Forced rigid tapping

[somename75]

When setting the speed and feed for a tapping operation mastercam forces them to match or be rigid in other words. A lot of our machines are not capable of rigid tapping so I have to use floating holders and hand edit the feed rate to allow the holder to do its job. I hate hand editing code in any way, so I'm wondering if there is a switch to turn off this setting in mastercam. Thanks for your help

[Chris Parish]

You could modify your post to use the misc 1 / misc 2 options as to use a floating tapping head option. We do that alot depending on operator, we use G84 (tap in/min) or G84.1 (tap in/rev). In this case you are really tapping / boring with a diffrent feedrate than spindle RPM

[mayday]

Huh?

 

1/4-20 tap = .05 pitch

500 RPM , 25 IPM floating or rigid what do you want as a default

[somename75]

The way I see it right now, If I want to tap a 1/2-13, and in the operation I put in 130 RPM it will force the feed to be 10. IPM, I would like to have it feed at 9.9 so the floating holder will work correctly. I have not been able to find a switch to get it to stop automaticly adjusting the feed based on RPM. I hope this is a little clearer. Thanks for your replys

[Chris Parish]

Rigid tap does just that, it syncronizes that spped and feed (No way around it I found). The alternative is to modify the post to out G84 (tap) / G86 (bore) but really using the floating tapping head - I modify it by using a different canned cyle option but achive the result I want.

[somename75]

Thanks Cparish, I have and will continue to work around this, it just seems kinda dumb for there to be not switch to disable that. Thanks for your help

[Chris Parish]

If you want me to take a look at the post, e-mail me and I will help you. It s neat litlle way of doing it (please include post and text file)

[Nominal]

You want to go into job setup and change it to get the feedrate from the tool rather than the material. Then you can set the feedrate to whatever you want in the tool parameters.

[Steve Biehl - Cimquest Inc]

it's easy to adjust the post to output a percentage of the calculated feedrate.

 

From Mpfan.pst:

code:

---

ptap            #Canned Tap Cycle

pdrlcommonb

result = newfs(17, feed) # Set for tapping Feedrate format

result = feed# <=== ADDED to save original feed

feed = feed * .99# <=== ADDED to reduce feed

pcan1, pbld, n, *sgdrlref, *sgdrill, pxout, pyout, pfzout, pcout,

prdrlout, *feed, strcantext, e

pcom_movea

feed = result# <=== Added to restore feed

!feed# <=== Added to update feed

---

[somename75]

Thanks for all the suggestions, I will probably edit the post this weekend. Thank god its friday

[chris m]

Damn Steve, you beat me to it

 

I was gonna say the same thing, but I'd go .98 as long as you don't do real deep holes with coarse threads as you'd run outta float

 

If you go tension/compression [which sucks, by the way] instead of straight tension you might be able to get away with 100% feed but I wouldn't

try it

 

C

[Frank]

Wow I've always used the straight feedrate, for floating holders, or for rigid tapping, and never had a problem ( I am talking 1000's of holes) it's a floating holder, I would think the optimate feedrate would be as if you were rigid tapping.

 

Am I wrong ??

[chris m]

If your machine has synchronized tapping; no. But if your machine has synchronized tapping you shouldn't be using floating holders anyway. If you don't have synchronized tapping it is typically safer to underfeed the tap slightly so that the tap is pulling on the tension spring in your holder; pushing against the tap will often result in breakage.

[Frank]

Wouldn't that throw off your depth of the tap ?

 

Frank

[Frank]

So I should multiply my feedrate (rigid) by .98 or what would be the exact formula ?

 

Thanks

[chris m]

1) The depth will be affected somewhat but it should repeat from hole-to-hole

 

2) I use .98 but some of the other guys use .99; personal preference

 

C

[Frank]

Thanks,