X Axis shifting during program

[SBC Cycle]

Originally Posted by iess525 How old the machine? is it AC/DC?

I did just some quick checking, this was machine was remanufactured in 2007, first installed in our shop as "new again" on 2-1-08. It does have the AC motors for sure. I can't personally attest that the machine has been "properly" grounded but I have service records where we had a ground put in back in 1997 for our first Fadals. They have never had this problem so I would think that I could rule that out but I have no technical experience with power (On makes it go, off makes it stop - that's the extent of my electrical knowledge )

As far as the RS-232 cable goes, again I cannot verify whether the cable was connected to the machine or not when the shifts have occured. The last time it happened it probably was: I powered the machine on, sent a program over the wire, then checked my fixture offsets and they were off. I haven't had this problem with my other 2 machines so I rate this as "not likely" the cause but until I know for sure I will say "possible".

At this point I will leave strict instructions on the machine to always disconnect the cable when in use. If it happens again, I can mark the cable off as a possible culprit.

ACI, I have heard from multiple sources that the coupler is suspect on the Fadals. When I have exhausted all other avenues with my machine dealer, I will check that myself. I'm hoping they will come out at some point and at least explore the possibility of a mechanical problem.

I will keep this thread updated until I have found a resolution. Thank you all for at least pointing me in some direction. Problems like these are easier to fix when you at least have a clue where to start.

[SBC Cycle]

Originally Posted by Neal SBC-- To clarify the RS-232 issue for you, If electrical noise of the correct frequency is received thru the RS-232 port, the machine can THINK it is getting a command and it could react to it causing some strange things to happen. This is not normally an occurance but it has been know to happen. That is another reason why we are so picky about proper grounding and keeping AC ripple and electrical noise down. Neal

Thanks for clarifying that. I couldn't think how that could possibly be the problem. Very good to know.

[Techman]

We had a similar problem with our Fadal after we had the machine a couple years. The first couple times the shift happend was in a heavy climb cut in the X direction. It turned out to be the coupling between the servo and the screw was slipping and it was an easy fix. Hope this helps!
Techman

[SBC Cycle]

Update.

I set a part in the machine on Saturday that I needed to bore out today. I indicated it in and set the fixture X-Y zero. Sent it home and shut it down.

This morning I fired the machine, did the CS, and put my indicator back in the spindle to re-check my zeros. 0.0505" off in X! I sent it back home and discovered that the marks weren't lined up. I lined them up, did another CS, then went back to rezero my part and it matches my fixture offset like it should.

So I seem to have 2 issues:

• The machine is not cold starting in the right position. This is what happened today.

• The machine is shifting in the middle of the program. This has happened a dozen times or so already.

I called my dealer today and let them know I was still having a problem. They are still convinced this is a software issue. There apparently is no mechanical problem that would be this consistent (0.050" +-0.0005").

The RS-232 cable was not connected to the machine either Saturday nor today so scratch that off the list.

I do not use SETX, SETY, SETZ or any G92. That was another question asked by a fellow Fadal user.

[mxz700]

I had the same problem with 1 of my fadals it ended up being the scales
they get wet or dirty.

[FUN4ME]

We had a similar problem on a 2005 VMC 15 XT.

see here

http://www.cnczone.com/forums/showthread.php?t=49984

alot more movement though

Hope this helps
Erich

[FUN4ME]

OK my memory is not as bad as I thought


We had a similar problem on a 2005 VMC 15 XT.
Our problem was on the x axis, I don’t recall how much it was moving .
It ended up being a resolver. After it was replaced we have not had any problems.
Hope this helps
Erich

[Tedger]

SBC Cycle-Did you find the problem?
Sounds like a classic case of Bad (or loose) X-Axis resolver.I had a similar problem that I only found after swapping out X for Y motors.
Let us Know.

[Neal]

SBC--
Check the axis controller cards. If tyhey are PCB-0340 or PCB-0336 they might be the cause of shifting on the fly randomly.

[SBC Cycle]

Neal,

Sorry for the delayed response, I've been working around the clock this week and this weekend. I wondered if maybe you were the guy that figured it out

The new axis card showed up the day after we spoke with California. John will be here on Monday to put it in. Would have liked to have the machine back up before then but it's the holidays I reckon.

Crossing my fingers...now I gotta get back at. Will keep this thread updated if that fixes the problem.

[grweldon]

I'm not a repair technician, but we have 2 Fadals, neither of which have had this problem. I must say that after reading the first posting on this that the first thought in my mind was a faulty coupling.

Also, as far as the cold start marks being aligned, Fadal has told me that they only need to be within .200" to successfully align correctly when entering a cold start and they will find the proper home position. Experience has shown this to be true.

I believe your problem is a mechanical one and I think it's time to start getting insistant with your dealer as a previous poster has suggested.

[SBC Cycle]

Just to update.

The machine had the wrong axis card in it. I believe ours had the PCB-0336 in it. From what I understand this should never be in any machine and I have no idea how it may have ended up in our machine. Just to reiterate, this is a MAG Fadal 4020 Factory Remanufactured machine. Rebuilt to "new" specs in '07, we bought it in March of '08 with a 6 month warranty. This problem popped up the first month the machine was on our floor and is now finally fixed.

My Fadal tech took the blame for the problem as it should have been the first thing checked knowing what this thing was doing. MAG Fadal, for their part, have been helpful and they ate all the cost of the hardware upgrades.

Eh, shouldn't be taking this up here. This isn't the place for it.

I'm still a fan of Fadal machines. I've even made a lot of money on this machine but I'm thinking it's time to make it someone else's problem. We might replace this one with a new Fadal but I believe a remanufactured machine is not for us.