Инвестиционное литье и 3D-печать

Investment Casting (The “Lost Wax” Process)

A traditional, subtractive-then-casting process for creating high-precision metal parts.

How it works:

• Pattern Creation: A wax or thermoplastic pattern of the part is made (often by injection molding).
• Assembly: Multiple patterns are attached to a central wax “tree.”
• Shell Building: The tree is repeatedly dipped in a ceramic slurry, coated with fine sand, and dried to build a thick, hard ceramic mold.
• Dewaxing: The mold is heated, melting out the wax (hence “lost wax”).
• Casting: Molten metal is poured into the hollow ceramic mold.
• Shell Removal & Finishing: The ceramic shell is broken away, and individual parts are cut from the tree, cleaned, and finished.

Key Advantages:

• Material Superiority: Uses real engineering alloys (titanium, superalloys, stainless steel) with excellent mechanical properties.
• Surface Finish: Very good surface quality straight from the mold.
• Economics at Scale: Cost-effective for medium to high-volume production (once the mold is made).
• High Precision: Excellent for complex geometries with fine details (e.g., jewelry, turbine blades).

Primary Limitation:

• High Setup Cost/Time: Creating wax injection molds is expensive and time-consuming. Not economical for prototypes or very low volumes.

3D Printing / Additive Manufacturing (AM)

A digital, additive process of building parts layer by layer from 3D model data.

Relevant Technologies for this comparison:

• SLA/DLP: Uses a laser or projector to cure liquid resin. High detail.
• Material Jetting: Drops and UV-cures photopolymer. High detail.
• SLS/Binder Jetting: Fuses nylon powder or bonds sand/certain metals.

Key Advantages:

• Design Freedom: Unmatched complexity (lattices, internal channels, organic shapes).
• Zero-Tooling, Fast Setup: Perfect for prototypes and one-off parts. Digital files drive production directly.
• Assembly Consolidation: Can print a single part that replaces multiple assembled components.
• Customization: Ideal for bespoke, patient-specific items (e.g., medical implants).

Primary Limitations:

• Material Constraints: Engineering thermoplastics and resins dominate; production-grade metals are expensive and often have limitations in size, surface finish, or isotropy.
• Speed at Scale: Serial process, usually slower for high-volume production.
• Post-Processing: Often requires support removal and surface finishing.

Conclusion: It’s Not “Either/Or” But “And”

Need 1-50 parts, urgently, with complex geometry? Use 3D printing (likely in resin or nylon).

Need 1-50 parts in a high-performance metal? Use 3D printing + Investment Casting (print the patterns).

Need 10,000+ parts in a standard metal alloy? Use traditional Investment Casting with injection molded wax patterns.

Need highly customized, dense metal parts with extreme complexity? Consider direct metal 3D printing (like DMLS/SLM), though at a higher cost.

Think of them as a continuum in digital manufacturing. 3D printing excels at agility and complexity without tooling, while investment casting excels at volume and material performance. By combining them, manufacturers get the best of both worlds: digital flexibility and superior metallurgy.