Hobbing is a gear machining process that generates gear teeth in a series of cuts using a helical cutting tool. The hob and gear blank rotate continuously until all teeth are 

cut. Hobbing can only be used to machine external gears. Advantages of hobbing

Lower total cost per gear than with HSS tools

High cutting speeds

Longer tool life and reduced downtime

Easy and repeatable tool indexing and handling

No additional regrinding or recoating costs

When to use hobbing

Roughing, semi-finishing and finishing

Tooth profiles meet the requirements of DIN 3972-2

Module range: 3–10

Gear hobbing machines, multi-task machines, 5-axis machines

How hobbing is applied

All teeth produce different chips. Tool life is limited by the heaviest cut and the thickest chip. By evaluating the chip thickness, the maximum chip thickness hex can be 

calculated to determine the axial feed rate. The maximum hex is calculated according to the Hoffmeister formula.

Recommended maximum hex = 0.18-0.22 mm (0.007-0.009 in.)

If possible, use the hob shifting feature to extend tool life

Dry milling is the preferred choice when using carbide tools and will achieve longer tool life than wet milling

If possible, use down milling to extend tool life