Milling Speed
Closely follow the proper cutting
Prior to machining, you need to determine the best speed to cut your workpiece, and then set that speed on the machine.
To determine the needed speed for milling:
1.Use the table in Figure 32 to determine the cutting speed required for the material of your workpiece.
Cutting Speeds for High Speed Steel (HSS)
Cutting Tools
Workpiece Material | Cutting Speed (SFM) |
|
|
Aluminum & alloys | 300 |
|
|
Brass & 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 |
|
|
Plastics | |
|
|
Wood |
Note: For carbide cutting tools, double the cut- ting speed. These values are a guideline only. Refer to the MACHINERY'S HANDBOOK for more detailed information.
Figure 32. Cutting speed table for HSS cutting
tools.
2.Measure the diameter of your cutting tool in inches.
Model G0517 Mill/Drill
3.Use the formula in Figure 33 to determine the needed speed for your operation:
Figure 33. Speed formula for milling.
Note: Always round to the closest RPM given on the spindle speed chart.
Example 1
You have a piece of aluminum stock, and you are using a 1⁄2" diameter HSS cutting tool.
Step 1:
300 (SFM from chart) x 4 = 1200
Step 2:
1200 / .5" (Diameter of cutting tool) =
2400 RPM
Result:
The best speed for this workpiece is 2400 RPM.
Example 2
You have a piece of stainless steel, and you are using a 1" diameter carbide cutting tool.
Step 1:
60 (SFM from chart) x 2 (for carbide tool) = 120
Step 2:
120 (determined SFM) x 4 = 480
Step 3:
480 / 1" (Diameter of cutting tool) = 480
RPM
Result:
The best speed for this workpiece is 480 RPM.
