Troubleshooting Guide

Problem

Cause

Solution

Chip Packing

Cause

• Feed per tooth too high
• Not enough chip room
• Not enough coolant

Solution

• Lower feed rate
• Use end mill fewer flutes
• Use more coolant to flush out chips

Rough Finish

Cause

• Feed too fast
• Slow speed
• Too much wear
• Feed per tooth too high

Solution

• Slow down to correct feed
• Use higher speed
• Regrind sooner
• Lower feed rate

Burrs

Cause

• Dull cutting edge
• Improper cutting angle

Solution

• Regrind sooner
• Change to correct cutting angle

Wandering

Cause

• Machine/Holder runout
• Not enough rigidity in machine/holder
• Not enough flutes
• Tool deflection

Solution

• Repair machine or holder
• Change machine or holder
• Use end mill with more flutes
• Choke up on shank or reduce feed rate

Chipping

Cause

• Feed too fast
• Feed too fast on the first cut
• Lack of machine/tool holder rigidity
• Loose holder
• Loose vise
• Lack of cutting tool rigidity
• Teeth too sharp

Solution

• Lower feed rate
• Lower feed on initial contact
• Change to a more rigid machine/holder
• Tighten tool holder
• Tighten workpiece fixture
• Choke up on shank; use shorter tool
• Choose a tool with correct primary relief angle

Excessive Tool Wear

Cause

• Speed too fast
• Hard material
• Feed too slow
• Improper cutting angle
• Primary relief angle too small

Solution

• Slow down speed, use more coolant
• Use better grade for cutter material, add a coating
• Increase feed speed
• Change to correct cutting angle
• Increase primary relief angle

Tool Breakage

Cause

• Feed too fast
• Chip load per tooth too great
• Flute length too long
• Overall length too long
• Too much wear

Solution

• Slow down feed
• Adjust to smaller chip load per tooth
• Choke up on the shank
• Use shorter end mill
• Regrind sooner

Tool Chatter

Cause

• Feed and speed too fast
• Poor rigidity of machine/holder
• Relief angle too large
• Loose workpiece holder
• Cutting too deep
• Flute length too long
• Overall length too long

Solution

• Adjust feed and speed
• Use better machine/holder
• Change to smaller relief angle
• Hold workpiece tighter
• Change to a smaller depth of cut
• Choke up on the shank
• Use shorter end mill