fanuc ot multiple lead threads

[Hofi]

Hello all,
Has anyone an Idea if it's possible to program a multiple leaded thread, on a turning machine controlled by a fanuc ot controller.

thank you for you help,
hofi

[Chris D]

Originally Posted by Hofi Hello all, Has anyone an Idea if it's possible to program a multiple leaded thread, on a turning machine controlled by a fanuc ot controller. thank you for you help, hofi

Do you mean mult-start thread?

[Hofi]

exactly a thread with two startpoint's ...

[Dan Fritz]

All you need to do is back up the starting point of the threading cycle by 1/2 of the thread lead.

All Fanucs use a "zero pulse" in the spindle encoder to start the threading pass. The zero pulse happens at the same spindle angle each time, so all you can do is shift the start point in Z to get your second threading pass that's 180 degrees out from the first pass.

For a 10 pitch thread, you have .1000 per revolution, so back up the Z start point by .0500 and cut the same threading cycle, using the same Z as the end point.

[Hofi]

Thank you very much, i definatly give that a try .........

[cogsman1]

Multi start threads


Feed rate will be PITCH x # of starts

Each start will back up one pitch

Exam:

3 start thread

32 tpi = .0313” pitch

feed = 3 x .0313” = .0938”

start 1st thread at .050”

second thread at .050” + .0313” = .0813”

third thread at .0813” + .0313 = .1126”

T0500
S1=2000M3
G0X.238Z-.05T5
G4U.5
G76P010015Q.003R.001
G76X.0996Z.8P.0192Q.0083F.0938
G0X.238
Z.0813
G4U.5
G76P010015Q.003R.001
G76X.0996Z.8P.0192Q.0083F.0938
G0X.238
Z.1126
G4U.5
G76P010015Q.003R.001
G76X.0996Z.8P.0192Q.0083F.0938
G0X.238

This would do a 3 start 32 pitch OD thread.