Foam is often cut for inserts and protection. Surface marking is a different operation: the mark must be visible without distorting the foam in a way that compromises its use. Suitability depends on the foam and the desired marking.
An opening is not an engraving
An opening through the entire foam sheet is a cut. Text or a symbol on the surface uses an engraving operation where the product supports it. The portal offers the operations available for that material.
The marking needs to remain recognisable
Cell structure, softness and dark colour can make small text less distinct. Use simple symbols and avoid details that only work when enlarged on screen. Intended viewing distance matters more than an on-screen font size.
Preserve the insert's function
Place markings on a visible area that is not essential to supporting the product. A deep or large marking can weaken a thin section. A simple symbol can be more useful than lengthy text.
A trial or another solution
For a new combination, make a small trial and inspect contrast and surface. If engraving does not suit the foam, consider a separate label or an engraved top layer in another material.
Compare the foam collection and read about cutting, line engraving and area engraving. For marking an existing foam product, see product engraving.