Claims
- 1. A superplastic forming system comprising:
- a free standing generally block-shaped ceramic monolithic die base having a bottom surface on which said die rests, and a top surface, opposite to said bottom surface, in which a forming cavity is formed and which is surrounded by a contact surface, said forming cavity having a shape like the desired shape of sheet metal parts to be formed by superplastic forming in said die;
- a die lid having a horizontal cross sectional shape and size approximately equal to said die base, and having a contact surface corresponding in size and contour to said die base contact surface, whereby said lid is placed on said base with said contact surfaces aligning and in contact;
- said die base being formed of a ceramic material that provides sufficient compressive strength to resist a compressive load exerted by a press to hold said lid on said die against oppositely directed force generated by gas at superplastic forming pressures within said die, and provides sufficient tensile strength, when in pressure of compressive loads exerted by said press to resist internal bursting forces exerted by gas at superplastic forming pressures within said die.
- a compressive assembly having upper and lower platens with substantially parallel upper an lower platen faces for applying compressive force to a die therebetween, a force generating assembly for applying a force on said platens to force said platens toward each other, and a separating means for separating said upper and lower surfaces sufficiently to locate said die therebetween;
- attaching hardware for attaching said die to said compressive assembly;
- a source for pressurized gas; and
- a gas conduit connecting said pressurized gas source to said die cavity.
- 2. A superplastic forming system as defined in claim 1, wherein:
- said ceramic material has a flexural strength of at least approximately 500 psi, a compressive strength of at least approximately 2000 psi, a coefficient of thermal expansion of no greater than approximately 0.70.times.10.sup..sup.31 6 in/in/.degree. F., and a maximum operating temperature of at least approximately 2000.degree. F.
- 3. A superplastic forming system as defined in claim 1 wherein:
- said conduit is formed having a plurality of discrete angular bends normal to said conduit's primary axis, said conduit having a coefficient of thermal expansion, and said ceramic also having a coefficient of thermal expansion, said coefficient for ceramic being substantially'smaller than said coefficient for said conduit;
- said conduit being embedded in said ceramic material, said superplastic forming including substantially elevating said die temperature, said die and said embedded conduit being heated during said superplastic forming process;
- said heat causing said conduit to expand at a rate different from said ceramic, said differential expansion causing said conduit to apply sealing force to said ceramic at said discrete angular bends.
- 4. A superplastic forming system as defined in claim 3 wherein:
- said plurality of discrete angular bends normal to said conduit's primary axis generally comprising an `S` shape.
- 5. A superplastic forming system as defined in claim 1 wherein:
- said die base has sides which taper from said base top surface outward to said base bottom surface at a taper angle exceeding two degrees.
- 6. A superplastic forming system as defined in claim 5 wherein:
- said taper angle is approximately five degrees.
- 7. A superplastic forming system as defined in claim 1 further comprising:
- a cavity in said lower external surface of said die, said cavity being a blow-out cavity;
- said blow-out cavity being located approximately under said forming cavity, said blow-out cavity having a depth into said die of at least approximately two inches, and a surface area on said die's lower external surface of between fifteen and one hundred square inches;
- said die having a material thickness between said blow-out cavity and said forming cavity of between approximately four inches and two inches;
- said blow-out cavity having a plurality generally cylindrical holes extending from said blow-out cavity to said die's exterior side, said holes being vent ports.
Parent Case Info
This is a division of U.S. application Ser. No. 08/130,545 filed on Oct. 1, 1993, now U.S. Pat. No. 5,467,626, and entitled "Integral Forming Die System and Method for Superplastic Metal Forming".
US Referenced Citations (10)
Divisions (1)
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Number |
Date |
Country |
Parent |
130545 |
Oct 1993 |
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