WAX 3D PRINTING FOR INVESTMENT CASTING

Investment casting: is a process used for manufacturing intricate metal components using high melting point materials like steel, Nickel and cobalt based alloys.

The process:

Investment casting is a tool-based manufacturing process in which the component to be produced will be initially molded using wax material and multiple such patterns will be joined together to form a tree. The tree is then dipped in a ceramic slurry to evenly coat the pattern, and the wax portion is removed in a subsequent process eventually leaving behind a cavity made of ceramic onto which the molten metal can be poured. The process flow is explained as below:

Investment Casting process flow

How can wax 3D printing be used in Investment casting?

Wax 3D printing comes in handy in instances where the parts are still in the virtual world and the designs are not finalized, but the client wants to have physical samples to test for functionality and durability of the component in the real-world scenario. During this stage the designs can be tweaked multiple times, allowing clients to test the component for different design iteration. Once the designs are finalized the process of manufacturing the tool can be initiated, allowing for an overall reduction in lead time during the process. The process flow for casting through wax 3D printing is as shown on the right. Once the Wax patterns are 3D printed the remaining processes will remain similar to the conventional investment casting process.

Wax 3D

How wax 3D printed component compares with molded component?

  • Dimension tolerance: The final castings manufactured through wax 3D printing route follow the dimensional tolernaces as per VDG P690 D2 standard which is the same standard applicable for castings manufactured through the conventional wax molding route which enables for actual usecase of the parts during the prototype stage.
  • Comparison of surface finish of the final casting:
  • Wax molding – 2.8~3.2 microns Ra
  • Wax 3D printing – 4.5~5 microns Ra

Printer specification:

  • Make and model: 3D Systems Projet MJP 2500 IC
  • Build box size(xyz): 294 x 211 x 144 mm
  • Resolution (xyz): 600 x 600 x 600 DPI
  • Print layer thickness: 42 µm

Raw material Specification: 

  1. Material- unfilled paraffin based wax with added resins
  2. Melting point: 61-66 °C
  3. This material emulates the melt and burn-out characteristics of standard casting waxes
Wax 3D Printing Machine

      ProJet MJP 2500 IC

Perks of Wax 3D printing:

  • Speed and efficiency: It allows for rapid prototyping of wax patterns in minimal lead time.
  • Cost effectiveness: Multiple design iterations and refinement is possible with wax 3D printing before the finalization of mass production mold enabling for cost benefits during the development stage.
  • Complex internal features: Complex internal features that requires use of ceramic cores for manufacturing using the mold can be directly formed in this process.
  • Multiple prototypes at once: Prototypes of multiple small components can be printed in a single build box enabling for faster prototype development time for clients.