Discontinuous Chips (不連續切削)• Consist of segments (片段) that attached firmly (黏附) or loosely (鬆散狀) to each other• Form under the following conditions:1. Brittle workpiece materials (脆性材料,無法承受高剪應變)2. Materials with hard inclusions and impurities (硬雜質)3. Very low or very high cutting speeds4. Large depths of cut5. Low rake angles6. Lack of an effective cutting fluid7. Low stiffness (剛性) of the machine tool 振動及顫動發生