Aluminum Sand Casting Step by Step

In aluminum sand casting, molten alloy is poured into a mold made of molding sand packed around a casting pattern. After the metal solidifies, the mold is broken up and the casting is cleaned and finished. Each mold is used only once, but the pattern can be reused many times.

Sand Casting Step by Step

1. Pattern and Core Boxes – the pattern reproduces the shape of the casting, enlarged to allow for metal shrinkage and machining allowances, with draft on the walls. It usually consists of two parts – cope and drag. Core boxes are used to make the cores.
2. Molding – the pattern is placed in molding flasks, and molding sand is fed in and compacted around it. Once the pattern is removed, a cavity remains in the sand.
3. Cores – made of core sand, they form the holes and internal shapes of the casting; in the mold they are seated in core prints.
4. Gating System and Risers – channels deliver the metal to the cavity, and risers feed the casting during solidification.
5. Mold Assembly – the mold halves are joined and secured against separating under the pressure of the metal.
6. Pouring – refined aluminum alloy at a controlled temperature is poured smoothly, without turbulence.
7. Shakeout – once solidified and cooled, the casting is removed from the broken-up mold.
8. Cleaning and Finishing – cutting off the gating system and risers, removing residual sand, grinding, inspection and, where needed, CNC machining, heat treatment and painting.

Molding sands

Molding sand is silica sand with a binder. Self-hardening sands set at ambient temperature after a hardener is added, while heat-hardening sands set when heated. A well-chosen and properly compacted sand gives a smoother casting surface and more accurate dimensions.

Sand Casting at Our Foundry

We cast aluminum parts in sand molds weighing from 1 to 100 kg, in flasks up to 1000 mm. We make patterns and core boxes in our own pattern shop, and the molding shop has a modern sand mixing system as well as automatic dosing and compaction. We use both self-hardening and heat-hardening sands.

See also: sand castings – parameters and applications, most common mistakes in sand casting i sand casting – our offer.