Техническая информация Sumitomo - страница 22

Tool Failure and Remedies SUMIBORON Edition

Type of Insert Failure Cause Countermeasures

Flank Wear

• Grade lacks wear resistance.
• Select a more wear resistant grade. （BNC2010,BN1000,BN2000）
• Cutting speed is too fast.
• Decrease the cutting speed. Reduce the cutting speed to less than v =200m/min.

c (Higher feed rate reduces the overall tool-to-work contact time.)

• Use an insert with a larger relief angle.

Crater wear

• Grade lacks wear resistance.
• Change to a high efficiency grade. （BNC2010,BNX25,BNX20）
• Cutting speed is too fast.
• Reduce cutting speed and increase feed rate (low-speed, high-feed cutting). Reduce the cutting speed to less than v =200m/min.

Breakage At Bottom of Crater c (Higher feed rate reduces the overall tool-to-work contact time.)

Flaking

• Grade lacks toughness.
• Select a tougher grade (e.g. BNC2020 and BN2000).
• Back force is too high.
• Select an insert with a stronger cutting edge (Increase negative land angle and edge honing)
• If the grade has enough toughness, improve the cutting edge sharpness.

Notch Wear

• Change to a grade with a higher boundary wear resistance (e.g. BNC2010 and BN2000).
• Increase the cutting speed (150m/min or more).
• High boundary stress.
• Change to "Variable Feed Rate" method, which alters the feed rate at every fixed number of outputs.
• Increase negative land angle and edge honing.

Chipping at Forward Notch Position

• Impact to front cutting edge is too large or there is constant occurrence.

• Change to a fine-grained grade with a higher fracture resistance (e.g. BNC300 and BN350).
• Increase feed rates

(Higher feed rates are recommended to reduce chipping.)

• Select an insert with a stronger cutting edge

(Increase negative land angle and edge honing)

Chipping at Side Notch Position

• Impact to side cutting edge is too large or there is constant occurrence.

N

• Select a tougher grade.（BN350,BNC300）
• Reduce feed rate.

Increase the side cutting angle

• Increase insert nose radius
• Select an insert with a stronger cutting edge

(Increase negative land angle and edge honing)

Thermal Crack

• Completely dry condition is recommended.
• Thermal shock is too severe.
• Select a grade with better thermal conductivity.
• Decrease cutting speed, depth of cut, feed rate.