1. What is Cutting Speed?

Cutting speed (SFM - Surface Feet per Minute) is the speed at the outside edge of the tool as it is cutting. It is measured in surface feet per minute (SFM) and is critical for proper tool life and material removal rates.

2. How Does the Calculator Work?

The calculator uses the cutting speed formula:

Where:

• \( CS \) — Cutting speed (feet per minute)
• \( Diameter \) — Tool or workpiece diameter (inches)
• \( RPM \) — Spindle speed (revolutions per minute)
• \( \pi \) — Mathematical constant (~3.1416)

Explanation: The formula converts rotational speed to linear speed at the tool's outer edge, accounting for the circumference of the tool.

3. Importance of Cutting Speed Calculation

Details: Proper cutting speed is essential for optimizing tool life, achieving good surface finish, and maintaining efficient material removal rates. Too high can cause tool wear, too low can cause poor finish.

4. Using the Calculator

Tips: Enter the tool or workpiece diameter in inches and the spindle speed in RPM. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What units should I use for diameter?
A: The calculator expects diameter in inches. For millimeters, convert to inches (1 inch = 25.4 mm).

Q2: How does cutting speed affect tool life?
A: Generally, higher speeds reduce tool life due to increased heat and wear, but too low can cause other issues like built-up edge.

Q3: What are typical cutting speeds for different materials?
A: Aluminum: 250-1000 SFM, Steel: 100-400 SFM, Plastics: 300-2000 SFM (varies by specific material and tool).

Q4: Should I use tool diameter or workpiece diameter?
A: For turning operations, use workpiece diameter. For milling/drilling, use tool diameter.

Q5: How does cutting speed relate to feed rate?
A: They work together - feed rate (IPM) = RPM × number of cutting edges × chip load (IPT).