Helical Ramp Entry Calculator
SI
Imp
Imperial
Inputs
View results
Path input
Choose whether you know the final entry bore/pocket diameter or the actual tool-center helix diameter from CAM.
Bore / pocket diameter
Tool-center path diameter
Tool diameter
(D_tool)
End mill cutting diameter.
in
Bore / pocket diameter
(D_bore)
Final diameter the cutter opens during the ramp. Tool-center path diameter is this value minus tool diameter.
in
Tool-center path diameter
(D_path)
Diameter of the circular path followed by the tool center.
in
Axial depth
(Z)
Z depth to reach at the end of the helical ramp.
in
Ramp angle
(alpha)
Angle of the helical path relative to the XY plane.
°
Entered allowable angle
(alpha_allow)
Your cutter or shop limit for ramp angle. The calculator reports utilization against it.
°
Flat milling feed
(Vf_flat)
Feed you would use for the same tool/material in a normal flat milling move.
in/min
Ramp feed percent
(k_feed)
Percent of flat milling feed to use during the ramp entry.
%
Spindle speed
(n)
Spindle speed used for chip-load during the ramp.
rpm
Flutes
(Zc)
Cutting flute count used for chip load.
flutes
Results
Default result
Edit inputs
Tool-center path diameter
(D_path)
0.5
in
Pass
Also computed
Helix pitch
(Pz)
Pass
0.06858
in
Z drop per full 360 degree revolution.
Revolutions
(Nrev)
Pass
7.29
rev
Entry feed time
(t)
0.5731
min
3D path length
(Lpath)
11.46
in
XY circular travel
(Lxy)
11.45
in
Angular travel
(theta)
2,625
°
Z per degree
(Z/deg)
0.0001905
in
Ramp feed rate
(Vf_ramp)
20
in/min
Axial feed rate
(Vz)
0.8724
in/min
XY feed rate
(Vxy)
19.98
in/min
Ramp chip load
(fz_ramp)
0.001667
in
Entry bore diameter
(D_bore)
1
in
Ramp angle utilization
(alpha/alpha_allow)
Caution
0.833
x
Show 7 more results
Helical ramp entry preview
Helical ramp entry
Tool-center helix geometry and feed-time screen.
Z depth
D_path 0.500 in
pitch / turn
0.0686 in
turns
7.29
entry time
34.4 s
Method notes
4 notes
Tool-center path diameter is bore diameter minus tool diameter.
Helix pitch is pi * D_path * tan(alpha), so shallow ramp angles create many turns and long entry time.
Ramp feed is 50.0% of the entered flat milling feed.
This is geometry and feed-time planning only; controller feed convention, CAM smoothing, cutter ramp limits, chip evacuation, machine acceleration and tool deflection are not modeled.
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