O-flute upcut bits are the preferred choice for CNC routing of plastics including acrylic, polycarbonate, PVC, HDPE, and similar materials. The single O-flute geometry creates a large chip clearance area that prevents chip re-cutting and heat buildup — the primary cause of melting and gumming in plastic cutting. The upcut spiral direction pulls chips up and away from the cut zone, keeping the flute clear at elevated feed rates. These bits produce clean, polished edges on transparent and colored plastics where surface finish quality is critical.