Fryer MC-60 10K Spindle Failures

[Carroll_1]

We have a Fryer MC-60 vertical machining center placed in service May 06. The machine is equipped with a 10K spindle and spindle chiller. The machine has approximately 2100 hrs machining 6061 T6 aluminum only. The complete spindle cratridge was replaced under factory warranty in July-06 and again in Oct-06. We had a third spindle failure last week and are in the process of looking at another replacement. All failures have been lower bearing failures attibuted to moisture. The machine has an air-purge system that blows low pressure air into the lower spindle housing specifically to purge coolant. Our service reps are blaming contaminated air supply for the failures, but we have previously installed an after-cooler, water and oil traps in front of the machine, and the air-purge circuit filters and collection bowl are clean.

My question. Has anyone had any similar spindle issues with a Fryer machine. Common sense tells me if we have a clean air supply, that there has to be an inherent problem in the machine's spindle cooler/spindle design, or in the air purge design. I'm almost beginning to believe the air-purge is drawing coolant into the bearings instead of protecting them!

Anyone have any experience with Fryer?

Thanks
Carroll_1

[dpuch]

No experience with a Fryer, but I have with 10k and up spindle machines. A few thoughts for you to ponder.

The machine did not come with a water separator, and a micron filter for the air line? That has been my experience with machines that had an air purge on the spindle bearings. If it didn't, that seems to be a design problem that they are relying on you to fix. If it did, and they can't show that they failed and it is your fault... That line seems like a weak excuse on their part, and them ignoring the facts about the filters you have.

10k and up spindles tend to be pretty sensitive to a lot of things. If your seeing moisture in the lower bearings, my guesses are from the air purge, condensation after it is shut down, coolant getting in due to poor air purge or failure. There are always other potabilities. If it is showing signs of rusting, I doubt it is coolant, they usually have anti rust qualities.

Take a chilled spindle, humid work area and turn off the machine (killing the air purge) and I can see a possibility where the humid air would get into and condense in the spindle.

Another issue is that spindles replaced in the field rarely live as long as factory installed ones. It just is not possible to take the same precautions and assure that there aren't any issues with the parts you aren't replacing.

My 2 cents
Dale

[PMT]

Had a Similar problem withone 8K and one 10K spindle in the past ( same shop). Turned chiller temp setting to 0 deg. (ambiant temp.) and no more problems. Dealing with NSK, the only thing we could determine was that after extended runs the inner races would heat up and expand where the outer chilled races would not. Chiller was set at 3 deg. below ambiant. Spindle would last about 6 months then crap out.
Also, I do not know what bearings are installed, but in my case NSK offered 2 bearings. One rated 10K Max 8K sustained which would not work for you. And the other about 2X the price, around 15K Max 12K sustained. These numbers are for grease fill.

Of course there are many other issues that would cause this and I do not type well enough to wright a book. But after 4 spindles on 2 machines, this was the simple fix for me.

If this is not it, NSK will analyse the bearings for you, if NSK.

[NC Cams]

10K spindles are not insensitive. They need to be properly broken in, properly warmed up and properly shut down.

When being trained at the factory on building/assembling a high speed spindle bearing set, I was AMAZED at the surgical precision used to do the work. I had packed wheel bearings with grease and figured the process would be much the same. NOT HARDLY.

The technicial LITERALLY mesured out the specified amount of grease. He then used dental tools to slowly and carefully PLACE the grease on each ball taking special care to make the amount and placement equal. All work was then re-inspected with a magnifying glass "just to make sure". The thing was then thermally fit so that NO force was used to install ANY of the races. The thing spun like glass smooth when done - I'd never seen anything like it. Oh, and the brand of grease was often VERY, VERY critical. Kluber was a notable favorite - which one of the many flavors they offer, again is/was an empirically derived spec that varied from spindle to spindl, speed to speed. The amount and type, again as spec'd by the OEM should be used. How it is applied DOES make a difference!!!!

Grease for high speed spindles is QUITE critical. Again, you don't just dump in wheel bearing grease or whatever PTI sells. Typically, the grease type and amount are carefully derived at by the spindle maker via testing/development. Once the spindle is built, then you slowly and carefully start it up in spurts and let it rise to temp slowly and carefully in prescribed stages. Shut downs are also typically done in a prescribed method to let the spindle bearing temps cool and stabilize.

IF the lube is becoming contaminated (solvents, moisture, whatever), you need to find the root cause of the contamination ingress. Contact the lube supplier or a local outfit that does lube analysis - Spectracheck was an outfit that we used. Have them analyize the grease. They'll tell you if it is contaminated and what's contaminating it. You can then go about figuring out where it came from and then stop it. If the bearings are failing due to grease contamination, you're problem is solved. IF/when you find grease contamination, you can then figure out where it is coming from and who's to "blame" for same (air, air filtration method, pizz poor design, etc).

ANY name brand bearing maker will do bearing failure analyisis. Sadly, the bearings that come in often DON'T have all the stuff needed to properly analyze the bearings. The service guy typicall washes out the grease or simply pounds them out with wild abandon. If you want/need to stop a repeated problem, you need to take the bearings out with as much care as you'd install new ones - you don't want to destroy evidence or create undue damage. Most service guys kluge the stuff apart and don't do anybody any favors in this regard.

The fit up of 8K versus 10K spindle bearings is NOT the same. Neither is/are the specs. THe higher speed spindles MUST be machined to closer/tighter tolerances. Fits are MUCH more critical - a few microns too loose or tight can/will make a difference. I've seen cases where "generic" bearings are inadvertantly fit to "custom" spindles. Contrary to what some guys think, ABEC 7 bearings are NOT universal in quality. SOME spindle makers take ABEC 7's and then tighten up the specs via selective fitting and/or special "tune ups" (IE: grade 3 balls, ABEC 9 inner ring rounouts, special concentricity containment over 15-17 revolutions, special size control, and on and on). Again, "generic" off the shelf bearings may NOT adequately service the spindle nor will one "rebuilt" out in the field be built with factory precision.

If the first spindle ran well and got hurt and you can't get or keep the new ones running. that should tell you something. If the damn thing never ran/lived, that tells you something else. TIme, money and some sharp detective work should enable SOMEONE to figure out what's wrong and how to fix it - as so many people say, "it ain't rocket science".

Somehthing's going on that shouldn't be - find out whats happening and why and you should be able to run the spindle at the advertised speed. That's assuming that the design is/was viable for 10K in the first place. Proving that, especially if all sorts of other things are going/have gone wrong can/will be quite difficult without expert help....

If the grease is getting contaminated, FIND OUT WHY. And, yest true high speed continuous used 10K spindle bearings WILL be much more costly than occasional burst 10K capable bearings - they aren't the same so don't think that because they both have 10K in the label that they will be.

[davereagan]

NC Cams knows a ton. Thank you. My gut feel is that few people run that machine at high rpms constantly the way you do and so you are basically giving free test data to the machine maker or even supporting their service department in the process. I wouldn't pay a thin dime for the same people to rebuild the spindle a fifth time. How about a spindle repair house that lives, eats, and breathes spindles only, with the kind of knowledge NC Cams described?

Dave

[Big_d]

The old chestnut " Coolant/Moisture contaminated spindle bearings".

The air you feed into the spindle bearing cavity needs to be the driest and cleanest you can achieve (As you have already identified). You may have the wrong size air service units (Oversized filters wont dry the air out effectively as the air wont run fast enough though) ? In a perfect world you want to get the dew point below -15c. This normally means a coalescing filter although some re fridge units can achieve this. It also helps if the air can return to room temp before it enters the machine (We use a receiver on ours). Always dry and filter air at the highest pressure you have as when it is regulated back down it will be drier. Also your air purge MUST be on for at least 24 hours after the machine has been shut down. When the air is clean and dry it can take up any small amounts of moisture that may get inside. What pressure does it use to purge the bearing housing?

I don't have any experience with this particular brand machine, Does it use an air blast on tool change? If so how is it routed, does it pressurise the bearing housing or is it sealed up with contact seals for this operation? Does it use through tool coolant? Nearly every high speed, long term grease is lithium soap based and I would guess that it is probably been filled with something like NBU15 Kluber. This washes out very easily and is susceptible to coolant used with aluminium. You will want to find coolant that has a close to neutral PH.

I have had a look on their web site and noticed that the nose of the spindle doesn't have any form of slinger on its nose, are you doing work with the nose close to the job?
Cheers
Daza

[NC Cams]

Some greases are water resistant and others are water absorbing. Big difference.

In one, the water mixes in and forms a gunky, milky emusion. If the grease wet down the spindle or raceways, it may not end up rusting or corroding. Regardless, water contaminated grease doesn't lube welll

In the other, the water literally absorbs the water and has chemicals in the grease to trap it and keep it from rusting/corroding the bearings. WHen enough water gets absorbed, the grease can't function and the grease fails. Either (absorbtion or emulsification) is an after the fact remedy that you don't want to avail yourself of if at all possible.

The better thing is to treat the grease to steady diet of PREDRIED air - in other words, keep the water OUT of it in the first plasce. This way, if the air is "dry" it will tend to absorb and extract (dry out) any water that gets into the grease before it can contaminate the grease and/or hurt its ability to lube the bearings - remember, water laden/contaminated grease sucks as a lubricant.

All this is conjecture and/or speculation until you have a grease sample independantly analyzed. Spectracheck or some other analysis firm should have a go at looking at the grease from the spindle - do so WITHOUT the knowledge of the bearing and/or machine maker. This way, you KNOW the answer before they can "interpret" the data for you.

If the grease is getting contaminated, THAT is what has to be addressed first. Contaminated grease WON"T live in a high speed spindle. It may simply be that simple - get and keep the grease clean. If the air purge is inadequate, find someone who can craft up one that WORKS. IF the spindle is geting contaminated due to poor rebuild or air purge or air drying schemes, these need to be addressed/fixed.

If the spindle is getting contaminated due to lame design and poor inherent sealing, that needs to be corrected by you or the machine tool maker.

NOTE: don't even start to tell me about the "seals" on the bearings. These usually are invisibly vented to prevent thermal rise from blowing out the seals as pressure builds in the bearing during use - these vents allow air and water to get sucked in as the bearing cools, especially if the seals see/get direct coolant impingement. DUH, you can't just rely on the "bearing seals" to seal the bearing.

Sadly, many a machine tool bearing user doesn't know or understand this and fails/neglects to use/install external positive seals or slingers on the shafts and housings - the client/user ends up paying for this deficient design practice. OOPS

You, or someone needs to figure out the root cause of the bearing failures. Until/unless this gets done FIRST, all the fixes everybody can conjure up will NOT adequately nor properly fix the problems that this machine is encountering.

You have some good starting points. I hope you use and follow up with them....

[fryermachine]

It is unfortunate that this customer had an issue with one of our machines. We do everything we can to work with a customer to have the machine running to their satisfaction. This customer ultimately sold the machine and the company that purchased it loves the machine and has not had any difficulties with it.

Sue Ostrander
Sales Manager
Fryer Machine Systems

[moneyhsk]

We just had our 8000 rpm spindle go out on our Fryer MC-45.
The machine is 1 year and 4 months old. We sent our spindle to Atlanta Spindles to have it rebuilt. Cost for rebuild was $4500, cost brand new from Fryer was $6000. We don't have a spindle cooler, and didn't have the spindle air curtain. We had the air curtain added when rebuilding the spindle. The lower bearings were contaminated by the coolant blowing back up at the spindle during pocket routines.

Atlanta spindle replaced the bearings with sealed bearings, had the spindle back to us in a week. The spindle is quieter now that it was brand new.

I didn't think a spindle should go bad in a year and a half, but was told that some do. Fryer has been a very good machine, missing a few nice features but we are happy with it so far, besides the spindle thing, lol.

[Kookaburra]

Guy's,

Fryer are an awesome machine. I agree that there is evidence of a problem here, however, Fryer Machines have over 10,000 machines in industry and here at CNC Zone we have only about 5 people who are dirty on Fryer. Take it from someone who knows how forums can tarnish a good product by only posting bad issues. Seek out those who are happy with the product. The happy people do not post here.

Please use your own mind. Fryer are as good as the rest of the machine tool manufactures and believe me the same problems exist with every machine tool make. I have had a gut full one Mori-Seiki machine but love the others I have, but I still think they are a good machine but I had major problem with one on several occasions, but I will not sit here a bag them out, they are a great machine. It is only what is said here that is what you hear. Look elsewhere for answers and if you are still worried, call the manufacturer to verify.

Dave

[fryermachine]

Thanks Dave for your comments.

We are proud of the Fryer name and we stand behind our machines. We use quality components and each machine goes through rigorous inspection prior to leaving the factory. I can say without hesitation that we strive to make each and every machine perfect before it goes on a customer's floor. But, as with any builder, occasionally issues crop up. In those instances, we do everything in our power satisify the customer.

My name is Sue Ostrander. I am the sales manager for Fryer Machine. I welcome anyone to call or email me if they have an issue they need help with or a comment they would like to pass along.

845-878-2500
sueo@fryermachine.com

[Daleb]

We have had a Fryer since June 2004. Once they fixed a few code issues when we first recieved the machine we have had very little trouble with the machine. We do not always run it 10M rpm , but we do run at that rpm fairly often.We also have ran the machine 24 hrs. straight for days at a time with no problems.