Mazak VCU spindle, replace/rebuild?

landm1 · Nov 15, 2018

Hello,

We have a 2014 Mazak VCU vertical machining center, 1200 rpm. Not a lot of hours on the machine was we never hit anything hard but it was purchased as a really nice used machine.
About a year ago the spindle would make an intermittent sound like a spun bearing, it seemed to be throughout the spindle vs top or bottom bearings but it made a real nice finish, end and side. It got a lot worse lately, today I noticed the last part they made had a bad finish, probably a 125 micro inch and with the machine off the spindle will spin freely but is sounds awful.
My question is is there anything in the spindle cartridge that can come apart other than the bearings?
Next is what is the best choice at Mazak, our spindle, tapper, run-out is great but I have to wait for prices from Mazak on all of the options? We had Setco do a rebuild on a Doosan horizontal a few years ago, they did a great job but on a run of the mill vertical cartridge I am thinking you just go with a rebuilt unit from Mazak if they will claim to have balanced and verified all of the specs to new condition.
Let me know is there is a standard path on this issue?

landm1 · Nov 16, 2018

Mazak quoted $21,000 for a new replacement with 30% core. Sill waiting for a rebuilt, balanced, burned in unit, I guess I will know more Monday!
I imagine since the are taking a core they must be selling rebuilds, any comments?

Milland · Nov 16, 2018

There's a lot of spindle rebuilders who are independent operators, and may be able to repair the current spindle if you're willing to wait for the rebuild process. A replacement from Mazak gives you a speedy return to service, and depending on your circumstances this may be the best move.

It's just a 12K spindle (you say 1200, I'm guessing that's a typo)? That's not that fast, it's a bit surprising that it would have failed in such a "young" machine. I'd want a thorough review of the lubrication system if oil, or contamination prevention if greased bearings. I'd also wonder if there was at least one crash during the previous owners use.

Have you tried to get any TIR readings from the spindle taper? Deflection under manual load? Any video with sound of the spindle running? More data is good...

noname777 · Nov 17, 2018

Milland said:
There's a lot of spindle rebuilders who are independent operators, and may be able to repair the current spindle if you're willing to wait for the rebuild process. A replacement from Mazak gives you a speedy return to service, and depending on your circumstances this may be the best move.

It's just a 12K spindle (you say 1200, I'm guessing that's a typo)? That's not that fast, it's a bit surprising that it would have failed in such a "young" machine. I'd want a thorough review of the lubrication system if oil, or contamination prevention if greased bearings. I'd also wonder if there was at least one crash during the previous owners use.

Have you tried to get any TIR readings from the spindle taper? Deflection under manual load? Any video with sound of the spindle running? More data is good...

what is the problem to pull everything apart and replace 4 bearings? what is it that needs to be balanced? 4 ball bearings, 12000 rpm is not super ultra fast hardware that MAzak sells right now. From the drawing , I marked in red color only one part ( they call it - sleeve ) that will determine bearings preload? I am under impression ( and I know people who just buy bearing and replace them themselves with even talking of going for some specialized place) . The only problem is to understand from the drawing is where bearings preload coming from and if new bearings slightly wider or thinner, machine the part that makes preload.

say, the bearing is KOYO HAR014CA-5DBBCS13/140S+15SX2 FGPZ

DBB in here is already matched stack of 4 DB bearings ( they are coming as 4 ball bearings with arrow printed on them > ) so you just replace them all , and then there will be a little dot on inner and outer ring , to show you max runout.

http://www.noc.ua/pdfs/koyo-b2005e-en.pdf

pdf that explains how to decode bearing part number. It even tells you what a preload must be for applicaton like milling machine spindle. I dont want to says it is easy job, never done it myself and dont really want to, but I guess lots of people can do it no drama at all

landm1 · Nov 17, 2018

Sorry, it is a 12,000 spindle. I will not run the spindle, I was not there when it ran the last part but the wall finish was a 125 finish at best. Spinning the spindle by hand with the machine off is noisy so I did not want to turn it on and risk further damage.
Looks like $7K is the average from non-Mazak repair people provided no grinding or plating is required. We have used Setco in the past, they are set up to balance and burn it in at speed for 24 hours, they did a spindle for a Doosan horizontal, it was great.
Beyond everything else, I still believe something in there came apart because even though it made intermittent noise it still made great finishes, you would think a spun bearing would stay spun?
Mazak offers one option of just replacing the bearings, we plan on keeping the machine so I am not real keen on doing it myself or go with a shop that is not set up to balance it.
Due to the bad finish on the last part I am not sure a dial test will tell us much but I would really like to keep this one, we never crashed it gave exceptional finishes so not very likely the original owner crashed it either.
Thank you for the info on the spindle, I will keep you posted, I am thinking the best deal would be a rebuild from Mazak but whatever we get I will want to see the specs.

landm1 · Nov 17, 2018

"Why not just replace the bearing myself", builders, including Mazak, will charge you to balance the spindle, Setco will as well but you do not have to, I imagine if you were going to sell the machine you could save a few bucks. Grease is an issue as well, not too much, not too little. I do not want to worry about this stuff year after year.
I am thinking we will crack the case upon removal and try and figure out what happened.

noname777 · Nov 17, 2018

landm1 said:
"Why not just replace the bearing myself", builders, including Mazak, will charge you to balance the spindle, Setco will as well but you do not have to, I imagine if you were going to sell the machine you could save a few bucks. Grease is an issue as well, not too much, not too little. I do not want to worry about this stuff year after year.
I am thinking we will crack the case upon removal and try and figure out what happened.

how much is a new cartridge from MAzak? I bet I seen word "cartridge" in parts manuals when it comes to spindles. Although I am still puzzled why balance already balanced spindle, when just replacing bearings. The only thing I would think of is that you have to install 4 bearings in a way to compensate their runouts, to minimize it.

landm1 · Nov 17, 2018

Mazak is quoting $21,000 for a new "cartridge", that being a brand new case, spindle ready to install as new.
From what I know "balanced" is in the assembled condition, that would account for housing journals, bearings and spindle, I believe that tolerance stack can be substantial even though each one of the components is supposed to be balanced. It is probably the difference between the spindle lasting 5 years and 30 years. If I were selling the machine I would probably do it myself. Mazak actually offers to "replace the bearings" for less money so if you buy a machine with a "Mazak rebuilt spindle" I would check into which "rebuild" they did, you could even grind the taper in the machine for a perfect run-out but that is still not balanced.

machtool · Nov 18, 2018

noname777 said:
what is the problem to pull everything apart and replace 4 bearings? what is it that needs to be balanced? 4 ball bearings, 12000 rpm is not super ultra fast hardware that MAzak sells right now. From the drawing , I marked in red color only one part ( they call it - sleeve ) that will determine bearings preload?

The part you have marked with the red arrow, is a shrink fit collar. It doesn't determine the preload. Thats within the bearings them self, and the innner & outer spacers that are between the two pair.

The collar has no threads. You can see in the drawing it has two ports. They are for hydraulic oil injection to blow the sleeve off. It takes enerpac pressure of around 700 bar to get them to move.

They're a bag of tricks to install. Induction heater or hot oil bath. They need to be 250C to drop on. When they cool, they contract away from the face of the bearing, and don't apply enough force to lock the inner rings to the shaft. Technically that is applying the preload, as it pulls the inner rings into the outers.

Once cool, they have to be oil injected again, so they move on the spindle, but they have to be subjected to the correct clamping force. Its equivalent to a torque specification, if it had a threaded nut. There's jigs and fixtures involved, and you have to be religious not to get a hydraulic oil leak, as the bearings will have been all ready packed with Kluber or equivalent.

And all this should happen in a clean room, as the bearings are open and exposed. Seldom can you do it once the spindle and bearings are back in the housing.

This is what happens when you take a hydraulic press and a cold chisel to get it apart.
https://www.practicalmachinist.com/vb/mazak/vtc-spindle-work-188392/

It gets interesting around post # 16.

Regards Phil.

Other Brother · Nov 18, 2018

^^^This^^^ Send it off to Melbourne, it will be less expensive than what Mazak is gonna charge you.

noname777 · Nov 18, 2018

Other Brother said:
^^^This^^^ Send it off to Melbourne, it will be less expensive than what Mazak is gonna charge you.

I will read this LINK and see if it makes any sense to me.

landm1 · Nov 19, 2018

Feedback from Mazak, the $21,000 quote for a "new" spindle turns out to be for a rebuilt spindle, they do not have any new ones, I think they said a new one, if they had one, would only get a 15 percent core charge.
we dropped out the spindle today and it is the spindle so we are going to send it out tomorrow to somebody to be rebuilt, balanced and burned in.

noname777 · Nov 20, 2018

landm1 said:
Feedback from Mazak, the $21,000 quote for a "new" spindle turns out to be for a rebuilt spindle, they do not have any new ones, I think they said a new one, if they had one, would only get a 15 percent core charge.
we dropped out the spindle today and it is the spindle so we are going to send it out tomorrow to somebody to be rebuilt, balanced and burned in.

i am not sure how many CNC you have, but something like this or similar would be helpful.

Machine spindle repair and diagnostics with Spindle Analyzer- Automated Precision

you can attach little sensor to spindle and read signals from it. Software will filter it and produce sort of specter full of harmonics that will indicate bearing balls movement, quality of
bearings track , god knows what else you can extract. you just check it from time to time and see if bearings deteriorate or, some other abnormalities appear. Good tool by the way, never seen it installed, but think the idea that is put behind is amazing.

machtool · Nov 25, 2018

landm1 said:
Feedback from Mazak, the $21,000 quote for a "new" spindle turns out to be for a rebuilt spindle, they do not have any new ones, I think they said a new one, if they had one, would only get a 15 percent core charge.

I do them for $10k plus parts, I'm on a really good discount with NSK-RHP, not many would go out the door past 12 -$13K. $13K AUD would be 0.72c or $9403.93 USD at today's exchange rate.

To be fair, I invested in all the force and strain gages years ago, and I have a lot of the spacers, cups, pushers involved.Odd ball spindle will go 18K Aus / $13k USD.

Regards Phil.

noname777 · Nov 26, 2018

machtool said:
I do them for $10k plus parts, I'm on a really good discount with NSK-RHP, not many would go out the door past 12 -$13K. $13K AUD would be 0.72c or $9403.93 USD at today's exchange rate.

To be fair, I invested in all the force and strain gages years ago, and I have a lot of the spacers, cups, pushers involved.Odd ball spindle will go 18K Aus / $13k USD.

Regards Phil.

big investment. makes sense

landm1 · Nov 29, 2018

Setco took apart the spindle, here are the comments:

The spindle bearings showed little sign of wear, ( the machine is only 4 years old).

The spindle bore is from .0002" to .0005" oversized(bell mouthed), when asked they said it was a manufacturing defect, they want to plate and grind it to the proper size.

There was evidence of contamination in there, they sent me a picture, it almost looked like rust or "fretting" to me? I was wondering if it was cooked Kluber grease?

So it looks like we need to go ahead and plate and grind the spindle cartridge, could be worse?

I am thinking of sending the findings to Mazak, I think I could have made something better on our lathe? we did not use the through coolant, perhaps the previous owner did.

Any comments, contamination and out of speck bore off of the production line, any one else had a problem like these on a newer Mazak? Are these spindle cartridges coming out of China?

landm1 · Dec 4, 2018

E-mailed everything to Mazak service and Mazak spindle. Mazak service said they care and were forwarding to Mazak Spindle, that was a week ago, never heard from Mazak spindle??
It does not look like Mazak is going to contest that these spindles are coming out of China and this one looks like a total lemon, .0005" oversized on the bore and lots of contamination, not cool!

noname777 · Dec 5, 2018

landm1 said:
E-mailed everything to Mazak service and Mazak spindle. Mazak service said they care and were forwarding to Mazak Spindle, that was a week ago, never heard from Mazak spindle??
It does not look like Mazak is going to contest that these spindles are coming out of China and this one looks like a total lemon, .0005" oversized on the bore and lots of contamination, not cool!

Let us know once Mazak admits any wrong doing or its own mistake, I will buy a bottle of red and celebrate this day

landm1 · Dec 16, 2018

No word back from Mazak Spindle so I guess we can run with a lemon spindle cartridge probably manufactured in China, just another day in paradise!

noname777 · Dec 27, 2018

spindles are made in Mazak Japan, but the way they run it and the way they take responsibility, no one from MAzak is going to confess of wrong doing. That is part of Japanese life. They work as a team, they share responsibility as a team. Means, there will be not a single person emailing you and telling : sorry

Think about it, country was absolutely devastated around 1945, then occupied till given some freedom to be able to recover themselves, obviously Americans helped them a lot to avoid any of Japan`s steering towards USSR financial support . You know, the first Japanese car Toyota was built without any foreign help at all? Japanese take enormous amount of pride in what they do as a Developed nation. And here you are , complaining about one single CNC spindle. Think what you are asking from them

Mazak VCU spindle, replace/rebuild?

Cast Iron

Cast Iron

Diamond

Hot Rolled

Attachments

Cast Iron

Cast Iron

Hot Rolled

Cast Iron

Diamond

Hot Rolled

Hot Rolled

Cast Iron

Hot Rolled

Diamond

Hot Rolled

Cast Iron

Cast Iron

Hot Rolled

Cast Iron

Hot Rolled

Similar threads