About Investment Casting
Also known as “lost-wax castings”, investment castings are made from a variety of materials. The steps to create a product from this method are as follows:
1) Create a master pattern from wax, plastic, wood, etc.
2) From the master pattern, a master mould is created.
3) A wax pattern is created from the mould and assembled into as many clusters as desired, each connected to the other by a sprue.
4) Investment material is then applied to surround the wax and is hardened. This investment material can be made of aluminum, stainless steel alloys, brass, or ceramic. 5) Once the investment material is hardened, the wax pattern is melted out in a process called “Dewaxing”.
6) The mould is preheated to prevent deformities from molten metal cooling upon contact.
7) Molten metal is poured into the mould and allowed to harden.
8) The mould is removed in a process called “divesting”. This is where the saying “breaking the mould” comes from!
The Federal Group’s Investment Casting Capabilities
The Federal Group has wax processing equipment that recycles used wax. Our shell making equipment and a semi-automatic wax injection machine allow for rapid pattern fabrication. Our dewaxing machine thoroughly and quickly melts the pattern so the initial expansion of the heated wax doesn’t crack the investment. When pouring the molten metal into the mould we can use our specialized equipment to reduce product defects from the presence of air bubbles:
- Horizontal Vacuum Precision Investment Casting Furnace
- Vertical Vacuum Precision Investment Casting Furnace
- High-pressure Gas Quenching Vacuum Furnace
We can work with the following materials and more:
- Stainless Steel, Duplex 2507: A super duplex stainless steel with 25% chromium, 4% molybdenum, and 7% nickel alloy. Designed for applications which require exceptional strength and corrosion resistance.
- Stainless Steel, Duplex 2205: A two-phase, ferritic, austenitic 22% chromium, 3% molybdenum, 5 to 6% nickel alloy. It is the most widely used duplex stainless steel grade and is characterized by high yield strengths. It has good fatigue strength and demonstrates outstanding resistance to stress corrosion cracking, crevice, pitting, erosion, and general corrosion in severe environments.
- Grey, Ductile, and White Iron: Used for a variety of purposes for ease of machinability, ductility, or compressive strength
- Aluminum: Investment casting of aluminum enables the casting of complex-geometry parts with shorter lead times, greater alloy flexibility, tighter dimensional tolerances and better surface finishes. The result requires less machining and processing.
- Brass/Bronze: Offers excellent machinability, corrosion resistance, and aesthetics.
The end result of investment casting yields highly intricate and accurate parts with tight tolerances to be used in aerospace, marine, and automobile manufacturing and beyond.