In modern manufacturing, the marriage of 3D printing and traditional casting techniques has opened up a world of possibilities. The ability to create custom molds with intricate designs and complex geometries through 3D printing has revolutionized the casting process. By harnessing the power of additive manufacturing, individuals and industries alike can now explore new avenues of creativity, efficiency, and cost-effectiveness in the production of high-quality cast objects.

This article serves as a comprehensive guide to the art of creating 3D-printed molds for casting. We will explore the step-by-step process of bringing your ideas to life and creating your casting mold through the use of additive manufacturing. 

1. Design a CAD Model

Begin by creating a 3D model of the mold using computer-aided design (CAD) software. Ensure that the model is designed with appropriate draft angles and parting lines to facilitate mold release and appropriate wall thickness for the casting material. Include mold features like sprues, runners, and vents to facilitate the casting process. Use CAD software to create the design such as: Autodesk Fusion 360®, SolidWorks®, Rhino3D®, AutoCAD®, and Tinkercad®, among others. 

When designing your model for 3D-printed molds, it's important to follow these guidelines, including: keep the design simple, avoid filled objects within hollow spaces, consider wall thickness, opt for symmetric designs, and design with final details in mind.

2. Determine if the Model Is Hollow or Solid

Depending on whether your model is hollow or solid, the casting process will differ. If your model is hollow on the inside, the casting process becomes more complex. Create a cast that supports the interior of the model and then remove the supporting structure from the final piece. Your final piece will have a hole somewhere, large enough to allow the removal of the supporting material when the cured resin is stretched.

However, if your model is solid, the casting process is simpler. Solid objects do not require any internal structures for support. In this case, you can skip ahead to step 4 of the casting process.

For more information, see our guide on Best 3D Printing Software.

3. Generate the Inside Structure for the Hollow Model

To generate the inside structure for a hollow model, there are several steps to follow. First, within the appropriate software, create a new solid block that is slightly smaller than the original hollow model. Then, position the original hollow model on top of the solid block and center it. Modify the properties of the original model to make it a "Hole" shape. This will ensure that the interior of the model will be filled in the next step. Merge the solid block and the modified original model. This will create an exact copy of the inside structure of the hollow model. To hold the inside structure in place within the final mold, add support pieces that will connect the inside structure to the external mold. These support pieces will be removed later on. Figure 1 illustrates the step-by-step guide to creating the inside structure for the hollow model:

How To Create 3D-Printed Molds for Casting