What is Investment Casting Process？

The investment casting process, also known as lost wax casting, dates back nearly 5,100 years to ancient societies that cast everything from small pieces of jewelry to large statues in paraffin wax. In the 20th century, paraffin wax has been replaced by a more modern polymer in which the wax maintains a good surface finish and excellent dimensional stability.

Although the process itself is more costly per unit than other manufacturing processes, it can produce alloy parts that cannot be made by other methods. It can also produce complex shapes that would be difficult or impossible to achieve with die casting, however, as with die casting, it requires little surface preparation and only a small amount of mechanical machining.

The advantages of investment casting.

• It allows parts that cannot be machined to be cast into shapes close to their net weight
• It is ideal for small production runs
• It offers excellent dimensional accuracy
• It can be used to cast complex shapes with undercuts
• It allows for smooth surfaces without parting lines
• It has low mold set-up costs and facilitates the pre-production of high-volume die-cast products

Investment casting process

Mold-making process: The CAD designer creates a 3D model of the mold from the CAD data.
Wax-making process: the wax pattern is created using a thermosetting wax injection molding machine with tools.
Wax pattern assembly process: the resulting sacrificial wax ‘pattern’ is attached to a ‘tree’ (essentially a central wax pattern).
Shell-making process: The wax assembly is coated with a liquid ceramic paste and then a dry layer of ceramic particles (mortar) is attached under environmentally controlled conditions, this process is repeated until the investment reaches the required thickness.
Dewaxing process: the ceramic shell is finally dried and then steam dewaxed to remove the wax.
Shell firing: the dewaxed ceramic shell is fired at high temperatures to sinter and improve the mechanical strength.
Casting process: molten metal (a range of metals including stainless steel, brass, aluminum, and carbon steel can be used in this process) is injected into the shell using a variety of techniques.
Deshelling: Once cooled, the ceramic shell is mechanically removed to reveal the cast metal mold beneath.
Finishing process: the metal casting is removed from the assembly by various cutting or plasma techniques and once removed, the individual castings can be machined individually.
Surface Finishing: The metal casting can be mirrored polished or brushed, surface blasted, surface painted, etc. using various abrasive belts or other equipment tools.
Inspection process: Once completed, the castings are inspected using various spectral analysis equipment and metrology techniques to determine compliance with drawing limits and specifications.

Vastcast uses the investment casting process to manufacture a wide range of products and components. The benefits of this process include the accuracy of design, the integrity of the casting, versatility of production, and low-cost repeat runs.
At vastcast, we can provide a complete solution to your casting needs.