AIR LEAK ? ? ?

[Kevin Watts]

global status7107
PH10t tp20
pc dmis 3.5 mr 1
calibration done march 06

For some reason when i raise the probe up to top it is making a loud noise that sounds like a kinked air hose and starts triggering hits like crazy, when i lower the probe it stops. Is this something that i should let our maintainence guy look at or is this too technical and needs professional assistance? i have had no crashes within the last couple months it just started this today.
thanks

[T Miller]

Can you tell when you raise it if it goes past the home position for z?

[Kevin Watts]

Yes i believe that it does go past the home for Z. it happens when i raise it almost 2 inches from the top

[T Miller]

Not sure what would all be involved I can not get the cover off unless I take the PH10 off . not sure how yours would be. if you can get the cover off I don't think it would hurt to take a look

[Matthew D. Hoedeman]

The problem is your counter-balance. It is an air piston and cylinder. Your piston/cylinder is wearing out. Mine did the same thing. I had 'repair' people order a new piston and ring. They put it in. It was worse. They altered the piston ring. It was worse still! I told him to put it back the way it was with the old piece. The noise level dropped back to where it was. After he left, I removed the piston, took the ring off it, put a thin piece of felt under the ring, in the groove in the piston, put it all back together, 95% of the noise is gone.

[thenettrainer]

RE: Yes i believe that it does go past the home for Z. it happens when i raise it almost 2 inches from the top . . .

As the doctor would say . . . Then don't raise it within 2" of the top.

Seriously, that's not all that uncommon for the Z axis to hiss some when you get to, or past the top limit switch.

[Jan d.]

There are 2 things that can cause this:

1) The rings around your counterbalance piston may leak (typically causing a hiss, but not false triggers). This can be due to a poorly aligned counterbalance wearing out the seals. When the machine was calibrated in March, they may have adjusted YZ or XZ squareness, without re-aligning the counterbalance. Although Matt may have done it himself, and he has bad experience with the B&S tech fixing it, I still would want B&S to fix this.
2) You run an air bearing off the rail. I have seen machines where for some reason the home position gets moved. The machine will then move beyond the end of the ram, causing the top air bearing to violently vibrate (causing lots of false triggers). This is easy to check: take the cover off and move up. If the bearing travels even as little as 0.100" over the edge of the ram, you may have to have your home position or soft limits adjusted.


Jan.

[SROLLKA1206]

i have a global advantage that been making a air leak noise from the air filter area in the rear of the machine. this is the first time this has happened and wondering if its a common problem and how to fix it