Chance to buy '94 Fadal VMC-15 ...

[kochevnik]

with low hours on it (1500). This has the FADAL 88HS control on it. I know next to nothing about these. Anyone know if they would have had Macros (or something like them) on one of these ?

Also I have a Renishaw probe - MP700 with the OMI interface - anyone know if I could hook this up to a machine this old ?

ANY advice about this particular machine would be greatly appreciated - was this a dog in it's day or decent or what ?

Many thanks.

[hardrocker]

Others here will know much better, but I think there was a change from DC to AC motors in the early 90s. I know of one user running several larger [4020] Fadals ['91 or '92 perhaps] who still curses spindle motor problems they had. Then again, I know of a '90 [+/- a year or so] 3016 that is still in use; by coincidence I just heard a few weeks ago is still doing well [though not in a production evironment as opposed the the previous example].

[DareBee]

Mine is a 94.
Last year for the DC drives.
Yes they are obsolete but they are bulletproof.
Your control will likely be a -3 version.
You will REALLY want/need to max the memory out (422K).
I also would want 4th axis or it least to have the driver and prewiring.
Important things to check before buying - ballscrews, way & Turcite wear, spindle, chiller system.
Make sure that they have and are ONLY running Dowfrost in the chiller or the whole system will likely have bad seals.
Spindles and ballscrews are not too bad for price.
Redoing the ways on the other hand.....

[Neal]

Morning all--
The VMC 15 is a DC servo machine. AC servos started in late 1996 and were never installed on the VMC-15 model machines. As for the clock hours, be aware that these clocks can be zeroed out at any time.

Neal

[Scott_bob]

Mr Neal,

On the older DC servo CNC a "resolver" was used, and on the AC servo system an encoder is used right?
What is the resolution of the Resolver in counts per revolution of the ballscrew?
What is the resolution of the Encoder in counts per revolution of the ballscrew?
At the higher degree of resolution of the AC / encoder design, how much more accuracy can be expected in the feedback loop system?

Perhaps you coud define what this "feedback loop system" is?

Sincerely,

[Neal]

ScottBob--
A DC motor with resolvers does not used line counts. It uses Sin/Cos for the fed back.
You already know what a feed back loop system is.

Neal

[Scott_bob]

Niel,

With all due respect, I don't know what the actual specification of Fadals feedback loop system is... Or the difference between resulting ballscrew accuracy from the DC drive / resolver system and the newer AC / encoder system.

Very Sincerely,

[carbidecraters]

15's are what the industry refers to as throw away machines. This is because they use linear ways and dont take kindly to large cuts. This is the attitude of many and some even state the larger boxed way machined are throw away machines. I believe each machine has its place but in our shop we wouldnt ever buy a vmc15. Used machinery dealers give $5-7K for a used VMC 15 if its 1997 or earlier.

[carbidecraters]

VMC15s usually have a grease packed spindle 7500rpm and dont come with a chilled spindle (IIRC). They all have 22X 16Y. The 88HS is a decent but slower control. Sometimes you will notice the machine will stop to think about a tool change for just about a second. Depending on the year the tool changer will index to each tool pot before changing tools. This means if you have T1 (tool 1) in your spindle and press M6T10 the tool carousel will rotate to each tool location from 1 to 10. If its a newer machine the tool changer simply swings ot the location saving you some cycle time. If it has low hours it probly is in very good condition and might be a decent deal.

[billystein]

i like the small fadals for the accuracy. where i worked we had the renishaw probe with the infared interface. it has the faal macro language. and i think will support our probe. i was impressed with the accuracy even after several years the machines are pretty tight. not like the larger 60 and 80 inch fadals which seem to get loose in a year or two.
like someone already stated these machines do not like heavy cutting.

[Shizzlemah]

Should have macros and no problem connecting a probe. Its 5 wires I think, real simple. Did one here not long ago (on a VMC40)

Oh, 1986 VMC40, ooooold style spindle- still running swell.

[Scott_bob]

Originally Posted by Neal A DC motor with resolvers does not used line counts. It uses Sin/Cos for the fed back. You already know what a feed back loop system is. Neal

Ok Neal, I admitt my question was a little "baited"
I do respect your position at Fadal, I really do...

Yeh, I know that legacy controlled Fadals have no "feed back loop" system, or any velocity feedback (tachometer for the servo motor)
For those who may be wondering what a feedback loop is:
http://www.utm.edu/departments/engin...Notes%2024.pdf
I also know that a control cannot "control" what it does not monitor...

Would you (Neal) ansewer this question: "Do the Fanuc controlled Fadal CNCs have the standard Fanuc feedback loop system?