1. End Milling Tool Basics
Computer Integrated Manufacturing
© 2013 Project Lead The Way, Inc.

2. Common Cutting Tool Materials
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Common Cutting Tool Materials
High Speed Steel (HSS)
Cobalt
Powered Metal (PM) Cobalt
Solid Carbide
Carbide-Tipped
High Speed Steel – Provides wear resistance and cost less than cobalt or carbide
Good for general purpose milling of both ferrous and non-ferrous materials
Cobalt (M-42: 8% Cobalt) – Provide better wear resistance, higher hot hardness and toughness than HSS. Allowed to run 10% faster than HSS. Cost-effective in machining harder materials such as cast iron, heat treated steels, and titanium alloys
Powered Metal (PM) Cobalt – Cost effective alternative to solid carbide, powered metal is tougher and less prone to breakage. Good for high-shock and high-stock application such as roughing
Solid Carbide – Primarily used in finishing applications. Carbide can run much faster than HSS and Cobalt due to its extreme hardness. 2-3x faster than HSS. Resistance to high temperatures and wear resistant. More rigidity than HSS which allows for higher accuracy with smaller tolerances. Carbide is brittle and tends to chip rather than wear. Heavy feed rates are more suitable for HSS and Cobalt
Carbide-Tipped – Offers similar advantages to Solid Carbide. More cost-effective than Solid Carbide especially for larger diameter tools
Project Lead The Way, Inc.
Copyright 2008

3. End Mill Types Square End Ball End Corner Radius / Bullnose Tapered
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End Mill Types
Square End
Ball End
Corner Radius / Bullnose
Tapered
Roughing End Mills
Coarse Profile
Fine Profile
Square End – Used for general milling applications
Ball End – Used for contour milling and pocketing applications. Used to produce a radius in the bottom of slots or pockets for added strength. Used to create compound curves for molds and dies where sharp corners must be avoided
Corner Radius – Helps reduce chipping on the tip. Best used in mold applications, removing more material faster than ball end mills.
Tapered – Results in faster and freer cutting due to more evenly formed chips over the length of the flute.
Roughing End Mills – Not designed to last long – designed to “hog” off material and increase productivity by taking heavier cuts in a fixed amount of time without creating vibration
Coarse Profile – most common type found for roughing end mills. Good for deep slotting and heavy side cuts
Fine Profile Designed to increase tool life. Good for profiling when conditions do not exceed (depth of cut) x (width of cut) > Diameter squared (D2)
Project Lead The Way, Inc.
Copyright 2008

4. Other Mill Types
Lollipop
T-Slot
Face Mill
Slot Drill

5. Flute Types Two Flute Three Flute Four/Multiple Flute More Chip Space
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Flute Types
Two Flute
Three Flute
Four/Multiple Flute
More Chip Space
Two Flute
Centercutting
Three Flute
Centercutting
Four Flute
Centercutting
Six Flute
Centercutting
Eight Flute
Centercutting
Two Flute – Greatest amount of flute space allowing for more chip carrying capacity. Used primarily in slotting and pocketing of non-ferrous materials
Three Flute – Wile this tool has the same flute space as two flutes, it has a larger cross sectional area providing for greater strength and the ability to pocket and slot both ferrous and non-ferrous materials
Four/Multiple Flutes – Ideal for finish milling. The additional flutes allow faster feed rates, but due to the reduced flute space, chip removal may be a problem. Produces a much finer finish than 2 and 3 flute tools
Harder Materials
Project Lead The Way, Inc.
Copyright 2008

6. End Cut Types Center Cutting Non Center Cutting
One or more cutting edges at the tip
Allows cutter to plunge, drill, or ramp
Greater variety of applications
Non Center Cutting
Used for side cuts of contouring an exterior surface.
Used where plunging is not necessary

7. Typical Surface Treatments
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Typical Surface Treatments
TiN (Titanium Nitrade)
TiCN (Titanium Carbonitride)
TiAlN (Titanium Aluminum Nitride)
ZrN (Zirconium Nitride)
TiN – Provides extreme hardness and heat resistance. Allows for higher speeds and feeds. Requires an increase of 25% to 30% in machining speeds vs. HSS
TiCN – Harder and more waer resistant than TiN under conditions of moderate cutting temperatures. Can provide the ability to run the job at higher spindle speeds (50% over TiN). Requires an increase of 35% to 50% in machining speeds vs. HSS
TiAlN – Ideal for extremely high temperatures. Allows for increase in surface feet per min (SFM), extended tool life. Requires an increase of 75% to 100% in machining speeds vs. HSS
ZrN – offers improved finish when used in aluminum, brass, copper and other non-ferrous materials. Prevents edge buildup
Project Lead The Way, Inc.
Copyright 2008

8. End Mill Selection Summary
Shortest possible end mill for greatest rigidity
Two or three flutes for slotting or heavy stock removal
Multiple flutes for finishing and greater rigidity
Largest diameter possible for added strength, rigidity and productivity
Cobalt, PM and Carbide for tougher and harder materials, and for high production needs
Apply coatings for higher feeds, speeds and tool life

9. Milling Formulas RPM = SFM x 3.82 / Tool Diameter
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Milling Formulas
RPM = SFM x 3.82 / Tool Diameter
IPM = RPM x # of Flutes x Chip Load
Chip Load = IPM / RPM x # of Flutes
SFM = .262 x Tool Diameter x RPM
Revolutions per Minute (RPM): Revolutions the cutter has in one minute
Inches per Minute (IPM): Number of inches the cutter passes through the workpiece in one minute
Chip Load: The amount that each flute cuts during a single revolution of a cutting tool
Surface Feet per Minute (SFM): This is the cutting speed of the end mill in the United States. It is the number of feet per minute that a given point on the circumference of a cutter travels per minute
Project Lead The Way, Inc.
Copyright 2008