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Hello,
I’ve been trying to fix this hydraulic turret for about a week or so after an operator had it crashed. It unclamps ok in all 12 stations, turns both sides as commanded but almost half of the times it skips the exact point of clamping back and after 2 or 3 seconds being stopped halfway between stations the alarm pops up. Looks to me like it is not reducing the turning speed at the appropriate moment and it skips the right position due to inertia. I’ve disassembled the whole turret, even the index motor has been taken apart without finding the cause or anything wrong. The solenoid valves and their coils are ok; I’ve changed the fwd, rev, unclamp and speed reduction relays already. I tested the encoder at bench and at PCM DGN status, I have also checked the clamp sensor. The turret can sometimes complete the 1 to 12 changes, one by one, but only in forward direction, if I go from say 10 to 9 it immediately fails. I’ve not found excessive wear at the main shaft or anywhere else, the lock pins at the main tool holder front plate were replaced after the crash. Everything is chip free and lubricated; the main hydraulic pressure is set at 600 psi as the manual says, the solenoid valve coils are 40 ohms.
What else should I check? ...Any and all the help is greatly appreciated.
Thanks.
Last edited by SINUMERIKO; 12-02-2009 at 10:35 AM.
Some pictures.
Today I tested the turret without the disc, just the main shaft without the heavy load, I only installed onto the shaft the spacer, the flange, the locking element and the lock nut so that the shaft could move back and forward when clamping/unclamping. The result was fine, in this way the turret changes perfectly all stations, both directions.... I just can´t figure out how the load affects its functions so bad, seems like if any of these were happening:
a)With the disc mounted, the hydraulic system is not "braking" or reducing the speed as needed when the exact point of entry is approaching.
b)The mechanical play that the shaft could have is somehow amplified by the weight of the turret disc and shows up only when this disc is mounted on the shaft.
Any ideas yet...somebody?
Last edited by SINUMERIKO; 12-04-2009 at 10:02 PM.
I've added a video showing this last test:
"http://www.youtube.com/watch?v=g_lR85CtNuE"]YouTube- Daewoo Lynx 210A hydraulic turret issue
Any ideas, anybody?
what's problem in your lathe machine? i read the description of the machine turret ,but dont understand the issue,please give me a copy of detailed file.
Originally Posted by SINUMERIKO
ok,u say your turret can forward turn,but cant reverse trun,can u tell the alarm from the machine?
Meelian,
The problem with the turret is that it won't always clamp, almost half of the times it will go beyond the exact point of clamping, the alarm is 2047.
NOTE: This only happens with the turret disc mounted on, if I try it without the disc, as in the video, it won't ever fail.
Thanks.
Last night I got the attached information from the index motor manufacturer's site. I strongly believe that this turret's problem happens because it is unable to (hydraulically) brake with enough power as explained on their page #8 of this catalog, just follow the ball in the graphics, 1 thru 8.
That would explain why it brakes OK without the disc.
Please take a look.
Last edited by SINUMERIKO; 12-05-2009 at 09:45 AM.
The turret's main shaft received a hard chroming process on its teeth, where it and the large gear work together, and later another process of grinding those teeth to bring them back to original dimensions, all this to eliminate the wear that was causing the mechanical play in the turret assembly.
I also performed some service on the machine´s hydraulic system, including the Japanese NOP index motor "O" rings replacement and a full service to the hyd unit, along with the encoder sync and the clamp sensor check. Once assembled, I tested the turret randomly, about 500 times, with balanced/unbalanced load, it NEVER failed.
I uploaded a new video with the final tests, I hope all this can be used as reference/help in the future for somebody out there.
Video: "http://www.youtube.com/watch?v=HEYooA7dWvU"]YouTube- SOLVED...Daewoo Lynx 210 turret issue
I started to have an intermittent similar problem with my Daewoo Lynx 200B. Without any warning it will not index to the next tool. One time when I sent the turret 'home' and restarted the program it will run ok for a few hours, then it will stop again due to not indexing to the next tool. Sometimes I have to turn power off and on again to get it to work. At the moment is running fine (18 hours).
Any ideas on how to approach this coming problem? Thanks
I have seen this problem before, usually you can see the turret dropping towards the floor when unclamping, another symptom maybe that the index is noisy, this is because the turret is dropping allowing the curvic coupling to hit itself. The usual cause is that the splined shaft has worn or the span ring holding the female portion is worn, another likely cause is that the lock nut has had the thread stretched and simply replacing the nut will rectify the issue. If not shaft and bearings. Please remember when you are refitting the turret and tightening the shaft that the machine should be in emergency stop as this will allow the turret shaft to move freely and also make it more easy to sufficiently tighten the lock nut. Hope this helps
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