Feed Rate Calculator
When milling or drilling, or creating a tool path for a CNC machine the feed rate must be determined. Materials have rated surface speeds for a given type of cutter. The harder the material the slower the speed. Given the diameter of the tool and the surface speed, the RPMs of the spindle can be calculated. Then if the tooth load for the cutter is know, and the number of teeth, the feed rate can be determined.
Milling Speeds (HSS End Mills) |
|
| Material | Average Tool Speed (S.F.M) |
| Magnesium | 300 |
| Aluminum, 7075 | 300 |
| Aluminum, 6061 | 280 |
| Aluminum, 2024 | 200 |
| Aluminum, Cast | 134 |
| Brass | 400 |
| Bronze | 150 |
| Copper | 100 |
| Cast Iron (soft) | 80 |
| Cast Iron (hard) | 50 |
| Mild Steel | 90 |
| Cast Steel | 80 |
| Alloy Steels (hard) | 40 |
| Tool Steel | 50 |
| Stainless Steel | 60 |
| Titanium | 50 |
| High Manganese Steel | 30 |
S.F.M. is surface feet per min.
Drilling Speeds (HSS Drills) |
|
| Material | Average Tool Speed (S.F.M) |
| Magnesium | 300 |
| Aluminum | 250 |
| Brass and Bronze | 200 |
| Copper | 70 |
| Cast Iron (soft) | 120 |
| Cast Iron (hard) | 80 |
| Mild Steel | 110 |
| Cast Steel | 50 |
| Alloy Steels (hard) | 60 |
| Tool Steel | 60 |
| Stainless Steel | 30 |
| Titanium | 30 |
| High Manganese Steel | 15 |
TOOL FEED (in/tooth) |
|
| Material | End Mills |
| Magnesium | 0.005 - 0.010 |
| Aluminum | 0.005 - 0.010 |
| Brass and Bronze | 0.005 - 0.010 |
| Copper | 0.004 - 0.008 |
| Cast Iron (soft) | 0.004 - 0.008 |
| Cast Iron (hard) | 0.002 - 0.006 |
| Mild Steel | 0.002 - 0.010 |
| Cast Steel | 0.002 - 0.006 |
| Alloy Steels (hard) | 0.002 - 0.006 |
| Tool Steel | 0.002 - 0.006 |
| Stainless Steel | 0.002 - 0.006 |
| Titanium | 0.002 - 0.006 |
| High Manganese Steel | 0.002 - 0.006 |
Design Equations
RPM = (12 * Surface_Speed) / (PI * Cutter_Diameter)
RPM= 3.82*Surface_Speed/Cutter_Diameter/p>
Fm= Ft x Num_Teeth x RPM, where Ft is feed/tooth, and Fm feed rate.
