peck tapping cycle

[jdsmith0524]

i started programming a mori 653 vmc w/ mitsu controls and i want to peck my tapping.in the manual it says to change the #8018 parameter for the amount i want to retract after each peck(tap .5 dp per peck and retract .375 each time)which i've done.
it shows the code like this...
M29 S255;
G84XOYOZ-1.Q.5R.2F.1;
G8O;
BUT I GET NOTHING!!!
Can any one help,im tired of taps breaking!!!

[Larry B.]

1st, I the M29 is a sync code for the spindle. It is required for Rigid Tapping, 2nd, I have never heard of peck tapping. I think you mean you want to pull the tap out at a certain depth and then re-tap to finish depth. If correct then I you will need a Compression Tap Holder, this will allow for the tap to start without cross-threading the previous thread and to compensate for Speed/Feed error. To do this you will need to output 2 G84 Cycles and different depths. I have done the in Stainless materials and it does work fine. You will not need to use Rigid Tapping, just a G84 without the M29.

[psychomill]

2nd, I have never heard of peck tapping

Many controls can rigid peck tap. Fanuc, Mazatrol, Haas, etc. I'm pretty sure that a Mitsubishi control can as well (being that they build the Mazak controls). You don't need a compression holder for this. Heck,... you shouldn't even need it for what you're doing. You should be able to do multiple depths in synch mode like this:

M29 S???
G84 X0 Y0 Z-.5 R.2 F??? (First depth)
Z-.75 (Second Depth)
G80

Most machines can do this all day long. You can even tap a bunch of holes, return to home, and run the tap cycle again and still pick up the lead. As long as you don't adjust the tool length, work offset, R plane, or change taps, you can just simply restart your tap cycle. You can even change the Z depth of the cycle and still come out fine if you're adjusting a set up.

Now, for peck tapping. JDSmith, you're code looks fine for most controllers. The "Q" will force the peck. For many machines, there are a couple of parameters that will control this. You may have another parameter that needs to be turned on to allow peck tapping. Or, be sure of the allowable value inputs for the retract parameter. Many machines will also have a parameter for the type of peck. You may have the option of full retract (similar to G83), deep hole cycle (similar to G73), or even a setting for "none". Look for this parameter as well. You're retract value is awfully big but if that's what you're looking for.....

One question, does your machine at least "appear" to be going through the motions? Also, noticed your "X0Y0" and G80 is using the letter "O" instead of a zero. Typo?

[Larry B.]

psychomill, I cant get the Rigid tapping to work the way you decribe without making my threads oversize. If I use a floating holder then it works fine. I have 3 machines only 3-6 months old and have the same problem with all of them. The 1st pass on the tap checks fine with thread gage, but when I repeat at deeper depth for the 2nd pass I get an oversize thread. The thread gage no-go will go about as deep as my 1st pass. I tried this with the floating holder and I get good results. The only time I need to repeat is with gummy materials to clean the tap so it wont break.

[psychomill]

Larry, what machine and control are you running? For the most part, if your machines are only 3-6 months old and running the tap "out of sync", then some adjustments need to be made or the parameters controlling the synch are a tad out of whack. It could also be the spindle parameter as well for orientation. Some machines (even to this day) still can't repeat the spindle synch. Just not nearly as many as it used to be....

[Larry B.]

psychomill,

These machines are Enshu JE80S. The controls are Fanuc 18i-MB. I think there is a problem with the Spindle Snyc. I have a call in for service, and will let you what they find. Thanks.

P.S. It is still my feeling that Rigid Tapping is great, but I still prefer using floating holders for rethreading.

[jdsmith0524]

thanks for your reply larry.heres a couple of thoughts and facts...peck tapping is the only way to go on larger or deep tapped holes as a way to reduce torque on the tool(breakage)on a machine equiped with rigid tapping(synchronise not asynchronise...think thats a bad spelling but im a programmer not a linguist!)if you dont change the starting z point or take the tap out of the collet you can always restart the tap again without cross threading and with the use of special holders(spring loaded).however,this is a lot of programming lines if you got a lot of holes!as i said this is mitsu not fanuc controls but the manual still explains the peck tap i just can't get it to work,also machine needs m29 for g84 to work since the feed in the line must be timed with the rpms.all i can think is im doing somethig wrong still.thanks any way and have a happy holiday!

[jdsmith0524]

thanks physcomill! i never thought of a 2nd z value after the g84 ill try it monday and let you know. if it works maybe you should help mori write their manuals cuz' i followed to the tee!

[psychomill]

JD, hope that works out for you. I used to program alot of Moris (SV series, SL lathes, etc.). But they all had FANUC controls. I don't see any reason why you shouldn't be able to use a "Q" for peck though, even with a Mitsu control. "Q" works on Mori with FANUC control. Should work for you. But the added Z depth I showed you should definately work and will give you a full retract between "pecks".

Larry, definately get that machine checked out. I have buddies of mine with the same machine/control and they are rigid peck tapping, and rigid re-tapping with no problems. Let us know how that machine checks out...

[Willbird]

You just need to learn Engrish JD. :-)

My favorite from way back in a manual for a motorycle on troubleshooting a switch. "If you suspect an evil spirit has taken over the switch........" Some things do not translate well :-). I have the manual for most machines to be a good mnemonic to help you remember what you figuired out a few years back when you did the thing last :-).


Bill