JPH06226367A - Molding device and molding method for superplastic metallic sheet - Google Patents

Abstract

PURPOSE:To prevent the deformation of a molded superplastic metallic sheet at the time of releasing and taking out this sheet out of metallic molds for superplastic molding in superplastic molding for molding the superplastic material. CONSTITUTION:This superplastic molding device has the metallic mold 2 enclosing the circumference of a metallic mold surface 4a with a wall part 4b and a cap part covering and hermetically sealing the metallic mold 2 in the state of holding the superplastic metallic sheet to be molded between this cap part and the metallic mold 2. Plural grooves 3 spaced from each other in the longitudinal direction of the wall part 4b of the metallic mold are formed in the corner parts formed of the upper surface of the metallic mold and the flanks on the metallic mold surface 4a side of the wall part 4b of the metallic mold. The molding is executed by heating the superplastic metallic sheet at a temp. at which the metallic sheet exhibits superplasticity and pressurizing the inside of the cap part segmented from the inside of the metallic mold 2 by the superplastic metallic sheet. The molding part molded in correspondence to the metallic mold surface 4a and the reinforcing part molded with ribs for reinforcement by the grooves 3 are formed on the superplastic metallic sheet, by which the deformation at the time of releasing and taking out is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for forming a superplastic metal sheet, and more particularly to improving productivity in forming the metal sheet.

[0002]

2. Description of the Related Art It has been a long time since a superplastic material has been developed which exhibits a significantly large elongation without causing local deformation (necking) when a metal sheet is stretched at a strain rate in a specific region at a high temperature. For example, in the case of Al alloy, Supurall (A
1- (Cu, Zn, Mg) -Zr system) and Al-Mg system and Al-Cu system each having a fine grain structure.
-Mn type, Al-Zn-Mg-Cu type (AA7075 alloy), A produced by a rapid cooling solidification method such as continuous casting and rolling
1-Zn-Ca alloys and the like are known.

Further, even in the case of the above alloy, a sheet having a crystal grain structure of a size insufficient for developing superplasticity is used as a starting material, and dynamic strain recrystallization is caused in the process of deformation,
A method of superplastic forming while forming a fine grain structure is also known. Conventionally, since superplastic forming of these alloy sheets has a small deformation stress, so-called blow molding is performed by applying a low fluid pressure (usually gas) of about several atmospheres from one side of the sheet heated to a specific temperature. A molding method is used.

[0004] Its characteristic is that it can be used for molding a molded product having a complicated shape or a large depth which is difficult to mold by a usual pressing method, or a molded product having a rib or an embossed pattern by utilizing its excellent deformability. Since it can be performed in a single step and the costly mold requires only one of a female mold and a male mold, it has been widely used.

[0005]

By the way, in the above-mentioned conventional superplastic forming, the forming requires a long time, for example, the forming takes from several minutes to several tens of minutes. Further, in superplastic forming, it is necessary to heat the superplastic metal sheet to a temperature at which the superplastic metal sheet exhibits superplasticity, and therefore the mold must also be heated to a high temperature. Therefore, when performing superplastic forming efficiently and continuously, in order not to take time to reheat the mold, without waiting for the temperature of the superplastic metal sheet and the mold to decrease, It is necessary to release from the mold.

However, it is difficult to remove the molded product from the mold, depending on the shape of the product. Mold release of a complex product having a deep bend has a gas pressure between the mold and the molded product. Is applied, or the pressure side is sucked, a vacuum is applied, and the mold is released. That is, when releasing a molded product, it is necessary to apply a force to the molded product, and if the molded product is taken out from the mold at a high temperature, the molded product may be bent and deformed at the time of taking out the mold. There is a problem that the yield becomes high and the yield of molded products deteriorates. Especially in the case of large-sized molded products, the rate of deformation during release from the mold was high, and the yield was low. Therefore, for the above reason, it has been difficult to achieve both the time efficiency of the superplastic forming process and the improvement of the yield of the molded product at the same time and to improve the productivity of the superplastic forming.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve productivity in superplastic forming by preventing deformation of a molded product when the molded product is taken out of the mold. It is an object of the present invention to provide a forming apparatus and a forming method of a superplastic metal sheet capable of achieving the above.

[0008]

A superplastic metal sheet forming apparatus according to the present invention is a superplastic metal sheet forming apparatus, in which a die having an upper die surface surrounded by a wall portion and a die to be formed between the die. A plastic metal sheet is sandwiched between the superplastic metal sheet so that the inside of the mold can be hermetically sealed, and a lid part for covering and sealing the mold is provided, and the superplastic metal sheet is heated to a temperature showing superplasticity, A pressurized fluid is introduced into the inside of a lid section partitioned from the inside of the mold by the superplastic metal sheet to form a pressure chamber, and the inside of the mold is adjusted to a fluid pressure lower than that of the pressure chamber to form a back pressure chamber. , Is for superplastically forming by pressing the superplastic metal sheet against the mold surface by fluid pressure, and the wall portion of the mold has a corner formed from the upper surface and the side surface on the mold surface side. In the part, a plurality of grooves are formed at intervals in the length direction of the wall part. It is.

Further, in the superplastic metal sheet forming apparatus of the present invention, the wall portion of the die surrounds the surface of the die and divides the upper surface of the die into a plurality of die surfaces, and A plurality of grooves are formed at intervals in the length direction of the wall over the entire corner formed by the upper surface and the side surface of the wall, which is the means for solving the above problems.

It is preferable that the groove is formed at a corner of the wall along a direction substantially perpendicular to a contour line along the outer periphery of the mold surface. It is preferable that a connecting groove is formed in the wall portion so as to communicate the adjacent grooves.

The method for forming a superplastic metal sheet according to the present invention is capable of sealing the inside of the mold with a superplastic metal sheet to be formed on a mold in which the periphery of the upper mold surface is surrounded by walls. A lid part for covering and sealing the die on the superplastic metal sheet, and heating the superplastic metal sheet to a temperature at which it exhibits superplasticity, and partitioning the interior of the die with the superplastic metal sheet. A pressurized fluid is introduced into the inside of the lid portion, the inside of the die is adjusted to a fluid pressure lower than that inside the lid, and the superplastic metal sheet is pressed by the fluid pressure against the die surface to superplastically form. In the method for forming a superplastic metal sheet, by forming a plurality of grooves at intervals in the length direction of the wall portion at a corner formed from the upper surface and the side surface of the wall portion of the mold. , Shape the superplastic metal sheet into a shape that corresponds to the mold surface. A rib corresponding to the groove is formed around the forming portion to be formed on the die surface, and then the formed superplastic metal sheet is released from the die and taken out, and then the rib is formed. The means for solving the above problem is to separate the periphery of the molded portion from the molded portion.

[0012]

According to the structure described in claim 1, since the grooves are formed at the corners of the wall portion surrounding the mold surface at intervals in the length direction of the wall portion, the superplastic metal sheet is formed. In the case of superplastic forming, a plurality of ribs are formed around the forming portion formed by the die surface of the superplastic metal sheet. By forming ribs around the molded portion of the superplastic metal sheet, it is possible to prevent deformation of the superplastic metal sheet when the molded superplastic metal sheet is released from the mold.

Further, according to the second aspect of the present invention, the upper surface of the mold is partitioned by the wall portion to form a plurality of mold surfaces, so that a plurality of molded products can be molded at a time by one mold. It becomes possible to do, and by forming the groove in this wall portion, the rib is formed around each of a plurality of molded portions formed in the superplastic metal sheet, similar to the above. It is possible to prevent the superplastic metal sheet from being deformed when the molded superplastic metal sheet is taken out from the mold.

According to the third or fourth aspect of the present invention, the groove direction is formed substantially perpendicular to the contour line of the mold surface, or a connecting groove for connecting the grooves is formed. , The deformation prevention effect of the superplastic metal sheet may be further enhanced.

Further, as in the structure described in claim 5, the superplastic metal sheet superplastically molded by the mold having the groove in the wall is released and taken out, and the molded portion molded on the mold surface. By separating from the portion where the rib is formed by the groove, a molded product whose deformation is prevented by the rib can be obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 are drawings for explaining a first embodiment of the present invention, and FIG. 1 is a mold of a forming apparatus for a superplastic metal sheet 1 (shown in FIG. 2) of the first embodiment. 2 shows the molding apparatus, and FIG. 3 shows the rib molding groove 3 formed in the mold 2.

As shown in FIG. 2, the molding apparatus of the first embodiment has a mold surface (a concave and convex formed on the mold surface is not shown in FIG. 1) 4a for molding the superplastic metal sheet 1, and A mold 2 having a mold body 4 having an outer peripheral wall 4b surrounding the mold surface 4a, and a lid 5 arranged on the mold 2 for sealing the inside of the mold 2 are basically configured. To do. The mold 2 includes the mold body 4, a bottom portion 6 that covers the lower surface side of the mold body 4, and a mold 2 on the upper surface of the outer peripheral wall portion 4 b of the mold body 4.
The metal bead 7 is provided along the outer peripheral edge of the metal bead 7 and serves as a sealing material for maintaining airtightness in the mold.

As shown in FIG. 2, the mold surface 4a of the mold body 4 is provided with irregularities for molding the supermetal sheet 1. Although the mold surface 4a is formed in a rectangular shape in the first embodiment, it is not necessarily limited to a rectangular shape. Pipes 8a, 8a for adjusting the fluid pressure inside the mold 2 are embedded in the mold body 4, one end of which is opened to the mold surface 4a and the other end of which penetrates a bottom portion 6 described later. 8b, 8 connected to a fluid pressure control device (not shown)
connected to b. The inside of the mold body 4 serves as a back pressure chamber 9 whose fluid pressure is adjusted as described later.

The outer peripheral wall 4b of the mold body 4 is formed in a rectangular frame shape because the mold surface 4a is formed in a rectangular shape in the first embodiment. Then, the outer peripheral wall portion 4a
The rib forming grooves 3 are formed on the upper surface of the outer peripheral wall 4a from the inside of the metal beat 7 to the inner surface of the outer peripheral wall 4a. That is, the rib forming grooves 3 ... Are formed in the corner portion 4c formed by the upper surface and the inner surface of the outer peripheral wall portion 4a.

A large number of rib forming grooves 3 are provided at substantially equal intervals in the lengthwise direction of the outer peripheral wall portion 4b.
Further, as shown in FIGS. 1 and 3, the rib forming groove 3 ... Has a rectangular mold surface 4a on the upper surface of the outer peripheral wall portion 4b.
Right-angled to the contour line of the outer peripheral wall 4 in the shape of a rectangular frame
It is formed so as to be perpendicular to each side of b, and is formed in the substantially vertical direction on the inner surface of the outer peripheral wall portion 4b continuously from the rib forming groove 3 on the upper surface side.

As shown in FIG. 3, a cut step 4d is formed on the inner surface of the outer peripheral wall 4b below the rib forming grooves 3 ... As will be described later, the cutting step 4d forms at right angles a portion for separating a forming portion formed by the mold surface 4a of the superplastic metal sheet 1 and a portion formed by the rib forming groove 3 ... It is a thing.

The metal bead 7 is engaged with the lower surface of the lid 5 through the superplastic metal sheet 1 when the metal mold 2 is covered with the lid 5 with the superplastic metal sheet 1 interposed therebetween.
The airtightness inside the mold 2 is maintained. The sealing material is not necessarily limited to the metal beads 7 and may be a heat-resistant packing material or the like, but as will be described later, the fluid pressure is applied and held in the mold 2 and the lid 5 which become hot. Therefore, the metal beat 7 is excellent in maintaining the airtightness.

The bottom portion 6 has the mold body 4 inside thereof.
Can be detachably inserted. Also, the bottom portion 6
In this case, pipes 8b, 8b for adjusting the fluid pressure of the back pressure chamber 9 inside the mold body 4 are arranged so as to penetrate the side wall of the bottom portion 6. In addition, the flow control valve 8c is provided in the pipes 8b and 8b.
Is installed. Further, electric resistance heating elements 11 ... Are embedded in the bottom portion 6, and the mold 2 and the superplastic metal sheet 1 are embedded.
Can be heated to a temperature at which the superplastic metal sheet 1 exhibits superplasticity.

The lid 5 is formed such that an outer peripheral edge portion 5a of the lower surface thereof is projected downward and a recess is formed inside the lower surface. Then, this concave portion serves as the pressurizing chamber 12. Further, the outer peripheral edge portion 5a is arranged to face the outer peripheral wall portion of the mold 2 with the metal beat 7 and the superplastic metal sheet 1 interposed therebetween. Inside the lid portion 5, the bottom portion 2
Similarly, the electric resistance heating elements 11 are embedded so that the lid 5 and the superplastic metal sheet 1 can be heated to a temperature at which the superplastic metal sheet 1 exhibits superplasticity. In addition, the lid 5 is provided with a pipe 10 that penetrates the lid 5 and opens to the pressurizing chamber 12 to apply a fluid pressure to the pressurizing chamber 12. A flow rate control valve 10a is attached to the pipe 10 and is connected to a fluid pressure control device (not shown).

FIG. 2 shows a state in which the superplastic metal sheet 1 is placed on the mold 2 having the above-described structure, and the superficial lid portion 5 is covered therewith, and the molding apparatus of the first embodiment performs superplastic molding. Is illustrated. In this state, the inside of the lid 5 above the superplastic metal sheet 1 becomes a pressurizing chamber 12 for applying a fluid pressure, and the inside of the mold body 4 below the superplastic metal sheet 1 is a fluid lower than the pressurizing chamber 12. The back pressure chamber 9 is adjusted to the pressure. A mold chamber 13 is composed of the pressurizing chamber 12 and the back pressure chamber 9. In the molding apparatus of the first embodiment, a pressing means (not shown) for pressing the mold 2 and the lid 5 against each other is provided, and the mold chamber 13 is kept airtight.

Next, a method of forming the superplastic metal sheet 1 by the apparatus for forming a superplastic metal sheet of the first embodiment having the above-mentioned structure and its operation will be described. First, as shown in FIG. 2, the superplastic metal sheet 1 is formed on the mold 2 so as to cover the upper surface of the mold 2.
Is arranged, the lid 5 is arranged thereon corresponding to the position of the die 2, and the die 2 and the lid 5 are pressed against each other by a pressing means (not shown).

Next, the electric resistance heating element 11 is used to form the mold 2.
Then, the lid portion 5 is heated to raise the temperature to a predetermined temperature at which the superplastic metal sheet 1 exhibits superplasticity, and the temperature is maintained at this temperature. Then
The pressure chamber 12 is pressurized through the pipe 10 so that the pressure chamber 12 has a predetermined fluid pressure. Further, in the back pressure chamber 9, the fluid pressure is adjusted via the pipes 8a and 8b so that a predetermined pressure difference with respect to the pressure chamber 12 can be obtained.

By adjusting the fluid pressures of the pressurizing chamber 12 and the back pressure chamber 9 as described above, the superplastic metal sheet 1 in the superplastic state is pressed against the die surface 4a of the die 2, Mold surface 4
It is molded into a shape corresponding to a. Further, ribs are formed by the rib forming grooves 3 provided in the wall portion 4b of the die body 4 around the peripheral edge portion of the superplastic metal sheet 1, that is, around the forming portion formed on the die surface 4a. .

After the molding is completed, the lid 5 is removed from the mold 2, and the molded superplastic metal sheet 1 is released and taken out. At this time, the temperatures of the mold 2 and the lid 5 should not be lowered so much that the temperature is slightly lower than the temperature indicating superplasticity,
The superplastic metal sheet 1 is taken out. Further, in the mold release of the superplastic metal sheet 1, when the molding is a complicated shape with a deep bend, application of fluid pressure between the mold 2 and the superplastic metal sheet 1 or the superplastic metal sheet 1 is performed. A method such as suctioning the pressure chamber 13 to make it vacuum is adopted, and the superplastic metal sheet 1 is taken out by using a well-known fork-type drawing device or the like.

In this case, since the ribs are formed by the rib forming grooves 3 in the superplastic metal sheet 1, deformation such as bending deformation does not occur at the time of taking out from the mold.
Further, by forming the ribs, it is possible to prevent deformation even when manufacturing a large-sized molded product. In the above superplastic forming operation, temperature adjustment, fluid pressure adjustment, etc. are performed based on the same method as the known superplastic forming method.

Next, in the mold 2, the superplastic metal sheet 1 to be molded next is set on the mold 2 while the mold 2 and the lid 5 are at a high temperature, and the molding operation is performed as described above. . By performing the superplastic forming in this way, the temperature rising time of the mold 2 and the lid portion 5 can be shortened, and the superplastic forming step which requires a long time can be shortened, and as described above. Since the ribs are molded, the yield of molded products does not deteriorate.

On the other hand, the formed superplastic metal sheet 1 is
In the bent portion formed by the step 4d formed below the rib forming groove 3 ... Of the outer peripheral wall portion 4b of the mold body 4,
By cutting with a laser cutter or the like, the molded part of the superplastic metal sheet 1 and the part where the rib is formed are separated, and the molded part is made into a molded product. Incidentally, the mechanism of action by which the superplastic metal sheet 1 is prevented from being deformed at the time of taking out from the mold by forming the rib forming grooves 3 ... Is not always clear, but it may be considered as follows. it can.

That is, a large number of ribs are formed around the forming portion of the superplastic metal sheet 1 by the rib forming grooves 3 ..., The strength around the forming portion of the superplastic metal sheet 1 is strengthened, Even when a force is applied to the superplastic metal sheet 1 at the time of release from the mold, the rib-formed portion absorbs the force, and the formed portion of the superplastic metal sheet 1 has a force enough to cause bending deformation. This can be prevented and deformation can be prevented.

Here, the shapes of the rib forming grooves 3 forming the ribs on the superplastic metal sheet 1 will be described. The shape of the rib forming groove 3 ... Is not always the same as that of the rib forming groove 3 of the first embodiment.
It is not limited to, for example, FIG.
As shown in (B), (C), (D), and (E), the cross section of the groove in the upper surface portion of the outer peripheral wall portion 4b of the mold body 4 is arcuate (rib forming grooves 3a, 3b), reverse. Triangular shape (rib molding groove 3
c, 3d), concave (3e), etc. can be used.

Further, the cross section of the outer peripheral wall portion 4b along the direction of the rib forming grooves 3 ... Is not limited to the shape shown in FIG. 3 of the first embodiment, and is not limited to that shown in FIG. B)
As shown in Fig. 3, the outer peripheral wall 4b has a shape in which the corner 4c is linearly cut (rib forming groove 3f), or the outer peripheral wall 4b has a shape vertically cut from the upper surface and the inner surface (rib forming). The groove 3g) may be used.

Further, the rib forming groove 3 of the forming apparatus of the present invention is used.
The shape of ... Is not limited to the shape shown in the first embodiment or the above-described FIGS. 4 and 5, but the superplastic metal sheet 1
As for the shape of the ribs formed in (1), it is preferable to provide a large number of small ribs rather than a small number of large ribs, because the effect of preventing deformation may be greater. Further, the shape of the rib-forming grooves 3 ... Is preferably such that the width of the groove is narrow and the depth of the groove is deep. Further, it is preferable that the rib forming groove 3 has a rigid shape with a small number of flat portions. A curved shape is preferable.

Further, in the first embodiment, the rib forming groove 3 ...
Is formed perpendicularly to the contour line of the mold surface 4a, but, for example, the rib forming grooves 3 may be formed along the direction toward the center of the mold surface 4a.
However, as a reinforcement of the superplastic metal sheet 1, it is better to provide the rib forming grooves 3 ... Vertically to the contour line of the mold surface 4a.

The grooves formed in the outer peripheral wall portion 4b of the mold body 4 are shown in FIGS. 6 and 7 (a), (b) and FIG.
As shown in (a) and (b), in addition to those provided perpendicularly to the contour line of the mold surface 4a, it is formed so as to connect adjacent rib forming grooves 3 ... The connecting groove 14 may be provided.

The connecting groove 14 is provided continuously along the entire length of the outer peripheral wall 4b of the mold body 4 along the lengthwise direction of the outer peripheral wall 4b. And FIG. 7 (A) and FIG. 8 (A)
As shown in the cross section of the outer peripheral wall portion 4b of the rib forming grooves 3 and 3g without portions and the cross section of the outer peripheral wall portion 4b with the rib forming grooves 3 and 3g of FIGS. , The connecting groove 14 so as to communicate with the upper end portions of the rib forming grooves 3 and 3g.
Is provided.

By thus providing the connecting groove 14 in addition to the rib forming grooves 3 and 3g, the deformation of the superformed metal sheet 1 at the time of taking out from the mold can be more reliably prevented. The rib forming grooves 3 and 3g shown in FIGS.
7, the rib forming groove 3 is different from the outer peripheral wall portion 4b in FIG.
8 has a shape that extends downward when it reaches the inner surface side, while in FIG. 8, the rib forming groove 3g remains at the depth of the upper surface side of the outer peripheral wall portion 4b, and It has an open shape.

The depth of the connecting groove 14 is the same as the depth of the rib forming grooves 3 and 3g on the upper surface of the outer peripheral wall portion 4b as shown in FIGS. As shown by the connecting groove 14a indicated by the dotted line in FIG.
The shape may be deeper (or shallower) than g, and the rib forming grooves 3 and 3g and the connecting groove 14 do not necessarily have to be formed at the same depth.

FIG. 9 shows a second embodiment of the forming apparatus for the superplastic metal sheet 1 of the present invention. In the molding apparatus of the second embodiment, by forming partition walls 22a and 22b in the mold body 21 of the mold 20 in the vertical and horizontal directions, the mold surface 21a ...
Is divided into a plurality of parts, so that a plurality of molded products can be manufactured by a single superplastic forming process.
The same components as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 9, in the mold body 21 of the second embodiment, in addition to the outer peripheral wall portion 21b, two horizontal partition walls 22a and one vertical partition wall 22b are provided. Are provided and the upper surface of the mold body 21 is partitioned, so that six mold surfaces (concavities and convexities for molding are not shown) 21a ... Are formed. In addition, the number of mold surfaces 21a to be partitioned,
Direction of partition walls 22a, 22b, partitioned mold surface 21a
The shape of ... Is not particularly limited.

The outer peripheral wall portion 21b is provided with the rib forming grooves 23 ... And the connecting groove 24 as in the first embodiment, and the partition walls 22a and 22b are similar to the outer peripheral wall portion 21b. The rib forming grooves 23a ... And the connecting groove 24 are provided. Further, the rib forming grooves 23a of the partition walls 22a and 22b are formed in the partition walls 22a and 22b at equal intervals in the lengthwise direction, similarly to the rib forming grooves 23 of the outer peripheral wall 21b. , Is formed perpendicular to the contour line of each mold surface 21a divided into a plurality of parts.

Further, in the outer peripheral wall portion 21b of the second embodiment, similarly to the outer peripheral wall portion 21b of the first embodiment, the connecting groove 24 may not be provided, or the connecting groove 24 may be provided.
When the grooves are provided, the connecting groove 24 and the rib forming grooves 23 may have the same or different depths. further,
The shape of the rib forming groove 23 ... Is not limited to the same shape as the rib forming groove 3 of the first embodiment.

Further, FIG. 10 (A) (A ') (B)
As shown in (B '), (C), (c'), and FIG. 11, in the partition walls 22a and 22b, the mold surfaces 21a are provided on both sides.
.. are provided, the partition walls 22a and 22b are provided.
Rib forming groove 23a so as to connect the upper surface and the left and right side surfaces
... is formed.

The connecting grooves 24, 24a pass through the central portions of the upper surfaces of the partition walls 22a, 22b and the partition wall 22.
It is provided along the length direction of a and 22b. Also,
As in the case of the outer peripheral wall portion 21a, the connecting grooves 24 and 24a may not be provided as shown in FIG. 10C. Further, the depth of the connecting grooves 24, 24a may be deeper than the rib forming groove 23a like the connecting groove 24a shown by the dotted line in FIGS. 10A and 11, or the connecting groove 24 shown in FIGS. 10b and 11. Rib forming groove 23a
The depth may be the same as, or may be shallower than the rib forming grooves 23a.

The rib forming groove 23a formed in the partition walls 22a and 22b has the shape of the partition wall 22 as described above.
The rib forming groove 23 is similar to the rib forming groove 23 of the outer peripheral wall portion 21b except that the rib forming groove 23 is formed on both side surfaces of the a and 22b, and its shape is limited similarly to the rib forming groove 23 of the outer peripheral wall portion 21b. is not. Such a mold 2 of the second embodiment
A superplastic metal sheet forming apparatus having a mold body 2
1 has the same configuration as that of the molding apparatus of the first embodiment shown in FIG.

The superplastic metal sheet forming method of the second embodiment is also the same as the forming method using the forming apparatus of the first embodiment. Then, according to the forming apparatus of the second embodiment as described above, as in the first embodiment, the rib forming groove 23,
23a or rib forming groove 23, 23a and connecting groove 2
Since the ribs 4 and 24a form ribs on the superplastic metal sheet 1, no deformation occurs in the molded portion of the superplastic metal sheet 1 at the time of taking out the mold after molding.

According to the second embodiment, the partition wall portion 22,
The rib forming groove 23a of 22a or the rib forming groove 23a and the connecting grooves 24, 24a form ribs not only on the outer peripheral edge of the superplastic metal sheet 1 but also inside the superplastic metal sheet 1. It can be something that will happen.

Therefore, even if the mold 20 and the superplastic metal sheet 1 are large-sized, the superplastic metal sheet 1 is not deformed at the time of releasing from the mold, and therefore the large mold 2 is used.
0 is divided into a large number of mold surfaces 21a ...
Since it is possible to manufacture many molded products with one superplastic forming by dividing into, it is possible to greatly reduce the manufacturing time in superplastic forming, which generally requires a lot of time for one molding. it can.

[0052]

As described above in detail, according to the first aspect of the present invention, the metal of the superplastic metal sheet is formed in the superplastic forming by the groove formed in the wall of the mold. Reinforcing ribs will be formed around the molding part formed on the mold surface, and the superplastic metal sheet after molding will be reinforced by the ribs, and when the mold release of the superplastic metal sheet is taken out from the mold, It is possible to prevent the superplastic metal sheet from being deformed when force is applied to the plastic metal sheet.

Therefore, even if the formed superplastic metal sheet is taken out from the mold at a high temperature and the next superplastic forming is performed before the temperature of the mold is lowered so much, the molded product is deformed. By doing so, the yield of the molded product does not decrease, and as a result, the molding efficiency of the superplastic metal sheet can be increased. Further, even in a large-sized molded product having a low yield, it is possible to prevent deformation and increase the molding efficiency, so that the production efficiency in superplastic molding can be significantly improved.

According to the second aspect of the present invention, ribs are formed in one superplastic metal sheet so as to divide the superplastic metal sheet, and the superplastic metal sheet after forming is formed. Can be made stronger. Therefore, by making the mold large and forming a large number of mold surfaces by the partition walls, it is possible to manufacture a large number of molded products by one superplastic forming operation, which conventionally takes a lot of time. Further, the time required for the superplastic forming process can be significantly reduced.

Further, as described in claims 3 and 4, the direction of the groove is made perpendicular to the contour line of the mold surface, and the connecting groove is formed, so that the superposition after molding can be more reliably performed. It is possible to increase the strength of the plastic metal sheet and reliably prevent the deformation of the superplastic metal sheet when the superplastic metal sheet is released from the mold.

Further, according to the method for forming a superplastic metal sheet according to claim 5, the superplastic metal sheet superplastically formed by a die having a groove in the wall is released and taken out, and the die surface is formed. By separating the molded portion molded into the rib from the portion where the rib is formed by the groove, a molded product whose deformation is prevented by the rib can be obtained, and the production efficiency of superplastic molding can be improved as described above. You can

[Brief description of drawings]

FIG. 1 is a perspective view showing a mold of an apparatus and method for forming a superplastic metal sheet according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an apparatus for forming the superplastic metal sheet.

FIG. 3 is a cross-sectional view showing a rib forming groove in a wall portion of the mold.

FIG. 4 is a cross-sectional view showing a modified example of the rib forming groove.

FIG. 5 is a cross-sectional view showing a modified example of the rib forming groove.

FIG. 6 is a perspective view of an essential part of a wall portion in which a connecting groove is formed in addition to the rib forming groove.

FIG. 7 is a cross-sectional view of a wall portion in which a connecting groove is formed in addition to the rib forming groove.

FIG. 8 is a cross-sectional view of a wall portion in which a connecting groove is formed in addition to the rib forming groove.

FIG. 9 is a perspective view showing a mold of a forming apparatus and a forming method for a superplastic metal sheet according to a second embodiment of the present invention.

10A and 10B are a plan view and a cross-sectional view showing a partition wall portion of the superplastic metal sheet forming apparatus of the second embodiment.

FIG. 11 is a cross-sectional view showing a partition wall portion of the superplastic metal sheet forming apparatus of the second embodiment.

[Explanation of symbols]

 1 Superplastic Metal Sheet 2 Mold 3 Rib Forming Groove (Groove) 3a Rib Forming Groove (Groove) 3b Rib Forming Groove (Groove) 3c Rib Forming Groove (Groove) 3d Rib Forming Groove (Groove) 3e Rib Forming Groove (Groove) 3f Rib molding groove (groove) 3g Rib molding groove (groove) 4 Mold main body 4a Mold surface 4b Outer peripheral wall portion (wall portion) 5 Lid portion 9 Back pressure chamber 12 Pressurizing chamber 14 Tether groove 20 Mold 21 Mold Main body 21a Mold surface 21b Outer peripheral wall part (wall part) 22a Partition wall part (wall part) 22b Partition wall part (wall part) 23 Rib molding groove (groove) 23a Rib molding groove (groove) 24 Connecting groove 24a Connecting groove

Claims (5)

[Claims] 1. A mold in which a mold surface, which is an upper surface, is surrounded by a wall portion, and a superplastic metal sheet to be molded between the mold and the mold can be hermetically sealed by the superplastic metal sheet. In a state of being sandwiched between the lid and a lid for covering and sealing the die, and heating the superplastic metal sheet to a temperature at which it exhibits superplasticity, and inside the lid portion separated from the inside of the die by the superplastic metal sheet. A pressurized fluid is introduced into the pressurizing chamber, and the inside of the die is adjusted to a fluid pressure lower than that of the pressurizing chamber to form a back pressure chamber, and the superplastic metal sheet is pressed against the die surface by the fluid pressure. In the forming apparatus of the superplastic metal sheet for superplastic forming, the wall portion of the mold has a corner formed from the upper surface and the side surface on the mold surface side in the length direction of the wall portion. A forming device for a superplastic metal sheet, wherein a plurality of grooves are formed at intervals. 2. The wall portion of the mold surrounds the mold surface, partitions the upper surface of the mold into a plurality of mold surfaces, and
2. The supermarket according to claim 1, wherein a plurality of grooves are formed at intervals in the length direction of the wall portion over the entire corner portion formed by the upper surface and the side surface of the wall portion. Equipment for forming plastic metal sheets. 3. The groove is formed at a corner portion of the wall portion along a direction substantially perpendicular to a contour line along the outer periphery of the mold surface. 2. The superplastic metal sheet forming apparatus described in 2. 4. The molding of a superplastic metal sheet according to claim 1, wherein a connecting groove is formed in the wall portion so as to connect the adjacent grooves to each other. apparatus. 5. A mold in which the upper surface of the mold surface is surrounded by a wall portion is covered with a superplastic metal sheet to be molded so as to seal the inside of the mold, and the mold is placed on the superplastic metal sheet. A lid part for covering and sealing is placed, and after heating the superplastic metal sheet to a temperature at which it exhibits superplasticity, a pressurized fluid is introduced into the lid part partitioned from the mold interior by the superplastic metal sheet. In the method for forming a superplastic metal sheet, wherein the inside of the mold is adjusted to a fluid pressure lower than that of the inside of the lid, and the superplastic metal sheet is pressed against the mold surface by fluid pressure to perform superplastic forming, wherein the mold is In the corner formed from the top and side surfaces of the wall of
By forming a plurality of grooves at intervals in the lengthwise direction of the wall portion, the superplastic metal sheet is molded into a shape corresponding to the mold surface and the molded portion of the mold surface is molded. Forming a rib corresponding to the groove on the periphery, then releasing the formed superplastic metal sheet from the mold and taking it out, and then separating the periphery of the formed part on which the rib is formed from the formed part. And a method of forming a superplastic metal sheet.