[mishikwest]

See attached photo. Getting the tool unclamped alarm because the drawbar is not traveling up enough to close the sensor. Any ideas why is causing this not to go into postion? Am I loosing drawbar pressure? Machine is about a 6-7 yr old vf5 that I know has used some long reach tools in the past, and a few of the holder are getting a bit of fretting.

[haastec]

The solenoid that is directly in front of the spring has a stone type exhaust fitting on it. Remove the exhaust and see if it works like it should. If it does, clean or replace the exhaust.

Next, try removing the smaller air hose on the right side of the same solenoid and try again. It will make a popping noise when disconnected, but it will be okay for troubleshooting. This hose provides the precharge air pressure to the drawbar. If the precharge is stuck on this can also cause your condition.

Try the exhaust first as this is a very common ailment.

Good luck!

[ToyMaker94566]

My VF3 gave me the exact same alarm awhile back. Turned out most of the draw bar springs were broken so the draw bar return was slow: "replaced". Still got the alarm and dropped tools, turned out the solenoid was misfiring: "replaced"; runs like new! There are a few things that can wear out in that system after awhile so don't hesitate to replace things. It cost less to replace a few parts then have to go back and tear it all down time and time again. Just my 2 cents... :cheers:

[mishikwest]

Thx fellas. Turned out I came into work the next day and the drawbar was now "up". I ran the machine for a while (one tool program) and noticed it creep upward even more. Hot job is now done and I'll start dismantling her.

[mishikwest]

Next, try removing the smaller air hose on the right side of the same solenoid and try again. It will make a popping noise when disconnected, but it will be okay for troubleshooting. This hose provides the precharge air pressure to the drawbar. If the precharge is stuck on this can also cause your condition.

Ok it's back! If I remove the hose from the right side of the solenoid the drawbar fully retracts...so it's probably the precharge stuck on? What is that, and what is the recommended fix. Thanks!

[dingo0722]

Pre charge is 4 PSI air that first enters the drawbar actuator. This closes the gap between the top of the draw bar and the nose of the actuator. After precharge, full pressure is sent into the actuator pushing the tool out. If precharge is not there, there would be a big bang every time the tool ejected. If the precharge is stuck on, you will need to replace the valve assembly that activates the tool release. It is about $500

[Machineit]

Ok it's back! If I remove the hose from the right side of the solenoid the drawbar fully retracts...so it's probably the precharge stuck on? What is that, and what is the recommended fix. Thanks!

Follow that air line back to its solenoid mounted on the back of the head. Replace or disassemble and clean that solenoid.

Mike

[mishikwest]

So the "main" solenoid is the one on the front (in my pic up there), and there is another behind the spindle for the precharge unit? ..and that one needs cleaning or replacing?

Looks like a hassle to get at, being around back?

Thanks for the replies

[haastec]

So the "main" solenoid is the one on the front (in my pic up there), and there is another behind the spindle for the precharge unit? ..and that one needs cleaning or replacing?

Looks like a hassle to get at, being around back?

Thanks for the replies

Yes, the one in front is the main solenoid and the pre charge is around back and yes again, it can be a little bit of a pain.

When you pull the pre charge air line off, is there air coming out constantly? If not, then the pre charge solenoid is not the problem.

[Machineit]

Yes, the one in front is the main solenoid and the pre charge is around back and yes again, it can be a little bit of a pain.

When you pull the pre charge air line off, is there air coming out constantly? If not, then the pre charge solenoid is not the problem.

When checking as per Haastec, do it with a tool change as sometimes the valve will be slow, not totally stuck.

When the change is done the air should be totally stopped. I have seen them with a small leak or flow and that is all it takes to prevent the changer from reaching the switch. Had a machine that did that and after about 30 to 45 seconds, the air would stop and the switch would be triggered. But of course, that was not in time to avoid an alarm.

Mike

[mishikwest]

Yes there is a slight hiss with the precharge line off.

[Machineit]

Yes there is a slight hiss with the precharge line off.

Yup, disassemble and clean or replace!

Mike

[ALyons]

Hello,

I know this is an older thread but i believe I am having a similar issue and maybe you can steer me in the right direction. I am working on a Year 2000 Haas VF-0E. When it goes to do a tool Change it will bring the spindle to the correct height then bring the tool changer in. When it goes to unclamp the tool it automaticaly goes into to "tool unclamp" alarm. I removed the covers and begun checking the air lines and selnoids as you gentelman have been disscussing. It appears that all of that is working correctly. Any thoughts on where to look next?

Thank you
Andy

[haastec]

Hello,

I know this is an older thread but i believe I am having a similar issue and maybe you can steer me in the right direction. I am working on a Year 2000 Haas VF-0E. When it goes to do a tool Change it will bring the spindle to the correct height then bring the tool changer in. When it goes to unclamp the tool it automaticaly goes into to "tool unclamp" alarm. I removed the covers and begun checking the air lines and selnoids as you gentelman have been disscussing. It appears that all of that is working correctly. Any thoughts on where to look next?

Thank you
Andy

Check to see if the drawbar clamp and unclamp switches are changing states; toggles between 1 to 0 . You can watch them toggle in the diagnostics page while manually pressing tool release.

If the control does not see the change, it could be one of the switches is bad or something could be mechanically wrong with the tool release piston ring which triggers the switches. Switches are located behind the head covers directly above spindle

Good luck!

[julianjackson1895]

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