This article describes the process and advantages of no-bond methods of vacuum molding and magnetic molding, with schematic illustrations. It also discusses the characteristics of plastic film and dimensional specifications of vacuum molding.

No-bake sand molds are based on the curing of inorganic or organic binders with either gaseous catalysts or liquid catalysts. This article reviews the major aspects of no-bake sand bonding in terms of coremaking, molding methods, and sand processing. It discusses the points to be noted in handling sand-resin mixtures for no-bake molds or cones and lists some advantages of no-bake air-set cores and molds. The article describes the process procedures, advantages, and disadvantages of gas curing and air-setting hardening of sodium silicates. It examines the members of the air-setting organic binders, namely, furan no-bake resins, phenolic no-bake resins, and urethanes. The article provides an overview of gas-cured organic binders. It also illustrates the three commercial systems for sand reclamation: wet reclamation systems, dry reclamation systems, and thermal reclamation.

Green sand molding and chemically bonded sand molding are considered to be the most basic and widely used mold-making processes. This article describes the sand system formulation, preparation, mulling, mold fabrication, and handling of green sand molds. It lists the advantages and disadvantages of green sand molding. The article discusses the primary control parameters for the sand system formulation. It describes two basic types of green sand molds: flask molds and flaskless molds. The article provides a discussion on molding problems, including springback and expansion defects. It considers a variety of sand reclamation systems, including wet washing/scrubbing and thermal-calcining/thermal-dry scrubbing combinations.

This article begins with a schematic illustration of basic principles of sand molding. It discusses the general design factors, such as parting lines, location of radii, bosses and undercuts, and rib locations, of sand molding. The article schematically demonstrates alternative design solutions to molding and coring problems and describes the molding sequence. Draft refers to the amount of taper given to the sides of a pattern to enable it to be withdrawn easily from the mold. The article concludes with a simple example demonstrating the influence of a casting requirement on the direction of draft.

Modeling of gas evolution during sand mold castings is one of the most important technical and environmental issues facing the metal casting industry. This article focuses on describing the capability of numerically predicting gas evolution for the furan binder/silica sand system. It illustrates numerical modeling to study the gas evolution from furan binder/silica sand mold aggregate for aluminum, cast iron, and steel alloy cast components. The article discusses simulation results and experimental validation for aluminum alloys, cast iron castings, and steel alloys, as well as a parametric study that investigated the effects of various variables. It concludes with information on the application of 3-D modeling methodology to investigate gas emissions in furan binder/silica sand castings for steel 4140 and aluminum A356 alloys.

This article discusses classification of foundry processes based on the molding medium, such as sand molds, ceramic molds, and metallic molds. Sand molds can be briefly classified into two types: bonded sand molds, and unbonded sand molds. Bonded sand molds include green sand molds, dry sand molds, resin-bonded sand molds, and sodium silicate bonded sand. The article describes the casting processes that use these molds, including the no-bake process, cold box process, hot box process, the CO2 process, lost foam casting process and vacuum molding process. The casting processes that use ceramic molds include investment casting, and plaster casting. Metallic molds are used in permanent mold casting, die casting, semisolid casting, and centrifugal casting.