Old Hardinge Conquest T51 SP going into Feed Hold in mid-cut

Tungsten Carbide · May 24, 2019

The machine is randomly stopping at different parts of the programs on different tools and going into Feed Hold. Part keeps turning, but tool stops in the middle of travelling and the red Feed Hold light comes on. When I press Start it picks up where it left off, but the part is already grooved where the tool stopped feeding and dug in. Anyone else ever have this on a Hardinge, or any other machine? Could it be a voltage spike that tweaks it out or something?

Gene

Ox · May 25, 2019

This is an 18T?

Does it happen often enough that you can watch the ladder while it runs?
(I'm guessing "not")

Could be that it is seeing the Feed Hold button even tho you are not pressing it?
If you find the Feed Hold button input in the ladder, see if there is any flicker at all.

I don't know the weather in NJ, but we are just now seeing short sleeve weather here.
I have started to add an air conditioner in the summer to keep a ghost out of my lathe.

On the 51, I removed the cheesy cooler that is on the back door and mounted a real A/C there, but that alone is not enough as the control is actually in a different hole above the spindle. So I popped some holes below and to the right of the RS232 / 120V AC out let cavity, and mounted a 4" 'putor box fan over it (drawing air OUT) and plug it into the outlet right there. This will pull fresh cool air through the cavity where the control lives.
[need to have a fresh air inlet on the opposite side tho to allow air flow through]

If you can't find a logical fix otherwise, this is worth a shot.

I would actually unhook the red button and try it like that first tho.

Doo to the fact that it happens with different tools at different places in the cycle, AND that the spindle stays running - I'm pretty sure that it is NOT a raw wire in the loom.

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Think Snow Eh!
Ox

Other Brother · May 25, 2019

Ox said:
Could be that it is seeing the Feed Hold button even tho you are not pressing it?
If you find the Feed Hold button input in the ladder, see if there is any flicker at all.

The Fanuc Feed Hold address is G8.5 if you want to do what Ox suggested. I would also run with the message screen up and see if an alarm or message temporarily pops up when this happens.

I believe the input for the Feed Hold button is X106.5

Perry Harrington · May 26, 2019

Are you running low on coolant? Pumping up the coolant will drain the tank, feed hold will allow time for the coolant to return and raise the level.

anonimasu · May 26, 2019

Also check the way lubrication being low on oil will also trigger feed hold

Ox · May 26, 2019

Low lube on this machine will put it into SINGLE BLOCK.
This takes off and runs as soon as he hits the green button again.

Mine doesn't have a coolant level or pressure indicator.
Not saying that a later model doesn't tho.
My TT65 had that.

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Think Snow Eh!
Ox

Vancbiker · May 26, 2019

Perry Harrington said:
Are you running low on coolant? Pumping up the coolant will drain the tank, feed hold will allow time for the coolant to return and raise the level.

anonimasu said:
Also check the way lubrication being low on oil will also trigger feed hold

Ox said:
Low lube on this machine will put it into SINGLE BLOCK.
This takes off and runs as soon as he hits the green button again.

Mine doesn't have a coolant level or pressure indicator.
Not saying that a later model doesn't tho.
My TT65 had that.

All the above behavior is determined by the machine builder, not Fanuc. The machine builder can tie the feedhold to any other input they choose to stop feeding.

You need to look at the feedhold circuit in the wiring diagram to see what devices, if any, are connected to it. Then you might need to also look at the ladder logic to see what logical conditions the machine builder programmed in that can enable feedhold.

Tungsten Carbide · May 28, 2019

Thanks for the help guys. The coolant was pretty low, so that might be it. If so, I will feel very stupid.

Ox · May 28, 2019

If so - it should have tossed a "low coolant" alarm.

Have you had the machine long?
Have you ever seen such alarm?

I doubt there is such a sensor on that machine.

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Think Snow Eh!
Ox

Tungsten Carbide · May 28, 2019

I've had it a year or two, but I'm not nearly an expert on it. I have gotten the low lube alarm, but I do not recall seeing a low coolant alarm. When I come back to the machine to find it in Feed Hold, it has left the Prog page and gone to the Message page, but there is no message there. Maybe the low coolant message pops up initially, but goes away once the coolant drains back into the tank?

Ox · May 28, 2019

If it had anything - it would likely be a coolant pressure sensor, and that wouldn't reset by itself.

However - the info that the screen is blank could help... :scratchchin:

How 'bout you hit the MESSAGE page and HISTORY page - and see what the last message was when this happens, or - if you know when it has happened in the past, you can scroll through the error messages and time stamps. (if your clock and calendar or correct?)

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Think Snow Eh!
Ox

Tungsten Carbide · May 28, 2019

It just happened 2 more times, so it's not the coolant level. The only messages in the history are the ones when you turn the machine on and take it out of E-stop.

Ox · May 28, 2019

Sure sounds like it's seeing the FEED HOLD button just slightly.

.. but then - the feed hold wouldn't take it away from the current screen tho either .... :scratchchin:

So prolly not that simple...

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Think Snow Eh!
Ox

Ox · May 28, 2019

Door limit switch!

I wonder if you have a flutter on that input?

You might be able to just reach up there and give it some flicks?
Might have better luck actually coming in from the back door with the opp door closed so that you can cycle the switch through it's travels better.

That would put up the blank screen and put you into feed hold, and if it is just a fluttery input - it would go away too.
I had a similar experience with the prox on the shot pin in the sub-spindle years ago on same machine.
It showed up on the ladder "fluttering".

edit:

Also - this would NOT show up on the FAULT report either.

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Think Snow Eh!
Ox

Tungsten Carbide · May 28, 2019

I looked through the ladder for something "fluttering", but I am not that experienced with ladder diagnostics. I did, however, find a whole section of Harley Davidson stuff in there. Parts of the ladder were labelled things like "Harley Davidson Sensor", etc. Does your machine have anything like that in the ladder?

Ox · May 28, 2019

I don't remember.
Been a while since I browsed through there, but I doo know that there is oodles of optional stuff covered in there!

LOL!

Maybe the Harley sensor felt a thunderstorm roll through and thought that it was a Harley funeral procedure, and paused for a moment of silence?

Well, no matter if you found it or not, just cycle it through it's travels and see if your problem changes for better or worse.

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Think Snow Eh!
Ox

Perry Harrington · May 28, 2019

The Harley sensor detects how many potatoes are in the machine, if it's more that 2 (potato potato), then it feed holds until the extra leave.

Tungsten Carbide · May 30, 2019

Ox,

I had loosened the door switch bracket and pushed it back so the machine would always think the door is closed, except for when I reach up and push it to get past the initial door verify on start up (sometimes I need to run with the door open). Today, every time I hit start I got an immediate door switch alarm. I moved the switch back to normal position and cycle start worked (with door closed). I'm pretty sure that proves your theory. If it drops back into Feed Hold on me, I guess I should get a replacement door switch? What do you think?

Gene

Tungsten Carbide · May 30, 2019

It just went into Feed Hold again. I guess a new switch should solve the problem. Thanks so much for the help.

Tungsten Carbide · May 30, 2019

I tried to take the switch apart, but the cable seems to be permanently attached. Could they sell it as a complete cable and switch assembly? If so, it will be a pain to try to follow that cable and switch it out.

Old Hardinge Conquest T51 SP going into Feed Hold in mid-cut

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