[J S Machine]

Is there a way to ontrol how many revolutions in reverse the machine performs when doing a peck tapping cycle?

I have the follwing code:

G84 G99 X*Y*Z* R.1 Q.1 F*

The Q is the feed rate down, which it is progressing into the hole .1" every time like it should. However, on the reverse, it only turns in reverse for maybe 1/8 of a turn before going back forward. Is there a letter designation to control this?

[the_gentlegiant]

You don't state your machine type or control model so are not helping yourself out any, especially because the settings you're after are parameter settings and not some generic G code manipulation. Give more and you get more. Just sayin...

Generic answer - the return, clearance-on-return and retract amounts and/or plains for canned drilling cycles are usually set in parameters. Get out your parameter manual and start digging. Maybe search "retract" or "clearance". That or scour the sections that have to do with fixed cycles.

On another note. Pecking is a chip breaking exercise, not a chip removal one. What your machine is doing now is satisfying that demand. Meaning that small back turn is definitely breaking the chip. Pecking tapping in hopes that the tap will carry the chip out of the hole is a shot in the dark. Drills are a little different in that their flutes will capture some chips and carry them out of the hole do to the speed of retraction and of the turning spindle. I don't believe you get that kind of chip removal action out of a tap. I have little experience in peck tapping but have a good imagination about the likely outcome. I don't see the chips behaving time after time.

Your best bet is use the proper tap, spiral flute for blind or spiral point for thru hole, and tap all the way there in one basic G84 without the Q. Better yet is to use a form tap for either, then your chip handling worries are over.

[J S Machine]

Sorry, I didn't realize the other factors were so important. It is a Hyundai Kia VX400 three axis vertical. The control is a oi-MC.

You are correct, it is definitely breaking the chip. This is also a blind hole situation and I am using the correct spiral flute tap to help evacuate chips. It is a deep hole situation though and I am trying to avoid breaking taps. I'm not trying to evacuate chips with the reverse motion, I am just trying to get a little more reverse motion than I am currently getting to maybe be a tad more effective.

I ran a Cincinnati Arrow machine with acramatic programming before and this was easily controlled in a G84.1. There was a letter value that could be changed in the line to control how many reverse turns the tap made.

[the_gentlegiant]

Ha... welcome to Fanuc.
Here is your info. Looks like possibly 5213. See attachments

BTW - that took me all of 90 seconds to find that information off the internet. Every Fanuc book ever written is on the www for free. Pretty much anyway.

[Armageddon]

Or 5101 RTR ?