Lost foam pattern making can be produced by several means. In volume production, multiple copies of patterns are prepared by moulding. It is also possible to machine foam patterns on a high speed CNC router. Both of these methods involve considerable capital investment, so most hobby casters fabricate their patterns by gluing together simple shapes to build up a complex pattern. This is cheap but time consuming though much less so than preparing a wooden pattern for green sand casting. If you would like to improve current production efficiency, if you would like to get time payback after investment, then start to consider to get a CNC router.
Polystyrene foam is available in different types. This is the type commonly used for packaging. It is suitable for most purposes but it does leave a surface texture on the finished casting. Large panels are available from builders merchants in various thicknesses for use as insulation. There is another type of foam with the trade name Styrofoam. This is extruded polystyrene foam. It is usually a pale blue colour. This is denser and more homogenous than the normal white packaging foam and it gives a much finer surface finish to the finished casting. It is mainly used as an insulation material. This is the reason we often call this purpose processing cnc router as styrofoam cnc router.