WO2020111061A1

WO2020111061A1 - Press formed article manufacturing method, metal plate set, press device, and press line

Info

Publication number: WO2020111061A1
Application number: PCT/JP2019/046170
Authority: WO
Inventors: 隆一西村; 鈴木　利哉; 吉田　亨
Original assignee: 日本製鉄株式会社
Priority date: 2018-11-28
Filing date: 2019-11-26
Publication date: 2020-06-04
Also published as: JPWO2020111061A1; CN113165299B; CN113165299A; JP7037132B2

Abstract

This press formed article manufacturing method includes: press forming a plurality of metal plates into press formed articles by using a die, a punch, and a moveable mold; and carrying out feedback press forming on at least one of the plurality of metal plates. The feedback press forming includes: measuring the shape of a previous press formed article; setting the initial position of the moveable mold on the basis of the shape of the previous press formed article; and carrying out press forming at the set initial position of the moveable mold.

Description

Method for manufacturing press-formed product, metal plate set, press device and press line

The present invention relates to a method for manufacturing a press-formed product, a metal plate set used in the manufacturing method, a pressing device, and a pressing line.

There is a technology that improves the dimensional accuracy of press-molded products by making part of the mold movable during press molding. For example, Japanese Patent No. 6179696 (Patent Document 1) discloses a press device including a die having a die pad and a punch arranged to face the die and having an inner pad. There is.

Japanese Patent No. 6179696

In press molding, a plurality of metal plates, for example, all metal plates in a manufacturing lot are press molded under preset press conditions. That is, if the first press-formed product is within the intersection, the subsequent press-forming is also performed under the same press conditions as those of the first press-formed product.

In the case where the characteristics of a plurality of metal plates are varied, the inventors do not obtain a desired shape even if the shape of the first press-formed product is the desired shape. I realized that there are cases.

Therefore, an object of the present invention is to provide a method for manufacturing a press-formed product, a metal plate set, a press device, and a press line that can reduce variations in the shapes of a plurality of press-formed products manufactured by continuous press-forming. ..

A method for manufacturing a press-formed product according to an embodiment of the present invention is a method in which a plurality of metal plates are continuously press-formed by a die, a punch, and a movable die whose relative position can be changed with respect to both the die and the punch. And making a plurality of press-formed products. At least one of the plurality of press moldings is feedback press molding. The feedback press molding is performed by measuring the shape of a press-molded article before the feedback press-molding among the plurality of press-molded articles, and based on the shape of the previous press-molded article, the movable metal It includes setting an initial position of the die with respect to the die or the punch, and performing press molding at the set initial position of the movable die.

According to the embodiment of the present invention, it is possible to reduce variations in the shapes of a plurality of press-molded products manufactured by continuous press-molding.

It is a figure which shows the structural example of the press line in this embodiment. It is a figure which shows the example of press molding. It is a figure which shows the example of press molding. It is a figure which shows the example of press molding. It is a figure which shows the example of press molding. It is sectional drawing which shows an example of a press molded product. It is a flowchart which shows the operation example of a controller. It is a graph which shows an example of the correlation shown by correlation data. It is a graph which shows the result of the amount of protrusion and the position accuracy of a flange of an Example. It is a graph which shows the result of the amount of protrusion and the position accuracy of a flange of an Example. It is a graph which shows the result of the amount of protrusion and the position accuracy of a flange of an Example. It is a figure which shows the modification of a structure of a press line.

(Method 1)
A method for manufacturing a press-formed product according to an embodiment of the present invention is a method in which a plurality of metal plates are continuously press-formed by a die, a punch, and a movable die whose relative position can be changed with respect to both the die and the punch. And making a plurality of press-formed products. At least one of the plurality of press moldings is feedback press molding. The feedback press molding is performed by measuring the shape of a press-molded article before the feedback press-molding among the plurality of press-molded articles, and based on the shape of the previous press-molded article, the movable metal It includes setting an initial position of the die with respect to the die or the punch, and performing press molding at the set initial position of the movable die.

In the above manufacturing method, a plurality of press-formed products having substantially the same shape can be continuously manufactured by repeating the press-forming for a plurality of metal plates. In the above manufacturing method, feedback press molding is performed at least once in the plurality of press moldings. Feedback press molding can be used to set the initial position of the movable mold during press molding using the measured shape of the previous press molded article made in the previous press molding. This makes it possible to properly adjust the initial position of the movable mold so as to suppress variations in the shapes of the plurality of press-molded products. As a result, it is possible to reduce variations in the shapes of a plurality of press-formed products manufactured by a plurality of continuous press-forming processes.

The initial position of the movable mold is the relative position of the movable mold to the die or punch in the initial stage of each of the multiple press moldings. In each press forming, the press forming is performed by bringing the die and the punch relatively close to each other from the state where the movable mold in the initial position is in contact with the metal plate.

For example, the movable mold may come into contact with the portion of the press-molded product (finished product) that will be the product during press molding. In this case, the movable mold controls the shape of the press-molded product (finished product). Depending on the initial position of the movable mold, it is possible to control the subtle shape of the press-molded product.

The movable mold may move relative to the die or punch during one press molding. Examples of possible dies of this type include punch pads, die pads, blank holders and the like. Alternatively, the movable mold may be fixed in its relative position with respect to the die or punch during one press molding. That is, the movable mold may not move (do not move) with respect to the die or the punch during one press molding. It should be noted that one press-molding is press-molding performed by a set of a die, a punch and a movable die to make one press-molded product.

▽ Setting the initial position of the movable mold in the subsequent press molding based on the shape of the previous pressed product is equivalent to performing feedback control of the initial position of the movable mold. The initial position of the movable mold is set so that the press-formed product approaches the target shape, for example. For example, by using a value indicating the measured shape of the previous press-formed product (for example, a value indicating the degree of difference between the measured shape and the target shape), the initial position of the movable mold in the subsequent press-molding or the initial position The amount of change can be determined. As the feedback control, for example, P (proportional) control, PI (proportional-integral) control, or PID (proportional-integral-differential) control can be used.

Also, it is possible to set the initial position of the movable mold in the subsequent press molding based on the shape of the plurality of previous press molded products. In this case, the initial position of the possible mold can be set using the values indicating the shapes of the plurality of previous press-formed products. For example, a representative value such as an average or a difference, or a value (predicted value) predicted from the shapes of a plurality of press-molded products can be used as the value indicating the shape of the plurality of previous press-molded products.

(Method 2)
In the above-mentioned method 2, the feedback press molding is correlation data obtained in advance, and the correlation between the initial position of the movable mold with respect to the die or the punch at the time of press molding and the shape of the press molded product is obtained. The method may further include acquiring correlation data that indicates. In this case, the initial position is set based on the previous press-formed product and the correlation data. Thereby, the initial position of the movable mold in the feedback press molding can be set according to the correlation between the initial position and the press-formed product. Therefore, it is possible to efficiently suppress variations in the shapes of a plurality of press-formed products.

(Method 3)
In the

above method

1 or 2, the previous press-molded product may be at least one of press-molded products that have been press-molded a predetermined number of times immediately before feedback press-molding. That is, the initial position of the movable mold can be set based on the shape of the press-formed product obtained by at least one of the press formings performed a predetermined number of times immediately before the feedback press forming. Thereby, in a plurality of continuous press-molding operations, the position of the movable mold can be feedback-controlled based on the shape of the press-formed product that has been press-formed at a similar time.

As an example, in feedback press molding, it is possible to set the initial position of the movable die with respect to the die or punch based on the shape of the press-formed product by any one of the first to fifth press forming. Further, of the predetermined number of times of press forming immediately before the feedback press forming, the press forming shape of two or more continuous or discrete press forming may be used for setting the initial position of the movable mold. For example, among the most recent 1 to 5 times before press-formed products, the shape of the press-formed product before 3 times, before 2 times, and once before may be used for setting the initial position, or before 1 time, 3 times. The shapes of the press-formed product before and after five times may be used for setting the initial position.

(Method 4)
In any one of the above methods 1 to 3, it is preferable that the plurality of metal plates to be press-formed are a plurality of metal plates obtained from the same rolling coil. A plurality of metal plates obtained from the same rolling coil have less variation in characteristics. Therefore, the effect of suppressing the variation in the shape of the press-formed product by adjusting the initial position of the movable mold by the feedback press molding becomes higher.

(Method 5)
In the method 2, in the plurality of metal plates, one of the two or more metal plates that are continuously press-formed and the metal plate that is next press-formed after the metal plate are adjacent to each other in a rolling order. Preferably. As a result, the difference in characteristics between the metal plate and the metal plate to be formed next becomes small. That is, variations in the characteristics of a plurality of continuously formed metal plates are reduced. The effect of suppressing the variation in the shape of the press-molded product by adjusting the initial position of the movable mold by the feedback press molding becomes higher.

(Method 6)
In the above-mentioned method 5, it is preferable that the metal plates are taken out from the metal plate set including a plurality of metal plates stacked in the rolling order and are pressed in the stacking order. Thereby, a plurality of metal plates can be pressed in the rolling order. As a result, the effect of suppressing the variation in the shape of the press-formed product by adjusting the initial position of the movable mold by the feedback press molding becomes higher. In the step of taking out the metal plates in the stacking order, the stacked metal plates may be taken out in order from the top or may be taken out in the order from the bottom.

(Method 7)
In any of the above methods 1 to 6, the tensile strength of the metal plate may be 980 MPa or more. It has been found by the inventors that a high-strength metal plate having a tensile strength of 980 MPa or more may have a large variation in the shape of the press-formed product due to the difference in the properties of the metal plate in continuous press forming. ing. According to the above methods 1 to 6, it is possible to effectively suppress the variation in the press-formed product in the press forming of such a high-strength metal plate.

(Metal plate set)
The metal plate set in the embodiment of the present invention includes a plurality of small packages. Each of the small packages includes a plurality of metal plates stacked in the rolling order. In each of the small packages, information indicating the relationship of rolling order with other small packages is recorded. From this metal plate set, a plurality of blanks can be taken out in the order of rolling. Therefore, for example, in the above methods 1 to 7, it is possible to take out a plurality of blanks from the metal plate set in the order of rolling and press-mold the press-formed product. As a form in which the information indicating the relationship of the rolling order is recorded in the small package, for example, a form in which the information is clearly specified in the small package or a form in which information is recorded in a recording medium such as a chip Etc. The plurality of metal plates included in the plurality of small packages of the metal plate set may be a plurality of metal plates obtained from the same rolling coil.

The metal plate sets used in the above methods 1 to 7 are also included in the embodiments of the present invention. In this case, a plurality of metal plates stacked in the rolling order in each small package of the metal plate set can be taken out in the stacking order and press-molded. Furthermore, it is possible to select a plurality of small packages in the order of rolling and press-form metal plates from each small package in the order of stacking.

(Structure 1)
A press device according to an embodiment of the present invention includes a die, a punch, a movable die whose relative position can be changed with respect to the die and the punch, and a controller for controlling the die, the punch, and the movable die. With. The controller performs the control so as to repeat a plurality of press moldings for a plurality of metal plates. The plurality of press moldings includes at least one feedback press molding. The feedback press molding is based on a measured shape of a press-molded product before the feedback press molding among the plurality of press moldings, and an initial stage for the die or the punch of the movable mold. Setting the position and performing press molding at the set initial position of the movable mold.

(Structure 2)
In the above configuration 1, the press forming apparatus may further include a supply unit that supplies the plurality of metal plates obtained from the same rolling coil to the pressing apparatus in the rolling order. The supply unit may be, for example, a transport device.

(Structure 3)
A press line including the press molding apparatus having the

above configuration

1 or 2 is also included in the embodiments of the present invention. This press line is a pay-off reel, an uncoiler leveler arranged downstream of the pay-off reel, a blanking device arranged downstream of the uncoiler leveler, and a conveying device arranged downstream of the blanking device, And a shape measuring device arranged in or downstream of the pressing device. The press device is arranged downstream of the transfer device.

A press line having the following configuration is also included in the embodiments of the present invention. This press line is a pay-off reel, an uncoiler leveler arranged downstream of the pay-off reel, a blanking device arranged downstream of the uncoiler leveler, and a conveying device arranged downstream of the blanking device, A press device disposed downstream of the transport device, a shape measuring device disposed in or downstream of the press device, and a controller connected to the shape measuring device and the pressing device. The pressing device includes a die, a punch, and a movable die whose relative position can be changed with respect to the die and the punch. The controller stores correlation data indicating a correlation between an initial position of the movable mold with respect to the die or the punch at the time of press molding and a shape of a press-formed product, and further, the correlation data and the shape measuring device. A storage device which stores a program for setting an initial position of the movable die for the die or the punch at the time of press molding by the press device based on the shape of the press-formed product press-molded by the press device measured in Equipped with.

According to the above configuration, the controller can set the initial position of the movable mold during press molding by the press device, using the shape of the press molded product formed by press molding by the press device and the correlation data. .. This makes it possible to properly adjust the initial position of the movable mold so as to suppress variations in the shape of the press-formed product. As a result, it is possible to reduce variations in the shapes of a plurality of press-formed products.

As an example, the pay-off reel rotatably supports the coil of the metal strip and controls the rotation of the coil. The pay-off reel rewinds the coil and pays out the metal strip. The uncoiler leveler flattens the metal strip ejected from the coil. A blanking device stamps the flattened metal strip to produce a blank. The transport device transports the blank. The press machine press-molds a blank into a press-molded product. The shape measuring device measures the shape of the press-formed product.

The controller may have a processor that executes a program. The processor may execute a process of setting an initial position for the die or punch of the movable mold during press forming by the press device according to a program stored in the storage device. The controller may set, for example, the initial position of the movable mold in press molding after pre-molding of the press-molded product whose shape has been measured by the shape measuring device, based on the measured shape.

[Embodiment]
(Press line)
FIG. 1 is a diagram showing a configuration example of a press line 100 in this embodiment. The press line 100 shown in FIG. 1 includes a payoff reel 1, an uncoiler leveler 2, a blanking device 3, a carrying device 4, a pressing device 5, a shape measuring device 10, and a controller 11. From the upstream, the payoff reel 1, the uncoiler leveler 2, the blanking device 3, the transport device 4, the pressing device 5, and the measuring device 10 are arranged in this order.

The payoff reel 1 is a device that supports a coil A of a metal strip and pays out the metal strip from the coil. The uncoiler leveler 2 is a device that flattens the metal strip Aa of the coil A with a roll. The blanking device 3 is a device that punches the metal strip Aa to generate the metal plate B. The transport device 4 is a device that transports the metal plate B. The transport device 4 may be, for example, a conveyor, a manipulator, a forklift, or the like. The transport device 4 is an example of a supply unit that supplies a metal plate to a press device.

The press device 5 press-molds the metal plate B into a press-formed product C. The pressing device 5 has a die 6, a punch 7, and movable dies 8 and 9 as dies. The

movable molds

8 and 9 can change their relative positions with respect to both the die 6 and the punch 7. The pressing device 5 arranges the metal plate B between the die 6 and the punch 7 and presses the metal plate B from both the die 6 and the punch 7 to press-mold the metal plate B.

Specifically, the pressing device 5 press-molds the metal plate B between the die 6 and the punch 7 while pushing the punch 7 inside the die 6 by the relative movement of the die 6 and the punch 7. In the press molding process for producing one press-molded product, the

movable molds

8 and 9 are in contact with the metal plate B and the relative positions of the

movable molds

8 and 9 and the die 6 or the punch 7 are fixed, The step of bringing the die 6 and the punch 7 relatively close to each other and pushing the metal plate B by the die 6 and the punch 7 is included. Further, in this press forming step, a step of forming a metal plate by changing the relative position of the die 6 or the punch 7 with respect to the

movable molds

8 and 9 while the

movable molds

8 and 9 are in contact with the metal plate B. Is included.

The shape measuring device 10 measures the shape of the press-formed product. The shape measuring device 10 may be configured to measure the shape of a press-formed product using an optical sensor, for example. Further, the shape measuring device 10 may be configured to measure the cross-sectional shape of the press-formed product with a laser displacement meter, for example. In this case, the shape measuring device 10 may be configured to measure the displacement of the press-formed product in the pressing direction (the displacement direction of the relative position of the die and the punch). For example, when the press-formed product is a hat member, the cross-sectional shape of the hat member can be instantaneously measured by measuring the displacement of the hat member with a laser displacement meter from above or below the hat member. The shape measuring device 10 may output a value indicating the shape of the press-formed product. For example, the shape measuring apparatus 10 processes a data (eg, a camera or a laser displacement meter) that measures the shape of the press-formed product and data such as an image of the press-formed product measured by the sensor to process the press-formed product. An arithmetic unit such as a computer that calculates a value indicating the shape may be included. Alternatively, the controller 11 may calculate a value indicating the shape of the press-formed product based on data such as an image of the press-formed product obtained by the shape measuring device 10.

The controller 11 is connected to the press device 5 and the shape measuring device 10. Here, the controller 11 may be wired or wirelessly connected to the press device 5 and the shape measuring device 10. The controller 11 can communicate with the press device 5 and the shape measuring device 10. In this example, the shape measuring device 10 is provided downstream of the pressing device 5, but the shape measuring device 10 may be provided inside the pressing device 5. For example, when the press device 5 includes a plurality of press mold sets, the shape measuring device 10 may be provided between the plurality of press mold sets. In this case, the shape of the press-formed product (intermediate material) conveyed between the press die sets may be measured by the shape measuring device 10.

The controller 11 can be configured by, for example, a computer including a processor 11a and a storage device 11b (memory). The following functions of the controller 11 can be realized by the processor 11a executing the programs stored in the storage device 11b. The controller 11 controls the initial position of the

movable molds

8 and 9 with respect to the die 6 or the punch 7 in the press molding by using the data regarding the shape of the press molded product measured by the shape measuring device 10. Specifically, the controller 11 sets the initial position of the

movable molds

8 and 9 with respect to the die 6 or the punch 7 based on the data on the shape of the press-formed product measured by the shape measuring device 10 and the correlation data. ..

Here, the initial position set by the controller 11 is, for example, a fixed position of the movable dies 8 and 9 relative to the die 6 or the punch 7, and the movable die is in contact with a metal plate and the die 6 and the punch 7 are in contact with each other. Can be set relatively close to each other and used as a relative position when press-molding. For example, in a press molding process for producing one press-molded product, as a press-molding initial setting, a relative position (that is, an initial position) of the

movable molds

8 and 9 with respect to the die 6 or the punch 7 is fixed at a set position. , The die 6 and the punch 7 are relatively brought close to each other, and then the relative position is changed from the set position, and the die 6 and the punch 7 are brought relatively closer to each other to perform the press molding. The controller 11 sets the relative position (initial position) of the

movable molds

8 and 9 with respect to the die 6 or the punch 7 in the press molding initialization.

The correlation data is data indicating the correlation between the initial position of the

movable molds

8 and 9 with respect to the die 6 or the punch 7 during press molding (for example, in the initial setting of press molding) and the shape of the press molded product. Specifically, the correlation data has a correspondence relationship between a value indicating the shape of the press-formed product obtained by measurement and a value for controlling the initial position of the

movable molds

8 and 9 with respect to the die 6 or the punch 7 in press molding. It may be the data shown. The data format of the correlation data is not particularly limited. The correlation data may be data (for example, table data, map data, etc.) that associates a value indicating the shape of the press-molded product with a value for controlling the initial position of the movable mold. Alternatively, the correlation data is data indicating a procedure for calculating a value for controlling the initial position of the movable mold by using a value indicating the shape of the press-molded product (for example, a function, a program or these parameters). It may be. The correlation data is stored in the storage device of the controller 11 in advance before the feedback press molding. The correlation data can be created, for example, based on the shapes of a plurality of press-molded products measured in the past and the initial position of the movable mold in the press-molding of these press-molded products.

For example, the controller 11 acquires data indicating the shape of the press-formed product from the shape measuring device 10. The controller 11 uses the correlation data to convert a value indicating the shape of the press-molded product into a control value indicating the initial position or the amount of change of the

movable molds

8 and 9 with respect to the die 6 or the punch 7. The controller 11 controls the press device 5 so that the

movable molds

8 and 9 at the time of press molding are at the initial position or the change amount indicated by the control value.

The press device 5 repeats press forming on a plurality of metal plates B included in the production lot to produce a plurality of press formed products. The controller 11 may set the initial positions of the movable dies 8 and 9 in the press forming of each of the plurality of metal plates of the manufacturing lot. The controller 11 sets the initial positions of the movable dies 8 and 9 in the press forming of a certain metal plate B, for example, the press forming from one time to five times before the press forming of the metal plate B. Data indicating the shape of at least one press-formed product among the press-formed products formed in 1. is used. This allows feedback control of the initial positions of the

movable molds

8 and 9.

The controller 11 uses the shape of the press-formed product of the press molding 6 times or more before in addition to the shape of the press-formed product of the press molding from 1 time before to 5 times before. The initial position may be set. For example, a representative value calculated from the values indicating the shape of the press molded product of all the press moldings before 1 time to the n times before (for example, the average of the values indicating the shape of the press molded product 1 time before to n times before). Value) may be used to set the initial position of the movable mold.

In the example shown in FIG. 1, it is preferable to press-mold a plurality of metal plates B produced by punching out the metal strips dispensed from one coil into a press-molded product to form one manufacturing lot. That is, it is preferable that the plurality of metal plates B press-molded in the manufacturing lot be a plurality of metal plates obtained from the same coil. Accordingly, it is possible to press-form a plurality of press-formed products from the plurality of metal plates B having a small variation in characteristics.

Further, it is preferable to punch out the metal strips dispensed from one coil to produce a plurality of metal plates B, and press-form the metal plates B in the order of production. Thereby, a plurality of metal plates B can be press-formed in the order of rolling. That is, a certain metal plate and a metal plate that is press-formed next to this metal plate are adjacent to each other in the rolling order. Therefore, it is possible to press-form a plurality of press-formed products from a plurality of metal plates B having smaller variations in characteristics.

(Example of press molding)
An example of press molding using a movable mold will be described. 2A to 2D are views showing an example of press molding. Here, as an example, a press-molding example using a press device including a punch-side pad 9 as a movable member will be described. In the example shown in FIGS. 2A to 2D, the die side pad 8 is arranged inside the die 6 and is movable in the pressing direction of the metal plate. Here, the pressing direction of the metal plate is the direction of relative movement of the die 6 with respect to the punch 7. The punch-side pad 9 is arranged so as to project outside the pressing surface 7a of the punch 7 and can be pushed to the same height as the pressing surface 7a of the punch 7.

Specifically, the die 6 has a recess 6a corresponding to the shape of the press-formed product inside. The punch 7 has a convex portion having a shape corresponding to the concave portion 6 a of the die 6. The upper surface of this convex portion serves as a pressing surface 7a for pressing the metal plate B. The punch side pad 9 is movable in the up-down direction (pressurizing direction) via a lifting mechanism (not shown) such as a hydraulic cylinder. The die side pad 8 is movable in the vertical direction via a lifting mechanism (not shown) such as a hydraulic cylinder. Further, the die side pad 8 is movable in the vertical direction together with the punch side pad 9 while being pressed against the metal plate B. On the bottom surface of the recess 6a of the die 6, a hole (not shown) is provided for passing the lifting mechanism. The punch-side pad 9 is arranged inside the recess formed in the pressing surface 7 a of the punch 7. The punch side pad 9 is biased upward by a gas spring 9s arranged inside the recess. Due to the biasing of the gas spring 9s, the upper surface of the punch-side pad 9 is in a state of being projected to the outside of the pressing surface 7a of the punch 7.

The pressing device 5 presses the punch-side pad 9 and the die-side pad 8 against the metal plate B in a state where the punch-side pad 9 is projected outward from the pressing surface 7a of the punch 7, while pressing the die 6 and the punch 7. Are relatively close to each other and the metal plate B is press-formed. At the forming bottom dead center, the metal plate B is press-molded until the punch-side pad 9 has the same height as the pressing surface 7a of the punch 7.

More specifically, first, as shown in FIG. 2A, the die side pad 8 is pressed against the metal plate B in a state where the punch side pad 9 is projected outward from the pressing surface 7a of the punch 7, The metal plate B is press-formed between the die 6 and the punch 7 by lowering the die 6 and the die side pad 8. At this time, the initial position of the punch-side pad 9 with respect to the punch 7, that is, the height (protruding amount) H of the upper surface of the punch-side pad 9 with respect to the pressing surface 7a of the punch 7 is fixed. In the metal plate B to be formed, a slack Ba is generated in the metal plate B according to the height (protruding amount) H of the upper surface of the punch side pad 9 with respect to the pressing surface 7a of the punch 7. Then, from this state, as shown in FIG. 2B, the press molding is continued by lowering the die 6 while controlling the slack Ba of the metal plate B to a predetermined amount. As shown in FIG. 2C, the die 6 is lowered to H before the bottom dead center of molding. At this time, the die 6 descends while the pressing mechanism of the die side pad 8 contracts.

In the steps shown in FIGS. 2A to 2C, the die 6 and the punch 7 are brought relatively close to each other in a state where the initial position of the punch 7 with respect to the punch side pad 9, that is, the protruding amount H is fixed. From the stage shown in FIG. 2C, that is, the stage in which the die side pad 8 is completely accommodated by being bottomed with respect to the die 6 (the stage in which the die side pad 8 projects from the bottom dead center by a distance H), the punch side pad 9 The distance between the upper surface and the pressing surface 7a of the punch 7 begins to shrink. From the stage of FIG. 2C to the stage of FIG. 2D, the relative position of the punch 7 with respect to the punch side pad 9 changes. As shown in FIG. 2D, the metal plate B is press-molded until the upper surface of the punch-side pad 9 has the same height as the pressing surface 7a of the punch 7. At this time, the slack Ba formed on the metal plate B is discharged toward the vertical wall portion between the punch 7 and the die 6 while receiving in-plane compressive stress. As a result, a press-formed product having a hat-shaped cross section can be obtained.

In the example shown in FIGS. 2A to 2D, the bending region is expanded by causing the slack Ba formed on the metal plate B to flow out toward the vertical wall portion. This makes it possible to balance spring back and spring go of the material to be press-formed. As a result, it is possible to reduce defective shapes of the vertical wall and the flange portion.

In the above example, in the press forming for one metal plate B, the die 6 is brought relatively close to the punch 7 in a state where the initial position of the punch side pad 9 with respect to the punch 7 is fixed (press initial setting state). The step of press-forming the metal plate B and the step of changing the relative position of the punch side pad 9 to the punch 7 to bring the die 6 relatively close to the punch 7 and press-forming the metal plate B are included. The relative position (initial position) between the punch side pad 9 and the punch 7 in the press initialization, that is, the protrusion amount H of the punch side pad 9 is controlled by the controller 11. The protrusion amount H is an example of the set value of the initial position of the movable mold.

Note that press molding using a movable mold is not limited to the above example. For example, in the press machine, either the die side pad 8 or the punch side pad 9 can be omitted. Further, although the above example is an example of press-forming the metal plate B of the intermediate material that has been bent and formed in advance, the pressing device may press-form a flat plate that is not bent and formed.

Generally, in bending, the die side pad is often set to prevent misalignment of the metal plate to the punch side pad or punch. In other words, the die-side pad may be omitted in the case of a shape that is not easily displaced. In the molding examples shown in FIGS. 2A to 2D, the die side pad 8 may be omitted in some cases. In the molding example shown in FIGS. 2A to 2D, when the die side pad 8 is omitted, the portion corresponding to the die side pad 8 is housed in the recess of the die 6 from the initial stage of molding to the stage shown in FIG. 2C. In this state, the die is integrated with the die. From the initial stage of forming to the stage shown in FIG. 2C, the center portion of the metal plate B in the cross-sectional width direction is press-formed while being lifted from below by the punch-side pad 9 as in the case of the die-side pad 8. Advances. After the step shown in FIG. 2C, the punch side pad 9 is pushed down by the die 6 and is lowered, and the press forming is completed as in FIG. 2D.

(Example of pressed product)
FIG. 3 is a sectional view showing an example of a press-formed product. The press-formed product 12 shown in FIG. 3 is obtained, for example, by the press-forming shown in FIGS. 2A to 2D. The press-formed product 12 has a hat-shaped cross section. The press-formed product 12 is a long member whose longitudinal direction is in the direction perpendicular to the cross section shown in FIG. It includes a top plate 12A extending in the width direction of the press-formed product 12 and a pair of ridge line portions 12B adjacent to both ends in the width direction of the top plate 12A. The press-formed product 12 includes a pair of vertical walls 12C extending from the ridge 12B to the back surface side (one side in the plate thickness direction) of the top plate 12A, and a pair of vertical walls 12C adjacent to the tips (lower ends) of the vertical walls 12C. And the ridge line portion 12D. Further, the press-formed product 12 includes a pair of flanges 12E extending from the pair of ridge portions 12D to both sides of the top plate 12A in the width direction. The angle θ2 formed by the top plate 12A and the vertical wall 12C is 90 deg. Not limited to. The angle θ2 is 90 to 125 deg. Can be illustrated. In the case of heavy working within this range, problems such as springback become particularly apparent, so the above feedback control becomes effective. The angle θ2 is 90 deg. If the acute angle is less than 100 mm, it may be difficult to remove the press-formed product from the mold.

The shape measuring device 10 may measure the angle θ1 formed by the top plate 12A and the flange 12E as the shape of the press-formed product 12, for example. For example, the top plate 12A and the flange 12E can be recognized in an image of the press-formed product 12 taken from the front in the longitudinal direction to calculate the angle θ1 between them. In this example, each θ1 formed by the top plate 12A and the flange 12E is a predetermined reference value θc showing a desired shape, in this case 0 deg. When it is larger than (θ1>θc=0 deg.), it becomes a spring back, and when θ1 is smaller than the reference value θc (θ1<θc=0 deg.), it becomes a spring go.

Note that the value indicating the degree of spring back or spring go is not limited to the angle θ1 in the above example. For example, the angle θ2 formed by the top plate 12A and the flange 12E, the vertical height difference T1 of the bottom surface of the flange 12E, or the like may be measured as a value indicating the degree of springback or spring go. In these cases, the above correlation data is, for example, data indicating the correlation between the value indicating the degree of springback or spring go and the initial position of the die or punch of the movable die. The shape of the press-formed product measured by the shape measuring device 10 is not limited to the values in the above example.

(Operation example)
FIG. 4 is a flowchart showing an operation example of the controller 11 in this embodiment. In the example shown in FIG. 4, the controller 11 first initializes the press conditions (S1). The pressing conditions include, for example, the initial position of the movable die with respect to the die or punch. As an example, the initial value of the protrusion amount H of the punch side pad 9 is set. The pressing condition is not limited to the initial position of the movable mold.

The controller 11 acquires the previously obtained correlation data (S2). For example, the controller 11 determines the correlation data to be used in the feedback process and makes it accessible. For example, the correlation data used for the processing is extracted from the data recorded in advance in the recording medium accessible to the computer of the controller 11 (the storage device built in or external to the controller 11) and stored in the memory (storage device 11b). To do. The correlation data is created in advance and recorded in a storage medium accessible by the controller 11.

FIG. 5 is a graph showing an example of the correlation shown by the correlation data. The graph shown in FIG. 5 shows the relationship between the protruding amount H of the movable mold (the punch side pad 9) and the spring back/spring go. The angle difference on the vertical axis of the graph is the angle θ1 formed by the top plate 12A and the flange 12E of the press-formed product 12 shown in FIG. 3 and the reference value θc, in this case 0 deg. And the difference (θ1-θc=0 deg.). The reference value θc is an angle formed by the top plate and the flange 12E when there is no spring back or spring go. When the angle difference is positive, it means spring back, and when the angle difference is negative, it means spring go. By using the correlation shown in the graph shown in FIG. 5, for example, the angle difference is +1 deg. In this case, it is possible to calculate how much the protrusion amount H should be reduced to eliminate the springback. The data indicating the correlation shown in the graph of FIG. 5 may be, for example, table data or map data in which the correspondence between various angle differences and the protrusion amount H is recorded, or the data indicating the function of the line of the graph. May be

In S3 of FIG. 4, the controller 11 controls the press device 5 to perform press forming of the metal plate B. Further, the controller 11 causes the shape measuring device 10 to measure the shape of the press-formed product press-formed in S3 (S4). As an example, the shape measuring device 10 measures an angle θ1 formed by the top plate 12A and the flange 12E of the press-formed product 12 shown in FIG.

In the feedback calculation of S5, the controller 11 uses the value (for example, the angle θ1) indicating the shape of the press-formed product measured in S4 and the correlation data to determine the initial position of the movable mold in the next press-forming ( For example, the protrusion amount H) of the punch side pad 9 is calculated. The controller 11 sets the value calculated in S5 in the pressing device 5 as the pressing condition (S6). As a result, the shape measurement result of the press-formed product one time before can be fed back to the initial position of the movable mold in the next press-molding.

The processing of S3 to S6 in FIG. 4 is repeated for a plurality of metal plates included in one manufacturing lot. This enables feedback control in each press molding of one manufacturing lot other than the first time.

(Example)
FIG. 6 is a graph showing the result of measuring the position accuracy of the flange when the protrusion amount H of the punch side pad 9 is feedback controlled. The vertical axis represents the protrusion amount and the flange position accuracy. As for the flange position accuracy, the target reference position is 0.0. From the results shown in FIG. 6, it was found that the position accuracy tends to be close to 0.0 by feedback controlling the protrusion amount H. In the result shown in FIG. 6, the standard deviation of position accuracy was 0.44 mm.

Note that the results shown in FIG. 6 are the results when the press forming order of multiple metal plates is not the rolling order. That is, in the experiment of FIG. 6, it is unclear whether or not the press-formed metal plate and the next press-formed metal plate are metal plates taken from the adjacent portions of the coil.

On the other hand, FIG. 7 is a graph showing the results of the amount of protrusion and the positional accuracy when a plurality of metal plates taken from the same coil are press-formed in the order of rolling. In the result shown in FIG. 7, the variation in the shape of the press-formed product is smaller than that in the result shown in FIG. In the result shown in FIG. 7, the standard deviation of position accuracy was 0.04 mm. In the experiment shown in FIG. 7, when the positional accuracy is within ±0.15 mm, feedback control of the protrusion amount to the next press molding is not performed.

FIG. 8 is a graph showing the results of the amount of protrusion and the position accuracy when a plurality of metal plates taken from the same coil are press-formed in the order of rolling. A metal plate with a large variation in characteristics within the same coil was used. In the result shown in FIG. 8, the standard deviation was 0.10 mm. It is considered that this is because the characteristics of the adjacent metal plates in the order of press molding do not change significantly, and thus the feedback control suitably operates.

(Modification)
FIG. 9 is a diagram showing a modified example of the structure of the press line. In the example shown in FIG. 9, the metal plates B cut out from the coil A are stacked and packed in the order in which they are cut out, and transported to a place where the press device 5 is located. In this way, the plurality of metal plates B can be stacked in the order of rolling by cutting out the plurality of metal plates B sequentially from the end of the metal strip Aa discharged from the coil A and stacking them in the order of cutting.

A plurality of metal plates B stacked in the rolling order are packed into small packages BS. A metal plate set including a plurality of small packages BS is transported to the place of the press device 5. In each of the plurality of small packages BS, information 13 indicating the relationship of rolling order with other small packages BS is recorded. The record of the information 13 may be in a form such as a label or a print that can be visually recognized, or may be electronic information such as an IC tag.

The small packaging BS is a collection of multiple metal plates B. The form of the small package BS is not particularly limited. For example, the small package BS may be a rack, a box, a band, or the like.

At the location of the press machine 5, a plurality of small packages BS included in the metal plate set are sequentially selected in the rolling order or the reverse rolling order, and the plurality of metal plates are taken out from each small package BS in the stacking order and press-molded by the pressing machine 5. To do. Thereby, the plurality of metal plates B included in the plurality of small packages BS included in the metal plate set are press-formed in the order of rolling. When the metal plates B of a plurality of small packages BS are sequentially press-formed, the forming of the metal plates B of one small package BS is completed, and when the metal plates B of the next small package BS are formed, the rolling order is The closest, i.e., adjacent, rolling order metal plates can be press formed. That is, even if the small packages BS are switched, the metal plates B can be press-formed in the order of adjacent rolling.

The above embodiment can be applied to, for example, a case where a metal plate is cut out from a coil of a metal band rolled by hot rolling and press-molded. In the process of hot rolling, the steel strip hot-rolled by applying heat and tension is sent to a down coiler and wound while being cooled by water on a run-out table. In this case, since the cooling conditions may differ depending on the location of the steel strip, the characteristics of the steel strip are not strictly uniform. However, it is almost impossible to subdivide all parts on the steel strip to collect characteristic values and set press conditions suitable for them.

The inventors noted that changes in properties of rolled steel strips tend not to occur rapidly. Further, the surface flaws (scale flaws) of the steel sheet have various causes, but the degree tends to gradually change in the rolling direction. Furthermore, scale flaws often occur at a certain width position rather than the full width. The inventors have found that it is desirable that the characteristics of the metal plate to be processed are similar in order to improve the accuracy of the feedback control of press forming.

In view of these circumstances, the inventors have found that, by press-forming metal plates in the rolling order, the characteristics and the distribution of the metal plates that are adjacent in the forming order do not significantly change. That is, it was found that in order to sequentially form metal sheets having similar characteristics, it is preferable to form the metal sheets in the rolling order (or the reverse order). According to the above-described embodiment, the accuracy of the shape of the press-formed product can be improved by sequentially press-forming a plurality of metal plates having similar characteristics and performing feedback control.

Generally, the mass of the coil of metal strip is often 10 to 20 tons. Thousands to tens of thousands of press-formed products can be collected from one coil. However, it is rare that thousands of press-formed products are required at one time. The number of press-formed products in one manufacturing lot is often hundreds to thousands. When a press-formed product that is not needed immediately is stored in a warehouse, the press-formed product has a three-dimensional shape, which requires an enormous storage capacity. It is also possible to manufacture the press-formed products as many as necessary so that the press-formed products are not inventoried more than necessary, and then bundle the coils of the pay-off reel and take them out from the press line. However, when the coil is taken out from the press line, the coil winding may loosen. If the winding of the coil is loose, the metal strips may rub against each other in the loose portion of the coil, causing scratches. Under such circumstances, it is sometimes preferable that the metal strips of the coil loaded in the pay-off reel are collectively cut into cut plates or punched metal plates. Since the cut plate and the metal plate are flat and can be stacked and stored, the capacity of the warehouse is not required as compared with the case of complementing the press-formed product. As in the modification shown in FIG. 9, by introducing a metal plate set in which information on the rolling order is recorded in a plurality of small packages, the metal plates are press-formed in the rolling order even when the metal plates are stored or transported. Easy to do. In the present disclosure, the metal plate includes both a cut plate obtained by cutting the metal strip of the coil and a metal plate obtained by punching the cut plate.

The material of the metal plate to which the present invention is applicable is not particularly limited. As the material of the metal plate, for example, a thin plate of 980 MPa class high strength steel plate (High Tensile Strength Steel Sheets) may be used. In recent years, in order to reduce the weight of press-molded products, the strength of press-molded products has been increasing. In line with that, the strength of press-molded products is also increasing. As the strength of the material increases, it becomes difficult to press-form into a desired shape. For example, spring packs generally become more aggressive as the material becomes stronger. According to the above embodiment, even if a metal plate having a tensile strength of 980 MPa or more is used, it is possible to reduce the variation in the shapes of a plurality of press-formed products within a production lot.

Further, for example, between a steel plate having a tensile strength of 270 MPa and a steel plate of 1.2 GPa, there is generally a tendency for the variations in plate thickness and tensile strength to be greater for a steel plate of 1.2 GPa. If there are large variations in material properties such as variations in plate thickness and tensile strength, the die shape is adjusted and even if the shape of the press-formed product that was press-formed at the beginning of the production lot is the desired shape, the production lot There is a high possibility that the press-formed product, which is later press-molded inside, will not have the desired shape. According to the above-described embodiment, even when a metal plate having a tensile strength of 980 MPa or more, which has a relatively large variation in the characteristics of materials, is used, the shape of a plurality of press-formed products in a production lot is controlled by feedback control. Can be reduced.

Although one embodiment of the present invention has been described above, the above-described embodiment is merely an example for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and can be implemented by appropriately modifying the above-described embodiments without departing from the spirit thereof.

1: Pay-off reel 2: Uncoiler leveler 3: Blanking device 4: Conveying device 5: Press device 6: Die 7: Punch 8: Movable die (die side pad)
9: Movable mold (punch type pad)
10: Shape measuring device 11: Controller 12: Press-formed product

Claims

A method of manufacturing a press-formed product, comprising:
Including a die, a punch, and a movable die whose relative position can be changed with respect to both the die and the punch to continuously press-form a plurality of metal plates to produce a plurality of press-formed products,
At least one of the plurality of press moldings is feedback press molding,
The feedback press molding is
Among the plurality of press-formed products, measuring the shape of the press-formed product before press-molding before the feedback press-forming, based on the shape of the previous press-formed product, the die of the movable mold or the Setting the initial position for the punch,
A method of manufacturing a press-formed product, comprising press-forming at the set initial position of the movable mold.
The feedback press molding is
Correlation data obtained in advance, further comprising acquiring correlation data showing the correlation between the initial position and the shape of the press-molded product with respect to the die or the punch of the movable mold during press molding,
The method for manufacturing a press-formed product according to claim 1, wherein the initial position is set based on the previous press-formed product and the correlation data.
The method for manufacturing a press-formed product according to claim 1 or 2, wherein the preceding press-formed product is at least one of press-formed products that have been press-formed a predetermined number of times immediately before feedback press-forming.
The method for producing a press-formed product according to any one of claims 1 to 3, wherein the plurality of metal plates to be press-formed are a plurality of metal plates obtained from the same rolled coil.
In the plurality of metal plates, one of the two or more metal plates that are continuously press-formed and the metal plate that is press-formed next to the one metal plate are adjacent to each other in rolling order, The method for manufacturing the press-formed product according to claim 4.
The method for manufacturing a press-formed product according to claim 5, wherein the metal plates are taken out from the metal plate set including a plurality of metal plates stacked in the rolling order in the stacking order and press-molded.
The method for producing a press-formed product according to any one of claims 1 to 6, wherein the tensile strength of the metal plate is 980 MPa or more.
With multiple small packages,
Each of the small packages includes a plurality of metal plates stacked in a rolling order,
A metal plate set in which information indicating the relationship of rolling order with other small packages is described in each of the small packages.
With a die,
With a punch
A movable mold whose relative position can be changed with respect to the die and the punch,
A controller for controlling the die, the punch, and the movable mold,
The controller performs the control to repeat a plurality of press forming for a plurality of metal plates,
The plurality of press formings comprises at least one feedback press forming,
The feedback press molding is
Setting an initial position for the die or the punch of the movable mold based on the measured shape of the press-formed product before the press-molding before the feedback press-forming among the plurality of press-molding, And a press device including press molding at the set initial position of the movable mold.
The press device according to claim 9, further comprising: a supply unit that supplies the plurality of metal plates obtained from the same rolling coil to the press device in a rolling order.
A press line including the press device according to claim 9 or 10,
Payoff reel and
An uncoiler leveler disposed downstream of the payoff reel,
A blanking device arranged downstream of the uncoiler leveler,
A transport device arranged downstream of the blanking device,
In the press device, or further comprising a shape measuring device arranged downstream,
The press device is a press line arranged downstream of the transfer device.