Vibration

​Cause

• Weak fixture

Solution

• Assess the direction of the cutting forces and provide adequate support or improve the fixture
• Reduce the cutting forces by decreasing the cutting depth, a_p
• Select a coarse and differentially pitched cutter with a more positive cutting action
• Select a L-geometry with a small corner radius and small parallel land
• Select a fine-grain, uncoated insert, or a thinner coating
• Avoid machining where the workpiece has poor support against the cutting forces

Cause

• Axially weak workpiece

Solution

• Consider a square shoulder cutter (90-degree entering angle) with positive geometry
• Select an insert with L-geometry
• Decrease axial cutting force – lower depth of cut, smaller corner radius and parallel land
• Select a coarse-pitch cutter with differential pitch
• Check tool wear
• Check tool holder run-out
• Improve clamping of tool

Cause

• Too long tool overhang

Solution

• Minimize overhang
• Use coarse-pitch cutters with differential pitch
• Balance radial and axial cutting forces – 45 degree entering angle, large corner radius or round insert cutter
• Increase feed per tooth
• Use a light-cutting insert geometry – L/M
• Reduce axial depth of cut, a_f
• Use up-milling in finishing
• Use oversize cutters and Coromant Capto coupling adaptors
• For CoroMill Plura and CoroMill 316, try a tool with fewer teeth and/or a higher helix angle

Cause

• Milling square shoulder with weak spindle

Solution

• Select smallest possible cutter diameter
• Select positive and light cutting cutter and insert
• Try up-milling
• Check spindle deflection to see if acceptable for machine

Cause

• Irregular table feed

Solution

• Try up-milling
• Tighten machine feed mechanism: adjust the feed screw on CNC machines.
• Adjust the locking screw or replace the ball screw on conventional machines.

Cause

• Cutting data

Solution

• Reduce cutting speed, v_c
• Increase feed, f_z
• Change cutting depth, a_p

Cause

• Bad stability

Solution

• Reduce overhang
• Better stability

Cause

• Vibration in corners

Solution

• Program large corner radii with reduced feed rate