Общий каталог Sumitomo 2018 - 2019 - страница 575

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Technical Guidance Cutting Edge Failure Technical Guidance SUMIBORON Tool Failure and Remedies Damage Remedies Large flank wear Tool material F Select a more wear resistant grade. Tool design F Reduce the cutting force. F Reduce the NL width and angle. F Positive inserts preferred Cutting condition F Check the cutting speed. F Reduce the cutting speed to less than 200m/min. F Higher feed rate reduces the overall tool-to-work contact time. Large crater wear Tool material F Crater wear resistant grades are recommended. Continuous ~ Light interrupted cutting = BNC2010 Light ~ Medium interrupted cutting = BNX20 Medium ~ Heavy interrupted cutting = BNX25 Tool design F Determine the cutting edge geometry after inspecting the used inserts closely. Breakage at bottom of crater F Sharpen the cutting edge to prevent crater wear. F Strengthen the cutting edge to prevent crater breakage. Cutting condition F Check the cutting speed. F Reduce the cutting speed to less than 200m/min. F Higher feed rates are recommended. Flaking Tool material F Flaking is caused by high back forces and back force is related to flank wear. F Select a more wear resistant grade. Tool design F A sharper cutting edge helps prevent flaking. F Reduce the NL angle and width F Positive inserts preferred Cutting condition F Reduce flank wear with lower speed and higher feed rates. F Reducing tool-to-work contact time effectively reduces flank wear. Chipping at notch position Cutting condition F If surface finish is affected, consider using the “Variable Feed rate” method to improve finishing. F For other cases, use remedies similar to that for normal wear. Chipping at notch position Tool material F Caused by impact shocks to the cutting edge. Chattering may also be a contributing factor. F Select a tougher grade. Tool design F Strengthen the cutting edge. F Large NL angle, Honing. Cutting condition F Higher feed rates are recommended to lessen the number of impacts. Chipping at nose position Tool material F Caused by impact shocks to the cutting edge. Chattering may also be a contributing factor. F Select a tougher grade. Tool design F Strengthen the cutting edge. F Large NL angle, Honing. Cutting condition F Higher feedrates are recommended to lessen the number of impacts. Thermal crack Cutting condition F Thermal shocks generate vertical crack lines across the cutting edge. Completely dry condition is recommended. F If dry condition machining is already observed, then reduction of cutting temperatures and cutting force is necessary. F Decrease cutting speed, feedrate, depth of cut. Tool design F Sharpen cutting edge. Tool material F Select more thermal conductivity grade. N20