Expendable Mold Casting & Difference Between It and Investment Casting

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What is Expendable Mold Casting & Does it Differ from Investment Casting?

September 5th, 2021

There are many terms that are used throughout the casting manufacturing process that may be confusing for many customers. These terms may refer to unique processes or may be another name for a specific process. One such term that a customer may hear is “expendable mold casting.”

You may be wondering what expendable mold casting is and what it refers to in production processes. You may also wonder whether it differs from investment casting. Let’s look at what this term signifies for your component manufacturing project.

What is Expendable Mold Casting?

Expendable mold casting refers to the molds that are used for the molten metal during the pour to create the part. Once the metal hardens, the mold is broken apart as it cannot be used to make another part right after.

Expendable mold casting refers to any manufacturing technique where the molds become expendable instead of reused. So, the lost-wax process, sand casting, and investment casting falls into the expendable mold casting category.

For processes that retain the mold so that it may be reused again and again, these techniques fall into the non-expandable mold casting category. Centrifugal casting, die casting, continuous casting and permanent molding are all non-expendable casting processes.

Investment Casting is an Expendable Mold Casting Technique

Investment casting falls into the expendable mold casting category as the ceramic mold is knocked out after the metal hardens. In certain manufacturing processes, the mold’s materials may be retained to form another mold in the future. This is the case with sand casting.

The sand from the mold is broken apart and shook from the formed metal part. The sand is reclaimed, yet because its molded form was broken when getting to the metal part, it cannot be reused immediately in the molten pour process. Instead, it will need to be reformed into the shell mold again.

Why Can’t Expendable Molds Be Reused Again?

Expendable molds are not used again typically due to how the metal part is taken from the mold’s shell. The mold becomes broken entirely from off the hardened metal. Other times, the mold cannot be used because the metal poured into it may have damaged the mold by causing minute cracks. The molten metal may also deform the mold’s cavity due to the extreme temperatures.

Here at Impro, we provide several expendable mold casting techniques such as sand casting and investment casting. Check out our processes to see which one would be right for your next project.

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