A Beginner's Guide to Investment Casting for Jewelry Manufacturing

If you're new to jewelry manufacturing, "investment casting" is the formal name for what's usually called the lost-wax process — carving or 3D-printing a wax model, encasing it in an investment (a plaster-like material), then burning out the wax and casting metal into the resulting cavity. It's the process behind the vast majority of production jewelry, from simple bands to complex pavé settings.

The process, step by step

1. Model creation — a wax model is hand-carved, injected from a rubber mold, or produced on a 3D printer.
2. Spruing — wax models are attached to a central wax stem ("tree"), creating channels for metal to flow through later.
3. Investment mixing — investment powder (a gypsum-based material) is mixed with water under vacuum to remove air bubbles, then poured around the wax tree inside a flask. A vacuum investment mixer handles the mixing and degassing in one step, which is where a lot of avoidable porosity gets designed out before casting even happens.
4. Burnout — once the investment sets, the flask goes into a burnout oven, where a controlled heating schedule melts and burns away the wax, leaving a clean cavity in its place.
5. Casting — molten metal is introduced into the still-hot flask, typically under vacuum or pressure, filling the cavity left by the wax.
6. Devesting and finishing — once cooled, the investment is broken away, the metal tree is cut apart, and each piece moves on to polishing and finishing.

Where quality gets won or lost

Most casting defects — porosity, incomplete fills, surface pitting — trace back to one of two steps: incomplete degassing during investment mixing, or an uneven burnout schedule that leaves wax residue or cracks the investment. Getting these two steps right consistently is a bigger quality lever than almost any other part of the process, which is why we treat mixing and burnout equipment as just as important as the casting machine itself.

Getting started

If you're setting up your first casting line, our team can walk through the full equipment list — mixer, oven, casting machine, and melting furnace — sized to your expected volume. Get in touch and tell us what you're planning to produce.