Fanuc Oi breaking taps

[MamboD]

Hi guys, I have a customer who is breaking m20 taps on a rigid tapping cycle. I've check the machine mechanically and it's all good, no backlash in the gearbox/spindle, backlash on the Z has been compensated for to the micron. The only thing left to check is Z to spindle synchronization which I will do next week.

I just wanted to post his programme for tapping so someone who know programming better can tell me of its A-ok. Or if our issue may be stemming from the code:

T5 MO6;
M01;
G80 G90 G17 G40 G00 G98
G55;
G00 X36.355 Y87.769 S200 M03;
G43 H5 Z100.0;
G84 Z-38.0 R5.0 M08 F500;
X67.175 Y67.175 G98;
G80;
G00 Z100.0;

Any help would be greatly appreciated

 

[usolutions]

Does it break mid thread or on entry? I have encountered this behaviour, that on G84 cycle spindle stops, does orientation of spindle and then starts thread, but during this process is already has axis syncronised and it makes a wierd jerk. By removing M03 and just leaving S command, I managed to get rid of this behaviour.

 

[angelw]

Hi guys, I have a customer who is breaking m20 taps on a rigid tapping cycle. I've check the machine mechanically and it's all good, no backlash in the gearbox/spindle, backlash on the Z has been compensated for to the micron. The only thing left to check is Z to spindle synchronization which I will do next week.

I just wanted to post his programme for tapping so someone who know programming better can tell me of its A-ok. Or if our issue may be stemming from the code:

T5 MO6;
M01;
G80 G90 G17 G40 G00 G98
G55;
G00 X36.355 Y87.769 S200 M03;
G43 H5 Z100.0;
G84 Z-38.0 R5.0 M08 F500;
X67.175 Y67.175 G98;
G80;
G00 Z100.0;

Any help would be greatly appreciated

In your program example, Rigid Tapping is being started with G84. For this to be valid, parameter bit 5200.0 needs to be set to "1". If set to "0", an M code will be used as set in parameter 5210 in the range of 0 to 255. If parameter bit 5200.0 is set to "0", and parameter 5210 is also set to "0", then the default "M" code M29 will apply. Also, as

usolutions mentioned, specify the spindle speed without M03, the Tapping Cycle will start the spindle.​

Regards,

Bill

 

[gmc1724]

Hi guys, I have a customer who is breaking m20 taps on a rigid tapping cycle. I've check the machine mechanically and it's all good, no backlash in the gearbox/spindle, backlash on the Z has been compensated for to the micron. The only thing left to check is Z to spindle synchronization which I will do next week.

I just wanted to post his programme for tapping so someone who know programming better can tell me of its A-ok. Or if our issue may be stemming from the code:

T5 MO6;
M01;
G80 G90 G17 G40 G00 G98
G55;
G00 X36.355 Y87.769 S200 M03;
G43 H5 Z100.0;
G84 Z-38.0 R5.0 M08 F500;
X67.175 Y67.175 G98;
G80;
G00 Z100.0;

Any help would be greatly appreciated

 

[gmc1724]

Should the F command have a decimal point?

 

[13engines]

Should the F command have a decimal point?

Not if the 20mm thread has a 1/2 mm pitch. (Programmed in Least Input Increment)

 

[SpeedsandFeeds]

Based off of your RPMs and feedrate you should be using a M20x2.5 tap. If your using a M20x1.5 tap your feed should be 300.

 

[MamboD]

Does it break mid thread or on entry? I have encountered this behaviour, that on G84 cycle spindle stops, does orientation of spindle and then starts thread, but during this process is already has axis syncronised and it makes a wierd jerk. By removing M03 and just leaving S command, I managed to get rid of this behaviour.

It only breaks on retraction. It will tap the hole perfect, and then when it reaches depth and extracts, it breaks the tap. I am going to the machine Wednesday for an indepeth evaluation

 

[sinha]

Please read post # 3, to confirm if you are actually using rigid tapping.

 

[13engines]

Not if the 20mm thread has a 1/2 mm pitch. (Programmed in Least Input Increment)

Everybody please continue to ignore post #6. Totally wrong and dumb answer, if I do say so myself. :-)

Iffen we're talking 2.5mm per, gmc1724 had it right all along.

 

[usolutions]

Add dwell to tapping cycle, should helo with direction change transition

 

[usolutions]

It only breaks on retraction. It will tap the hole perfect, and then when it reaches depth and extracts, it breaks the tap. I am going to the machine Wednesday for an indepeth evaluation

Hi, So have you managed to fix your problem?

 

[Mtndew]

What is being used to drive the tap?
Is it a tap collet that has a square?
Is it a tap holder that actually has some give to it or is it just a plain jane ER collet holder?
Get an actual tap holder.
What material are you tapping? 200rpm is on the slow side in mild steel for a 20mm tap.
If it's a mild steel I'd be going about 340rpm and a feed of 33.4545 ipm (.09842 inch per rev for an M20 x 2.5 tap)

 

[BobM3]

Don't you need an M29 to sync the spindle and vertical?