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Genos L250 Z Over Travel (MACHINE DOWN)

seasyl

Plastic
Joined
Jan 24, 2019
Ran into a problem with my lathe today. The machine over traveled in Z by over .200" . Luckily I was running one of those Kalamazoo 5C fixtures so it only wiped out some of the collet and left the spindle untouched. Because it didn't stall there was no alarm. I figured that I might have just fat fingered something but I have verified that all of my numbers were correct and after the fact I jogged the same tool over to Z -1.75" (end point of my part) and it went to the correct location with clearance between the chuck. I had just run a 20 piece job and it seemed as though my Z wear offsets weren't properly working, but I was able to remedy this by changing the hard number since it was only a matter of .002". This could be related to the problem I am having or it could be coincidental. Regardless, my machine is down for the time being since I don't want to risk a bad crash. Anyone had similar problems?
 
I think it's more likely you're having problems with your fixturing than your machine. IF you are not torquing your parts down to the same amount, or they vary in diameter, your fixture will vary in Z. If your chuck is right at the end limit of its stroke, it may not clamp well once rotating. An Okuma not repeating within .002 is generally rare enough to rule the machine out. Getting work holding to make a part to repeat in Z by .002 is sometimes a challenge. It's not going to miss by .200" in Z unless the ball screw mounts are fucked, and that would be blatantly obvious.
 
You're quite sure you didn't type a .200 wear offset by accident at some point?
I had a problem last year on a different brand/model machine where my Z changed by about 1" suddenly (away from chuck thankfully) while running a large batch of parts. Turned out the Z coupling screw had come loose off the Z servo. It would still move the turret but above about 50% load it would start slipping.
 








 
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