Cutting Force Calculation for Estimating Spindle Torque

Accurate cutting force calculation is essential for selecting the proper spindle torque and power specifications in machining processes. Cutting forces are influenced by various factors such as cutting speed, feed rate, tool diameter, and material coefficient. The following explains three major calculations: cutting parameters, drilling power, and milling force.

 

1. Cutting Speed and Feed Rate

Spindle speed (n, rpm) is calculated as:

n = (Vc × 1000) / (π × ØD)

• Vc: Cutting speed (m/min)
• ØD: Tool diameter (mm)

Feed rate (f, mm/rev) is calculated by:

f = fz × z

• fz: Feed per tooth (mm)
• z: Number of teeth

 

2. Drilling Power and Torque

To estimate drilling power (Pc) and drilling torque (Mc):

Pc = (K × D² × n × (0.647 + 17.29 × f)) / 106 

Mc = (K × D² × (0.63 + 16.84 × f)) / 100

• K: Material coefficient
• D: Drill diameter (mm)
• f: Feed per revolution (mm/rev)
• n: Rotation speed (rpm)

These formulas help evaluate the load required from the spindle during drilling, preventing overload and tool failure.

 

3. Milling Power and Torque

Milling power (Pc) is calculated by:

Pc = (Kc × ap × ae × Vf) / (60 × 106 × η)

• Kc: Specific cutting force (N/mm²)
• ap: Depth of cut (mm)
• ae: Width of cut (mm)
• Vf: Feed per minute (mm/min)
• η: Machine efficiency

Milling torque (Mc) is:

Mc = (Pc × 30 × 10³) / (π × n)

      By estimating milling power and torque, users can properly match spindle torque capabilities to cutting demands.