​There is a material hardness limit. It must be a Vickers Harness (HV) of 200 or less on the printing surface.

Common Acceptable Material Types:

• Aluminum, Brass, Bronze, Copper, Mild Steel, Yellow Gold, Silver, Nickel (surface must have a luster finish or plated)
• Plastic or acrylic (transparent or semi- transparent for best results

Not Recommended Material Types:

• Material with a Matte surface
• Deep acrylic colors, opaque plastics
• Glass, stone, china, porcelain and wood
• Rubber or elastic type of plastic