SAND CASTINGS

Ductile Iron, Gray Iron, Steel, Stainlesss Steel, Aluminum, Brass

CASTING SOURCE Div.- Your Solution to Global Sourcing

Global Out Sourcing of High Quality - Low Cost Castings, in Ductile Iron, Gray Iron, Steel, Stainless Steel, Aluminum & Brass

SAND CASTING PROCESS

In this casting process a pattern is made in the shape of the desired part. This pattern is made out of wood, plastic, or metal. Simple designs can be made in a single piece or solid pattern. More complex designs are made in two parts, called split patterns. A split pattern has a top or upper section, called a cope, and a bottom or lower section called a drag. Both solid and split patterns can have cores inserted to complete the final part shape. Where the cope and drag separates is called the parting line. When making a pattern it is best to tapper the edges so that the pattern can be removed without breaking the mold.

The patterns are then packed in sand with a binder, which helps to harden the sand into a semi-permanent shape. Once the Sand mold is cured, the pattern is removed leaving a hollow space in the sand in the shape of the desired part. The pattern is intentionally made larger than the cast part to allow for shrinkage during cooling. Sand cores can then be inserted in the mold to create holes and improve the casting's net shape. Simple patterns are normally open on top and melted metal poured into them. Two piece molds are clamped together and melted metal is then poured into an opening, called a gate. If necessary, vent holes will be created to allow hot gases to escape during the pour. The pouring temperature of the metal should be a few hundred degrees higher than the melting point to assure good fluidity, thereby avoiding prematurely cooling, which will cause voids and porosity. When the metal cools, the sand mold is removed and the metal part is ready for secondary operations, such as machining & plating. Sand casting is the least expensive of all of the casting processes.

The other main methods of producing castings are Die Castings and Investment Castings.

See Comparison Chart of Casting Methods.

Out Sourcing your Sand Castings with high quality - low cost off shore suppliers can provide you with savings of 20% to 60%. That means improved margins and increased market share.

SAND CASTING PROCESS

Simple Solid Pattern

Shrinkage Metal shrinks as it cools. Therefore, a casting is larger when it is hot than after it cools. When making a die, the diemaker has to make the die slightly larger than the finished casting. The amount of shrinkage depends upon the type of metal being cast, and on the whether the mold will cool quickly or slowly. For small castings, the shrinkage rate is: Iron - 1/8" per foot Steel - 1/4" per foot Aluminum - 5/32" per foot Brass - 3/16" per foot

Typical Split Mold

ADAVANTAGES Least Expensive Casting Process Castings can be up to Severlal Tons Less Expensive than Machining Shapes from Bar Stock Can cast Shapes Can be Used with Most Pourable Metals and Alloys
DISADVANTAGES Can Only Cast Basic Part Shape Castings Require Secondary Machining Rough Surface Finish

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CASTING SOURCE DIV.

Global Out Sourcing of Castings

Die Castings, Investment Castings & Sand Castings in Iron, Steel, Brass, Aluminum