What is the difference between cast and extruded acrylic on a CNC router?

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Accepted Answer

Cast acrylic is made by pouring liquid methyl methacrylate between glass plates. It has a higher molecular weight, a higher melting point, and machines cleanly into crisp, brittle chips. Cast acrylic yields polished, frosted edges and is the preferred substrate for retail displays, architectural lettering, and edge-lit signs. Extruded acrylic is formed by pushing acrylic mass through an extrusion die. It is softer, has a lower melting point, and tends to gum up or chip if heat is not strictly controlled. Extruded acrylic requires conservative feed rates, lower spindle RPM, and polished O-flute tooling to prevent chip welding.

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