JPH04322821A - Method and die for bending sheet metal - Google Patents

Abstract

PURPOSE:To execute bending with high accuracy without correcting a die by adjusting the parallelism of a punch of a die and the die, and also, adjusting the position accuracy of the punch and the die. CONSTITUTION:A stock 16 to be worked is placed on a die 2. The position of the stock 16 is determined by a positioning pin 9. When the upper die set plate 13 is lowered, a plate holder 3 comes into contact with the stock 16 and the stock 16 is pressed by the spring force of a second spring 11. When the upper die set plate 13 is further lowered, a punch 1 comes into contact with the stock 16 and the stock 16 is pressed between the punch and the die 2 by a first spring 10 to be formed. Subsequently, the bending angle of a formed part is measured and compared with a target value. An error in the parallel direction to a bending line is corrected by moving a cotter 8 horizontally and varying the inclination of the punch 1. An error in the orthogonal direction to the bending line is corrected by changing an adjusting block provided on both sides of the die 2, and setting it to a prescribed value. Subsequently, second forming is executed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin plate bending method and a bending die, and more particularly to a thin plate bending method and a bending die suitable for hat-shaped bending of extremely thin plates.

0002

[Prior Art] Generally, bending is performed using a mold, and the accuracy of the product depends on the accuracy of the mold (processing accuracy and assembly accuracy of mold parts), the accuracy of the material (variations in plate thickness, etc., and yield). It is determined by variations in mechanical properties such as stress) and variations in processing conditions. In the case of hat bending of thin plates, for example, press processing handbook (Maruzen Co., Ltd., 1975
(Published on October 25th), page 208,
It is processed using a pair of male and female dies. FIG. 8 is a diagram showing an example of a material to be processed, and (a)
is a plan view, and (b) is a cross-sectional view. Further, FIG. 9 is a diagram showing a head support spring according to an example of a processed product,
(a) is a plan view, (b) is a side view, and (c) is a BB sectional view of (a). Figures 8 and 9 show the outline of the shape and dimensions with the main dimensions noted.

As shown in FIGS. 8 and 9, in the case of extremely thin products such as head support springs used in magnetic recording devices with a plate thickness of 100 μm or less (made of stainless steel), the mold accuracy must be extremely high. required. Precision on the order of microns is required for mold parts, and similar precision is required for assembly. However, it is difficult to manufacture such a high-precision mold, and it becomes impossible to obtain the desired product. For this reason, it is necessary to repeatedly make product prototypes and modify the molds by experts.

0004

[Problem to be solved by the invention] The modification of the above mold is as follows:
The mold is disassembled, minor additional work is done, and then reassembled, which takes a considerable amount of time, lasting several months, and requires skilled technicians with advanced know-how. Also,
When molds are used to manufacture hundreds of thousands or millions of products, parts wear out and parts need to be re-polished or replaced. In this case as well, trial production and modifications will be repeated. Furthermore, the materials that are generally processed are not uniform and have variations in shape (plate thickness, etc.) and mechanical properties (yield stress, tensile strength, etc.). For example, as the yield stress increases, springback increases and the bending angle of the product decreases. In particular, when the material lot changes, the shape and mechanical properties often change significantly (so-called lot-to-lot variation), and it may be necessary to ensure processing accuracy by adjusting the mold or the like. However, when the plate thickness is extremely thin, mold adjustment requires precision on the order of microns, which is difficult to achieve with conventional technology, often relying on trial and error, and requiring a large amount of time.

The present invention has been made in order to solve the problems of the prior art described above, and provides a method and a bending mold for bending a thin plate, which allows highly accurate molding without modifying the mold. The purpose is to

[0006]

[Means for Solving the Problems] In order to achieve the above object, the thin plate bending method according to the present invention has a structure in which a thin metal plate workpiece is positioned between a punch and a die of a mold, In the method for bending a thin plate by pressing and bending it into a hat shape, the bending process is performed by adjusting the parallelism between a punch and a die of a mold by adjusting at least one of the punch and the die. It is something. Further, the bending process is performed by adjusting the positional accuracy of the punch and die of the mold by adjusting at least one of the punch and the die. The parallelism between the punch and die of the mold is preferably adjusted by adjusting the parallelism in a direction parallel to the bending line. Further, it is preferable to adjust the positional accuracy of the punch and die by adjusting the position in the direction perpendicular to the bending line.

In addition, in order to achieve the above object, the structure of the thin plate bending die according to the present invention is such that a thin metal plate workpiece is positioned between a punch and a die of the die, and is pressed into a hat shape. In a bending die for a thin plate for bending, the mounting angle of the punch and die of the die can be adjusted to adjust the parallelism of at least one of the punch and the die to a predetermined bending line of the workpiece. It is equipped with a means to Further, the die is provided with a means for parallel movement that can adjust the positional accuracy of at least one of the punch and the die in a direction perpendicular to a predetermined bending line of the workpiece. It is.

[0008]

[Function] In this thin plate bending method and bending die, the parallelism between the punch and die of the mold is adjusted and the positional accuracy of the punch and die is adjusted to perform the bending process. Adjustments can be made within the mold, eliminating the need to disassemble the mold and repeat corrections through trial and error. Further, since adjustments can be made after the mold is assembled, re-polishing the mold and replacing parts can be easily carried out. This eliminates the need for repeated mold corrections based on the know-how of skilled technicians, and allows mold adjustments to be made without requiring particularly high-level skills. Furthermore, changes in product precision due to changes in material lots can be easily corrected by adjusting the mold.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 7. FIG. 1 is a front view showing the structure of a bending mold according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of section A in FIG. 1, and FIG. 3 is an enlarged side view of FIG. In the figure,
1 is a punch, 2 is a die, 3 is a plate holder for positioning the workpiece, 4 is an arm related to holding means for the punch 1, 5 is a pin for attaching the punch 1 to the arm 4, and 6 is a pressurizing member. jig, 7 is a holder, 8 is a cotter, 9 is a positioning pin, 10 is a first spring provided on the pressure jig 6, 11 is a second spring provided on the plate holder 3, 12 is a , a third spring for positioning, 13 an upper die set plate, 14
15 is a lower die set plate, 15 is an adjustment block, and 16 is a workpiece. This workpiece 16 is, for example, a head support spring shown in FIG.

The upper die set plate 13 is attached to the head (not shown) of the press machine, and the lower die set plate 14 is attached to the bed (not shown).
The upper die set plate 13 moves up and down as the head of the press moves up and down. The arm 4 is attached to the upper die set plate 13 so as to be movable in the vertical direction, and the movement is performed by a tapered portion provided on the cotter 8 as the cotter 8 moves from side to side. A punch 1 is rotatably attached to the lower part of the arm 4 via a pin 5. On the other hand, the upper left part of the punch 1 is in contact with the pressing jig 6. Therefore, by moving the cotter 8 left and right, the pin 5, that is, the right part of the punch 1, moves up and down, and the inclination of the punch 1 changes. As a result, the inclination of the punch tip 101 of the punch 1 that processes the workpiece 16 also changes. On the other hand, die 2
The die 2 is inserted into the hole provided in the lower die set plate 14.
It is fixed together with adjustment blocks 15 arranged on both sides of.

Next, the operation of this thin plate bending die, that is, the thin plate bending method according to the present invention will be explained. First, the workpiece 16 is placed on the die 2. At this time, the position of the workpiece 16 is determined by the positioning pin 9. Next, when the upper die set plate 13 descends, the plate holder 3 comes into contact with the workpiece 16 and presses the workpiece 16 by the spring force of the second spring 11. Further, when the upper die set plate 13 is lowered, the punch 1 comes into contact with the workpiece 16, and the spring force of the first spring 10 presses the workpiece 16 against the die 2 to form the workpiece. after this,
The upper die set plate 13 rises to take out the workpiece 16 and the molding is completed.

Next, the bending angle of the molded product is measured and compared with the target value, and the error in the direction parallel to the bending line is corrected by moving the cotter 8 left and right. and change the inclination of punch 1,
The error in the direction perpendicular to the bending line is set to a predetermined value by replacing the adjustment blocks 15 disposed on both sides of the die 2. Thereby, the second molding is performed. After that, this operation is repeated until the target accuracy is satisfied and mass production begins. Also,
The same procedure can be used to stabilize the precision of molded products, even when the precision of molded products shifts when changing material lots.

Next, the results of molding according to the method of the present invention will be explained with reference to FIGS. 4 to 7. Figure 4 shows
A diagram showing the relationship between the punch tip angle and the bending angle parallel to the bending line, FIG. 5 is a diagram showing the relationship between the punch tip angle and the bending angle parallel to the bending line, and FIG. 6 is a diagram showing the relationship between the punch tip angle and the bending angle parallel to the bending line. Diagram showing the relationship between angle and parallelism in the direction perpendicular to the bending line,
FIG. 7 is a diagram showing the relationship between the punch-die misalignment amount and the parallelism in the direction perpendicular to the bending line.

FIG. 4 shows the relationship between the punch tip angle φp (see FIG. 2) on the horizontal axis and the bending angle θy2 parallel to the bending line on the vertical axis, and the die angle φd (see FIG.
(Reference) shows 39' and 24'. Moreover, in FIG. 5, the relationship between the two is investigated with the punch tip angle φp as the horizontal axis and the bending angle θy3 in the direction parallel to the bending line as the vertical axis. It shows about. Here, subscripts y2 and y3 of the bending angles θy2 and θy3 indicate measurement positions, and y is shown in FIG. 9(a).
2, y3, and the bending angle θ is shown in FIG. 9(b). When the punch tip angle φp is increased, both the bending angles θy2 and θy3 in the direction parallel to the bending line become larger.

On the other hand, FIG. 6 shows the relationship between the punch tip angle φp on the horizontal axis and the parallelism θx in the direction perpendicular to the bending line on the vertical axis. This is shown for degrees θx2 and θx3. Here, x2 and x3 are measurement positions, as shown in FIG. 9(a). In this case, even if the punch tip angle φp is changed, the parallelism θx in the direction perpendicular to the bending line hardly changes. From these results, by changing the punch tip angle φp, the bending angles θy2 and θ parallel to the bending line can be changed.
It is possible to change y3, in which case the parallelism θx in the direction perpendicular to the bending line is hardly affected.

In FIG. 7, the horizontal axis is the amount of misalignment δ between the punch and die, and the vertical axis is the parallelism θx perpendicular to the bending line.
The relationship between the two is investigated, and the case where the punch tip angle φp and the die angle φd are 39' is shown. By changing the amount of misalignment δ between the punch and die, it is possible to change the degree of parallelism θx in the direction perpendicular to the bending line. The above description has been made of the case where the tip angle of the punch is adjusted and the case where the position of the die is adjusted, but similar effects can be obtained by adjusting the tip angle of the die and the position of the punch.

As described above, according to this embodiment, it is no longer necessary to make a prototype of a product and repeatedly modify a mold by a skilled person, which has been done in the past. Furthermore, even if the precision of a molded product shifts when changing material lots, it is possible to quickly stabilize the precision using the same procedure. Furthermore, the mold can be easily adjusted, eliminating the need for skilled technicians with advanced know-how.

[0018]

[Effects of the Invention] As described above in detail, according to the present invention, it is possible to provide a method and a bending mold for bending a thin plate, which enables highly accurate molding without modifying the mold. .

[Brief explanation of drawings]

FIG. 1 is a front view showing the structure of a bending die according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of section A in FIG. 1;

FIG. 3 is an enlarged side view of FIG. 2;

FIG. 4 is a diagram showing the relationship between the punch tip angle and the bending angle in a direction parallel to the bending line.

FIG. 5 is a diagram showing the relationship between the punch tip angle and the bending angle in a direction parallel to the bending line.

FIG. 6 is a diagram showing the relationship between the punch tip angle and the parallelism in the direction perpendicular to the bending line.

FIG. 7 is a diagram showing the relationship between the punch-die misalignment amount and the parallelism in the direction perpendicular to the bending line.

FIG. 8 is a diagram showing an example of a material for processing.

FIG. 9 is a diagram showing a head support spring according to an example of a processed product.

[Explanation of symbols]

1 Punch 2 Die 3　Plate holder 4 Arm 6 Pressure jig 7 Holder 8 Cotta 9 Positioning pin 10, 11, 12 spring 13 Upper die set plate 14 Lower die set plate 15 Adjustment block 16 Work material

Claims (8)

[Claims] Claim 1. A method for bending a thin metal sheet, in which a workpiece of a thin metal sheet is positioned between a punch and a die of a mold, and is pressed and bent into a hat shape, in which the punch and die of the mold are parallel to each other. A method for bending a thin plate, characterized in that the bending process is performed by adjusting the degree of bending of at least one of the punch and the die. 2. The parallelism between the punch and die of the mold is adjusted by adjusting the parallelism in a direction parallel to a predetermined bending line of the workpiece.
The described thin plate bending method. 3. The method for bending a thin plate according to claim 2, wherein the parallelism between the punch and die of the mold is adjusted by a punch holding member on the punch side. 4. A method for bending a thin metal sheet in which a workpiece of a thin metal sheet is positioned between a punch and a die of a mold, and is pressed and bent into a hat shape, wherein the position of the punch and die of the mold is A method for bending a thin plate, characterized in that the bending process is performed by adjusting the accuracy of at least one of the punch and the die. 5. The positional accuracy of the punch and die of the mold is adjusted by adjusting the position perpendicular to a predetermined bending line of the workpiece.
The described thin plate bending method. [Claim 6] The positional accuracy of the punch and die of the mold is
6. The thin plate bending method according to claim 5, wherein the adjustment is performed using a position adjustment block on the die side. 7. In a thin plate bending die in which a metal thin plate workpiece is positioned between a punch and a die of a die, and is pressed and bent into a hat shape, the punch and die of the die are bent.
1. A bending die for a thin plate, comprising means for changing an attachment angle of at least one of the punch and the die to adjust the parallelism of the workpiece to a predetermined bending line. 8. In a thin plate bending die in which a metal thin plate workpiece is positioned between a punch and a die of a die, and is pressed and bent into a hat shape, the punch and die of the die are bent.
1. A bending die for a thin plate, characterized in that the bending die for a thin plate is provided with a parallel movement means capable of adjusting the positional accuracy of a workpiece in a direction perpendicular to a predetermined bending line of at least one of the punch and the die.