Fadal 904-20 (VMC 20) pre purchase reality check request
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  1. #1
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    Default Fadal 904-20 (VMC 20) pre purchase reality check request

    I have been researching for a while now.
    Thanks to the guys here, I think I know what I am getting myself into, but could certainly use another set of eyes on it

    First VMC, making some pretty decent parts on a Acer/Anilam 2axis machine. Want an enclosure and tool changer(just like everyone told me when I bought the Acer) , but Iím still glad I went that route first.

    I could have bought a new machine, but I know Iím going to crash it at least once ,so I rather learn on this. Plus it wont see full time use for another 2-4 years



    Made an offer that was accepted.

    Pending inspection I bought a 1993 Fadal VMC 20

    Nice overall condition, way covers not dented, lots of original paint still on the bottom of the enclosure. New spindle drive(maybe a con, see below)
    Ways looks great, all axis jog and tool changer works.



    I think I am aware of its cons:
    1) slow cutting feeds 140-200ipm max depending on where you read.

    2) Rapids max out at 400ipm

    3) itís DC drives- brush maintenance, but supposedly more robust than the AC ones??

    4) itís a box way machine, the pictures the tech sent me show intact turcite, but it will be the first thing I check.

    5) it has a newish spindle drive with an intermittent issue where it wonít ramp up to speed. The drive is a Baldor H2 VMC drive, I think they didnít even come out until 2008 and stopped selling in 2014?
    I was a control tech and electrician in another life, Iím gambling that I can trouble shoot the issue, it looks like worst case scenario is $2500 for a drive??? Iím guessing based on research here that itís power or set-up related.

    The point of the post:

    1) some of the turcite is hard to get to for inspection , if the X axis is good, are the other axis generally ok? I looked at another machine and it was easy to see where the x axis had failed , but I didnít look farther at the Y and Z on that machine.

    This machine seems to have good bond on the X axis

    2) the machine has CNC88HS with 166k extended memory and external high speed buss and graphics.

    Looks like the cpu is -4, thatís one of the faster ones right? (Except the $5000 upgrade to -5??)

    - what is graphics??

    What can I expect for profiling/3D ?
    I can live with the slow rapids and feeds if the finish is ok. Will the machine come to a screaming halt on 3D stuff? I had previously seen a video that seemed ok,but canít find it.

    I have a paid Fusion 360 subscription and am pretty good with it on my 2axis.
    There seems to be a few good F360 posts floating around, anyone want to share a proven one?



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    Default Fadal 904-20 (VMC 20) pre purchase reality check request



    Itís got 4th axis prewire(edit typo), where would the card be if it was there?


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    Forgot to ask- the spindle is listed as 10,000 rpm, how do I know that the machine is rated? Rate rpm seems to be 6500,7500, or 10 ,000.
    Some machines have a big sticker on the front, might be obvious when I see it in person- itís 10 hour round trip.



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    Congratulations!
    I hope it works great for you!
    Iím just lurking/watching for responses.

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    How much money for the machine?


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    It’s got 4th axis prewire(edit typo), where would the card be if it was there?
    /
    Don't get too excited, it does not mean that you have everything for a
    4th axis in the machine.. It basically means that it was cheaper to
    build one type of a wiring harness than it was to build one for 3axis
    and then 4axis machines.. It also allowed Fadal to easily just add
    a 4th, which means that it is also fairly easy for you to add a 4th..

    Though, if you want a machine with a 4th, buy one that already has a 4th
    on it.. Even though the machine is "Pre-Wired", you still have a lot
    of stuff to do and buy which can cost almost as much as the machine itself,
    Driver board, controller card, the 4th itself, some more wiring, some stuff
    to do with the 4th axis brake. Look at ITS, they have kits to put a 4th
    on a "pre-wired" machine, they aren't free.

    Machines with a 4th aren't valued all that much higher than ones without.
    And they are common, probably 1 out of 4 or 5 Fadals you come across will
    have a 4th.

    Occasionally when you are hunting Fadals, you will come across some that
    already have all the goodies for a 4th, except for the 4th itself, and some
    people don't even realize it. Just look for 4 driver boards, side cabinet,
    about half way up on the right, standing vertically. Also look for a black
    plastic lump in the right rear in the machine on the ceiling.. That is where
    you plug the 4th in.. And that is not included in the "Pre-Wire"..

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    Bob thanks for the detailed reply I was hoping you would see the thread.
    I wonít have physical access to the machine for another week.

    On this machine there are 4? driver boards ,x,y,z and ďAĒ . In the pic above(not sure how clear it is on a pc) the black board to the left of the x,y,z boards is labeled ďaĒ , but I donít know if thatís for 4th axis or the spindle ? Does the spindle get a driver board outside the VFD?

    Did you see the question about the turcite? If both sides of the Table are intact and well bonded, is it reasonable to assume the Y is good? On a different machine I didnít see a easy way to inspect the Y??(on that machine the X was delaminates from the table)

    Thanks again


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    The X-axis is probably the least likely to have Turcite problems. I think it is Z then Y then X. The Z-axis problem is if the wear is not compensated for in a timely manner, look for head nod. The Y-axis supports more weight than the X so it should have problems first. As for how fast you can feed it all depends on how much servo lag you can live with, Fadals are kind of bad about this.

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    I can deal with wear, the machine doesnít have much use( compared to most I have seen)
    My concern is the issue where the turcite is no longer attached to the saddle or table


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    Woops, I didn't even see the pic, or I did last night and forgot about it...

    Its got all the stuff in there to run a 4th.. Driver board, and controller card.
    That's not "pre-wired", that's about $4000 of extra equipment that the seller
    doesn't seem to realize is there.

    In a 3axis machine the wires that go to that 4th board are just hanging there in
    space.. It really doesn't add much to the value of the machine, but its nice to
    have there if you can find a 4th axis at a good price.

    As for turcite, I don't know enough about it to really comment on it.

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    Default Fadal 904-20 (VMC 20) pre purchase reality check request

    Those are really long forks!
    I take it that you bought it?
    Congratulations!

    Looks like you have to make it less tall to get under that garage door.

    I had the same thing.
    I parked the spindle nose on wood blocks and removed the Z axis motor and unbolted the cable track.
    And I removed my tilt up garage door entirely.



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    Itís in the shop now. I did the same thing with the Z Servo and the cable chain. Being an ex-wire biter type, I Wasnít happy with the tension that laying the cable chain at a 45 put on the wires and hydraulic/lube lines, but it worked out fine




    The forks are 8í. Choice was too long or marginal, as long as they donít get too thick, longer usually wins.
    The longer forks were really to allow me to easily push it further in the shop and spin it, but I hosed my back the week before the move and didnít have enough left in me to get it up on skates or pipes once it was inside, as long as it was inside and the door closed, I was good.

    I finish PT on my girly back this week and hope to valid the Fadal still works this weekend.





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    Question--What was the height of the opening the machine fit through?

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    83 3/4Ē
    Thatís to the weather stripping that I did not remove, my back was killing me by that point, I failed to get pics. My son and it did the job and we donít weigh 280 together wet



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    Congratulations!

    If you end up having to replace the spindle drive: I really like the Glentek spindle drive that ITS sells as a drop in replacement for Fadals. I have installed two of them and been very happy with both. Install is really easy and you'll be back up and running in less than an hour, and the drive itself seems massively overbuilt and practically bulletproof.

    On the other hand: RUN away from any seller that is selling Yaskawa spindle drives 'setup' for Fadals. I have dealt with a few of them and they really (REALLY) suck. Messy unclear wiring harnesses, and the drives that I tried were setup to run in open loop mode (VFD) rather than sensored/sensorless vector mode. When I tried the Yaskawa drive it doubled the already 'relaxed' Fadal spindle acceleration time... The Glentek bolted right in with no problems. I'm not shitting on Yaskawa drives here as I know they can be good when setup right, but the people selling them as 'replacements' for Fadals have no idea what they're doing in terms of setting them up.

    You won't have any issues running HSM/3D contouring toolpaths with a CNC88HS control and the -4 boards. I have the same setup on my VMC10 which also has brushed DC servos. You can see a video of it running HSM toolpaths here. In most cases I'm limited by the material, not the machine:



    I run 3D contouring on my machine in hardened A2 tool steel (63HRC) for about 8 hours every day at 60IPM with no issues.

    Also worth noting that I doubt you'll have to do much 'brush maintenance' on those DC servos. I have a couple of machines that I don't think ever had a brush replaced and after 25 years they still have plenty of life left in them... I keep a spare set on hand as cheap insurance but it's not something I ever worry about.

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    Aaron- thanks for checking in, I had watched many of your videos and they were definitely helpful, not much out there on Fadals using adaptive tool paths.
    Good to know on the spindle drives, I had seen that Glentek on ITS for $2500, thatís why I decided it was a gamble I could afford. I did not know about the other being a headache.

    Iím pretty excited, hope to not let too much smoke out when I fire it up this weekend.

    I know I read, but canít recall where I read which leg of the incoming power should be the generated leg from my rotary converter?? Itís a American rotary cnc rated 10hp unit.
    Can I run the control power straight from 110 and not work about it?




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    Quote Originally Posted by aarongough View Post

    Also worth noting that I doubt you'll have to do much 'brush maintenance' on those DC servos. I have a couple of machines that I don't think ever had a brush replaced and after 25 years they still have plenty of life left in them... I keep a spare set on hand as cheap insurance but it's not something I ever worry about.
    The tachometer brushes on the DC servos will cause more issues than the motor brushses. If the servo jerks backwards and forwards ove rshort distances, more than likely it's the tachometer brushes, or the commutator needs cleaning


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