Reply with QuoteBob,
Need more description.
Rapid? Feed? Caned Cycle?
Same machine?
You think higher temps lead to more issues with reliability?
On that subject, I aggree completely.
I assume you have tried to improve ventalation?
run run run away......
New world record:
3 runaways in one day, have not had the problem in 3 months, thought
the winter weather brought the problem to an end.
Any thoughts, any one else having this problem??
Bob,
Need more description.
Rapid? Feed? Caned Cycle?
Same machine?
You think higher temps lead to more issues with reliability?
On that subject, I aggree completely.
I assume you have tried to improve ventalation?
Scott_bob
run away
Have you figured this out yet? I am having the same problem with my 91
VMC 15. I just got this machine it seems to have trouble with small moves
the backlash is pretty bad and I wondered if that might have something to dowith it. My shop is not to hot right now so that shouldn't be the problem.
Thanks for the input.
When any axis runs away it is because the computer doe not know that it is moving. This could be either a resolver/encoder, controller card, mill interface, or cablining issue.
On rare occasions, excessive heat build up could cause a component failure. This is highly unusual but has happened.
Neal
I think you should add to that list loss of feed back from the tach.
If you have a plus command, minus feed back from the tach holds
the feed rate down.
How to explain,,,.,.... Computer starts to count in that direction, axis is no longer inposition, as computer continues to count, error increases. The drive senses the error and starts to try to correct the error. the tach tries to hold the entire operation back depending on the following error adjustments. With out tach feed back, you have a runaway. I would start looking for broken wires, loose wires, loose connections, corroded connections, broken wires where the crimp on occured. Hook up a meter from this end to that end and start moving the wire harnesses around to see if you can see the break occuring. Anything to isolate the problem so your not looking through the entire hay stack while looking for the broken piece of straw.
I have ran external wires (tach and encoder) outside of the wire tracks, tape them in place and run the machine. See if if fixes the problem. Therefore trying to isolate the problem.
Rots of Ruck.
Walt.
Just thought I would update everyone. My runaway problem was caused by a communication error from my slave pc. I used a different pc and so far so good. The strange thing is the first pc worked it just sent goofy #s some times. The only way I caught it was by watching the screen I noticed the cnc #s didn't match my program that I was dnc. It was putting the decimal in the wrong place.
Thanks for all the help
Joe
run away maybe solved....
Found some loose boards on the machine i.e. the axis drive boards.
The service guy actually was able to cause the machine to fault out by tapping on the boards.. Solution was to clean the board contacts with an eraser to get them to shiny copper condition again...
Then it happened again, this time I did the wiggling (cheaper to do the wiggling yourself)... Found a connector that runs from the front control to
the main board where the drives are, when I wiggled the connector the machine would fault out... So I tried to hose the connector out with tuner cleaner and circuit board cleaner from radio schack and put some anti oxidant grease in the connector (not sure if this is a bad idea or not.....) plug it all back in and all the wiggling I could do would not wig out the machine.
We have only put it through a couple details milling so far......
It seems vibration may be the ultimate enemy.
And we beat the tar out of our machines ====> Loosens it's Teeth.
The service guy put the machine into some kind of cycle where all the axis
would jog slowly back and forth, then he did the wiggling, when the axis stoped moving we found the bad wiggle spot. Anyone know what routine
he would have been running. It might be useful to others....
Bob--
Most likely that was the service amplifier balance program #O5811. You can load it in by entering TA,7 for a few of the most used service programs. You can load ALL the service programs in by using TA,2. They are hard coded in the machine system. Load them in anytime you need the and delete them from machine memory when finished.
Neal
Tried the TA,7 listed below, not sure if the vintage machine we have has it, anyone else know what/where this program is?Originally Posted by REVCAM_Bob
Had a bad runaway Y axis last night and need to track this down NOW.
program
you can download the manuals at fadalcnc.com the service programs are in the back.you can just type by hand.the axis tune program is" m49 g1 g8 g90;x-5.y-5.z-5. f150.;x0y0z0;m99p2; '' the following error will be 595,600,or 302 depending on machine and software,dc inch pich screws are 595.dc mm screws are 302,ac mm screws are 302 w/old software or 600 w/ac0017 and newer axis software.if you do not know what you have go with what is close to what you have now.if the monitor is giving load % and not following error change the parameter.the causes of runaways are listed well in prior posts.if the motor always runs away pull the coupler off untill it gets resolved so the machine does not get damaged.
Thanks for all of the input guys. We started by removing each card individually and Scotchbrighting the contacts. This is a 90 4020 that had been sitting for 4-5 yrs. All of the cable connectors were loose so I bent the retaining tabs to clip the cables better and I closed the bullet connector sockets with pliers to get a firm insertion "feel" when I put them in. They all felt like they could almost fall out of the bullet connectors before I did this.
It has only happened twice before, both times a heavy roughing pass with a very aggressive 2 flute insert cutter. We'll get some cutting in this week and see where to go from there.
run away axis
sounds like your on the right track loose bullet plugs have caused many a problem in the past.
Posting Permissions
