Общий каталог Sumitomo 2018 - 2019 - страница 558

Technical Guidance Tool Failures and Tool Life Forms of Tool Failures Cat. No. Name of Failure Cause of Failure Resulting 1~5 Flank Wear Due to the scratching effect of hard grains contained in the work from material. Mechanical 6 Chipping Fine breakages caused by high cutting loads or chattering. causes 7 Fracture Due to the impact of an excessive mechanical force acting on the cutting edge. Resulting 8 Crater Wear Swaft chips removing tool material as it flow over the top face at high from temperatures. Chemical 9 Plastic Deformation Cutting edge is depressed due to softening at high temperatures. reactions 10 Thermal Crack Fatigue from rapid, repeated heating and cooling cycles during machining. 11 Built-up Edge Work material is pressure welded on the top face of the cutting edge. Tool Wear Forms of Tool Wear Flank wear Crater wear Bad chip control Crater wear depth KT (mm) Flank wear width VB (mm) Cutting edge fracture Burrs occur Creater wear KT Initial wear Poor surface finish Side flank wear Sudden VN1 increase in wear Face flank wear VN2 Steady wear Flank wear VB Cutting Time T (min) Cutting Time T (min) Edge wear VC Higher cutting force Wear is rapid initially, then it proceeds Poor machining accuracy more gradually in proportion with Crater wear is more progressive with Burrs occur cutting time until a certain limit, beyond no sudden breakdown pattern. which it increases rapidly again. Tool Life (V-T) Measure the relative tool lives of the specified wear, over a range of cutting speeds, then plot the tool life along the X-axis and the cutting speed along the Y-axis on a double logarithm graph. Flank wear Crater wear Crater wear width (mm) Flank wear width (mm) V1 V2 V3 V1 V2 V3 V4 V4 Tool wear VB KT T1 T2 T3 T4 T’1 T’2 T’3 T’4 Cutting Time T (min) Cutting Time T (min) Cutting speed (mm/min) Cutting speed (mm/min) V1 V1 V2 V2 V3 Tool life V3 V4 V4 T1 T2 T3 T4 T’1 T’2 T’3 T’4 Tool life (min) Tool life (min) Technical Guidance N3