Milling Cutters

Axial - going into the spindle. Radial - on the side. Tangential - tries to stop cutter from spinning

Used on CNC machines. Also called down milling. Chip is thick to thin. Not recommended on manual machines.

Used on conventional machines. Also called up milling. Chip is thin to thick. Not recommended on CNC machines unless there is no other option.

Square shoulders/ Think walled Workpieces/ High Radial Forces 

General purpose for flat surfaces/Maximum feed per tooth/ Chip thinning/Balanced Radial and Axial forces

Thins the chip slightly/ For when a 45° cutter has insufficient fixture clearance/ Reduced radial forces

Reduces harmonics/ stops chatter and vibration

End cutting/ plunge cuts/ stronger flutes/ centre cutting

Cheaper/ Lighter Cuts

Produces Precise Radii on part/ Mould Making/ Solid carbide or Indexable (steps)

Coarse or Fine pitch/ free cutting/ leaves ribbed finish

Interchangeable heads

Various Insert Widths available/ Interpolates ID or OD grooves

Multiple insert corners/ tangential forces/ tang mill style

Aluminum body made lighter for higher rpm/ Poly Crystaline Diamond

Each cutting edge spins on a bearing/ should cause even wear on each cutting edge

Slots and Grooves

High metal removal/ multiple inserts/ leaves rough finish/ not end cutting

Used for removing material from the top or sides of a work piece/ 2,3,4,6,8 teeth/ some endcutting/ limited depth of cuts/ more precise/ various ground radii possible/ regrindable/ long cut length on walls

for producing very thin slots

for making dovetail shapes and woodruff keyseats

produces a corner radius at a customer specified size

To produce unique profiles/ CNC ground/ Virtually any shape possible

Used to make large threaded holes without using a tap

2/3 (70%) of the cutter needs to be engaged  in the cut and 1/3 (30%) needs to be out of the cut

90 degree creates a big chip/ 45 degrees creates a thinner chip

Never Use Coolant when Milling

Pros - Robust milling cutters/ very flexible for face milling and profiling/ high performance multi-purpose cutters 

Cons - round inserts requires more stable conditions 

Forces - radially/axially/and in between

Pros - general choice for face milling/ balanced radial and axial cutting forces/ smooth entry into cut

Cons - max cutting depth 6-10mm 

Forces - equal axial and radial forces

Pros - great versatility/ first cutter generating true 90 degree square cuts / light cutting inserts with true four edges 

Cons - Max cutting depth .157in 

Forces - only radial

Fewer inserts (4)/ lower feedrate/ less vibration

Double inserts (8) higher feedrate/ more vibration

Inserts further apart, higher stability

Fewer teeth require less HP and induce less axial pressure. Moving the cutter off centre creates less vibration. Differential pitch where the teeth are unevenly distributed around the mulling cutter creates varying frequencies to combat harmonics.