Investment casting, also known as lost wax casting, is a traditional process and goes back thousands of years; dating back to when beeswax were used for casting patterns. It was originally used to produce ornaments and jewellery for idols and royalty. Examples of ancient investment castings have been found all over the world; containing elements of copper, bronze and gold. It is a versatile process, typically consisting of steel, stainless steel and aluminium alloys, and is still widely used to manufacture a broad range of parts, such as golf club heads and water taps.
Majorfax’s investment casting process is split into the following steps:
- Forming the Pattern and Gating System: The first step is to create the casting pattern. This is achieved by injecting molten wax into a die. Several of these wax patterns are then attached to a gating system, resembling a tree-like feature. This gating system will be used to transfer the molten metal into the moulds for casting.
- Mould Creation: The tree is then dipped into a ceramic slurry and is then left to dry. This process is repeated several times until the desired thickness is achieved. Once the ceramic coating has dried, it will then be able to retain the molten metal for casting.
- Pouring the Molten Metal: Once the mould has been formed, molten metal is poured into the mould cavities. Pouring is generally achieved using the force of gravity, but other methods can be used; such as making use of pressure and vacuum.
- Solidification and mould removal: The molten metal is now left to solidify to form the casting and the mould shell is then separating from the casting. Separation is achieved via the use of water-jets, hammering, or dissolving the shell to release the casting.
- Finishing: Once formed, the casting may undergo grinding, sandblasiting or machining to allow for a smooth surface finish. To complement its investment casting service, Majorfax offer a range of surface finishing and painting options to suit your finishing and budgetary requirements. To find out more about this, please click here: https://www.majorfax.co.uk/services/finishing/.
A key benefit with investment casting is the freedom of design. The expendability, coupled with the versatility and convenience when forming and separating the wax and mould, allows for complex designs to be cast. This also allows for reduced machining costs, whilst maintaining high dimensional accuracy with a high quality, smooth surface finish.