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.

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].

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.....

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

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,

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

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,

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.

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.

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.

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.

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/lemaster/Auto%20Prod%20Sys/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?

vmc15=junk imho

Scott--
The Fadal machine with the Fanuc control have a complete Fanuc servo drive system. There is only one Fadal interface item that being an interface for the Chiller system.

Neal

Yeh, I know that legacy controlled Fadals have no "feed back loop" system, or any velocity feedback (tachometer for the servo motor)


Alright SB, I'll take the bait.

Hoooowwww do fadals work with no servo feedback???

Heck, that's awesome. No feedback devices to wear out, fewer electronics to fail.

I can see that no feedback is required for hitting travel extremes, but I find that most of my milling is in the middle of the table.

Perhaps my meaning was mis-understood! The Fadal machines with the Fanuc control use the Fanuc drive motors, servo amps, and all Fanuc related feed back devices.

Neal

My question was meant for scott bob.

Sounds like without feedback on my legacy control, my table should have shot clean off the mill long ago :)

Perhaps my meaning was mis-understood! The Fadal machines with the Fanuc control use the Fanuc drive motors, servo amps, and all Fanuc related feed back devices.

Neal

Neal,
Are you saying that the Fanuc machines Fadal is building have linear type scales providing exact position feed back? I would expect that they only use the encoders on the motors to count pulses. The machine does not 'know' where it is at at any given time (except when it SLAMS into the limits). This is why you can "home" the machine at most any location.

The feed back is via Absolute Pulse Coders

Neal

Alright SB, I'll take the bait.
Hoooowwww do fadals work with no servo feedback??? Heck, that's awesome. No feedback devices to wear out, fewer electronics to fail. I can see that no feedback is required for hitting travel extremes, but I find that most of my milling is in the middle of the table.

Well it seems to me that if your only concern is keeping that table on your mill, then maybe you should get a manual mill. Less electical stuff to go wrong and all... I doubt the technical arguements for a "closed loop feed back system" would sway a machinist like you anyway. Have you ever heard someone say: "A real toolmaker can make whatever, with a worn out machine, and a file"

Just outright ignorance I say...

Perhaps my meaning was mis-understood! The Fadal machines with the Fanuc control use the Fanuc drive motors, servo amps, and all Fanuc related feed back devices.

Neal


Wow Neal, I guess you need to have knowlege of a few different systems, not just the control, in order to work on a FADAL. I imagine the AB controls have their own system. The parts dept must have a whole Fanuc section. I just thought (assumed) they would all use the same motors, amps, etc. There is probably some simialrities, but I am impressed. They must all have their own little quirks.

Well it seems to me that if your only concern is keeping that table on your mill, then maybe you should get a manual mill. Less electical stuff to go wrong and all... I doubt the technical arguements for a "closed loop feed back system" would sway a machinist like you anyway. Have you ever heard someone say: "A real toolmaker can make whatever, with a worn out machine, and a file"

Just outright ignorance I say...


SB,

Repeat- I asked you how it is possible to run a servo system without any feedback. Pretty certain I can handle a technical argument here but I would like to know your thoughts.

Can you answer that question before you call me ignorant ?

Sprew--
We used to also have the Siemens 840D and 810D control. So there was another complete system I had to learn. No wonder I'm balding and grey haired as well as over weight!!

Neal

I did not say "you" were ignorant, but that the person who thinks "a good Toolmaker can make anything with a worn out machine and a file". That person is who I call ignorant! I also asked you if you had ever heard this comment...

To ansewer your question about Fadals "feed back loop system", I should have said "closed loop feed back system"

I said: "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": (see image).

A CNC control cannot "control" what it does not monitor...
Let me put it this way:

You are driving a car, and your objective is to be accurate in your chosen route, and to get to your destination at exactly the arrival time, and to maximize gas mileage and control your speed. This car has no cruise control. Only a crude speedometer that reads in 10 mile per hour increments. Now, you a a hopless lead foot. It is just the way you were designed, speed up, and slow down without much care for precision. It's not that you are a terrible driver, your are just functioning the way you were designed, you don't know any better...

This describes a Fadal legacy control... and it's inadequate "feed back loop system" (no cruise control, no tachometer). The most inaccurate part of this system is the really crude motion control algorithms that make up the MCU of this CNC, almost like a drunk driver, who is all over the road.

I like this comparision, it works on soo many levels.

They have Macros Kochev and you can use your Renishaw too.

I had a 95 VMC 15 for about 4-5 years. It was a great little machine, cut anything I put in there. Mine had a "real" 10 HP Baldor motor DC drives. I upgraded the control so I could have 4 megs of memory, cost was 5k to have a current control not bad. The best thing about these is that anyone can fix them and take them apart. The manuals are very complete unlike Haas. Parts are very cheap in comparison to something like a Mazak and (at least a year or two ago) could be ordered on line right from Fadal.

Plus you have Neal here to help you out if you have a problem :)



Scottbob, the horse died a long time ago you can stop kicking the corpse. :)



Dave

Neil D is a great resource!!


:rainfro:

I will support that statement,,

Neal is an asset to this forum and has lead me in the right direction many times.

Neal " You Are The Man"

Make no mistake about it...


Chips!!

Neil has also helped me with a few problems on my 94 VMC15. It's nice to have some inside help when you need it. :)