custom tapping cycle to feed in/feed out at different feed

Is it at all possible to write a custom tapping cycle to feed in at one pitch (thread the insert in the part) and feed out at a different pitch (unscrew the drive from the insert)? machine Toshiba with Tosnuc control.

cheers
T

If you're talking about thread inserts like Helicoils and such, you don't need to do what you're asking, as the thread in pitch and the remove tool pitch are the same. If you're talking about something completely different, you could write a subroutine like below.

We'll leave out the fact for now that you'd likely have to do the entire process of tapping and inserting starting with a spindle orient (M19) on each hole. It's slightly possible you could get away without on the inserting with the tension compression holder. That is... with a lot of luck.

Let's use 20 threads in and 18 out. Four holes in a line. Threading in about 1/2" deep. Using a tension compression holder for your tool. This is generic Fanuc G codes. Not sure exactly what your Tosnuc control uses.

T2M6 (THREAD INSERT TOOL)
G17G20G40G49G54G80G90G98

M00 (LOAD INSERT)

G0X1.Y1.
G43Z0.1H2S300M3
M98P20
X2.
M98P20
X3.
M98P20
X4.
M98P20
G53Z0.Y0.
M30


O20 (THREAD INSERT SUBROUTINE)

G0Z0.1S300M3
G4P500
G1Z-0.425F15.
M5
G4P500
S306M4Z0.1F17. (May need to experiment and possibly put this info on two lines. Here is where the tension compression holder is going to come in handy.)
G0Z5.M5
M00 (LOAD INSERT)
M99

You'd have to experiment with the depth and dwells depending on how fast your spindle stops and starts. May be able to skip the M5 in some spindles. (Like built in type.)

But really I think you have nothing to worry about. (See first sentence)

much appreciated the_gentlegiant,
These guys are self threaded inserts for plastic, lifting points. The internal thread is M8X1.25 and the outside is a m12X1.75. My machine have some extra modal codes which don't work for this application so, I'm ordering a floating tapping head and thinking on running a tapping cycle at F1.75 and see how that goes. Either way, I will be needing a floating head.
in this particular case, the ideal would be going in at F1.75 and out at F1.25

I will be trying your suggestion indeed. But I need the feed to be synchronized with the spindle and I don't see that on your program and subroutine. Are you calling the G95?

cheers

If I'm understanding you correctly, these inserts are driven into a drilled hole and cutting their own threads in the process. That makes all this so much easier. The programming I offered is still suitable for this. Understand that most machines without Rigid Tapping are tapping with non - synchronized feed and spindle rotation. That's the whole reason you use tension - compression holders on these machines. The holders compensate for the less than perfect tapping system. I'll change this to metric as I see that's what you work in. Plus it's so much easier. I'll also slow it down a little.

T2M6 (THREAD INSERT TOOL)
G17G21G40G49G54G80G90G98 (Placing machine in clean, ready state w/G54 work offset)

M00 (LOAD INSERT)

G0X25.Y25.
G43Z5.H2S100M3
M98P20
X50.
M98P20
X75.
M98P20
X100.
M98P20
G53Z0.Y0.
M30


O20 (THREAD INSERT SUBROUTINE)

G0 Z5. S100 M3
G4P500 - (Dwell 1/2 second)
G1 Z-12.5 F175.
M5 - (Stop spindle)
G4P500
Z5. F125. M4 - (Using same spindle speed so no need to call it again. Just reverse spindle.)
G0 Z250. M5
M00 (MACHINE STOP - LOAD INSERT)
M99

This programming will likely work. The synchronization in the above is for all practical purposes the same as a standard G84 tapping cycle on a machine without Rigid Tapping. (G84 Fanuc right hand tapping cycle) You can play with the dwell as needed, even to the point of possibly removing it.

nice!!! and, yes, these inserts are driven into a drilled hole and cutting their own threads in the process.

I'm ordering a tension/compression collet holder tomorrow---I was hoping that I could just do it with a normal collet holder like we do all the time in the lab.
Last time I used a tension/compression tapping holder was probably around 15 tears ago...

Thank you so much, tomorrow I'll try this first thing and will post the results on here :)
cheers

hy print, i did not have patience to read the entire conversation in detail, but, if you have a tapping cycle, then it may be possible to feed out at faster speed by changing a parameter inside the controller :) so far i have used to feed out at 130-170%, but i don't know about such a parameter for your machine :) such a parameter may also manage the reversal spindle rpm ...

Quote:

---

I'm ordering a tension/compression collet holder tomorrow-

---

if you wish to keep your process stable, and also feed out faster, then you need to know how the machine behaves

for example, when feeding in, how much does the spindle phase deviate from the linear axis, so to know what "extension" is needed inside that custom holder; maybe you need 0.3mm, or 6 mm ?

also, when you feed out faster, again, you must know those lags, so to have the "extension" as long as it should

also, there is a lag when rpm changes direction, and maybe, you need a clutch ?

what i am tring to say, is, if you don't know these values, you may ruin the holder :) thus it may start to extend/compact beyond his capability; for example :
... if machine has lag, then you need greater extend/compact capabilities and to use lower rpms
... if machine has small lag, thus it syncs ok, then you need small extend/compact capabilities ( like 0.1-0.5 ), and you may use higher rpms

so, is good to know those numbers :)

also, there are some custom holders with clutch, that protect the tool when depth is reached, and, when feeding out, they can reverse faster, even if feed out is = feed in; of course, they are a bit more expensive / kindly :)

Hi Print,

Glad to hear you think it will work out.

What deadlykitten is talking about with the lag and all is directly related to the dwells and clearance heights I offered, They're there to help deal with the lag, and is why I said you'll have to experiment with them. You'll even need to adjust your tapping Z height because it will take a second for the spindle to stop, so your insert will go in slightly farther than programmed. Though at the slow rate of 100 RPM's, you won't have tons of trouble with that. Only when you start really speeding things up will that become a bigger factor. I suggest you do some testing in front of a part or in front of something that will give you reference to watch how your machine moves. How the timing of everything is. You might be able to make some obvious adjustments before trying it in a real hole.

Deadly also mentioned the parameter change to come out of a tapped hole faster then going in. This functionality does exist, but it will do you no good because there aren't also provisions to change the feed rate along with the speed, and you need that in your situation. In a Rigid Tapping cycle, the synchronization is set by the feed and spindle speed entered at the beginning of the cycle. I know of no place to change the feed mid cycle. If someone knows of such a thing, I'd love to hear about it.

Not sure how and where you'd get a custom tension compression holder. The clutch tap holders mentioned help limit the torque a tap will see. They'll help for a while if you bottom out on a blind hole, but if you also bottom out your tension.compression holder, you're still going to break the tool/tap, clutch or not. You may end up having to grind down the shank of your insert tool to match some sized tap collet.

Anyway... good luck with it all.

Hi the_gentlegiant,

It works indeed. I just tried it with a collet holder and works good, it just leavs a tinny damage to the insert because of the "lag"... I might need to play around a little more with the dwell. I figured that I need to go 2MM shallow in order to acquire the desired depth.

N180 M69 (C AXIS BRAKE OFF)
N190 G00 B0. C-270.
N200 G57 H902
N210 G173 W-250.
N220 M68 (C AXIS BRAKE ON)
N230 G57 H902
N240 G173 W-250.
S100M3 F262.500
N260 G00 G90 X0. Y0.


N270 G43 H28 Z100.
G0Z10.

G4P5
G1Z-12.F180. (desired depth = 14)
M5

G4P5
Z10.F125.M4
M5

M01 (LOAD TRISERT)

The tension/Comp TAP Chuck that i might order, will decide Monday, is the item 1288256 from Kennametal.

Thanks a lot!!!
Cheers

Hi Print,

Cool... glad it's working out. Your code with a C axis makes me think you're running a lathe? I was programming for mill. No experience here on CNC lathes, only manual. I see you got your in feed at 180. Is that on purpose? Thought you were after 175.

Would be great if you got it working without spending the cash on a tension compression holder. Anyway... glad to help. Have at it!

Hi the_gentlegiant,

This is a huge Milling Horizontal table/table configuration, I love this machine, I've been doing all kind of crazy stuff on this...from 1.5meter diameter vessel ball with 264 stubs sticking out to spiders and all kind of stuff really. 5-axis/multiaxis is my forte.
It improved the damage a little changing it to 180.

Totally, I wouldn't be paying for the tool but you are right!!!
hey! have a great weekend!