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Looking at Advanced/Mighty VMC 520

rpseguin

Stainless
Joined
Jun 28, 2006
Location
Napa, CA
I have been looking for a small footprint VMC or HMC that will fit my small budget.

I went and looked at an 1995 Advanced VMC 520 (big label on spindle/Z axis says Advanced VMC-520, but one plate says Model: VMC 500P, another plate says Model VMC-500S). Also known/sold as Mighty Comet, I think. Shop is moving and downsizing.

Mitsubishi control, 8000RPM, box ways, 16 station carousel ATC, BT40.

I jogged it under power and ran the spindle through various speeds up to max of 8000 RPM and it sounded good. All axes sounded good. Did tool changes.
CRT looked good, no burn in.
Shop said it’ll easily holder better than 0.0005”
He said that the only problem with it is that the X axis stopped referencing recently and that it’s probably a limit switch that needs cleaning up or fixing or replacing.

Asking price is close to being in my budget.
What would you pay for a 24 year old VMC with the X axis not referencing (but maybe easy fix)?

Informed opinions on Advanced (Mighty?) VMCs? Quality? Reliability?
What are the things I’m forgetting to ask or check?
What sort of headaches can I expect from an old VMC?
Anybody here have an old similar/same VMC this age and still holding good tolerances, making good parts?
How long can/will such a machine last?
 
Any bargains on newer, nicer, more modern small footprint VMCs or HMCs around?
Under $5000 would be good. I know this is probably unlikely.
 
If the seller thinks it's such any easy fix then they should have no problem fixing it. I recently purchased an 1989 OKK PCV-40 that says it has 3000 hours on it. Turcite lined box ways, linear scales, side mount tool changer, 800 IPM rapids, 4th axis prep, optional 10hp spindle, Meldas w/HSM option. She will hold a few tenths. I didn't pay much over scrap price for it. I personally love machines of this vintage but wouldn't pay much for them because there are a lot out there and not much demand. A friend of mine has over 2 dozen cnc machines from the 70's and 80's and does quite well with them.
 
If the seller thinks it's such any easy fix then they should have no problem fixing it.


Yeah. That thought crossed my mind more than once...


I recently purchased an 1989 OKK PCV-40 that says it has 3000 hours on it. Turcite lined box ways, linear scales, side mount tool changer, 800 IPM rapids, 4th axis prep, optional 10hp spindle, Meldas w/HSM option. She will hold a few tenths. I didn't pay much over scrap price for it.

Nice!!! I wish I could find a deal like that!

I’d love to have a sidemount/swingarm toolchanger, but I have very limited clearance under my tilt up garage door.

How do you check for the HSM option?

I personally love machines of this vintage but wouldn't pay much for them because there are a lot out there and not much demand. A friend of mine has over 2 dozen cnc machines from the 70's and 80's and does quite well with them.

Thanks for the response!
 
I forgot to mention that the seller also has a Haas 5C indexer that works with the VMC.
Indexing only, not continuous profile machining/simultaneous 4 axis interpolation.
He’s asking $2500 for it separate/on top of VMC price
 
Machine values vary by location. In my area, I would expect that machine to top out at ~$4k and probably closer to $3k to move it.

Mighty did reasonable iron and so so on wiring and control integration. Some buyers will be put off by the Mits control. I am going to guess that it has an M50 on it. Not a bad control at all, just a bit different if you are not familiar with Meldas.

A really important thing is to be sure it has documentation. At the very least a wiring diagram and ladder logic diagram. If those are lost, drop the price by half. Those are very difficult to get when a machine gets old and they are critical to being able to troubleshoot and repair electrical and control problems. Mighty operation, maintenance, and parts manuals are next in importance. Many Mitsubishi manuals are able to be found online with a bit of searching.
 
Machine values vary by location. In my area, I would expect that machine to top out at ~$4k and probably closer to $3k to move it.

Thanks for the response!
They are asking $4000, as is with 1 Kurt D60 vise and 6 BT40 holders.
Of course they said they have other people asking about the machine as well.
With the X axis not referencing problem, I am inclined to offer much less.
I guess I can bide my time and keep my eyes open for deals like the OKK other post mentions.
I’d love to find something newer, but the price seems to scale as some exponential function of “youth”.

Mighty did reasonable iron and so so on wiring and control integration. Some buyers will be put off by the Mits control. I am going to guess that it has an M50 on it. Not a bad control at all, just a bit different if you are not familiar with Meldas.

Thanks!
The machine looked in decent condition, but I didn’t try putting a test indicator on the spindle or anything.


A really important thing is to be sure it has documentation. At the very least a wiring diagram and ladder logic diagram. If those are lost, drop the price by half. Those are very difficult to get when a machine gets old and they are critical to being able to troubleshoot and repair electrical and control problems. Mighty operation, maintenance, and parts manuals are next in importance. Many Mitsubishi manuals are able to be found online with a bit of searching.

Great point!
They said some manuals are included and I just texted and he said he’d check tomorrow and get back to me.
 
I always call the MTB up to find out what to expect from them for technical help and parts, before buying the machine. You don't want to find out they are of no help AFTER you bought the machine.
 
Yeah. That thought crossed my mind more than once...




Nice!!! I wish I could find a deal like that!

I’d love to have a sidemount/swingarm toolchanger, but I have very limited clearance under my tilt up garage door.

How do you check for the HSM option?



Thanks for the response!

I got the original build sheet with the machine with all the options its equipped with. Keep an eye open on ebay and don't be in a rush, deals pop up when places need to get old machines out of the way.
 
Oh another thing I like to do is if the backlash checks good, go into the parameters and make sure a large number hasn't been entered into backlash comp to compensate for wore ballscrews/nuts/balls. If you are not familiar with the controller you'll have to check the manual to figure out how to do this.
 
I had that same machine (Viper VMC500) made me tons of money and cost me money. I ended up scrapping it and buying a new haas.

The biggest con is support mighty viper is useless and wouldn't expect much better even if brought new from them.
 
I had that same machine (Viper VMC500) made me tons of money and cost me money. I ended up scrapping it and buying a new haas.

The biggest con is support mighty viper is useless and wouldn't expect much better even if brought new from them.

Thanks for the response!
Good to know!
I emailed Mighty last night asking about parts and docs.
They responded already with the 1691 page operators guide (easiest probably) and said other things are available upon request.
 
Thanks for the response!
Good to know!
I emailed Mighty last night asking about parts and docs.
They responded already with the 1691 page operators guide (easiest probably) and said other things are available upon request.

That's about where it stops as far as service. I got the same manual mins but they charged me for the pdf
 
Oh another thing I like to do is if the backlash checks good, go into the parameters and make sure a large number hasn't been entered into backlash comp to compensate for wore ballscrews/nuts/balls. If you are not familiar with the controller you'll have to check the manual to figure out how to do this.

Good idea!
I will grab a dial test indicator and see if I can bring it over.
Backlash test suggestions?
At various locations along an axis, jog over an inch or two, zero out indicator and count # of 0.0001” clicks before it moves?

G2/G3 circles and compare end position to start position? (At various positions along each axis).

Zero out indicator, relative G1 move 1.0” and then relative G1 -1.0” and look for deltas? Do this at several locations along each axis.



How do you check powered hours and spindle running/cutting hours on the Mitsubishi Meldas control?
 
Good idea!
I will grab a dial test indicator and see if I can bring it over.
Backlash test suggestions?
At various locations along an axis, jog over an inch or two, zero out indicator and count # of 0.0001” clicks before it moves?

G2/G3 circles and compare end position to start position? (At various positions along each axis).

Zero out indicator, relative G1 move 1.0” and then relative G1 -1.0” and look for deltas? Do this at several locations along each axis.



How do you check powered hours and spindle running/cutting hours on the Mitsubishi Meldas control?

I simply use the MPG with a dial indicator and reconcile it with the readout of the machine when changing direction, no need to count clicks. If you check X,Y,Z I don't see any need or reason to interpolate a circle.

My OKK has a Meldas M320, I don't know what controller you are looking at and if it will be the same but I will take a look later today as I don't remember the sequence to display the hours off the top of my head but when I'm at the control I can get there.
 
IIRC the small Mighty machines with Mits controls used the M50. To see the run hours, you press the COMMAND softkey then page down to screen 3. This is from the Mits manual. I can't double check it on my M50 because it has a Mori U/I with touchscreen and some of the menus are set up a bit differently.
 
Hours can be reset so don't put any value on what you find. Plus do the hours count above 9,999 on these controls? Being a box way machine check for head nod to make sure the wear isn't too much to deal with. Not having support from the MTB is a pretty big deal IMO. Being able to call them up for a PDF on the procedure to fix some little problem is a real lifesaver, let alone parts.
 
Yes what Vancbiker said!

m320.jpg

If the M50 is like the M300 to check the backlash setting you need to enter "M" mode first by

-go to diagnostics screen (alarm button)
-enter (1001) ( ) (M) input

-then go to parameters
-then axis
page right or left for X Y Z, Backlash comp is number 12 IIRC
 
Be real.

Whaddaya-gonna do where the mechanics have some more slop at some point geometrically ?
They probably do, but so what.

Around a few k, 4k$, there is nothing to negotiate down.

Old CNCs are a crapshoot, where any single issue can cost 1-2-4k$, and is somewhat likely to appear once put into service again (stressed by heat).
A fadal is good because it is more modular than most and most modules can be repaired or swapped easy(ish) or cheap(ish).

New screws, linear bearing blocks, bearings, are all easy to do, for not too much money.
Fairly fast.

Value:
If the control runs, as-is, the machine has some usage value.
When, not if, the control fails, then what ?

How much time in hrs and $$ in parts will it take to get it operational again ?
Find someone who has one.
Ask the current Manufacturers rep. for references with the same type of machine tool.

If they won´t give You a reference, it means they see Your future trade as a negative value.
What does that tell You ?

Forget retrofits.
If You personally havent done one, or built a VMC, You are unlikely to have a realistic understanding of a proper retrofit near industrial needs.
Simply wiring, connecting, getting to work a 3-axis is 200+ IO plus a huge amount of sw stuff in arcane languages.
 
Here’s a picture of the control:

f413c4e8c7c844821bcd06d359c8b375.jpg



Guts in the cabinet:

0a26779d1e26df97bd00c72c3845bd69.jpg


eb6318259f4ced86ab1e7f7536628b4d.jpg



And if the pics he sent of the manuals are right, then I guess the control is a 3xx series:


4ce4901b4dc88d994a1f6b32cfda7324.jpg


895d0f431a4198f138a448cfcae6f079.jpg


Yes what Vancbiker said!

View attachment 266536

If the M50 is like the M300 to check the backlash setting you need to enter "M" mode first by

-go to diagnostics screen (alarm button)
-enter (1001) ( ) (M) input

-then go to parameters
-then axis
page right or left for X Y Z, Backlash comp is number 12 IIRC




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