Frequently Asked Questions - Milling Troubleshooting

Problem	Cause	Solution
Chipping	Feed rate too high Chattering Loose tool Tool rigidity Low cutting speed Loose toolholder	Reduce feed rate Reduce RPM Remove, clean, and retighten Shorten LOC, place shank further up holder Increase RPM Remove from spindle, clean and replace
Wear	High cutting speed Low feed rate Poor chip evacuation Hard material	Reduce RPM Increase feed rateu Reposition coolant lines, use air blasting Change to recommended helix angle Use coated tool
Breakage	Excessive spindle TIR Feed rate too high Depth of cut too large Poor tool rigidity Tool wear Poor chip evacuation	Reduce feed rate Reduce depth of cut Shorten LOC, place shank further up holder Replace/regrind sooner Use air blasting
Chattering	Speed and feed too high Poor toolholder rigidity Poor spindle rigidity Workpiece rigidity Relief angle too high Depth of cut too large Poor tool rigidity	Reduce feed rate Replace with shorter/more rigid holder Use larger spindle or different machine tool Tighten workpiece holding method Regrind with smaller relief angle Reduce depth of cut Shorten LOC, place shank further up holder
Chip Packing	Feed rate too high Low cutting speed Insufficient chip room	Reduce feed rate or increase speed Increase RPM or reduce feed rate Use tool with less flutes, increase helix
Poor Surface Finish	Feed rate too high Low cutting speed Tool wear Edge build up Depth of cut too large Chip welding	Reduce feed rate Increase RPM Replace or regrind tool Increase RPM, switch to higher helix tool Reduce depth of cut Increase volume of coolant
Burring or Workpiece Chipping	Excessive spindle TIR Tool wear Improper helix angle Feed rate too high Depth of cut too large	Replace or regrind tool Change to recommended helix angle Reduce feed rate Reduce depth of cut
Workpiece Inaccuracy	Loose/worn toolholder Poor toolholder rigidity Poor spindle rigidity Insufficient number of flutes Tool deflection	Repair or replace Replace with shorter/more rigid toolholder Use larger spindle or different machine tool Use tool with higher flute quantity Shorten LOC, place shank further up holder