[Wade C]

If you frequent the PM forum youve likely seen this already... but I thought I should try here as well...

Im gonna copy paste as to save some time retyping...

Saturday:
Today just hasnt been my day... at least it doesnt feel like it.
I started out running a batch of parts and everything went well... (must have been the kiss of death) wrote the program, ran the test part, and it was off to the races, bar puller and all. Ran those, and setup for the next part. Got it setup easily as well, one test part, an adjustment, and off again. About half way through the batch, the boring bar starting acting up - loading up and the material (acrylic) would melt to the bar. So battled that and battled... no idea what changed or what is going on . Completely changed the program and the process and went to roughing feeding Z- and then finish feeding Z+ and it seemed to be okay. So I commenced on with the last 10 parts. And all of a sudden, I started getting a vibration. It seemed to be worse at certain RPMs (1500 was the worst) and better at others like 800 and 2000 rpm but still there. It almost felt like the chuck was out of balance, but I dont see how from one part to the next it would be (cutting 2.6" long chunks of 1.375 cast acrylic rod in the 3jaw with soft jaws)

I was snooping around looking, and seemed to be either accentuated at the back of the spindle where the hyd actuator connects - or thats where it was originating from. I wiggled it and it did not have any wobble, but there was some end play - which I would assume would be bearings - enough to feel, but also not horrible (reminded me of a wheel bearing that was just lose enough to feel, but if you tightened it to the next notch on the castle nut it would be too tight for comfort)

I was thinking the next move might be to take the actuator off the back of the spindle and see if the vibration goes away, but I have tried in the past to take it off and there must be a trick, or a need for enough force that I was too chicken to go far enough. The manual I have doesnt show the exact Hyd actuator as I have on my machine... so Im concerned about getting serious on it til I know what is really in there. Im also assuming that the actuator needs to be mounted very straight - and so how that is accomplished I dont know, but would guess that is what makes it a bit tougher to remove than just pull the SHCS's and pull it off.

Im just not sure what to do now or where I should start looking.

I checked the belt in case it was lose and flopping, positions of the soft jaws on the chuck in case one slipped. When it was running, if I lifted up on the back of the actuator it seemed to smooth out.

Any suggestions on what I should check next or how I might get the actuator off the back of the spindle to see if thats whats causing it? I saw a post a while ago about a generic shematic of an hyd actuator - Ill see if I can dig that up and see if it explains anything.

Open to any ideas anyone might have.

Of course, now I have three huge batches of parts that have the first op done and needing the second op run, but I dont know that I want to start in on them without knowing whats going on.

(some replying - some new info - so some of it might not make sense)

Monday:
Its a problem, loaded spindle or not... but the op I was running was not a bar pull setup. Blanks front loaded into the chuck. It does it with chuck, 5 collet nose, no chuck at all.... And it really looks like its all "shaking" at the hyd closer.

So I spent a few hours... okay - 9-10 hours dinking... tearing down looking and learning.

I know know how the Hyd Closer works... didnt take apart the main body.. but separated the "piston and housing" from the hyd body.... so I understand it now. I also checked spindle bearings... and from what I have heard, they arent spring chickens, but they arent ready for burial.... I go out the federal test master DTI and a chunk of bar. from what I can tell (mind you Im not experienced at this - never done it before) with the DTI set on the back of the spindle flange (where the hyd closer mounts - but it was removed, and all belts were removed) Lifting up I got .0007 to .0008 lifting up with about all Im worth. Then pressing down, all my weight (175 lbs on a rod that stuck out from the back about 2 feet) I got .0003-.0004". On the front bearing, I got .0003-.0004 up and .0002 - .0003 pressing down. Front to back I could only get .0002 - .0003" tops.

Then I remembered someone talking about alignment of everything back there being a big deal when I had asked about extending the back of the spindle to accomodate something.... so I got out the dial indicator. (had to use a cheapo chinese one cause the mitutoyos were at home and it wasnt worth the 40 mile round trip for curiousity....
So I checked the flange at the back - measured in quadrants I guess yould call it... every 90° of rotation. On the flange, it was looking good, 0 - 0 - 0 - +.001 (think of the numbers in order of taking them... set the indicator, zero it, rotate 90° take reading, and repeat until you get back to the spot you zeroed at to double check.) Then I went to the flange where the closer piston mounts, it was out farther... 0 - +.009 - +.006 - -.004 or there abouts - going from memory here... Then to the piston body, close to same measurements. Then I checked the next joint which is the hyd body to the piston cylinder, it came out very close to the same as the previous joint. Checked both sides of each joint rather than assuming one side was the same as the other. So it appeared my wobble of the actuator might be from misalignment. So out came the deab slow hammer... loosened the SHCS's and some light taps and countless turns of the spindle and I got to where the max "runout" of the flange that mounted to the actual spindle flange was .002". It was the best I could do with what I had on hand. Could never get it to be right on. As soon as Id get one quadrant to .001 the others would jump out. Then I checked for the vibration again. This time it was less.. but still very noticeable.

So I took the dial indicator to the body of the actuator and spun the spindle - and was getting a range of .018". -.009 to +.009ish.
So I checked each joint - working my way back again to see if I could find where the problem was. After my inital adjustments of the first joint, everything was within a .002" range... including the last joint. So, now Im thinking its not run out, but lack of parallelism. It was late when I got to this thought... so its still an unknown - but Im wondering... could something have come lose in the hyd body and it got slightly cocked off? Something bent? out of adjustment?

So now Im thinking maybe I need to look more at the alignment of things rather than actual bad parts causing the issue... Am I crazy?

What kind of measurements would be acceptable? Any tips or tricks to getting the the root of the problem? Any information at all?

Maybe Im just stark raving nuts.... and its just a bad bearing in the hyd body?
=======================================

So from what I have learned and read and dinked with so far.... I think I need specs on alignment... not only the actuator to the spindle, but the piston to the actuator and so on... all the parts and pieces.. I havent taken it COMPLETELY apart yet... but I feel it coming on

As well any ideas or tips on things I should look into that I havent already... Any input surrounding this in any way would be welcome information.

Thanks!
Wade

[Geof]

You have checked there is not a loose piece of something inside the spindle, I guess I should say inside the drawtube.

I have fired up a machine and had it shake like crazy because there was a short bit of bar inside that I didn't know about.

[Wade C]

Spindle is completely empty... No draw bar no chuck...
That was one of the first things I checked... but knew it couldnt be because I have to clean out the draw tube every 3-4 parts as chips get pushed in from the boring bar (acrylic plastic so not very heavy). But i checked it with everything off and out. I am still trying to figure out how to run it with the Hyd actuator off to check that... the control has to have pressure to enable the spindle... so I cant just take it off. I dont know if plugging the two hyd hoses or putting them together with a union would be safe or not for the valves and such.

Thanks! ANY ideas are appreciated!
Wade

[OkumaWiz]

Have you run the spindle without the actuator? That may indicate if it's in the spindle or in the actuator. Although one time I did see a bad rear bearing that ran fine when the actuator was off and not when it was on. Typically the actuator should only have .001" - .002" runout anywhere on it - better if possible. It will definitely cause vibration with runout in the .01" range.

Another question - were there any balancing weights that may have come off, or when you disassembled, did you mark orientation to make sure it went together the same way as it came apart? Balance is of course important.

If the spindle liner has over about .03" clearance that can cause vibration as the bar whips off center too, but it's usually not that bad with plastic since the weight isn't that great.

Other than that, you may want to listen to the bearings with a mechanic's stethoscope or check them for vibration professionally.

Good luck!

[Geof]

..... I dont know if plugging the two hyd hoses or putting them together with a union would be safe or not for the valves and such.

Thanks! ANY ideas are appreciated!
Wade

Cap them don't connect them, I think connecting just lets the fluid go straight back to the tank.

[Wade C]

Have you run the spindle without the actuator?

Havent figured out exactly how to do that yet... have to have Hyd pressure to have the control start the spindle. Ill probably try and do something this weekend. Any ideas if I would cause any issues with anything if I plugged the hose ports or put a union between the two hoses - in essence creating the pressure it needs to activate the spindle but not have the actuator hooked up?
Ive been trying to figure out how to do that since the weekend thinking it would be a decent indicator.

That may indicate if it's in the spindle or in the actuator. Although one time I did see a bad rear bearing that ran fine when the actuator was off and not when it was on. Typically the actuator should only have .001" - .002" runout anywhere on it - better if possible. It will definitely cause vibration with runout in the .01" range.

Okay - a number I can use... I havent been able to get even that out of Kitagawa or any other CNC service guys... So more than .010" is bad juju.... I can work with that! I got it down from .030-.035 to .020" so maybe there is more in there I can get out... Ill be spending some quality time with the ole gal to see what I can do this weekend and that helps a TON!
What kind of specs should I "have no more than" when it comes to the spindle bearings? I have more on the back bearing than the front... but still under .001" Ive always wondered if building a support for the Hyd Actuator would not be a better thing for the back spindle bearing instead of just letting it hang there and rattle.

Another question - were there any balancing weights that may have come off, or when you disassembled, did you mark orientation to make sure it went together the same way as it came apart? Balance is of course important.

No weights that I know of... the way its set up it doesnt appear to have any. I have attached the drawing if you want to check it out. I didnt see anything there that would be a counter balance... and there was nothing on the OD Of the spindle. I marked all the orientations when it came off... I only separated in two places... the spindle flange to the actuator piston mounting flange (basically where it would go together if it didnt have an actuator and were adding one on) and then the next joint in - the actuator body to the piston body... and it could only go together one way.

If the spindle liner has over about .03" clearance that can cause vibration as the bar whips off center too, but it's usually not that bad with plastic since the weight isn't that great.

It does it with a bare spindle... no draw tube no material no chuck, no liner.... nada... just the spindle, pulleys, and actuator and does it just the same.

Other than that, you may want to listen to the bearings with a mechanic's stethoscope or check them for vibration professionally.

Good luck!

Yeah the "professionally" part is what worries me.... Im 200 miles from the nearest "big town" so getting a tech out... yeah - big dollars... and they dont like it when I tell em the machine... as I think most of them are not all that familiar with a 30 year old machine.

I think one of my big problems is lacking the frame of reference... I can spin the spindle by hand and hear the bearings... but I have no idea if what Im hearing is normal or bad... or bad enough to cause my problems. I think if the spindle bearings are bad... then that makes the machine parts... as they bearings sound like they will be many times more money than I paid for the machine as a whole in working condition. (cant say I didnt get the good out of it for the last 5 years... its paid for itself in about 3 years - including the one year of "learning how to use a CNC")

Thanks for all the input... I am eager to learn more... just scared of the price tag.

Wade

[OkumaWiz]

Based on what you say, I'd say that you've got a bad bearing at the rear of your spindle. If you can hear the bearings with everything removed, that's not normal. They will usually be as smooth as silk and you will have trouble hearing them even with a mechanic's stethoscope. As you stated, they are expensive, but you may be able to find them aftermarket using the numbers on the bearing raceways. It's always cheaper than getting them from Okuma, but be sure to get a high class bearing. I think Okuma uses class 7 if I remember right. There's also a technique to the assembly and the preload which I'm not all that familiar with, but do know that they will check the temp of them while running them in to see if it's correct. I do know a local guy that can do this, but you'll be paying around 125 /hr. + parts and I'm not sure where you're located...you may just want to bite the bullet call you local rep and have them do it so you get the warranty. If you took them the headstock, I'm sure it would save some money, but you'd have to align it when done. Not a bad thing to do I guess.

Best of luck!

[Wade C]

Im in Colorado... right on the CO/KS border on Highway 36. So Id guess the closest will be the Denver area.

Ill start thinking about it....

Does it sound logical to you that the problem might just appear all of a sudden? From one part to the next part?

For the stuff I make... I could live with not having the tolerances from the spindle... but if its detrimental to the rest of the machine (which Im sure it probably is) then it needs to either be fixed or part out the machine....


Thanks again for all the info!
Wade

[OkumaWiz]

Yes, it does happen all of a sudden once they reach their "point of no return". I think you have a distributor in Denver, so give them a call and see what they say...they are pretty good guys out there.

FYI pretty much any Okuma can be brought back to original factory tolerances by replacing the needed components and you'll get lots of life out of them as you already know.

Best regards,

[Wade C]

Yeah they seem to run for ever....
Im just worried, if I sink 2-4k into new spindle bearings and the problem is the Hyd Actuator bearing.... Im at the end of my money before the actuator can get fixed. Then I have to worry about the next thing breaking... Im getting pricing from Hartwig (they have ALWAYS been SUPER helpful and friendly and have shared more info with me than I ever thought a company would - including drawings, pdfs and so on...)

So I feel good about giving them my money as far as the people go... its the money and the duration of up time that Im worried about... maybe it would run for ever... maybe it will die next week and it will take a $3000 control card that no one has.... Oh the drama.... Especially when from what Ive seen a few places... I could get a different machine that is in pretty decent shape for what the spindle bearings will cost to do... but then there is the learning curve and so on...

Wish there was someone close that used to work for Okuma that wanted some side work... or would be able to walk me through doing it myself... always been a DIY kinda guy...

Thanks for all the info!! Its greatly appreciated!

Wade

[Algirdas]

have You tried just to simple balance the hydraulic cylinder?

[Wade C]

Sorry guys, I never got back to you all on this with the "solution"

When it first acted up, I tried aligning/balancing the actuator. I could never get closer than .030" runout.

I ended up pulling the actuator, cleaning surfaces, and checking stuff out. I now know how that critter works But in the process, I found the castle nut on the back of the mounting flange loose. I tightened that up, then went about re-indicating the actuator and BINGO!

She runs smoother that she ever has since I got her. I used to never go above 2500 RPM cause it vibrated more than I cared for and NEVER went to 4000. Now, I can run 4500 and she is smoother than she ever was at 2000.

So all is well... and it was basically an alignment issue, and appeared to be rooted in a loose castle nut.

Thanks again for all the help and suggestions!

Wade