing block needs to be adjusted to meet the edge pressing requirement, and when y/w is larger than 2, the width of the edge pressing block is adjusted to place the minimum integer block edge pressing block to meet the edge pressing requirement. The edge blocks are closely arranged and the width (and thickness) of each edge block in the same circumferential region is the same.

In another alternative embodiment, the number of the radial edge pressing blocks can be determined according to the punching depth h of the piece to be punched or the radial flowing distance of the plate.

In an exemplary embodiment, the profile of the bead block is the same as the profile of the corresponding bead region, and the thickness of the bead block is the total thread length h of the pressure sensor₀1.5 to 2.0 times of the total weight of the composition.

In step S404, for each blank region, the blank force is dynamically controlled to perform stamping to obtain a to-be-stamped part.

In this embodiment, the step S404 includes the steps S102 to S104, or S202 to S204, or S302 to S306, which are not described herein again.

Therefore, according to the stamping method of the embodiment of the disclosure, by obtaining the profile characteristics of the to-be-stamped part, the blank holder of the stamping device is divided into s regions along the circumferential direction according to the profile characteristics of the to-be-stamped part, wherein s is an integer greater than 1, and for the ith region, i ∈ {1,2, …, s), the ith region is divided into k regions along the radial direction according to the width of the flange region corresponding to the plate material and the thread parameters of the pressure sensor_iA binder region where k_iThe method comprises the steps that each edge pressing area corresponds to one pressure sensor and one edge pressing block which are in threaded connection, edge pressing force is dynamically controlled for each edge pressing area to perform stamping to obtain a piece to be stamped, so that the edge pressing areas are divided for the pieces to be stamped with different shapes and characteristics, the edge pressing areas are designed according to the profile characteristics of the pieces to be stamped, the edge pressing force is changed for different areas, accurate control of the edge pressing force is achieved, and forming quality is optimized.

Compared with the current single edge pressing area division, the edge pressing area division is carried out according to the relation among different shapes, different internal characteristics and internal characteristics, and the requirement matching of edge pressing force of each area of the multi-characteristic curved surface is realized. Compared with the traditional mode of generating the blank pressing force through a hydraulic cylinder loop, the electronic control permanent magnetic chuck realizes the matching of the blank pressing force generated by each area and the blank pressing force requirement, the blank pressing force generating capacity of each blank pressing area is improved, and the energy consumption of the production process is reduced.

In an exemplary embodiment, the stamping process may be described as: starting the system, inputting the variable blank holder force function into a controller of a punching device for each divided blank holder area, placing a plate on the blank holder, descending a female die of the punching device to a designated position to press the plate, executing a PID control program by the controller, outputting a pulse signal to a distributed magnetizing and demagnetizing circuit corresponding to the PID control program for each blank holder area, operating a cycle interrupt program in the PID control program, and operating a counter N₁Working, N for each cycle of circulation₁Is n +1, variable blank holder force function F_ij＝f(t_ij) As a PID control program C_ijIs varied with time and at time t_ijInner, F_ij＝f(t_ij) The real-time edge-pressing force data G measured by the pressure sensor is 0 when the plate material reaches the inner edge of the innermost side edge-pressing block and is continuously reduced along with the movement of the plate material_ijInput into the controller and the upper computer of the stamping device, the upper computer has a data processing function and receives the blank holder force data G_ijWith a preset blank holder force curve F_ijComparing the real time values of F (t) and calculating the error e ═ F_ij-G_ijAnd the controller sets the PID parameters according to the error e so as to adjust the state of each solid-state relay, when the plate material moves to the inner edge of the innermost side edge pressing block, the counting value of the counter reaches a set value, the edge pressing force is zero, the female die rises to a specified position, the plate material is taken down, and the work is finished.

Fig. 5 shows a schematic view of a stamping device 500 according to an embodiment of the invention. As shown in fig. 5, the punching apparatus 500 includes: the blank holder 501, the blank holder 501 has a plurality of blank holding areas divided according to the outline characteristics of the workpiece to be stamped; a plurality of pressure sensors 502, a plurality of pressure sensors 502 and a plurality ofThe edge pressing areas are in one-to-one correspondence, and each pressure sensor is used for every other cycle period t₀Collecting blank holder force data G corresponding to the blank holder area; and the controller 503 is configured to control the blank holding force of each blank holding region according to an error e between the blank holding force data G and a value F of the blank holding force function which is set for each blank holding region and changes along with time and is in the current time, wherein the error e is equal to F-G, and the blank holding force is stamped under the blank holding force to obtain a to-be-stamped part.

According to the embodiment of the disclosure, the blank holder of the stamping device is divided into a plurality of blank holder areas according to the contour characteristics of the part to be stamped, a blank holder force function which changes along with time is set for each blank holder area according to the shape characteristics of each blank holder area, and for each blank holder area, a cycle period t is arranged every other₀The method comprises the steps of collecting blank holder force data G, calculating the error e between the collected blank holder force data G and a blank holder force function at the current time value F, wherein the error e is equal to F-G, controlling the blank holder force of each blank holder area according to the error, and stamping the plate under the blank holder force to obtain a to-be-stamped part, so that different blank holder forces are provided for forming areas with different characteristics at different stamping stages, and meanwhile, a negative feedback mechanism is utilized to carry out real-time and dynamic monitoring on the blank holder force, the blank holder force loading precision is improved, the metal flow of the plate is accurately controlled, the forming quality is optimized, the energy consumption is reduced, and the defects of cracking, wrinkling and rebounding of a formed part are avoided.

Fig. 6 shows a schematic view of a stamping device 600 according to another embodiment of the invention. As shown in fig. 6, the stamping apparatus 500 includes a binder ring 501, a plurality of pressure sensors 502, a controller 503, a plurality of distributed magnetization and demagnetization circuits 504, a plurality of displacement sensors 505, a data acquisition card 506, and an upper computer 507. Wherein the distributed magnetizing and demagnetizing circuit 504 comprises a plurality of solid-state relays K_iWhere i ∈ {1,2,3,4 }.

In the exemplary embodiment, blank holder 501 has a plurality of blank holder regions divided according to the profile characteristics of the part to be stamped, and a plurality of pressure sensors 502, each for every cycle period t, are in one-to-one correspondence with the plurality of blank holder regions₀Collect the binder force data G corresponding to the binder region, and the controller 503 is used for rootAccording to the blank holder force data G and the error e between the value F of the blank holder force function which is set for each blank holder area and changes along with the time and is in the current time, at least one of a switching value signal, a pulse signal and a PWM (pulse width modulation) signal is output to the distributed magnetizing and demagnetizing circuit 504 corresponding to each blank holder area so as to control the blank holder force, thereby improving the control precision of the blank holder force, weakening the influence of multi-magnetic field coupling and external interference, the blank holder force generated by the electric control permanent magnetic chuck is stable and continuous, the loading capacity of the blank holder force is improved, and the energy consumption of the blank holder process is reduced.

In the exemplary embodiment, each distributed magnetization and demagnetization circuit 504 includes four solid state relays K_iWhere i ∈ {1,2,3,4}, the controller 503 is further to: to solid state relay K₃Output pulse signal to make solid-state relay K₃Cycling on and off at a fixed duty cycle; adjusting the duty ratio of the PWM signal according to the error to make the solid-state relay K₄The PWM signal is circularly switched on and off at a variable duty ratio, wherein the absolute value of the error is in direct proportion to the duty ratio of the PWM signal; when the error is larger than zero, the relay K is turned to a solid state relay₁Output positive switching value signal to make solid-state relay K₁Closed to magnetize the distributed magnetization and demagnetization circuit 504; and when the error is less than or equal to zero, the solid-state relay K is started₂Output positive switching value signal to make the solid-state relay K₂Closed to demagnetize the distributed magnetization and demagnetization circuit 504.

In an exemplary embodiment, the blankholder function is set to a value of zero when punching the inner edge of the innermost blankholder region away from the slab edge. Each displacement sensor 505 is arranged to be displaced every cycle period t₀The deformation data of the plate is collected, and the controller 503 is further configured to: and when the deformation data is more than 1.5 times of the initial thickness of the plate, sending an alarm instruction and stopping stamping.

In an exemplary embodiment, the data acquisition card 506 is connected with the pressure sensor 502, the displacement sensor 505 and the upper computer 507 to store the data fed back by the sensors and provide the data to the upper computer 507, and the upper computer 507 analyzes the data provided by the data acquisition card 506. Controller 503 and pressure sensor 502 and displacementSensor 505, solid state relay K in distributed magnetizing and demagnetizing circuit 504_iAnd the upper computer 507 is connected with the solid-state relay to control the on-off of the solid-state relay according to the result analyzed by the upper computer 507. The distributed magnetizing and demagnetizing circuit 504 is connected to an electrically controlled permanent magnet chuck (not shown in fig. 6) to perform magnetizing and demagnetizing on the electrically controlled permanent magnet chuck, so as to attract an energizing plate (not shown in fig. 6) to generate a blank holder force.

With regard to the apparatus in the above-described embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment related to the method, and will not be elaborated here. In addition, the division of the regions regarding the binder has been described in detail in the method embodiment, and is not described herein again.

By the embodiment of the invention, the blank pressing areas can be divided aiming at the parts to be pressed with different shape characteristics, and the blank pressing areas are designed according to the contour characteristics of the parts to be pressed so as to provide variable blank pressing force aiming at different areas, thereby realizing accurate control of the blank pressing force and optimizing the forming quality.

Specifically, referring to fig. 7, taking a box-type stamping part as an example, fig. 7 shows a schematic structural diagram of a stamping device according to an embodiment of the present invention, which includes a blank holder 501, a plurality of pressure sensors 502, a plurality of displacement sensors 505, a female die 508, an electrically controlled permanent magnetic chuck 509, a male die 510, and a force-increasing plate 511. The blank holder 501 is divided into s regions along the circumferential direction on a two-dimensional plane, and the ith region is sequentially divided into k regions along the radial direction_iA blank holding region of

And the binder regions can be obtained by dividing according to the method embodiment corresponding to fig. 4, and the divided binder regions are shown in fig. 8. In the embodiment shown in fig. 8, the width of the flange area corresponding to the plate material of each area is the same, and the thread diameter of each pressure sensor is the same, so that the number of the blank pressing areas obtained by radially dividing each area is the same.

Each edge pressing region corresponds to an edge pressing block in three-dimensional space, and any edge pressing block is represented as Y_ijI ∈ {1,2, …, s }, j ∈ {1,2, …, k }. Each of the edge-pressing blocks andthe corresponding electric control permanent magnetic chuck 509, the booster plate 511, the pressure sensor 502 and the displacement sensor 505 form a blank holding unit, and any blank holding unit is represented as D_ij. The electric control permanent magnetic chuck 509 is arranged above the force increasing plate 511, the pressure sensor 502 is arranged below the edge pressing block, and the displacement sensor 505 is arranged between the force increasing plate 511 and the male die 510.

And edge pressing unit D_ijThe connected distributed magnetizing and demagnetizing circuits 504 are denoted as U_ijI ∈ {1,2, …, s }, j ∈ {1,2, …, k }. In distributed magnetizing and demagnetizing circuit U_ijMiddle and solid state relay K_iBy PID control program C_ijOn-off control and distributed magnetizing and demagnetizing circuit U_ijAnd outputting the pulse current. Fig. 9 shows a circuit diagram of a distributed magnetization and demagnetization circuit according to an embodiment of the present invention.

For each edge pressing unit D_ijThe electric control permanent magnetic chuck 509 is composed of a distributed magnetizing and demagnetizing circuit U_ijThe output pulse current is used for magnetization and demagnetization, and the force increasing plate 511 is attracted to generate a blank holder force. The blank holder power that automatically controlled permanent magnetism sucking disc produced is stable and lasting, has improved the loading capacity of blank holder power, has reduced the energy consumption of blank holder process.

The pressure sensor 502 is cycled every other cycle period t₀Collecting blank holder force data, displacement sensor 505 every other cycle period t₀The deformation data of the sheet is collected and input into the controller 503 and the data acquisition card (not shown in fig. 7).

The data acquisition card transmits real-time data measured by the pressure sensor 502 and the displacement sensor 505 to an upper computer (not shown in fig. 7). The upper computer is internally provided with a data processing program which stores and analyzes data and feeds the data back to the controller 503.

The controller 503 can adjust the loading of the pulse current according to the magnitude of the feedback value to weaken the influence of multi-magnetic field coupling and external interference, and improve the control precision. Specifically, when the deformation data is greater than 1.5 times of the initial thickness of the plate, the controller 503 sends an alarm command and controls the punching process to stop. According to the difference e between the currently acquired blank pressing force data G and the value F of the blank pressing force function at the current time, which is F-G, the controller 503 controls the blank pressing force applied to the region, so that the actual blank pressing force approaches the value of the blank pressing force function at the time of acquiring the blank pressing force data G.

Specifically, the controller 503 outputs a switching value signal, a pulse signal, and a PWM pulse width modulation signal to the distributed magnetization and demagnetization circuit 504, thereby controlling the state of the solid-state relay. Solid state relay K₁Controlled by switching value signal, solid-state relay K₁Closed, indicating that the circuit is charged; solid state relay K₂Controlled by switching value signal, solid-state relay K₂Closed, denoted as circuit demagnetization; solid state relay K₃Controlled by pulse signals, solid-state relays K₃The circuit is circularly switched on and off at a fixed duty ratio, and the circuit outputs pulse current to carry out magnetization and demagnetization; solid state relay K₄Controlled by PWM pulse width modulation signal, solid state relay K₄And the circuit is circularly switched on and off by a variable duty ratio, and the change of the magnetizing and demagnetizing rates of the circuit is represented, so that the blank holding force of each blank holding area is controlled.

In an exemplary embodiment, referring to fig. 10, a door-shaped stamping is taken as an example, and fig. 10 shows a perspective structural view of a stamping device according to an embodiment of the present invention. The punching device comprises a plurality of pressure sensors 502, a plurality of displacement sensors 505, a female die 508, an electric control permanent magnetic chuck 509, a male die 510, a force-increasing plate 511, a force-increasing plate connecting rod 512, a blank holder connecting rod 513, a connecting block 514 and a guide rod cylinder 515.

Specifically, the lower surface of the electric control permanent magnetic chuck 509 is a magnetic force generating surface, a female die 508 with a multi-characteristic curved surface outline is arranged at the center of the electric control permanent magnetic chuck 509, the upper surface of the female die 508 is flush with the lower surface of the electric control permanent magnetic chuck 509, and a plate 517 is placed below the female die 508; a blank holder 501 is arranged right above the outer edge of the plate 517, blank holders are connected to the upper bottom surface of the pressure sensor 502, the lower bottom surface of the pressure sensor 502 is connected to the upper bottom surface of a blank holder connecting rod 513, the lower bottom surfaces of the blank holder connecting rods 513 are connected to the radial inner side of a connecting block 514 and are sequentially arranged from inside to outside, the radial outer side of the connecting block 514 is connected to the lower bottom surface of a reinforcing plate connecting rod 512, the upper bottom surface of the reinforcing plate connecting rod 512 is connected to a reinforcing plate 511, the reinforcing plate 511 is distributed right below the electric control permanent magnetic chuck and is parallel to the lower surface of the electric control permanent magnetic chuck, and the moving direction of the reinforcing plate 511 is perpendicular to the lower surface of the electric control permanent magnetic chuck 509; a displacement sensor 505 is arranged on the outer side of the connecting block 514, and the displacement sensor 505 is vertical to the plane of the force-increasing plate 511; the lower bottom surface of the connecting block 514 is connected with the guide rod side of the guide rod cylinder 515, the cylinder side of the guide rod cylinder 515 is connected with a connecting plate 516, the center of the connecting plate 516 is provided with a male die 510 with a multi-characteristic curved surface outline, the number of the guide rod cylinders 515 is determined by the weight and the size of the connecting block to meet the bearing requirement of the connecting block and is arranged at the opposite center, and the guide rod cylinder 515 can ensure that all the edge pressing blocks return to the same horizontal plane when the device does not work.

The thickness of all the force increasing plates is the same as that of the edge pressing blocks, the inner edge of the innermost force increasing plate is parallel to that of the electrically-controlled permanent magnetic chuck and is positioned on the same horizontal plane, the shape of the inner side boundary of the innermost force increasing plate is determined by the shape of the electrically-controlled permanent magnetic chuck corresponding to the edge pressing area, the upper and lower boundaries are determined by the extension lines of the perpendicular lines of the division points of each edge pressing area, the outer boundary is determined by the width of the force increasing plate, the width is determined according to the required edge pressing force, the shape of the inner boundary of the adjacent outer force increasing plate is the same as that of the outer boundary of the innermost force increasing plate, the upper and lower boundaries are determined by the extension lines of the perpendicular lines of the division points of each edge pressing area, the outer boundary is determined by the width of the force increasing plate, the width is determined according to the required edge pressing force, and finally the widths of all the force increasing plates are the same as that of the electrically-controlled force increasing permanent magnetic chuck so as to ensure that the force increasing plates are sufficiently stressed.

The blank holder 501 is divided into s regions along the circumferential direction on a two-dimensional plane, and the ith region is sequentially divided into k regions along the radial direction_iThe front end of the edge pressing block of the ith area is connected with the tail end of the edge pressing block of the (i + 1) th area, and the edge pressing areas are arranged in the same area

The shape of the binder region, which is surrounded by the binder 501, is the same as the shape of the cavity 508, and can be obtained by dividing according to the method embodiment shown in fig. 4, and the divided binder region is shown in fig. 11. In the embodiment shown in FIG. 11, the width of the flange area corresponding to the plate material of each area is the same, and the thread diameter of each pressure sensor is the sameFor example, the number of binder regions obtained by dividing each region in the radial direction is the same.

In an exemplary embodiment, the distance between the force-increasing plates corresponding to two adjacent edge pressing areas is 2 mm-3 mm, so that the extrusion of the force-increasing plates in different areas after being stressed is reduced. The distance between the connecting blocks 514 corresponding to two adjacent edge pressing areas is 2 mm-3 mm, so that the connecting blocks 514 can have a buffering space when small displacement occurs due to stress in the stamping process.

The connecting block 514 is connected with a required number of guide rod air cylinders 515, and the guide rod air cylinders 515 can ensure that all the edge pressing blocks return to the same horizontal plane when the device does not work.

The present invention also provides a non-transitory computer readable storage medium, wherein instructions of the storage medium, when executed by a processor, cause the processor to perform the method described in the embodiments of the present invention. The non-transitory computer readable storage medium may be a ROM, a Random Access Memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like.

It is to be understood that the term "plurality" as used herein refers to two or more, and other terms are intended to be analogous. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. The singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It will be further understood that the terms "first," "second," and the like, are used to describe various information and should not be limited by these terms. These terms are only used to distinguish one type of information from another and do not denote a particular order or importance. Indeed, the terms "first," "second," and the like are fully interchangeable. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present invention.

It will be further understood that, unless otherwise specified, "connected" includes direct connections between the two without the presence of other elements, as well as indirect connections between the two with the presence of other elements.

It is further to be understood that while operations are depicted in the drawings in a particular order, this is not to be understood as requiring that such operations be performed in the particular order shown or in serial order, or that all illustrated operations be performed, to achieve desirable results. In certain environments, multitasking and parallel processing may be advantageous.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims

1. An electromagnetic stamping method, comprising:

dividing a blank holder of a stamping device into a plurality of blank holder areas according to the profile characteristics of a workpiece to be stamped, wherein the stamping device comprises a plurality of distributed magnetizing and demagnetizing circuits in one-to-one correspondence with the blank holder areas, and each distributed magnetizing and demagnetizing circuit comprises four solid-state relays K_iWhere i ∈ {1,2,3,4}, and K_iThe sheet metal is in a disconnected state in an initial state of stamping;

setting a blank pressing force function which changes along with time for each blank pressing area according to the shape characteristics of each blank pressing area;

for each of the binder zones, every cycle period t₀Acquiring blank holder force data G, and calculating an error e between the acquired blank holder force data G and a value F of the blank holder force function at the current moment, wherein the error e is F-G; and

according to the error to every distributed magnetization and demagnetization circuit that blank pressing zone corresponds exports at least one in switching value signal, pulse signal and the PWM pulse width modulation signal to control every blank pressing force in blank pressing zone, and be in carry out the punching press to the panel under the blank pressing force in order to obtain treat the stamping workpiece, include:

to solid state relay K₃Output pulse signal so that the solid-state relay K₃The PWM control circuit is circularly switched on and off at a fixed duty ratio, and the frequency of the pulse signal is more than 5 times of the frequency of the PWM signal;

adjusting the duty ratio of the PWM signal according to the error to enable the solid-state relay K₄Cycling on and off at a variable duty cycle, wherein the absolute value of the error is proportional to the duty cycle of the PWM pulse width modulated signal;

when the error is larger than zero, a solid-state relay K is started₁Output a positive switching value signal so that the solid-state relay K₁Closing to magnetize the distributed magnetizing and demagnetizing circuit; and

when the error is less than or equal to zero, the relay K is turned to a solid state relay₂Output a positive switching value signal so that the solid-state relay K₂And closing to demagnetize the distributed magnetizing and demagnetizing circuit.

2. The method of claim 1, wherein a current value of the blankholder function, F ═ P × S, where P is the pressure required to stamp the sheet at the current time and S is the contact area of the sheet and the blankholder area at the current time; the hold-down force function value is zero when the sheet edge is away from the inner edge of the hold-down region.

3. The method of claim 1 or 2, further comprising:

every other cyclet₀And collecting the deformation data of the plate, and sending an alarm instruction and stopping stamping when the deformation data is more than 1.5 times of the initial thickness of the plate.

4. An electromagnetic stamping device, comprising:

the blank holder is provided with a plurality of blank holding areas which are divided according to the outline characteristics of the part to be stamped;

a plurality of pressure sensors in one-to-one correspondence with the plurality of binder zones, each pressure sensor for every cycle period t₀Collecting blank holder force data G corresponding to the blank holder area;

a plurality of distributed magnetization and demagnetization circuits, a plurality of distributed magnetization and demagnetization circuits with a plurality of blank pressing regions one-to-one, every distributed magnetization and demagnetization circuit includes four solid state relays K_iWhere i ∈ {1,2,3,4}, and K_iThe sheet metal is in a disconnected state in an initial state of stamping;

a controller, the controller is used for according to blank holder power data G and for every the error e ═ F-G between the value F of the blank holder power function that changes with time that blank holder region set up at the present moment, to every distributed magnetization and demagnetization circuit output switching value signal, at least one in pulse signal and the PWM pulse width modulation signal that blank holder region corresponds, with control every the blank holder power of blank holder region, and with blank holder power is to the panel material punching press in order to obtain treat the stamping workpiece, the controller is used for:

when the error is larger than zero, relaying to the solid stateDevice K₁Output a positive switching value signal so that the solid-state relay K₁Closing to magnetize the distributed magnetizing and demagnetizing circuit; and

5. The apparatus of claim 4, wherein the current value of the hold-down force function, F, is PxS, where P is the pressure required to stamp the slab at that time and S is the contact area of the slab and the hold-down region at that time; the hold-down force function value is zero when the sheet edge is away from the inner edge of the hold-down region.

6. The apparatus according to claim 4 or 5, further comprising a plurality of displacement sensors in one-to-one correspondence with the plurality of binder zones, each displacement sensor being configured to detect at intervals of a cycle period t₀The deformation data of the plate material is collected,

the controller is further configured to: and when the deformation data is more than 1.5 times of the initial thickness of the plate, sending an alarm instruction and stopping stamping.