We have read and learnt about the different types of metal castings in an iron foundry but this blog talks about the versatile form of casting – Investment Casting. Often known as ‘lost-wax’ casting, this process uses an expendable mould to create well-defined and fine surfaces. The precision and versatility of this process make it the number one choice for well-detailed cast objects. The moulds can be used to achieve the desired shape as it can be carved in wax and can be coated. Sure, this process tends to be a little more on the expensive spectrum but the end products can be complex and smooth as opposed to sand casting.
Common Investment Casting Products
Operational pieces of precision machines are often made via Investment Casting. For example, the fans, camera and other engine parts with complex shapes that need mobility and fine surfaces are made via Investment Casting. It is commonly used for detailed jewellery, vintage and contemporary decor items.
The Investment Casting Process
The basic structure of an Investment Casting Process consists of an expendable pattern of wax mould: a ceramic mould material, and a kiln.
Expendable or Wax Pattern
This wax pattern is an exact replica of the final product one needs. It is filled in with an injection mould made of aluminum or steel. These moulds are usually machined, 3-D printed and hand-carved and owing to this, the process is more expensive than sand casting. Once the injection mold has been created, wax patterns are fast-tracked to allow the cast to solidify.
The second step is to assemble these wax patterns and allow multiple items to be cast together in the tree formation (the casting system). Made from solid wax, tree-like channels are used to carry molten metal to the final product. To ensure efficiency, these structures should be assembled carefully.
Ceramic ‘investment’ mold
On assembling the tree structure, the whole thing is dipped in a ceramic bath and is let to dry, These baths are repeated several times to allow each coat to harden and create a thick mold. The tree is then heated to melt the wax and once removed, the mold is heated to a higher temperature and molten metal is poured inside. This process ceramics dipping and heating is the ‘investment’ of investment casting.
The entire process is let to cool down and once that happens, the ceramic mould is removed to unveil the finished product. Once done, if required, additional finishing or treatment procedures are done.
That is all about investment Casting. Find more about other casting processes and products on www.govindsteel.com. Govind Steel Company Limited is a 55-year-old company that has continually grown to become one of the largest and leading foundries for Grey Iron Castings and Ductile Iron Castings in India, with an installed capacity of 24, 000 MT. Contact Govind Steel today!