What's new
What's new

M30 safety issue I found.

SmlG54

Aluminum
Joined
Apr 5, 2018
Found hiccup in M30. Could be safety hazard.

Problem: Even though there was an "M30;" at end of program, control returned to beginning of program but IMMEDIATELY started running from line 1.

Solution: I realized I accidentally engaged the "ARS" switch on my machine (HWACHEON with FANUC O-T)

Other machines may probably have a different "automatic return to start" button.

Could be dangerous and wanted to share solution I found.

I tried to post this already, could populate twice.
 
Well, that's a new one. Repeating the program is normally done with code and would provide for such operations as open chuck, bar pull, close chuck, etc. to allow for a repeat cycle on the next part.

That must be a machine-side Hwacheon feature. My solution would be to break off that toggle switch and weld the hole shut.
 
"My solution would be to break off that toggle switch and weld the hole shut."

I like where your head is at. ;)
 
Don't know what machine you have, but if a lathe equipped with barfeeder it is not uncommon to have a switch for single cycle (ie. stops at M30 and resets the program to top) and continuous cycle (ie. M30 resets program to the top and executes again). This is particularly prevalent on CNC screw machines.

The behavior of M30 can be affected by the machine builders ladder, not entirely under Fanuc's control.
 
I get what you're saying Vanc, but should it not be on the head of the programmer to specify M30 or M99 if/when needed?
Really common on Stars and Miyano's. They have a "One Cycle" button. Turn that off and it will run continuous. Cant see many ways around it on a bar feed lathe. If the M30 was to stop the cycle, the operator would have to cycle start each part.

Regards Phil.
 
Really common on Stars and Miyano's. They have a "One Cycle" button. Turn that off and it will run continuous. Cant see many ways around it on a bar feed lathe. If the M30 was to stop the cycle, the operator would have to cycle start each part.

Regards Phil.

Phil, I believe I get what you're saying but...
Should there not be an another alternative to M30, M02 or M99 instead of a switch?

I don't have, nor have I ever ran a dedicated bar feed machine, so I'm just asking...
 
I get what you're saying Vanc, but should it not be on the head of the programmer to specify M30 or M99 if/when needed?

I for one would rather not depend on Mr. Cherry-Toggle to decide what an M30 does.

Wasn't trying to say it was right or wrong, just an observation that a machine builder can choose to implement things their own way. It is up to the user to learn how their machine operates.

Personally, on a bar fed lathe I like a single cycle/auto cycle selector. Want to inspect the current part or check a tool? Just flip the switch to single cycle and machine stops at the end of the program. All good? flip the switch back to continuous cycle press cycle start and she's back in production.

On machines without this type selector many end their program with...

/M99
M30
%

or

/M30
M99
%

Then with the use of the block skip switch they control a single cycle or continuous cycle. The downside is it does not allow one to use the block skip function for other uses.
 
i had the same on a cmz lathe running billets.damm machine wouldnt stop.yes a button in the top right corner was active.even after power up power down
 
The downside is it does not allow one to use the block skip function for other uses.

For sure!


Obviously many of you have never ran a bar-fed lathe before.


--------------------

Think Snow Eh!
Ox
 
....Should there not be an another alternative to M30, M02 or M99 instead of a switch?

There could be an M-code to run in continuous cycle, it is totally up to the machine builder. You still would like to have some method to stop at the end of a cycle or let it run. One could watch the cycle and turn on single block near the end or something like that, but IMO that is more tedious than just having a selector that determines how M30 behaves.


I believe that the OP probably has a lathe that has a barfeed interface installed even if it currently does not have a barfeed installed and is being used as a chucker. The presence of an continuous auto cycle switch is a natural for use with a barfeeder.
 
I believe that the OP probably has a lathe that has a barfeed interface installed even if it currently does not have a barfeed installed and is being used as a chucker. The presence of an continuous auto cycle switch is a natural for use with a barfeeder.

New to shop, not sure how machine has been utilized prior. We are about to run a job that could sure use a bar feeder but its seems like that would be uncharted waters here, just vibe im getting.

Just wanted to give a heads up in case, or show possibility of danger for those who were unaware.

ONE possibility if available: Call M00 after the part counter has reached certain pre-tool failure count. Or for inspection every 10 parts or such.

(EDIT) yep, boss said (although we dont have one) it is bar feeder compatible.
 
For sure!


Obviously many of you have never ran a bar-fed lathe before.


--------------------

Think Snow Eh!
Ox


Ox, I have not, and I have said as such.
Nonetheless, I still think it's kinda dangerous to to enable M30 to do something it's explicitly NOT supposed to do.
I believe it would be a better practice instead to DISABLE the M99 from restarting using the switch.
 
A) M30 (M2) still ends the prog. It is allowing a re-start AFTER completion of the current program.
It really has nothing to doo with M30.


I believe it would be a better practice instead to DISABLE the M99 from restarting using the switch.

B) 6 of one - half dozen of the other? (You see some difference here?)



C) I have no clue what y'all find so dangerous about this? This isn't an open stamping press, and even if'n it was, you should have your pull-backs on. If you don't, don't blame M30.


This is how any HMC with multiple pallets works too.

This is nothing new folks.... :Yawn:



Actually - a progressive die running continuous would be the same thing, just a mech dog instead of an M code.


-----------------

Think Snow Eh!
Ox
 
....I still think it's kinda dangerous to to enable M30 to do something it's explicitly NOT supposed to do.

What is M30 supposed to do in your understanding? All it really indicates is the end of the program and prepares the control to begin execution at the beginning of the program. The fact that it resets the modals and stops further program execution on the machines you have experience with does not mean that is the one and only way it can function.

I believe it would be a better practice instead to DISABLE the M99 from restarting using the switch.

Unfortunately, that would also disable the use of subprograms. Subs are commonly used on bar fed machines to handle feed out and new bar cut-off.
 
Problem: Even though there was an "M30;" at end of program, control returned to beginning of program but IMMEDIATELY started running from line 1.
Interestingly enough. Tonytn36 gave you a like for that. In his world rewind / start again is measured in tenths of seconds.

I'm lost.

Regards Phil.
 
My Tsugamis have it as "cont", short for continue.

Machine sees the M30, and starts the program over. Can be run where the bar never stops spinning even after seeing the M30 if you like(Shortens cycle time on bar re-grip).

It's a must on the swiss machines, but can see it might cause some surprise if not aware of the buttons use and it's hit by accident.
 
On my Hardinge GT27 the cycle repeat is used when feeding bars and when the auto-door opener is used when chucking. Without the cycle repeat you have to push the start button twice when the auto-door is used, only once with the cycle repeat active. The GT has this button on the far left away from the collet chuck and start buttons, and it does have an indicator light when active.
On the machines that have the cycle repeat button or switch and it is safety concern would 2 consecutive M30s work? maybe with a .1 second pause between them?
As mentioned on the previous post the M30 does not stop the spindle when cycle repeat is active. When chucking and using the auto door, I have already turned the spindle off before pulling the last tool away so the spindle has stopped before the door opens.
 
...Unfortunately, that would also disable the use of subprograms. Subs are commonly used on bar fed machines to handle feed out and new bar cut-off.
My lathe doesn't have any switch for auto restart.

On barfeed programs, I begin the program with the barfeed sub, and end the main program with M99. If I don't want a continuous loop, I end the program with M30. I put an M01 after each tool so I can stop the cycle to measure the part.

Morning startup- just push the material into the collet so it clears, run the last (partoff) tool in air, control reads the M99, returns to the start of the program and the barfeed subroutine positions the material for the first part of the day.

I put a block skip at the M98 line in case I want to skip the barfeed sub, but I never use it...
 
So to everyone who already knows about bar feeder applications, pallet changing and all that: ....well then obviously there was nothing to learn or no danger present if already aware of functionality, right?

This was meant for those who were not aware and how to possibly resolve issue (just an easy little toggle switch).:cool:
 








 
Back
Top