Chip Curl (切屑捲曲)• Chips will develop a curvature (chip curl) as they leave the workpiece surface-塑膠及木材• Factors affecting the chip curl conditions are:1. Distribution of stresses in the primary and secondary shear zones(主剪切區及次剪切區).2. Thermal effects.3. Work-hardening characteristics(加工硬化特性) of the workpiece material4. Geometry of the cutting tool5. Processing variables (製程變數)6. Cutting fluids (切削液)