Sand Mold Casting

Sand mould casting is widely used in industry to make from small items to large items and from very simple items to complex items. Sand casting is used for both ferrous and non-ferrous materials. Sand is used to make molds and a small amount of clay and water is added to improve bonding grains and cohesion and mold-ability.  Mold is usually made in two pieces.

Figure 1: Sand Mold Casting

Pattern

The required shape on the top and bottom halves of a sand casting mould is prepared by patterns. Patterns approximately duplicate the casting shape. A pattern provides the required shape of the product and sand is packed around the pattern. When removing the pattern, the mould cavity can be shown to pour liquid materials.

Core

The core is used to place into a mould cavity to form the interior surface or features of the castings.

Flask

This is used as a frame to hold the moulding material. This is a rigid wood or metal frame.

Cope

This is the top half of the mould or core of a two-part mould, flask and pattern.

Drag

This is the bottom half of the mould or core of a two-part mould, flask and pattern.

Mold Cavity

This is the cavity of the desired shape to be cast.

Riser

The riser is also used as a reservoir of liquid material. Liquid material in the riser flows into the mould cavity to compensate for any shrinkages.

Gating system

A gating system is used to deliver the molten material to the cavity. A gating system is a network of connected channels.

Vent

This is an additional channel to remove gasses which are in the cavity or generated during the pour.

Parting line

The parting line is the interface between the cope and drags halves of the mould, core or pattern.

Sprue

The vertical portion of the gating system.

Choke

This is the cavity which is located at the base of the sprue. This allows to flow of liquid material smoothly into the casting cavity.

Runners

Horizontal channels are called runners.

Pouring Basin

The top of the sprue is made large. This is called pouring basing to ease the pouring of liquid material without spilling.

After solidifying the liquid material, if the mould is broken remove the cast item. Therefore, a new mould is needed for each casting. Therefore, sand casting is an Expendable casting process.