Unresolved Print Getting Off Center After Each Layer

Hello,

Yesterday I printed something, and it worked perfectly. Today, I had a print about halfway done during a 90 minute print, and suddenly it was printing off center. After I tried again, it was working fine for maybe 15 minutes, then it was off center.

This last attempt, I made a point to watch it more closely, and it looked to be adjusting further down the Y-Axis. This just started and I can't really tell what might be the culprit...

Thanks for any advice you can offer! Things had been working pretty well up until now!

 

I lifted up the plate and looked around/moved up and down the y-axis, but nothing stood out to me as off...any suggestions of other areas I could look at?

 

I also had this issue when the cooling fan for the Ramps underneath the printer was failing on my Robo, so it may be worth checking to make sure the fan underneath the printer is actually blowing/setting the printer up on some blocks so the fan can actually pull air (the stock robo without feet doesn't really allow for very good air flow for that cooling fan).

 

I'm assuming that is underneath the print bed, so I'd need to take off all the screws to get there? I'm never gone in there before and just want to make sure that is the right place!

 

All you need to do is lift the glass bed off all of the magnets and carefully move it out the back of the printer and out of the way. The set screws for the gear in question are on the center gear and you should be able to get to them with the correct sized allen head wrench.

The only reason to remove the bottom cover and go poking around down there is to fool with the electronics.

 

Alright, so I think I'm looking in the right place - the metal piece in the very center. Are the screws set inside? It looks like I have two holes in there where screws should have been, but I don't see any Allen-wrenchable screws down there...

 

Thanks for all the help. I attempted to use an Allan Wrench to tighten the two screws I think were there in the center metal piece and will try to print again tomorrow...

 

Yeah, the set screws in those holes are very tiny/short. If you didn't get that feeling of tension on the wrench when tightening then you may need to source some set screws.

Does anyone know the size of the Y-axis set screws? @Harry ? @Jerry RoBo 3D ?

One quick way to check is to loosen the belt at one end of the Y-carriage (simply unscrew the screw on one end until the belt is loose) then see if the middle gear can be pulled off the shank.

 

So looking back at this thread and doing a little more testing, I *think* the ribbon cable in the back was getting caught on the bed. No idea why that started now but I adjusted it and will try and print something today. Thanks for all the help! I'll be sure to check back and let you know how things turned out.
(By the way, this is probably the most helpful and responsive forum I've ever been a part of!)

 

Same issue...thought it was working, got about halfway through a print, then it happened again. The first couple "off" layers weren't off by much, then it was a couple CM jump. I feel like I've done everything suggested above so kind of at my wits end...

 

Mark,

I guess that would be the next step...so I should remove the screws completely, and put loctite on them, then put them back in? Is loctite something I can pick up at like a Walmart/Target, or hardware store?

Thanks! Crazy day today...

 

Yeah, don't use the RED unless/until you get everything really as tight as it needs to be and only for something that never needs to be taken apart for maintenance.

EDIT: If we could get some confirmation on the set screws used on the axis GT2 belt gears I could point you to set screws with nylock patches on the threads on McMaster-Carr that would keep them from backing out once installed.

 

Okay, just to be absolutely clear - this thing I'm linking a picture of is what I'm focusing on? I'm trying to use the allan wrenches but I swear nothing is budging...

https://drive.google.com/file/d/0B6F12PL17U4Cc3RzZWRLY1BYakU/view?usp=sharing