The G76 threading cycle is an essential feature in CNC programming for creating precise threads on a workpiece. Fanuc 10/11/15T controls utilize a one-line format for this cycle, which simplifies the programming process while ensuring accuracy and repeatability.

Usage Format

The one-line format for the G76 threading cycle is as follows:

G76 X... Z... I... K... D... A... F... P...

Explanation

• X: Final thread diameter
• Z: Position of the thread end
• I: Amount of taper for the thread
• K: Single thread depth
• D: Depth of the first pass
• A: Thread angle
• F: Thread lead or pitch
• P: Infeed method

Each parameter is critical for defining the thread’s characteristics, ensuring that the machine executes the cycle according to the specified requirements.

Example

Let’s consider an example where we need to program a thread with a final diameter of 50mm, a length of 100mm, a taper of 0.5mm, a single thread depth of 0.25mm, a first pass depth of 0.05mm, a thread angle of 60 degrees, a pitch of 1.5mm, and a straight infeed.

The G76 threading cycle would be programmed as:

G76 X50 Z-100 I0.5 K0.25 D0.05 A60 F1.5 P...

Text Diagram

Here’s a text diagram to illustrate the threading cycle:

|-----------------100mm-----------------|
|                                       |
|                                      /
|                                     /
|                                    / 0.5mm taper
|                                   /
|                                  /
|---------------------------------| 50mm diameter

In this diagram, the taper is represented by the lines converging towards the end of the thread, and the diameter is indicated by the width of the thread at the base.