Castings that are produced by utilising the lost wax and ceramic dipping processes are known as investment castings due to the process of "investing" or dipping in a slurry. Correctly designed, investment castings provide excellent strength to weight ratios.

Repetitive dimensional accuracy makes it possible to minimize or even eliminate machining operations completely.

RelyIntraCast implemented the lost wax process to produce investment castings in 1972. A significant ongoing investment in people and equipment includes a robotic dipping line and state-of-the-art spectrometer. The company is believed to be the only investment foundry in South Africa that uses robotics, which ensure uniform quality and consistency of the product.

The company is able to economically produce both small and large batches. This gives engineers and designers both flexibility and the assurance that every casting will meet design specifications with tolerances as tight as 0,125mm over 25mm.

Investment casting is the ideal process:

• where close casting tolerances are required (approx. 0,125mm per 25mm)
• where intricate or complex shapes reduce or preclude machining
• where superior finishes are required – for example, carbon steel finishes are generally about 36 micrometers, compared to machine cut finishes of about 24 micrometers
• where subsequent machining should be minimised due to expensive or difficult to machine alloys
• where changes in material specification could be required (prototyping or sampling)
• where good strength to weight ratios are required (thin sections can be cast in light alloys)
• where repeat orders or batch delivery is a requirement - thanks to low tooling costs and an almost indefinite life for wax injection dies - RelyIntraCast can deliver repeat orders within short lead times.

How is it done

1. A pattern die is designed and manufactured from drawings or samples supplied by the customer. RelyIntraCast's in-depth knowledge of alloys, casting processes and application of the final component ensures optimal strength, design quality and material use.
2. Dies are manufactured using precision CAD/CAM tooling and machinery to ensure quality and minimise (or preferably eliminate) split lines in the actual dies.
3. Liquid wax is injected into the metal die to produce a high-definition wax pattern. RelyIntraCast makes use of state-of-the-art wax paste technology which provides wax patterns of exceptional dimensional accuracy.
4. After the wax has solidified, the component is removed from the die. Sets of the wax are assembled in a “tree”, which is then coated (or invested) with layers of ceramic. A number of layers are applied until the shell is thick enough to withstand the rigors of molten metal being poured into it. 
5. The completed mould is placed in a pressure vessel, and the wax steamed out to create a hollow ceramic mould ready for firing. The firing of moulds develops its strength and removes residual wax.
6. The selected alloy is melted in electric coreless induction furnaces and gravity poured into the investment mould. RelyIntraCast's 13 furnaces have capacities from 25 - 500kgs.
7. After the casting has solidified, the ceramic mould is removed. After the individual castings have been cut from the tree, stubs are removed using abrasives, and the castings heat treated to enhance mechanical properties, or to homogenize the casting.

Metallurgical control and analysis by qualified and experienced technical staff, working in superb laboratory facilities maintain the company's reputation for consistent quality and its ISO 9001:2000 accreditation.