The investment casting process can be traced back to 4000 years B.C and has been used for art casting over the centuries. It is also used extensively for jewellery and dental work. In the late 1930’s net shape cobalt based castings were produced for aircraft turbines. Investment casting markets gradually expanded into the field of commercial castings, and soon the engineering industry used castings produced from a wide range of ferrous, non-ferrous and light alloys. The process is versatile and competes very effectively with other manufacturing processes, often producing a better component at less cost.

Summary of Process Steps:

• Producing a disposable pattern in wax from a die. Dies can be manual for small runs or fully automated for larger runs. (Note: All customer’s dies are stored in a purpose built firesafe room).
• Pattern Assembly - wax patterns are glued to a runner / pouring cup assembly (often called a tree).
• The ceramic Shell Mould - the ‘tree’ is dipped in a high temperature resistant ceramic slurry and coated with ceramic stucco several times to form a shell (i.e. the wax is ‘invested’ with ceramic). When fully coated the mould is de-waxed using steam and then fired at 1050 deg c.
• Casting - molten metal is poured into the hot shell.
• Cleaning - after cooling the mould material is removed. The castings are then cut, dressed and cleaned.

125 kw induction units

We are proud to be an approved supplier to AS/NZS ISO 9001:2000. It is imperative that buyers and investment casters agree on the meaning of quality, specification and acceptance criteria for individual products. Two 125kw induction power supplies are used for melting, with furnaces ranging 15kg to 200kg capacities.

We can melt up to 300kg per hour. Every steel melt is controlled using clean, pre-analysed and graded steel stock. Chemical specifications of alloys are tightly controlled and archived using an ARL Spectrometer before pouring.

Several factors must be considered when selecting an alloy for investment
casting. Often designers have a choice between alloys.

Five areas that should be examined are:

• Environment and intended use of the part
• Mechanical property requirements
• Foundry characteristics of the alloy
• Fabricating and machining characteristics
• Cost factors

We can offer a wide range of alloys in these categories:

• Carbon and low alloy steels
• Hardenable stainless steels.
• Austenitic stainless steels.
• Tool steels.
• Aluminium.
• Copper-base.