Troubleshooting Threading

Problem:

Thread with Town Finish

Cause:

• Burrs
• Torn Finish
• Steps

Solutions:

• Use positive rake or full profile insert
• Increase coolant concentration
• Alter infeed
• Increase sfm
• Check machine "Z" travel axis
• Check insert form
• Check for correct shim in LT system
• Use CB inserts

Problem:

Chatter

Cause:

• Poor rigidy
  
• Incorrect Speed
  
• Insert movement
• Improper infeed
• Off centerline
• Wrong edge prep

Solutions:

• Minimize tool overhang
• Check for workpiece deflection
• Adjust sfm
• Check insert and clamp
• Use modified feed angle
• Verify that tool cutting position is at workpiece centerline
• Adjust hone level by ordering special insert

Problem:

Built-Up Edge

Cause:

• Speed too low
• Insufficient coolant
• Chip load
• Wrong edge prep

Solutions:

• Increase sfm
• Increase coolant concentration and/or flow
• Adjust infeed angle
• Increase depth of cut per pass
• Adjust hone level by ordering special insert
• Use cermet grade KT315

Problem:

Deformation

Cause:

• Wrong grade
• Speed too high
• Improper infeed angle
• Insufficient coolant

Solutions:

• Use a more wear-resistant grade (i.e. KC5010)
• Reduce sfm
• Alter infeed method/angle
• Increase coolant flow

Problem:

Chipping

Cause:

• Improper infeed
• Chip load
• Wrong grade
• Incorrect speed
• Poor rigidity
• Wrong edge prep

Solutions:

• Alter infeed to modified flank
• Adjust chip load
• Increase or decrease number of passes
  
• Eliminate spring passes
• Use tougher grade (i.e. KC5025)
• Increase sfm if chipping on trailing edge
• Decrease sfm if chipping on leading page
• Minimize tool overhang
• Check for insert movement/check clamp
• Check for possible part deflection
• Adjust hone size by ordering special insert

Problem:

Broken Nose

Cause:

• Heavy chip load
• Small nose radius
• Wrong grade
• Improper feed
• Wrong edge prep

Solutions:

• Decrease chip load
• Use large nose radius if allowable
• Use tougher grade (i.e. KC5025)
• Alter infeed to modified flank
• Adjust hone size by ordering special insert

Problem:

Flank Wear

Cause:

• Wrong grade
• Insufficient coolant
• Off centerline

Solutions:

• Use a more wear-resistant grade (i.e. KC5010)
  
• Increase coolant flow
  
• Check the centerline height of the tool (the smaller the diameter, the more critical the need for centerline accuracy)