At Harrison Castings, we produce over 1,500 tonnes of quality aluminium sand castings every year, manufacturing large quantities of small castings or large aluminium sand castings up to 350kg in weight.
For over 100 years our Leicester based foundry has produced raw and fully machined castings for tier 1 and OEM business in a wide range of industries. Businesses use our services because of our experience and expertise. Our key strengths include:
- We continually invest in our facilities, technologies and staff.
- Our focus is primarily on providing excellent customer service. Our customers use us again and again.
- We can provide full project support from prototype development, pattern making right through to supplying fully machined castings.
What Is Sand Casting?
Sand casting is an efficient metal casting process in which sand is used as the mould material. Over 70% of the world’s metal castings are produced via the sand casting process, and Harrison Castings have the largest sand casting foundry in the UK.
The two most common types of casting processes are Green Sand Casting and the Air Set Casting method. We moved away from the traditional Green Sand moulding method in the early 1990s in favour of Air Set moulding
Why Use Sand Casting Over Other Casting Methods?
Casting in sand is a highly efficient and cost-effective process because up to 80% of the moulding sand we used is reclaimed and reused. This streamlines our manufacturing process whilst greatly reducing the cost and amount of waste produced.
The sheer strength of the moulds created means that a much greater weight of metal can be used, allowing for the casting of complex components that might otherwise have been fabricated from individual parts.
Moulds can be created for a lower initial setup cost compared to aluminium gravity die casting and other casting methods.
The Air Set Moulding process is typically used for larger castings with highly complex geometries. Moulds are comprised of chemically bonded dry sand. This process offers a better and more consistent surface finish over green sand often reducing finishing time to obtain the desired results. The Air Set Moulding process also allows customers with demanding combinations of size and complexity to attain the desired end product in a single casting.
Silica sand is mechanically mixed with binders to produce a hardened sand mould. Our moulding sand is a special blend of thermally reclaimed, mechanically processed and virgin silica sand.
We then follow a multiple step process to produce a two part mould, a top and bottom, termed a Cope and Drag:
- Fill each half moulding box with sand to create the mould.
- Strip or remove the pattern from the two mould halves and put together.
- Fill mould with quality molten metal.
- Allow the metal to cool.
- After metal has solidified and cooled, break the sand away from casting and finish processing the casting.
Advantages of Air Set Moulding
There are many advantages of Air Set Moulding, a process developed to satisfy the ever-increasing demand placed on the foundry industry by casting design engineers and best suited to larger, heavier, and intricate castings. This process provides an excellent as-cast surface finish for those products demanding high aesthetic standards.