The following data is a partial listing of information needed to assist in determining the approximate size of a spindle for a particular application.
For more complete information on speeds, feeds, materials,operations, power requirements, etc., consult Machinability Data Center (Metcut Research Associates, Inc.) handbook or similar publications.
•Use lower speeds for side and slot milling, heavy roughing cuts, hard, tough or abrasive materials, rigid parts and fixtures and maximum tool life.
•Use higher speeds for face milling, light finishing cuts, soft materials and less rigid parts and fixtures.
•Use slower feeds for side and slot milling, light finishing cuts, hard materials and less rigid parts and fixtures.
•Use faster feeds for face milling heavy roughing cuts, soft,or abrasive materials and rigid parts and fixtures.
The above information and data in tables at left is generally accepted as good practice, however variables such as part configuration, type of fixturing, dimensional tolerances, surface finish, tool geometry, tool overhang etc., all affect performance. Therefore the recommendations for speeds, feeds and horsepower are nominal and should be considered as good starting points. For final selection, consult a cutting tool specialist for the latest in cutting tool performance data.
Some helpful suggestions: keep cutter or tool extension to a minimum; use sufficient and the proper type of coolant; prevent chips from accumulating near cut; protect spindle from coolant and chips with adequate guarding.
Consult SKF's Engineering and Sales Department for assistance in selecting a spindle suitable for a particular application providing the following information:
1.Material being machined and hardness.
2.Tool material, diameter, and number of teeth.
3.Type of operation face milling, slot milling, boring etc.
4.Maximum depth and width of cut or maximum area of material being machined in plane at right angles to the direction of feed.
5.HP and RPM required.
Machining formulas
FPM = Peripheral speed of tool in feet per minute
RPM= Speed of tool in revolutions per minute
IPT= Feed rate of tool in inches per tooth
IPR= Feed rate of tool in inches per revolution
IPM= Feed rate of tool in inches per minute
D= Tool diameter in inches
N= Number of teeth in tool
d= Depth of cut in inches
w= Width of cut in inches
A= Area of material machined at right angles to direction of feed
P= Unit power factor in HP per cu. in. per min.
(At motor, corrected for 80% drive eff.)
RPM= 3.82 x FPM ÷ D
FPM = RPM x D ÷ 3.82
IPM= RPM x IPT x N = RPM x IPR
Boring HP = 12 x FPM x IPR x d xP
Gun drilling HP = .79 x D2x IPM x P
Milling HP = d x w x IPM x P = A x IPM x P
Torque (in.-lbs.) = HP x 63025 ÷ RPM |
