Need Help!- G76 Threading cycle

[noshibby]

I've been perusing a peter smid book on cnc programming.

Currently I'm using a G92 threading cycle to look like:

N620T0404
N630G97S300M03
N640G00X5.174Z0.77
N650G92X4.828Z-4.360I-0.430F0.2501
N660X4.818
N670X4.788
N680X4.758M08
N690X4.728
N700X4.698
N710X4.664
N720X4.634
N730X4.614
N740X4.594
N750X4.584
N760X4.574M09
N770G00Z14.0

And I'm trying to make it into the allegedly superior G76 function.

I'm cutting API 60° threads, 4 TPI 2TFP 0.121 final thread depth

So far I've got it to

G97S350M03
T0400
G00 X5.174 Z0.77 T0404 M08
G76 X4.828 Z-4.360 I-0.430 K0.121 D0140 A60 P2 E0.250

I'm almost certain the "D" is wrong, and I'm still currently missing the "X" value for it to calculate the first thread diameter.

The book ive been referencing is located at Link

at page 352ish.


Just looking for some help as I have no idea where I find what I want those values to be. I believe my control is a Fanuc 0i

[dcoupar]

Originally Posted by noshibby I've been perusing a peter smid book on cnc programming. Currently I'm using a G92 threading cycle to look like: N620T0404 N630G97S300M03 N640G00X5.174Z0.77 N650G92X4.828Z-4.360I-0.430F0.2501 N660X4.818 N670X4.788 N680X4.758M08 N690X4.728 N700X4.698 N710X4.664 N720X4.634 N730X4.614 N740X4.594 N750X4.584 N760X4.574M09 N770G00Z14.0 And I'm trying to make it into the allegedly superior G76 function. I'm cutting API 60° threads, 4 TPI 2TFP 0.121 final thread depth So far I've got it to G97S350M03 T0400 G00 X5.174 Z0.77 T0404 M08 G76 X4.828 Z-4.360 I-0.430 K0.121 D0140 A60 P2 E0.250 I'm almost certain the "D" is wrong, and I'm still currently missing the "X" value for it to calculate the first thread diameter. The book ive been referencing is located at Link at page 352ish. Just looking for some help as I have no idea where I find what I want those values to be. I believe my control is a Fanuc 0i

Noshibby,

First, I've never cut API threads, so...

If X4.574 worked in your G92 cycle it should work in your G76 cycle.

G76 X4.574 Z-4.360 I-0.430 K0.121 D0140 A60 P2 E0.250

4.574 + 0.121 + 0.121 = Dia 1st pass (0.014) is calculated from, so if I'm not mistaken your first pass target X will be X4.778.

[sinha_nsit]

Are you sure one-line G76 applies to your machine?

[dcoupar]

Originally Posted by sinha_nsit Are you sure one-line G76 applies to your machine?

If it doesn't you can change the highlighted setting to enable one-line cycles.

[underthetire]

And don't forget, there are A,B,C type canned cycles. Found that one out trying to use a canned cycle and watching the machine turn in to metric.

[dcoupar]

Originally Posted by underthetire And don't forget, there are A,B,C type canned cycles. Found that one out trying to use a canned cycle and watching the machine turn in to metric.

I'm assuming since his G92 is cutting a thread and not performing a coordinate system preset, he's got G-Code System A