At A Glance
SLA investment casting combines high-resolution 3D printed patterns with traditional metal casting to accelerate production of complex, high-performance parts. By replacing wax tooling with accurate SLA patterns, manufacturers can reduce lead times, improve surface finish, and produce intricate geometries, all while lowering labor and process risk.
Why 3D Print Investment Castings?
Investment casting, also known as lost wax casting, is a proven process for producing metal parts with excellent surface finish, tight tolerances, and complex geometry. Traditionally, a wax pattern is created using tooling, assembled with bonded sprues and vents, coated in ceramic slurry to form a shell, then melted out and replaced with molten metal. Unfortunately, this workflow introduces tooling lead times, manual assembly steps, and design constraints.
With SLA 3D printing, manufacturers can reduce labor and time. Patterns are printed with high dimensional accuracy and smooth surface quality straight off the printer, eliminating the need for hard tooling and making design iteration faster and more flexible.
Modern SLA workflows also allow sprues, vents, and pouring cups to be built directly into the printed pattern. This reduces bonding steps, can eliminate autoclave dewaxing, and lowers the risk of shell cracking caused by thermal expansion during processing.
Rather than replacing investment casting, SLA has proven to refine it by streamlining existing processes and accelerating production, without disrupting established foundry operations.
The Process, Explained
The primary SLA investment casting process follows the same set of steps. With this workflow, the standard user saves approximately one full day of processing time, plus several hours of manual labortime compared to traditional methods.
1. Design
Design the final metal part and plan the gating system, including sprues, vents, and pouring cup. These can be added later using wax or printed directly with the pattern. Optional lattice structures can reduce material while maintaining pattern strength.
2. Print SLA Pattern
Print the casting pattern using SLA technology and casting optimized materials.
Standard, industry-proven materials include:
- WaterShed XC for high accuracy patterns and tooling steel casting applications
- WaterShed AF for investment casting patterns requiring clean burnout performance
3. Add Sprues and Vents
Choose one of two methods:
Traditional Method
- Attach wax sprues and vents
- Requires bonding labor
- Requires autoclave dewax step
Printed Method – No Additional Labor Required
- Print sprues, vents, and pouring cup with
the pattern - Reduces labor and preparation time
- May eliminate autoclave step
- Helps reduce shell cracking risk
4. Build Ceramic Shell
Coat the 3D printed pattern in the ceramic slurry to create a strong mold shell.
5. Autoclave and Dewax (If Was Is Used)
If wax sprues or vents are attached, use an autoclave to melt the wax out before burnout.
6. Burnout
Heat the ceramic shell in a furnace to remove the SLA pattern and prepare the mold for casting.
7. Pour Metal and Finish
Pour molten metal into the ceramic shell, allow it to cool, then complete final finishing.
Proven Results
With validated workflows and proven material performance, companies can confidently move from design to cast component. For high-mix, low-to-mid volume production, SLA printed patterns offer a practical, efficient, and production-ready manufacturing solution.
If you’re exploring investment casting with SLA patterns, our team can help you identify the right workflow for your parts and production goals.
Reach out to learn more!
