Simplify complex castings with fewer cores and less machining.

Lost foam gives engineers another way to simplify difficult casting geometry and produce more of the finished shape in a single part.

Why use lost foam casting?

Lost foam gives engineers more freedom to create complex shapes and internal features that can be difficult to produce with conventional casting methods.

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More complex shapes

Create shapes and internal features that can be difficult to produce with conventional molds.

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Fewer cores

Reduce the need for separate sand cores when creating complex internal geometry.

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No mold parting line

The foam pattern stays in place until pouring, so conventional mold halves aren’t needed.

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Better surface finish

Improved surface finish compared with conventional sand casting.

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    How lost foam casting works

    A foam pattern is made in the shape of the finished component, coated and surrounded by compacted sand. When the metal is poured, it progressively replaces the foam and takes its shape.

    Make the pattern
    The foam pattern reproduces the geometry of the casting. More complex patterns can be made from several sections joined together.

    Coat the pattern
    A refractory coating is applied to the foam. It helps to release gas, reduce warpage and improves the overall surface quality.

    Pack it in sand
    The coated pattern is placed in a flask and surrounded by dry sand, which is compacted around the entire shape.

    Pour the metal
    Molten metal replaces the foam pattern. Once the casting has cooled, the sand is removed and the part can move into finishing and machining as required.

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    When lost foam makes sense

    Lost foam earns its place when it makes the whole part easier to manufacture, not simply because the geometry is complex.

    • Complex housings and casings
    • Parts with difficult internal geometry
    • Components that would otherwise need several sand cores
    • Designs made from several cast or fabricated pieces
    • Parts that currently require a lot of machining or finishing

    The real opportunity can sometimes be bigger than changing the casting process. A part originally designed around conventional molding, cores or assembly may be able to be redesigned as a simpler single casting.

    Materials for lost foam casting

    The right alloy needs to be considered alongside the part geometry, performance requirements and casting process. Milson can help you assess the material and manufacturing method together, rather than treating them as separate decisions.

    Ductile iron

    Selected for strength combined with toughness and wear resistance.

    Steels

    Strong and versatile for structural and mechanical parts. Used in heavy-duty applications where toughness and durability are critical.

    Stainless grades

    Used in environments requiring corrosion resistance alongside structural integrity.

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    Choosing the right casting process

    Lost foam is useful when it solves a real manufacturing problem. It isn't the right process for every part.

    Our engineers look at the geometry, material, volumes, tolerances, machining and how the part needs to perform before recommending the best way to make it.

    Because Milson works across multiple casting processes, we'll recommend the approach that makes the most sense for the part — whether that's lost foam or something else.

    • Engineering support from design through production
    • Multiple casting processes and material options
    • Machining, metallurgy and quality support
    • Practical advice focused on making the part simpler to produce
    Learn more about Milson

    Could lost foam simplify your part?

    If you're dealing with multiple cores, too much machining or a part that's difficult to make consistently, send us the drawing or tell us what isn't working. Our engineers can help you work out whether lost foam is the right approach.

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