CNC Machining Processes for Non-Metallic Materials

　　Non-metallic materials, including plastics, composites, wood, and ceramics, require specialized CNC machining processes due to their diverse properties—ranging from soft and flexible (e.g., PVC) to hard and brittle (e.g., alumina ceramics).

　　For plastics (e.g., PEEK, acrylic), tool selection focuses on reducing melting. High-speed steel or carbide tools with polished flutes prevent material buildup. Spindle speeds are high (5,000–15,000 RPM) to minimize contact time, while feed rates (0.1–0.5 mm/rev) depend on rigidity; softer plastics (e.g., HDPE) need slower feeds to avoid deformation. Coolants are often unnecessary but may be used with water-soluble solutions for heat-sensitive plastics like nylon.

　　Composites (e.g., carbon fiber-reinforced polymer, CFRP) demand abrasive-resistant tools. Diamond-coated or carbide tools with fine grits cut through reinforcing fibers without fraying. Low feed rates (0.02–0.1 mm/rev) and moderate speeds (3,000–8,000 RPM) prevent delamination. Vacuum workholding secures flexible composite sheets, while peck drilling reduces heat in thick sections.

　　Ceramics (e.g., zirconia) require ultra-hard tools (diamond or cubic boron nitride, CBN). Slow speeds (500–2,000 RPM) and light feeds (0.01–0.05 mm/rev) avoid cracking. Coolant (oil-based) dissipates heat, and rigid machine setups prevent vibration.

　　Wood machining uses carbide-tipped tools with high rake angles. Speeds (3,000–10,000 RPM) and feeds (0.2–0.8 mm/rev) vary by wood type; hardwoods (e.g., oak) need slower feeds than softwoods (e.g., pine). Air blasts clear chips, and dust extraction systems maintain air quality. These processes enable non-metallics to meet applications in aerospace (composite panels), healthcare (ceramic implants), and consumer goods (plastic components).