JPH074628B2 - Superplastic forming die and superplastic forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a superplastic forming die used when a gas pressure is applied to form a superplastic plate material, and a superplastic forming die using the superplastic forming die. The present invention relates to a method for forming a plastic plate material.

[Conventional technology]

Conventionally, when superplastically forming a superplastic plate material using gas, as shown in FIG. 5, the superplastic plate material 5 is fixed between the upper mold 1 and the lower mold 2 ′ so as to sandwich the periphery, After heating the mold 1 and the lower mold 2'to a predetermined molding temperature, pressurized gas is supplied from the passage 3 for supplying or discharging gas provided in the upper mold 1, while the superplastic plate material 5 and the lower mold 2'are supplied. The gas existing during the period was discharged from the gas vent hole 4 and the superplastic plate material 5 was pressed against the lower mold 2 '.

The material used to manufacture the upper and lower molds is tool steel for molds such as SKS, SKD, and SKT specified in JIS, graphite, and ceramics, and is cut into a predetermined shape by a method such as cutting or casting. It was made.

Further, as the superplastic plate material, duplex stainless steel, titanium alloy plate having a composition of Ti-6% Al-4% V, AA7075 (Al-5.6% Zn-2.5% Mg-1.6% C)
u-0.3% Cr), Supral 100 (Al-6% Cu-0.4% Zr-0.2
5% Mg-0.1% Fe-0.05% Mn), A8090 (Al-2.5% Li-1.
2% Cu-0.7% Mg-0.12% Zr), aluminum alloy plate such as Al-33% Cu, zinc alloy such as Zn-22% Al, 4 / 6Brass
(Cu-40% Zn), C6301 (Cu-10% Al-6% Ni-4% Fe)
-1% Mn), Cu-10% Mn, and other copper alloy plates are known.

In order to impart a shape to the molded product of the superplastic plate material using the conventional superplastic molding mold, it is necessary to use a superplastic molding mold having a mold inner surface of the outer surface whole surface shape replication of the molded product, Therefore, in order to manufacture a plurality of molded products having different outer surface shapes, it is necessary to prepare a plurality of superplastic molding dies.

Further, in order to form a molded product surrounded by a free-form surface, it is necessary to form it using a superplastic forming die having a duplicate free-form surface on the above-mentioned free-form surface. In order to form it on the inner surface of the mold, it is expensive because it is formed by using a highly precise cutting technique and / or an electric current machining.

Therefore, in order to manufacture many types of superplastic molded products, it is necessary to prepare a large number of expensive superplastic molding dies, and the price of superplastic molded products manufactured using expensive superplastic molding dies is high. Is also expensive.

In order to solve these problems, a lower mold having an opening of a predetermined size in the center of the thick plate, and a superplastic plate material placed on the lower mold and held by the upper mold to form a superplastic plate material. A superplastic forming method has also been proposed in which the lower die is extruded from the front side to the back side through an opening, and the superplastic plate material is pressed against an auxiliary die to form a die (see JP-A-63-290632).

[Problems to be Solved by the Invention]

However, a superplastic molded product produced by a superplastic forming mold consisting of the above-mentioned conventional upper mold and a lower mold having an opening, when the molded product is larger than the opening diameter of the lower mold, the obtained superplastic molded product is Since it cannot be taken out from the lower mold, the conventional superplastic forming method described above is limited to the production of a superplastic molded product having a diameter smaller than the diameter of the opening.

[Means for Solving the Problems]

Therefore, the present inventor conducts research to develop a superplastic forming die that can easily take out the superplastic formed article from the lower die even if the superplastic formed article becomes larger than the opening diameter of the lower die. As a result, they have found that the lower die of the superplastic forming die should be a split die that can be divided.

The present invention has been made based on such knowledge, and (a) is for superplastically forming a superplastic plate material using a gas composed of an upper mold and a lower mold having a passage for supplying or discharging gas. In the molding die, the lower die is a superplastic molding die including a split die having an opening penetrating from the front surface to the back surface and a holding ring capable of holding down the periphery of the split die, and (b) A molding die comprising an upper die having a passage for supplying or discharging gas, a split die having an opening penetrating from the front surface to the back surface, and a lower die having a holding ring capable of holding down the periphery of the split die. By sandwiching the superplastic plate material between the upper mold and the lower mold of the molding die and pushing the superplastic plate material from the front side to the back side of the lower mold while supplying gas from the supply passage of the upper mold. Larger than opening diameter by putting out And a superplastic forming method for forming a superplastic molded product having a diameter of

When the lower mold is used, even if a superplastic molded product having a diameter larger than the opening diameter is obtained, the pressing ring can be released, and then the split mold can be divided and taken out.

The number of openings penetrating from the front side to the back side of the lower mold is not limited to one and may be plural. The opening is composed of a curved surface with an arbitrary radius of curvature from the front side to the back side according to the shape of the molded body, and the thickness of the thick plate that constitutes the lower mold does not need to be constant, depending on the location. The thickness may vary. Further, the lower mold may be configured by combining plates having different plate thicknesses.

A superplastic plate material is sandwiched between such a lower mold and a normal upper mold, and gas for pressurization is supplied from the passage for supplying or discharging the gas of the upper mold, and the space from the opening of the lower mold toward the space. It can be freely deformed into a convex shape, and can be pressed into an auxiliary mold placed below the lower mold to be molded into a predetermined shape.

The split mold that constitutes the lower mold is fixed around the periphery with a press ring so as not to separate during molding, but any shape can be used as long as the inner shape of the press ring matches the external shape of the split mold. Good. Moreover, the wall thickness of a plurality of split molds can be changed.

As the material for producing the superplastic forming die of the present invention and the superplastic plate material to be formed, the usual materials described above can be used.

〔Example〕

 Next, the present invention will be specifically described with reference to the drawings.

FIG. 1 is a cross-sectional view of a state in which a superplastic plate material is used to form a hemispherical shape using the superplastic forming die of the present invention, and FIG. 2 is a lower die used in the superplastic forming die of FIG. Is a plan view of.

As shown in FIG. 2, the lower die 2 used in the superplastic forming die of the present invention has a structure in which split dies 21, 21 having, for example, a half ring shape are aligned and the periphery thereof is held by a holding ring 6. Those that are preferable. The superplastic plate 5 is placed on the lower mold 2, the upper mold 1 is placed on the lower mold 2 and fixed by a fixture (not shown), and pressurized gas is supplied from a passage 3 for supplying or discharging gas. Then, as shown in FIG. 1, the superplastic plate material 5 is deformed from the front side of the lower mold 2 to the back side space through the opening 7 and is superplastically formed.

In order to take out a molded product having a diameter larger than the diameter of the superplastically molded opening 7, the pressing ring 6 around the split molds 21 and 21 should be removed and the split molds 21 and 21 should be split and taken out. You can

Further, as illustrated in FIG. 3, when an auxiliary die 8 is placed below the lower die 2 and the superplastic plate material 5 is sandwiched between the upper die 1 and the lower die 2 to perform superplastic forming, a superplastic molded product is obtained. The bottom shape of can be molded into a desired shape.

Furthermore, by giving the inner surface of the opening 7 a taper or a curved surface, it is possible to produce superplastic molded products of various shapes such as a cup shape and a flask shape, and by forming the auxiliary mold 8 into a desired shape. The shape of the bottom of the molded product can be any desired shape.

FIG. 4 shows another embodiment of the superplastic forming die of the present invention. The lower mold 2 in FIG. 4 is provided with a plurality of openings 7 in a thick plate, and can form a plurality of different shapes on one superplastic plate material. For such a large lower mold 2, it is preferable to use one or a plurality of thick plates having different thicknesses depending on the location in consideration of strength. The auxiliary mold does not have to be singular, and a plurality of auxiliary molds 8 ', 8'can be used in combination depending on the shape to be molded.

The lower mold that combines a plurality of thick plates with different thickness, for example,
The lower mold 2 can be formed by forming stepped holes 23 having different diameters and loading the lower molds 22 having different plate thicknesses into the holes 23.

〔The invention's effect〕

The superplastic forming die of the present invention is composed of a split die that can divide the lower die and a holding ring that holds the die,
Even if a superplastic molded product having a diameter larger than the diameter of the opening is manufactured, it can be easily taken out, and a superplastic molded product having a diameter of an arbitrary size can be manufactured. is there.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a superplastic plate material is formed using the superplastic forming die of the present invention, and FIG. 2 is a plan view of a lower die used in the superplastic forming die of FIG. FIG. 3 is a cross-sectional view showing a state in which a superplastic plate material is formed using an auxiliary die, and FIG. 4 is a lower die having a plurality of openings, and a plurality of different shapes are formed on one superplastic plate material. FIG. 5 is a cross-sectional view showing a state in which the molding is applied, and FIG. 5 is a cross-sectional view of a conventional superplastic molding die. 1: Upper mold, 2, 2 ', 22: Lower mold, 3: Passage for supplying or discharging gas, 4: Gas vent hole, 5: Superplastic plate material, 6: Press ring,
7: Opening part, 8, 8 ′, 8 ″: Auxiliary type, 21: Split type, 23: Hole.

Claims (6)

[Claims] 1. A molding die for superplastically forming a superplastic plate material using a gas comprising an upper die and a lower die having a passage for supplying or discharging a gas, wherein the lower die has a front surface to a back surface. A mold for superplastic forming, comprising a split mold having an opening penetrating toward the front and a pressing ring capable of pressing the periphery of the split mold. 2. The superplastic forming die according to claim 1, wherein the split die is provided with a plurality of openings penetrating from the front side to the back side. 3. The superplastic forming die according to claim 1, wherein the opening of the split mold is formed of a predetermined continuous curved surface from the front surface to the back side. 4. An upper mold having a passage for supplying or discharging gas, a lower mold comprising a split mold having an opening penetrating from the front surface to the back surface, and a holding ring capable of pressing the circumference of the split mold. Using a molding die consisting of, sandwiching the superplastic plate material between the upper mold and the lower mold of the molding mold, while supplying gas from the supply passage of the upper mold, the superplastic plate material from the front side of the lower mold. A superplastic forming method characterized in that a superplastic forming product having a diameter larger than the opening diameter is formed by extruding convexly through the opening toward the back side and into the space on the back side of the lower mold. 5. The convex portion of the superplastic plate material formed in a convex shape from the front side to the back side of the lower die is pressed against an auxiliary die placed below the lower die to form a predetermined shape. The superplastic forming method according to claim 4, wherein 6. The superplastic forming method according to claim 5, wherein the auxiliary mold comprises a plurality of divided auxiliary molds.