[Fadal Error]

Getting the "Waiting on air valve" error message when trying to change tools. I can't get it to accept a tool.

Where is the air valve that tends to corrode when water gets in the air lines?

[Fadal Error]

More specifically, where is the brass piston mentioned here? http://cnczone.com/forums/showthread...ting+air+valve

[David Michael]

I wrote a lot of the Fadal CNC software back in the "old Fadal" days...
The problem could be feedback related. The CNC is waiting for one of the Hall Effect sensors.
You can turn this feedback sensor test off in the the SETP command.
Older machines didn't have feedback. So when you update an old machine you'll get this message and need to set the parameter FEEDBACK to NO then power off/on the machine and that message will go away.

In your case I'd turn the FEEDBACK off, then you can do a tool change (without a tool) and see what mechanics are or not working.

You can also use the DI command and then enter DS command to display the swiches (all feedbacks). Enter command X to cancel the DS feature.

You can email me directly at [email protected] if this becomes an emergency... David

[Fadal Error]

Thanks David.

I forgot to mention that this is a 94 VMC 4020

[Fadal Error]

I don't see any settings for feedback in the parameter menu.

[David Michael]

The 94 machine will have this parameter, I don't have access to a machine at the moment but here's the wording out of the manual to look for:

AIR VALVE FEEDBACK
DO YOU HAVE AIR VALVE FEEDBACK?
1)NO
2)YES

[little bubba]

The 94 machine will have this parameter, I don't have access to a machine at the moment but here's the wording out of the manual to look for:

AIR VALVE FEEDBACK
DO YOU HAVE AIR VALVE FEEDBACK?
1)NO
2)YES

Have a '94 sitting out here in the shop and just wandered out there in boxers and slippers, that parameter is not there.

Fadal Error, I'm assuming you are getting the error on an automatic tool change(only time I've ever seen it)? First thing, can you pull tools out of the spindle manually[tool in/out button]? If you can, its a sensor problem, the sensor may need adjusting, or it may be toast. If you can't change tools manually, its an air or mechanical problem.

Just re-read your original post, "can't get it to accept a tool", I'm guessing that means you can't manually insert a tool. I have had the tool change piston bind in its bushing. I would check air pressure to the piston first.

The valves you want and the little things to push, they are near your way lube pump, but down lower. If you are looking at the back cabinet with the spindle drive in it. Look to the lower right of that cabinet. The air valves are usually a funky blueish color and hanging below a small metal enclosure.

[Fadal Error]

Have a '94 sitting out here in the shop and just wandered out there in boxers and slippers, that parameter is not there.

I couldn't find it either and I checked three times.

Just re-read your original post, "can't get it to accept a tool", I'm guessing that means you can't manually insert a tool. I have had the tool change piston bind in its bushing. I would check air pressure to the piston first.

That's it. I can't even put a tool in by hand. When I enter TC,1 it moves the tool carousel to the tool change position and cycles the valve over and over while giving me the WAITING ON AIR VALVE error message. The air pressure coming out of the spindle/drawbar is much lighter than normal.
This happened after leaving the machine sitting overnight with no tool in the spindle, which I usually don't do.

The valves you want and the little things to push, they are near your way lube pump, but down lower. If you are looking at the back cabinet with the spindle drive in it. Look to the lower right of that cabinet. The air valves are usually a funky blueish color and hanging below a small metal enclosure.

OK. I found that assembly and disassembled it and cleaned it, but I didn't find a brass plunger as described in the post I linked.

[Fadal Error]

I called the Fadal tech (not a factory tech) and he wanted me to check something behind the sheet metal cover on the spindle. He said something about an aluminum plate that may be cracked. I was supposed to get back to him after I got the cover off, but I couldn't get through to him before the end of the day.
Maybe tomorrow...

[David Michael]

In following up...
The FEEDBACK: parameter is around V97 and newer
In all older versions the parameter was reworded as:

ENTER THE PENDANT STYLE:
1 - KEYBOARD BESIDE VIDEO TUBE

The above setting tells the CNC software to ignore the feedback tests. The earliest machines had a different pendant and that's how we distinguished feedback present or not.

If you can't remove the tool, the plate they are taking about is the tool in/out air cylinder. It is directly above the spindle, behind the sheet metal cover and pushes down on the draw-bar.
It square, roughly about 10" x 5" x 2". Sometime the Aluminum plunger inside cracks in time or you have a gasket problem or it just needs lubrication. It needs about 1000 lbs of force to overcome the draw-bar springs (square inches x air pressure = force).
Years ago I made the first prototypes and thought a square air cylinder was a bit strange but it was a matter of fitting it all behind the sheet metal.
6

[David Michael]

In following up...
The FEEDBACK: parameter is around V97 and newer
In all older versions the parameter was reworded as:

ENTER THE PENDANT STYLE:
1 - KEYBOARD BESIDE VIDEO TUBE

The above setting tells the CNC software to ignore the feedback tests. The earliest machines had a different pendant and that's how we distinguished feedback present or not.

If you can't remove the tool, the plate they are taking about is the tool in/out air cylinder. It is directly above the spindle, behind the sheet metal cover and pushes down on the draw-bar.
It square, roughly about 10" x 5" x 2". Sometime the Aluminum plunger inside cracks in time or you have a gasket problem or it just needs lubrication. It needs about 1000 lbs of force to overcome the draw-bar springs (square inches x air pressure = force).
Years ago I made the first prototypes and thought a square air cylinder was a bit strange but it was a matter of fitting it all behind the sheet metal.

[Fadal Error]

No feedback mode didn't make a difference, except that I got no error message. The drawbar still won't release.

This is the problem in action.
http://s115.photobucket.com/albums/n...t=MOV04410.flv

[scadvice]

I can't now look at your vid., but if none of the other ideas work and you are hearing the air valve recycling continously, Your valve most likely needs to be rebuilt. Look on the valve and get the name of the manufacture. Call their service and buy a new one... then/or send the old one in for repair and to have as a spare. Much cheaper way to go. I did this years back on my 1989 vmc40.
Steve:wave:

[David Michael]

From what I can see in the Video, it looks like the drawbar is indeed coming down.
After a time out when the hall effect magnet inside the drawbar cylinder doesn't activate the Hall Sensor, the CNC begins the "Tap-Tap" cycle as the service department liked to call it.
We used the orientation arm to tap on the top of the spindle and create a shock to the tool and help release a stuck tool.
If the drawbar is indeed coming down in full force, the tool could possibly be stuck in the spindle taper; needing more force to pop the tool out than the drawbar cylinder can provide.
Try this:
Hold the tool in/out button down so the drawbar cylinder pushes down and while it's pushing, tap (not pound) on the side of the tool holder to create a shock.
Be careful, if the tool is really stuck in the taper, the shock will release the tool and it will come shooting out. We use to put a waste basket below to catch the tool holder.
Its a problem of pulling with high retention force, when the spindle gets hot it expands and sucks the tool holder up into the taper. When it all cools down, it can get really tight.

[Fadal Error]

There is no tool in the spindle. I can't get one in.

[scadvice]

I'll try to look at your vid. tonight. I maybe missing something here, but it still sounds like the air valve bank that sits just under the back elect. cab (that has the spindle drive in it and main transformer). If you listen right at the valve, do you hear it cycling about twice every second until the control times out? That would seem to be a sticky valve. You might be able to take it apart and clean it??

Steve

[Fadal Error]

If you listen right at the valve, do you hear it cycling about twice every second until the control times out?

Yes.

That would seem to be a sticky valve. You might be able to take it apart and clean it??

I cleaned it already. What should I have lubed it with? I used Marvel Mystery oil on one piston that seemed a bit sticky.

[David Michael]

OK, I couldn't tell in the video...

For some reason the CNC isn't seeing the drawbar down feedback.
Its got to be either:
1) Faulty feedback
2) The cylinder isn't traveling down to actuate the feedback and accept the tool.

Because you can't get a tool IN, it sounds like #2
You can power the cylinder manually at the air connection of the cylinder to see if your getting enough pressure and volume. That would indicate a value-air supply problem.
Otherwise your going to have to open up the air cylinder and see what's going on inside. It's a simple assemble inside.

[Fadal Error]

Just to make sure I get it right, where is the air cylinder assembly?

[scadvice]

I don't know about the M. oil, but would think it would be fine. If it is still sticking then I guess I would try polishing the bore (Very carefully). As I said I ordered a whole new bank and had the old one rebuilt. it was quite awhile back, but I think the whole bank only cost about 190 bucks and they had it to me in two days. Steve
PS: Fadal wanted 500 bucks for a new one.