How it works
- Upload a printable product model
- Choose mold clearance, wall and split settings
- Preview the generated mold parts and interfaces
- Download each print-ready STL or the ZIP set
AUTOMOLD3D · TOOLS
Free STL Mold Generator for 3D Printable Molds
Create a configurable two-part rigid mold from a supported mesh file. Set wall thickness, model clearance, parting controls and alignment settings, then inspect and download printable STL parts.
Open tool ↓Open in the mold studio
STL Mold Generator
What this tool does
- Two mold halves with adjustable split controls
- Alignment pins and mating clearance controls
- Sealing-channel dimensions tied to wall safety
- Model-to-mold clearance and pour opening controls
Common uses
- Rigid printed mold parts
- Silicone-mold masters and casting preparation
- Candle, soap, resin and craft workflows
STL Mold Generator
Create a configurable two-part rigid mold from a supported mesh file. Set wall thickness, model clearance, parting controls and alignment settings, then inspect and download printable STL parts. Supported mesh inputs are STL, OBJ, 3MF, GLB, GLTF and FBX. STEP, STP and IGES should be exported to a mesh format first. The geometry workflow runs in your browser. Quote and account actions are separate services and are only used when you submit them.
Frequently asked questions
How do I make a mold from an STL file?
Upload a supported mesh, choose the two-part mold workflow, set clearance and wall controls, then generate and inspect the two mold halves. Download the STL pieces only after checking the split, cavity and alignment geometry.
Can you 3D print a silicone mold?
Most common desktop 3D printers do not directly print a silicone casting mold. A practical workflow is to print rigid mold parts or a master, then use the material and casting process appropriate for your project.
How do I make a two-part silicone mold?
A two-part mold needs a sensible parting line, two matching halves, alignment features and a cavity around the original shape. AutoMold3D generates rigid mold geometry; choose your silicone and casting procedure separately.
Does an STL need to be watertight to make a mold?
A closed, well-behaved mesh is safer for mold generation. If the model has holes or non-manifold connections, inspect it first with the repair check and visually review the result before making a mold.
How thick should mold walls be?
Wall thickness depends on the mold size, material, printing process and the model geometry. Use the adjustable wall control and keep enough material around channels and cavities rather than relying on one universal number.
How do mold halves stay aligned?
The two-part workflow includes configurable alignment features and mating clearance controls. They help halves return to the same position, but the printed result should be test-fitted before casting.