Method of making a mold
AssigneePCC Airfoils, Inc.
InventorsDaniel P. Carson, Francis E. Cozza
Life of this patent
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Abstract
Both a pattern member and a body of expansion material are covered with a layer of ceramic mold material. The body of expansion material has a coefficient of thermal expansion which is greater than the coefficient of thermal expansion of the ceramic mold material. The layer of ceramic mold material and the body of expansion material are heated. This results in a cracking of the layer of ceramic mold material by the body of expansion material due to greater thermal expansion of the body of expansion material as it is heated. During the step of heating the ceramic mold material and body of expansion material, the pattern member is melted to separate the pattern from the layer of ceramic mold material.
Claims24
A method of making a ceramic mold, said method comprising the steps of providing a pattern, providing a body of expansion material which has a greater coefficient of thermal expansion than the ceramic material of the mold, covering the pattern and body of expansion material with a layer of ceramic mold material, heating the layer of ceramic mold material and body of expansion material, and cracking the layer of ceramic mold material during performance of said step of heating the ceramic mold material and body of expansion material by thermally expanding the body of expansion material to a greater extent than the layer of ceramic mold material.
A method of making a ceramic mold assembly having a plurality of mold sections, said method comprising the steps of providing a first pattern section having a configuration corresponding to the configuration of one of the mold sections, providing a second pattern section having a configuration corresponding to the configuration of another mold section, providing a plurality of bodies of expansion material having a coefficient of thermal expansion which is greater than the coefficient of thermal expansion of the ceramic material of the mold, interconnecting the first and second pattern sections with the bodies of expansion material disposed between the first and second pattern sections at a plurality of spaced apart locations to thereby form a pattern assembly, covering the pattern assembly with a layer of ceramic mold material which extends between and overlies the first and second pattern sections at the plurality of spaced apart locations where the bodies of expansion material are disposed between the first and second pattern sections, disconnecting the portion of the layer of ceramic mold material overlying the first pattern section from the portion of the layer of ceramic mold material overlying the second pattern section at the plurality of spaced apart locations where the bodies of expansion material are disposed to thereby form separate mold sections, said step of disconnecting the portion of the layer of ceramic mold material overlying the first pattern section from the portion of the layer of ceramic mold material overlying the second pattern section includes the steps of heating the bodies of expansion material and the layer of ceramic mold material and thermally expanding the bodies of expansion material to a greater extent than the layer of ceramic mold material, and, thereafter, interconnecting the mold sections at a plurality of joints disposed at locations corresponding to the locations of the bodies of expansion material during said step of heating the pattern assembly.
A method of forming a mold having a central opening and a baffle plate, said method comprising the steps of providing a mold pattern having a configuration corresponding to the configuration of the mold, providing a pattern plate having a major side surface with a ring of expansion material projecting from the major side surface of the pattern plate, connecting the mold pattern with the major side surface of the pattern plate with the ring of expansion material aligned with a central opening in the mold pattern, covering the major side surface of the pattern plate and the mold pattern with a layer of ceramic mold material having a coefficient of thermal expansion which is less than the coeffient of thermal expansion of the ring of expansion material, heating the layer of ceramic mold material and the ring of expansion material, and disconnecting the portion of the layer of ceramic mold material within the ring of expansion material from the portion of the layer of ceramic mold material outside of the ring of expansion material during performance of said step of heating the layer of ceramic mold material and the ring of expansion material.
A method of making a ceramic mold, said method comprising the steps of providing a pattern, providing a body of expansion material which has a greater coefficient of thermal expansion than the ceramic material of the mold, covering the pattern and body of expansion material with a layer of ceramic mold material, heating the layer of ceramic mold material and body of expansion material, cracking the layer of ceramic mold material during performance of said step of heating the ceramic mold material and body of expansion material by thermally expanding the body of expansion material to a greater extent than the layer of ceramic mold material, said step of cracking the layer of ceramic mold material including forming a crack which divides the ceramic mold material into first and second sections, separating the first section of ceramic mold material from the second section of ceramic mold material, and, thereafter, interconnecting the first and second sections of ceramic mold material to at least partially assemble a mold.
A method of making a ceramic mold assembly, said method comprising the steps of providing a first pattern section having a first configuration, providing a second pattern section having a second configuration, providing a body of expansion material having a coefficient of thermal expansion which is greater than the coefficient of thermal expansion of the ceramic material of the mold, interconnecting the first and second pattern sections with the body of expansion material disposed between the first and second pattern sections to thereby form a pattern assembly, covering the pattern assembly with a layer of ceramic mold material which overlies the first and second pattern sections, heating the pattern assembly and the layer of ceramic mold material, thermally expanding the body of expansion material to a greater extent than the layer of ceramic mold material, cracking the layer of ceramic mold material during performance of said step of thermally expanding the body of expansion material to divide the ceramic mold material into first and second mold sections, separating the first mold section from the second mold section, and, thereafter, interconnecting the first and second mold sections at a joint disposed at a location corresponding to the location of the body of expansion of material during said step of heating the pattern assembly.
Dependencies are inferred from the claim text.