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?
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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