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LC-10 OSP3000 control - Turrent not always making it to position before clamping

Wade C

Stainless
Joined
Jul 21, 2004
Location
Wiggins CO. USA
1980 Okuma LC-10-1ST, OSP3000 control, Single turret

Had an odd situation show up yesterday. On a tool call or manual index the turret started turning just a touch slower than I remember it used to, and it would start to clamp before it had made it completely into position. But you could tell the motor was still on cause it would usually get the rest of the way before the clamp seemed to get to full clamp pressure.

Occasionally, it would get stuck, and a little bump and into position she goes. I also noticed the turret doesnt have the oomph behind it that it used to. I hit the tool change button and tried to hold the turret back from rotating. I dont know that Ive ever tried before now, but it was easy to hold it back. When let go, it would continue on like it was before. In MDI and I commanded a tool, it would go to or attempt to go to the correct position, but may or may not make it. I MDI'd a tool change and held the turret, and then let go, and it still went to the right tool, but may or may not make it, and either way, it would stop short either a little, and still make it into position, or a bit more and not get there. But always at the correct tool.

So I tied into the parts diagram, and from what I saw, it looked like all the shafts in the turret had a key on them for the gears, but the hyd motor looked like like it had a key way on the motor shaft, but didnt see a key in the parts drawing, and did see a set screw. So I thought maybe the set screw and lack of key was sort of a safety thing... a place to yeild if the turret got blocked or hung up. So, took the back of the turret apart, pulled the motor mounting plate off to check out my theory - thinking the set screw might have loosened up and was allowing the motor to spin in the gear. No dice, it does have a key. So everything is keyed.

Nothing was loose when I went in... checked the turret position encoder/switch do-dad, it was tight and hadnt moved.

So now Im trying to figure out my next move/guess at what it might be.

Like a fool, I tore into it before I checked two things, that I should have... Hyd pressure and the turret flow valve... I should have verified the system pressure - spaced that... but it was its normal 240ish last week when I was back there adjusting the chuck for a job. And thinking back, I remember thinking to myself then, that the turret looked slow, but it always made it to position. Just seemed a bit slow, which I really didnt have much to draw on other than memory... and having a hard time remember what I had for breakfast... I didnt give it much thought at the time.

The second thing, the flow valve for the motor... that thought popped into mind after it was apart... but it has an adjustment for rotational speed - and supposedly (if I remember right - havent looked it back up yet) it should make a full revolution in 2 seconds. But when I was in there 6-7 years ago doing seals, I had set it to spec and it was awful clunky and loud at tool change, which I didnt like, so in an effort to sacrifice change time for longevity, I slowed it back down a touch so it wasnt so rough. But I dont remember what rate I slowed it down to.

So, now Im wondering if I should be looking at a flow or motor problem. I could see that maybe that flow control valve has an issue or is plugged up (not enough flow to the motor weakening it), or maybe the valve adjustment screw just vibrated loose over time (it doesnt have a lock nut). Or maybe the motor is bad? (I dont know much about Hyd motors) Or something else I should be looking at?

Oil was clean at every point I cracked it open.

So i thought while I was pondering and pouring over the parts book and going through the manual for adjustment of turret flow valve, as well as putting things back together so I can double check system pressure and flow valve setting - I would post up my little escapde and see if anyone had any other thoughts to look into before I got everything completely put back together.

Thanks
Wade
 
We had similar issues on our LC-30 a few years back so our maintenance department changed the hydraulic motor. That didn't fix anything, so they tore apart the whole hydraulic system and they found a mesh screen in the hydraulic tank that was completely clogged. This screen was not a filter that was known to them and had never been cleaned or replaced in at least 20 years! So between a new hydraulic motor and a clean screen not only did turret rotate with more oomph, the chuck clamped about 2x as fast.
 
Thanks for the reply!

I had thought about pulling the entire Hyd unit apart for a cleaning (from bottom of tank up) - but sort of been trying to talk my self out of the effort... but sounds like it will be a good thing to do, so I can check the sump screen.

Thanks again
Wade
 








 
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