From Concept to Casting
STEP ONE : THE IDEA
At the start of every great casting is your idea. We work alongside designers, sculptors, scientists, prop makers and many more to bring these ideas to life.
Our facilities allow us to produce sand castings for a diverse range of industries all over the world.
We specialise in:
STEP TWO : THE PATTERN
The key to producing good quality castings starts with the development of a design which is suitable for pattern making, moulding, and casting. As every casting is different, serving a difference purpose and in different materials, this can be a challenging process. We work with highly skilled patternmakers who produce a wide range of tooling for the foundry industry. Or alternatively we can work with a pattern that you have had designed yourself. We assist our customers through the whole process from concept, design and sample stage to the finished production. Patterns can be modified, adapted and repaired on site giving you a fast and reliable turnaround.
STEP THREE : SANDCASTING
This is where the true alchemy begins!
The pattern is placed into a wooden moulding box ready to be filled with sand. The sand is mixed with a hardening agent and forms a solid mould around the pattern. A typical moulding box has a top, known as the cope, and a bottom known as the drag. The now hardened sand moulds are then removed by machine or hand from their wooden boxes and joined together to form a closed casting cavity.
If apertures are required within a casting, sand cores are manufactured separately using a core box manufactured out of resin (or metal for shell cores). Cores are inserted into the sand mould after the removal of the wooden moulding box but before the cope and drag are assembled. Cores are located in the sand mould by the use of core prints.
To enable the molten metal to travel to the casting cavity, a running system is designed and incorporated into the pattern, which is then replicated in the sand mould. Molten metal enters the sand mould through a dypur or down sprue, and passes through a filter before entering the cavity. The molten metal then fills the cavity and the risers assist in feeding the metal during pouring.
This is the most critical element of the casting process - the pour refers to the gravity feed of molten metal into the sand mould. Traditionally poured by hand using ladles the molten metal must enter the sand mould at the correct pouring temperature in order to reach all parts of the cavity. Flow is regulated by the filter, which also acts to remove any impurities that might compromise the finished casting integrity. To allow for shrinkage during cooling a reservoir of molten metal is provided by the risers which is part of the built in running system. Test bars and dabs are produced during pouring for internal analysis to check on the metal composition for material certification.
STEP THREE : FINISHING
Once cooled the casting is released from its sand mould and shot-blasted to prove its surface integrity before being linished and fettled. Linishing and fettling are the first stages in any aluminium sand casting and gravity-die casting finishing process. Fettling involves the removal of the risers and any excess material while linishing involves grinding or sanding the component to improve the surface flatness. These techniques can be carried out using manual cutting, grinding or automated tools.