Pattern and core box materials

By C.A. Lawton | January 26, 2022
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The C.A. Lawton Co. can make patterns and core boxes from various materials. Here are the options we offer.

Metal: Typical materials used include aluminum and steel. Advantages are high tolerance and excellent durability. Downsides are long lead times and high costs. Metal patterns are best suited for high production run-parts (EAU 200 castings or more), such as automotive components. In addition, they require a temperature-controlled environment for storage.

Red Board: This is a hard urethane material. Advantages include high tolerance, excellent durability, and a lower cost than metal. It’s long-lasting, less expensive, and requires a shorter lead time than metal. Red board is well-suited to high production run-parts (EAU 100-200 castings or more). Like metal patterns, it requires a temperature-controlled environment for storage.

Wood: Common materials used to create patterns are mahogany and pine wood. Advantages include moderate cost, tolerance, and lead times. However, wood’s sweet spot in casting quantity is EAU 10-100 castings. In addition, wood patterns hold up best when stored in a temperature-controlled environment.

Styrofoam: Of all materials used to create patterns, styrofoam offers the lowest cost, shortest lead time (3-4 weeks), and lower tolerance. It’s best suited for prototype projects and/or EAU of 1-5 castings. Styrofoam is a one-time use material because the pattern and core box tooling are destroyed during the casting production process.

Pattern Bottom or Insert Boards: Wood bottom or insert boards function as a “backplate” for the pattern, which is permanently mounted to the board’s surface. It secures the pattern during the casting production process and transportation from storage to production. Bottom or insert boards are not required for a styrofoam pattern.

Be sure to talk with an engineer to help you choose the right material for your needs.