Provided is a casting method using lost foam capable of forming a small highly-finished hole with a diameter of 18 mm or less and a length of 50 mm or more by casting. A casting method using lost foam of the present embodiment includes the steps of embedding, in foundry sand, a casting pattern formed by applying a mold wash with a thickness of 1 mm or more to a surface of the foam pattern, the foam pattern having a hole with a diameter of D (mm); replacing the foam pattern with molten metal by pouring the molten metal into the casting pattern and losing the foam pattern; and forming a casting having a small hole with a diameter of 18 mm or less and a length of 50 mm or more by cooling the molten metal, and the method satisfies the following formulas (0) and (1):
2<D19.7Formula (0)
c0.36+140/D.sup.2Formula (1) where c (MPa) is transverse rupture strength (bending strength) of the mold wash that is heated to decompose resin constituting the mold wash and then returned to room temperature.

A method for casting cast parts in which a casting mould is provided. The casting mould is enclosed in a housing, forming a filling space between an inner surface section of the housing and an associated outer surface section of the casting mould. The filling space is then filled with a free-flowing filling material and molten metal is poured in the casting mould. As a consequence binder of the mould material begins to vaporise and combust disintegrating the casting mould. During the filling of the filling space, the filling material has a minimum temperature, starting out from which the temperature of the filling material rises, to beyond a boundary temperature at which the vaporising binder ignites and combusts.

Refractory slurry for use in coating a foam cluster to provide a foam pattern for lost foam casting is provided. The slurry includes a catalyst capable of catalyzing reactions for vaporizing the foam cluster. A foam pattern with a refractory coating including the catalyst and processes for preparing the foam pattern and using the foam pattern are also provided.

A prefabricated sprue assembly provides attachment to independently-produced investment casting molds to substantially reduce the need for pattern material. Installable connections between the prefabricated sprue assembly and the investment mold allow substantial reduction of scrap loss caused by errors in production of individual investment molds by culling defective molds before installation to the sprue assembly.

A method to manufacture reticulated metal foam via a dual investment solid mold, includes pre-investing a precursor with a diluted pre-investment ceramic plaster to encapsulate the precursor; and investing the encapsulated precursor with a ceramic plaster within an mold of a varied cross-section. A varied cross-section mold includes a mold thickness adjacent to an outer periphery of a pattern at a top of the varied cross-section mold is between 200-500% a thickness between the outer periphery of the pattern at a base of the varied cross-section mold. A varied cross-section mold includes a trapezoidal prism shape with a pour cone in a top, the top larger than the base.

A method for evaporative casting includes the steps of: using three-dimensional (3D) printing to print only a hollow shell in 3D of a full-sized target part according to an algorithm, forming a hardened coating of ceramic mold over an entire exterior surface of the 3D printed hollow shell, forming a pre-cast assembly by connecting the hardened ceramic mold to an end of a conduit, burying completely the pre-cast assembly under compacted sand or ceramic beads while an inlet to the conduit is kept free and open at an upright position to receive a selected cast material in a molten state, the selected cast material in molten state evaporating the 3D hollow shell to completely fill up an entire volume enclosed by an inner surface of the hardened ceramic mold, and cooling to solidify the selected cast material inside the pre-cast assembly to yield the at least one full-sized target part.

A process for casting castings in which a casting mold is provided, the casting mold is enclosed in a housing, forming a filling space between at least one inner surface section of the housing and an associated outer surface section of the casting mold, the filling space is filled with a pourable filling material having a bulk density that allows gas to flow through the filling material after the filling of the filling space, and a metal melt is poured into the casting mold. The casting mold radiates heat as a result of the heat input caused by the metal melt, and as a result of the heat input caused by the metal melt, the binder begins to evaporate and burn, no longer binding the molding material, and the casting mold disintegrates into fragments. The filling material has a temperature of less than 100 C. when filled into the filling space.

Methods for forming metal articles are provided. The methods include forming foam casting molds from polylactic acid for use in lost foam and sand casting processes. The PLA-based foam casting molds advantageously reduce cycle time, reduce overall cost, increase reusability of the foam casting molds, reduce costs associated with shipping the foam casting mold, and improve yield and quality of cast metal articles.

Methods for creating partially reusable casting molds and/or multiple copies of a part using the same, along with related systems, molds, and parts, are disclosed. Reusable outer shells and sacrificial inserts for placement inside the reusable outer shells are generated by way of additive manufacturing. The sacrificial inserts and reusable outer shells are assembled into a mold such that the sacrificial inserts are placed within the reusable outer shells and define an internal cavity for the past to be casted. Casting material is poured into the internal cavity to cast the part such that a portion of the sacrificial inserts are sacrificed. The part is excavated, including removing the reusable outer shells for reuse and remaining portions of the sacrificial inserts for disposal.