Sandvik Coromant Threading - Manual (Page 82)

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4. Troubleshooting – Thread milling
Thermal cracks
• Temperature variations from varying
cutting fl uid supply or intermittent
machining leading to small cracks
perpendicular to the cutting edge,
insert frittering and poor surface
fi nish
• Apply cutting fl uid in large amounts,
or not at all
• Reduce cutting speed
Crater wear
• Excessive wear causing a weakened
edge
• Cutting edge breakthrough on the
trailing edge leading to poor surface
fi nish
• Reduce speed to reduce tempera-
ture
• Reduce feed
Problem Cause Solution
Plastic deformation of edge, depres-
sion or fl ank impression, leading to
poor chip control, poor surface
fi nish and insert breakage.
• Cutting temperature and pressure
too high
Plastic deformation
• Reduce cutting speed
• Reduce feed