Speeds and Feeds
© 2013 Project Lead The Way, Inc.Computer Integrated Manufacturing
In This Lesson
• Identify common cutting tools• Learn the definition of speeds and feeds• Calculate cutting speeds and feed rate
Center Cutting End
Mill
Ball End Mill
Non-Center Cutting End
Mill
Indexable Shell Mill
Basic Cutting Tools
Basic Cutting Tools
Combination
Drill & Countersink
Spotting Drill
Countersink
2 Flute End Mill
• More room for chip evacuation
• Used for light metals
• Weak, short tool life
4 Flute End Mill• More cutting edges,
longer tool life
• Used for harder metals
• Clogs easily in deep cuts
Flutes
2 Flute Center Cutting
4 Flute Center Cutting
4 Flute Non-Center
Cutting
Center Vs. Non-Center Cutting
Tool Description Application
¼” 2 Flute HSS Single End Mills for cutting aluminum – 3/8 shank x 1 ¼ cutting length
Facing, profiling, pocketing, slotting, roughing, and finishing
¼” 2 Flute Ball End Mill for aluminum – 3/8 shank x 1 ¾ cutting length
Surfacing, slotting, profiling, roughing, and finishing
Milling Tools
Tool Description Application
¼” Countersink & De-burring tool – 90 Degree
Engraving, de-burring, countersink, spot drilling
#3 Combined drill & countersink 90 degree
Spot drilling, engraving
Milling Tools
Tool Description Application
¼” Spotting drill 90 deg
Spot drilling, engraving
Milling Tools
Cutting Tool Material Video
• Cutting Speed – The rate of a tool measured in surface feet per minute
• Spindle Speed – The number of revolutions per minute (rpm) that is made by the cutting tool of a machine
• Feed – The distance advanced by the cutting tool along the length of the work for every revolution of the spindle
Definitions
• Defined in revolutions per minute (rpm)• Found by dividing the cutting speed by the
circumference of the tool
N =CS
CC = circumference
CS = Cutting speed (surface ft / min)N = Spindle speed (rpm)
d = Diameter (in.) / rev
Spindle Feeds Formula
N =CS 12 in.
dft
Milling Speeds for High Speed Steel Tools
Material Cutting Speed in Surface ft/min
Magnesium 300
Aluminum 250
Brass and Bronze 150
Copper 100
Cast Iron (Soft) 80
Cast Iron (Hard) 50
Mild Steel 90
Cast Steel 80
Alloy Steel (Hard) 40
Tool Steel 50
Stainless Steel 60
Titanium 50
High Manganese Steel 30
Note: Double Speed for Carbide Cutting Tools
Recommended Cutting Speeds
N =CS 12 in.
dft
What spindle speed should be used to mill aluminum with a ½ inch end mill?
Example
Cutting Speed for Aluminum is 250 surface ft/min
N = = 1,910 rpm250 ft 12 in.
0.5 in.ftmin
rev
What spindle speed should be used to mill Brass with a ¼ inch end mill?
Your Turn
N =CS 12 in.
dft
See teacher for solution
fm = ft x nt x N
fm = Feed rate in.
ft = Feed in.
nt = Number of teeth on the tool
N = Spindle speed =
Calculating Feed Rates
CS 12 in.
dft
min
tooth rev
Tool Feed (in./tooth/rev)
Material Face Mill Side Mill End Mill
Magnesium .005-.020 .004-.010 .005-.010
Aluminum .005-.020 .004-.010 .005-.010
Brass and Bronze .004-.020 .004-.010 .005-.010
Copper .004-.010 .004-.007 .004-.008
Cast Iron (Soft) .004-.016 .004-.009 .004-.008
Cast Iron (Hard) .004-.010 .002-.006 .002-.006
Mild Steel .004-.010 .002-.007 .002-.010
Alloy Steel (Hard) .004-.010 .002-.007 .002-.006
Tool Steel .004-.008 .002-.006 .002-.006
Stainless Steel .004-.008 .002-.006 .002-.006
Titanium .004-.008 .002-.006 .002-.006
High Manganese Steel .004-.008 .002-.006 .002-.006
Note: Double Speed for Carbide Cutting Tools
Recommended Tool Feed
Tool Feed (in./tooth/rev)
Calculate the feed rate for end milling aluminum with a 2 flute, ½ inch HSS end mill.
fm = ft nt N
ft=0.005 in.
Example Feed Rate
tooth ● rev
nt = 2 teeth
fm = 19.1 in.
fm = ft nt N ft=0.005 in.tooth rev
= 1,910 rpmN =CS 12 in.
dft =
tooth revfm = 0.005 in. 2 teeth 1,910 rpm
min
250 ft 12 in.
0.5 in.ftmin
rev
Calculate the feed rate for end milling aluminum with a 2 flute, ½ inch HSS end mill.
Example Feed Rate
See teacher for solution
Your TurnCalculate the feed rate for face milling aluminum with a 4 flute, ½ inch HSS end mill.
• Power of spindle motor• Condition of cutting tool• Depth of cut• Quality of surface finish required• Roughing vs. finish cuts• Condition of the machine• Strength of fixture
Factors That Affect Feed Rates
• Feed rate at which mill can plunge into material
Plunge Feed Rate
pfr = fm
2pfr = Plunge feed rate in.
fm = Feed rate in.min
min
fm = ft nt N pfr = ft nt N2
= 687 rpm
fm = ft nt N pfr = ft nt Npfr = fm
2 2
nt = 4 teeth
ft = 0.002 in.tooth rev
N =CS 12 in.
dft =
tooth revpfr = 0.002 in. 4 teeth 687 rpm
2pfr = 2.7 in.
min
90 ft 12 in.
0.5 in.ftmin
rev
Calculate the plunge feed rate for plunging into mild steel with a 4 flute, ½ inch HSS end mill.Reference charts on next slides
Example Plunge Feed Rate
Milling Speeds for High Speed Steel Tools
Material Cutting Speed in Surface ft/min
Magnesium 300
Aluminum 250
Brass and Bronze 150
Copper 100
Cast Iron (Soft) 80
Cast Iron (Hard) 50
Mild Steel 90
Cast Steel 80
Alloy Steel (Hard) 40
Tool Steel 50
Stainless Steel 60
Titanium 50
High Manganese Steel 30
Note: Double Speed for Carbide Cutting Tools
Recommended Cutting Speeds
Tool Feed (in./tooth/rev)
Material Face Mill Side Mill End Mill
Magnesium .005-.020 .004-.010 .005-.010
Aluminum .005-.020 .004-.010 .005-.010
Brass and Bronze .004-.020 .004-.010 .005-.010
Copper .004-.010 .004-.007 .004-.008
Cast Iron (Soft) .004-.016 .004-.009 .004-.008
Cast Iron (Hard) .004-.010 .002-.006 .002-.006
Mild Steel .004-.010 .002-.007 .002-.010
Alloy Steel (Hard) .004-.010 .002-.007 .002-.006
Tool Steel .004-.008 .002-.006 .002-.006
Stainless Steel .004-.008 .002-.006 .002-.006
Titanium .004-.008 .002-.006 .002-.006
High Manganese Steel .004-.008 .002-.006 .002-.006
Note: Double Speed for Carbide Cutting Tools
Recommended Tool Feed
Now Your Turn
See teacher for solution
Calculate the plunge feed rate for plunging copper with a 4 flute, ¼ inch HSS end mill.
Other special operations require slower speeds:
Reaming – ½ to ⅔ of that used for drilling the material
Counterboring – ¼ of that used for drilling the material
Countersinking – ¼ of that used for drilling the material
Tapping (threading) – Determined by many factors (usually range from 50 to 300 rpm)
CS 12 in./ft
dN =
Special Operations
Black, J., Kohser R. (2008). DeGarmo’s materials and processes in manufacturing (10th ed.). Danvers, MA: John Wiley & Sons, Inc.
Kibbe, R.R., Neely, J.E., Meyer, R.O., & White, W.T. (2002). Machine tool practices. Upper Saddle River, NJ: Prentice Hall.
Oberg, E., Jones F. D., Horton, H. L., & Ryffell, H. H. (2000). Machinery’s handbook (26th ed.). New York, NY: Industrial Press Inc.
References
Recommended
