Abstract: An improved method incorporating investment burn out at a predetermined ideal temperature. The investment encasing the wax-like model of the desired casting is placed in an oven preheated to an ideal burn out temperature. The oven is maintained at that temperature while the pressure in the oven is increased to a predetermined pressure and maintained at that pressure for a given time. Following that time, the pressure is cycled between the predetermined pressure and atmospheric pressure or below for a second predetermined time.

Abstract: A ceramic molding composition comprising an alcoholate of aluminum or a metal of the fourth sub-group of the Periodic System, a refractory metal oxide and a polyvalent alcohol, an improvement in the formation of a ceramic product wherein a ceramic molding composition is shaped and hardened, which improvement resides in employing the above defined ceramic molding composition.

Abstract: The present invention provides an improved method of forming a metal article having a plurality of airfoils which extend outwardly from a hub. The metal airfoils are formed separately from the hub. In forming a mold to cast the article, blade portions of the metal airfoils are coated with wax. The metal airfoils are then placed in a circular array and are covered with a coating of liquid ceramic mold material. This wet coating of ceramic mold material is dried to form an annular mold wall section having a plurality of recesses in which the blades of the metal airfoils are disposed. The wax coating over the metal airfoil blades is subsequently removed from the recesses to provide space between the blades and the side walls of the recesses. The annular mold wall section in which the blade containing recesses are formed is then connected with top and bottom mold sections to further define a mold cavity having a configuration corresponding to the hub portion of the article.

Abstract: Method and apparatus for preparing a wax replica of a dental prosthesis is disclosed. The method of the invention is carried out by preparing a composite dental model which includes a base portion, an odontal die projecting from the base portion having a cavity in which the dental prosthesis is to be implanted, and an index pin embedded within the composite dental model. A complementary dental model having an odontal projection defining an occlusal surface for engaging the odontal die is also prepared. The index pin includes an anchor shank portion embedded within the odontal die, an alignment shank portion embedded in the base portion and a radially projecting collar portion disposed in the interface of the base portion and the odontal die. The odontal die and embedded index pin are removed from the base portion of the composite dental model and a die spacer is placed around the alignment shank portion of the index pin.

Abstract: A ceramic molding composition comprising an alcoholate of aluminum or a metal of the fourth sub-group of the Periodic System, a refractory metal oxide and an agent selected from the group consisting of diketones of the formula ##STR1## wherein R.sub.1 and R.sub.2 are each independently an aliphatic radical of between C.sub.1 and C.sub.18 carbon atoms or an aromatic radical from C.sub.6 to C.sub.18 carbon atoms, a hydroxycarboxylic acid compound of the formula ##STR2## wherein R.sub.3 is an aliphatic radical of C.sub.1 and C.sub.18 or an aromatic radical from C.sub.6 to C.sub.18, and R.sub.4 is hydrogen or an alkyl radical of C.sub.1 to C.sub.4, and a polyvalent alcohol, an improvement in the formation of a ceramic product wherein a ceramic molding composition is shaped and hardened, which improvement resides in employing the above defined ceramic molding composition.

Abstract: A method of manufacturing a mold adapted to be used for casting bodies of ber-reinforced composites. A model of the body to be cast is prepared and coated with a one piece dense shell of refractory metallic oxide deposited by plasma or flame spraying and the model is then separated from the shell by conventional physical or chemical treatment.

Abstract: An improved mold for casting single crystal metallic articles is disclosed and comprises a ceramic investment mold having a main article cavity and having embedded at its lower end below the article cavity and in communication therewith a preformed ceramic single crystal starter insert. The preformed starter insert generates a plurality of single metallic crystals in a growth cavity and then selects one crystal for further propagation through the article cavity. A method for making such a mold is also disclosed.

Abstract: Disclosed is an improved method for making molds and mold components for use in casting single crystal articles. According to the improved method, a preformed and reusable replica of a mold growth cavity and crystal selector passage is provided, the replica including a cylinder in the form of the desired growth cavity and a helical strand in the form of the desired crystal selector passage, one end of the strand being attached to an end of the cylinder such that their axes are coincident. In one embodiment, the replica is coated with a thin layer of wax or other removable material and then utilized in a variety of mold making processes, including investment molding, to form a growth zone and helical crystal selector in the mold.

Abstract: A pattern assembly for use in the lost pattern process of investment casting characterized by a center tree or sprue member including a central stem and a plurality of laterally projecting collars spaced apart along the stem and united therewith to provide the surface area for gating the patterns, the cross-sectional size of the stem being greater than the projecting width of the collar, whereby the stem serves to form a riser.

Abstract: The present invention provides means for the improved positioning of a strongback in a pattern mold for formation of expendable patterns thereon. Investment casting molds formed around the assembly of strongback and patterns are characterized as having the strongback precisely and reproducibly suspended therein. Articles, such as turbine blade halves, cast in such investment molds have mating surfaces in close dimensional relationship and can be bonded one to any mating other to form a finished product.In particular, a strongback having bonding locators near the opposite ends thereof is provided with additional locators to be used in suspending the strongback in the pattern mold. According to the invention, these pattern mold locators are colinear with and in close proximity to the bonding locators and are engaged by locating means in the pattern mold for establishing precise positioning of the strongback therein.

Abstract: The present invention provides a method for improved positioning of a strongback in a pattern mold for formation of expendable patterns thereon. Investment casting molds formed around the assembly of strongback and patterns are characterized as having the strongback precisely and reproducibly suspended therein. Articles, such as turbine blade halves, cast in such investment molds have mating surfaces in close dimensional relationship and can be bonded one to any mating other to form a finished product.In particular, improved positioning of the strongback in the pattern mold is achieved by suspending the strongback from the bonding locators by expendable locating means; that is, locating means which are incorporated into the patterns formed on the strongback surfaces. The use of expendable locating means enables the bonding locators to also serve as locators for positioning the strongback in the pattern mold and essentially eliminates errors in strongback positioning due to tolerances associated therewith.

Abstract: An improved investment casting process for producing dental restorations, particularly a dental crown, comprising the steps of fixing a wax pattern onto a truncated cone in a metallic ring having a lining of a cushioning material, pouring an investment material into the space around the wax pattern in the metallic ring, drying the resultant product, melting out the invested wax pattern, curing the resultant product at a temperature of 700.degree. to 950.degree. C for 20 to 150 minutes to give a mold, fixing the mold thus obtained to a centrifugal casting machine and casting a molten chromium-cobalt and/or nickel alloy in the mold maintained at a temperature of 100.degree. to 500.degree. C.

Abstract: A precision investment casting ceramic mold of the self-casting type is made as a unitary mold by providing separately a pattern for a wax charge-holding assembly and a pattern for a wax article casting assembly, each including an alignment portion. The two patterns are secured together at the alignment portions and are supported and located one with respect to the other by a plurality of supporting and locating members. The assembled patterns then are used in the conventional manner to make a ceramic casting mold.

Abstract: An investment casting method for making a desired casting of a relatively large size by the use of a mold of one-piece construction within close dimensions, which comprises preparing a thermally fusible pattern which is a replica of the desired casting, forming a refractory investment enveloping the thermally fusible pattern, melting the thermally fusible pattern out of the investment leaving a cavity in the refractory investment, and heating the investment to provide a rigid ceramic mold of one-piece construction. Melting of the thermally fusible pattern out of the investment is carried out in contact with a vaporized organic solvent without causing the thermally fusible pattern to thermally expand which may otherwise result in formation of cracks in the refractory, investment, that is, mold.

Abstract: A method of molding finger rings of the type having a hollowed-out interior portion, but whose exterior surfaces are identical to rings without such hollowed-out portion comprising securing a wax, shell ring pattern to the exterior surface of a wax, tubular section to form a wax ring pattern and molding a finger ring from said wax ring pattern via an investment method of casting.