Acceptable Materials

for CNC Processing

Material Selection

Good material preparation is critical. The most common problems we experience are the de-laminating of material during cutting as a result of poor preparation and improper understanding of material types. Ensure that all material is laminated with a continuous layer of material-appropriate glue and clamped with adequate pressure for at least 24 hours. Also, understand the type of material you are using and what the outcome will look like.

Blue Foam – (extruded polystyrene)

Recommended for people new to milling and test cuts or surfacing.

pros: inexpensive, lightweight and transportable, mills easily, paint-able with water-based paints.

cons: unstable if cut thin so must be mounted to a more rigid backing, color may require painting, will not withstand significant wear and tear, makes a large mess while milling.

sources: available in 2’ widths up to 8’ in length 2” thicknesses from the Materials and Methods store in Parker 2 or Home Depot/Lowe’s.


High-density Foam/Tooling board/Renboard – (extruded polyurethane)

pros: uniform color, homogenous material, mills quickly and easily, capable of being milled into thin surfaces.

cons: relatively expensive, limited sizes, must order from vendor well in advance.

sources: available online from Freeman Supply.


Plywood – (Grade A recommended)

pros: withstands wear and tear, layers create interesting effect (can be distracting).

cons: potentially expensive, layers are of different quality and may contain knots and glue.

sources: available at the Materials and Methods store in Parker 2 and locally (check outside suppliers).



Hardwood materials come in a range wide range of hardness with varying grain qualities.

pros: looks nice, will withstand wear and tear.

cons: can be expensive, limited sizes. Very hard woods may require more complex milling strategies and can be slower operations.

sources: available at the Materials and Methods store in Parker 2 and locally at Thruway Hardwood/Plywood, Advantage Lumber.