Sandvik Coromant Threading - Manual (Page 77)

77
A
B
4. Troubleshooting – Thread turning
Insert breakage
• Wrong turned diameter prior to
threading
• Infeed series too tough
• Wrong grade
• Poor chip control
• Incorrect centre height
Built-up edge (BUE)
BUE (A) and edge
frittering (B) often
occur in combina-
tion. Accumulated
BUE is then ripped
away together with
small amounts of in-
sert material, which
causes frittering.
• Often occurs in stainless material
• Often occurs in low carbon steel
• Unsuitable grade
• Cutting edge temperature too low
• Increase cutting speed
• Choose a grade with good tough-
ness
• Turn to correct diameter before
threading operation (0.03 – 0.07
mm, .001 – .003 inch) radially larger
than max. diameter for thread
• Increase number of infeeds. Reduce
size of the largest infeeds
• Choose a tougher grade
• Change to C-geometry and use
modifi ed fl ank infeed
• Adjust to correct centre height
Problem Cause Solution