Rubber molds for jewelry production are how designers turn a single approved piece into many identical copies. Once a design is finalized in CAD and a master model is made, a rubber mold lets a caster inject waxes again and again for repeat casting. Our jewelry services team in Los Angeles helps designers prepare models and masters for molding. Here is how the process works and when it makes sense.
When Do You Need a Rubber Mold?
If you are making a one-of-a-kind piece, printing a castable wax or resin directly from CAD is usually the most efficient route. But if you plan to make the same design repeatedly, such as a collection, a best seller, or wholesale orders, a rubber mold can lower the cost per piece and speed up production.
The Production Workflow
- CAD design. The piece is designed and approved.
- Master model. A master is created, typically cast in metal (often silver or brass) from a printed pattern, then cleaned and polished to a high standard. Every flaw on the master will appear on every copy.
- Mold making. The master is placed in a mold frame with a sprue, surrounded by rubber, and the mold is cured and cut open.
- Wax injection. Molten wax is injected into the mold to create wax copies.
- Casting. Waxes are treed, invested, burned out, and cast through the lost-wax process.
- Finishing. Pieces are cleaned, polished, and set with stones if needed.
Vulcanized vs. Room-Temperature (RTV) Molds
Vulcanized rubber molds
Vulcanized molds are cured with heat and pressure. They are durable and suitable for long production runs. Because the process involves heat, the master must be metal.
RTV silicone molds
RTV molds cure at room temperature, so they can be made from masters that cannot take heat, including some resin masters. They capture fine detail well but may not last as long as vulcanized molds for high volumes.
Why Shrinkage Matters
Each step in the process can introduce slight shrinkage: the rubber mold, the wax, and the metal casting itself. Across a master-mold-wax-cast chain, the final piece can end up slightly smaller than the original design. For rings, this can affect sizing. In CAD we can compensate by scaling the master appropriately, which is one of the advantages of planning production from the design stage.
Designing for Molding
- Avoid deep undercuts that make wax removal difficult, or plan for multi-part molds.
- Keep sections thick enough for wax to fill completely.
- Plan sprue locations that do not interfere with important details.
- Consider designing ring families in a way that allows sizing after casting.
Master Quality Is Everything
A master should be carefully finished, with crisp details and a smooth surface. Small scratches or pits multiply across every piece produced. Investing in a high-quality master saves finishing time on every copy.
Is Molding Right for Your Line?
Molding makes the most sense for designs you will produce repeatedly. For limited editions or frequently changing designs, direct printing of castable patterns may remain more flexible. We are happy to talk through volume, budget, and timeline to find the right approach.
Scale Your Jewelry Line in Los Angeles
eCadCam has more than 22 years of experience in jewelry CAD, wax printing, and casting preparation. Visit us at 4212 San Fernando Rd, Glendale, CA 91204, call 213.489.1173, or request a quote to plan your production.