G76 malti purpose threading cycle

G76 Threading Cycle Tips for Thread Pass Control

The below cnc program code is the typical format which a cnc machinist use while programming threading with G76 threading cycle.

N5 G76 P010060 Q100 R0.05
N6 G76 X30 Z-20 P1024 Q200 F2
Depth of First Pass
With Q parameter in second-block of G76 threading cycle you can change the threading depth of First-pass of threading operation.
In the above code Q200 value is given so while threading our tool will take 0.2(mm or inch) deep cut for the first pass.

Depth of Each Pass
For remaining passes depth of cut G76 use First-block Q parameter which is given above as Q100 (0.1 mm or inch).

Depth of Last Pass or Finish Cut
Last of Finish cut is also programmed with G76 as in above code First-block R parameter is given R0.05 (0.05 mm or inch)

Number of Spring Passes
Once the threading cycle has completed the Finish-cut (R parameter in first-block) you can program tool to take extra passes (spring pass) on the same depth for multiple times (to smooth or finish thread surface).
Spring passes can be controlled through P parameter in First-block of G76 threading cycle

P : P actually control three different values which control the thread behavior,

01 : Number of spring passes or spring cuts.
00 : Thread run out at 45 degree
60 : Flank angle or Infeed angle
For spring pass control only first pair value is used of P parameter, as above 01 is given, the tool will take one extra pass, you can change this value according to your requirements.