Z Axis Brake Problem

[Brass Monk]

Has anyone had a problem with their Z Axis motor brake locking up? I have a 2003 VF3 which does not have a counter weight system, just a brake on the motor that drives the Z axis 40 MM ball screw. I was experiencing some uncommanded Z movement (always in the Z minus direction) and at 100% rapid the machine would alarm out with a "Z axis servo error". Initially I thought it might be a mechanical problem in the Ball Screw, bearings or motor but an inspection with the way covers off did not reveal an obvious problem. Today the machine finally locked up. During start up the Z axis will not home (though I can manually jog it) and I get a "Z axis overload error". Speaking with Sal (service tech) at HAAS he suspects that the problem is in the motor brake and wanted me to check some voltages on an amplifier. However, I don't have a key to open the rear case so I called my local HAAS dealer and explained the situation. I've been placed on a waiting list for scheduling a service tech to come out a fix my expensive paper weight. I'm hoping the fix can be simple and cheap but I did find out that repacing an amplifier is only $1100 plus labor. Oh well..... its only money I don't have.

[Bryan33]

I am a tech at the factory. The voltage that you need to check is on the I/Opcb Its the 24v for the brake. What is your serial number. I will give you the pins on the I/O to check it. that is if you can get your door open

[Brass Monk]

Hi Bryan,

Thanks for a quick respone. My serial # is 32991. My local HAAS dealer has yet to schedule a service visit so maybe I can do a little trouble shooting on my own if I can find a key that fits. If I find that the voltage is low, what is the next step?

[Brass Monk]

Finally got the machine fixed. The HAAS tech from my local dealer was finally able to track down the problem and fix it. Voltages were checked, drive screw inspected, even had the Z Axis drive motor replaced. The culprit was the Z axis amplifier. Replaced the amp and the machine is acting like its' old self again. I hope it stays that way. Not looking forward to the bill though.....
Hope this info will help someone with a similar problem.

[Bryan33]

fUN fact for you EBC break rotors are machined on an HS1RP