rigid tapping - G94 or G95???

[DavidB]

quote:

---

I have found that the only way I can rigid tap is if I use a floating tap holder, or I'll just keep breaking taps

---

Sounds to me like the spindle and feed are not in sync.

Sounds like your missing a M code in before your tappimng cycle .

[Guest]

It ain't rigid tapping if you have to use a floating head. I know people who insist on floaters even with rigid tapping but with rigid tapping you do not NEED a floating head.

 

I agree with David, it sounds like there is a sync code that is missing, M29 on Fanucs, G93 on older Matsuura's, G84.1 on several machine types.

 

It would seen you are missing something.

[Guest SAIPEM]

It's a distinct possibility that his code is perfect but the machine itself hasn't been properly tuned.

 

I see that all the time.

[mrainey]

We had some Okuma Howas with Fanuc 16M controls that required M29 and the spindle speed in every G84 line.

[BuxtonMachine]

Saipem

I think your right, i don't believe the machine is properly tuned. I did a simple test....I programed it to tap a hole 1" deep at 10 TPI at 350RPM. I ran the program and counted the number of revolutions on the spindle...it should be exactly 10....but came up short by about 10 degrees. By dropping the RPM I could get the spindle within 5 degrees....by increasing the RPM it was even further off (45deg or more). I even got the spindle to miss a beat after it retracted if I ran it at 750 RPM or more. ( It would hunt for it's align position and go heywire as if it lost it's position). SOMETHING IS WRONG HERE !!!! Time to get this machine retuned.

Doesn't really suprise me though, I've had nothing but problems with this machine from the day I bought it.

[c-hook]

Try using just G84 intead of 84.1

[cadmonster66]

Psycho,

I too for many years also programmed in IPR till bout 3 years ago when we got the 2 Cinn. machines Arrow and a Saber. With their rigid tapping cycle all i put in for a feed is like I said F1/20 for the 1/4-20 and a rpm,somehow haven't figured it out yet the control calculates the feed rate for me automatic. When dry running the tapping cycle I will watch the feedrate in my display. Usually the control comes up with a feed rate that i can agree with 70% of the time. If i dont't like the feed just play with RPM either up or down till i get a feed rate i can live with. Pretty much have it down to my first RPM input now. Now you guys got me wondering gonna have to call Tech support in the morning see how the controller figures it out

thx

John

[Psychomill]

Haven't programmed Cinncinati's in many moons.... Can't even recall it... must be a mental block

 

All kidding aside... Looks as if the controler calculates the feed based upon the pitch you're giving it. F1/20 is the same as F.05 . It's probably related to the use of macro calculations. I'm betting if you tap an 8-32, you're "F" would be F1/32 ... in other words a feed of .03125 . You're "canned cycle" is probably inputting a value into variable "F" in which the machine is picking up as a feed rate.

 

[machtek]

Hey John, got any extra monkeys?? Mine always change tap cycles to 1/4-20: 200rpm G94 10 IPM

1/2-13: 130 rpm 10 IPM

 

Buxton, sounds like a loose or malfunctioning spindle encoder. Does the rpm jump around when not under a load??

[BuxtonMachine]

Machtek

It turns out that the main problem with not being able to rigid tap is with the Gain levels on the C-axis drive motor. I'm in touch with Seimens and they are walking me through how to adjust the drives and other parameters.

I don't know about anyone else out there but don't buy a machine from Mighty....I have had nothing but problems with it since the day I bought it.( simple problems like the spindle bearing retaining nut that was never tightened, or limit switches that filled up with coolant because they failed to use waterproof connectors, etc, etc, etc) I think they have monkeys putting their machines together.

[machtek]

Buxton, the thing that made me say encoder was dropping a round or being off by 45 deg. If gain is off you should get a following error or not in-position error unless both of those param's are set really wide.

[BuxtonMachine]

Machtek

The in position specs were way off which is why I wasn't getting an error. It makes me wonder what else isn't set correctly.

[machtek]

Kinda sounds like they loosened up the params to get the thing on your floor. You weren't really supposed to challenge the specs like that, you might void the warranty!!

[BuxtonMachine]

What warranty? I'm way past that point.... unfortunately when i bought the machine years ago the job it was purchased for got cancelled 2 weeks after the machine was installed on the shop floor... and the other work I had lined up was not suited for the machine. So it sat idle for quite some time.... and when I did get back to it and started having all the problems with the machine it was by then out of warranty .... And do you think the dealer or manufactured cared? They just wanted me to trade it in and buy something bigger that cost more $ when I was still making payments on what I had. Needless to say I have had a crash course in trouble shooting and repairing this machine. I would get a job for it and something else would go wrong....I was about to have it airlifted to California and have it dropped through the roof of the factory.