Technical Information

How Investment (Lost-Wax) Casting Works

Investment casting, also called lost-wax casting, is a technique for making highly complicated, near-net-shape metal parts — the same process behind every casting we ship.

The Process, Step by Step

The process starts by using injection molding to create a wax pattern that resembles the actual part, then applying multiple layers of ceramic sand to form a hard shell coating on the wax pattern. When the shell is heated, the wax melts out, leaving a hollow space into which molten metal is poured. After cooling, the shell is broken and the desired metal part is removed.

Illustration of the investment (lost-wax) casting process
Courtesy of custompartnet.com

Breakdown

Four Stages, One Near-Net-Shape Part

  1. 01

    Wax Pattern Injection

    Injection molding creates a wax pattern that resembles the finished part, ready to be built up into a mold.

  2. 02

    Ceramic Shell Build-Up

    Multiple layers of ceramic sand are applied over the wax pattern, forming a hard shell coating.

  3. 03

    Dewax & Pour

    The shell is heated so the wax melts and drains out — "lost" — leaving a hollow cavity that molten metal is then poured into.

  4. 04

    Shell Removal & Finishing

    After the metal cools, the ceramic shell is broken away and the finished part is removed, ready for machining, polishing, or shipping as-cast.

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